Nice to see this tip. I've been doing this for twenty years or so and never had a problem. Sometimes, depending on the situation, I turn off the spindle, let it coast to get the tap started, then finish by hand. Thanks again for posting his video. I heard about it on the PM forum.
Thanks, I'm glad you enjoyed it. There has been a fair amount of traffic from PM lately, so I figured there must have been some mention of my channel there. Tom
I've used this a bit on a regular drill press. Clamp work down, drill hole, power tap down (turn switch on and off real fast to not go too far), then you have to hand crank back out. You can also hand crank both directions, the drill press is just a jig to align the tap. Works great, I rarely use the tap wrenches.
I have been using a cordless drill with my hand tapper, I took off the handle and made an adapter to work with my cordless drill. It aligns the tap and the clutch on the drill can be set to the size of the tap, I start off on a lower setting and work my way up. The hand tapper I bought only came with fractional sizes to fit the taps but to my surprise they also fit most of the metric sizes as well. When I machined the adapter I made both sizes without removing it from the lathe chuck then I sawed it off. Well they must not have aligned the hole straight so I just put the whole thing in the lathe and trued it up. Worked great and it feels quite safe to use.
Tom, I sincerely appreciate the plethora of invaluable knowledge you so freely share. I have most of your videos saved and go back when I need to be sure. They are my measure twice before I cut guide.
Most hand taps are four-fluted and have long lead in angles on the cutting edge. Both of these features make them easy to start. They will also often be made of carbon steel rather than high speed steel and are cut rather than ground. Machine taps are normally two or three-fluted, are always high speed steel and will have ground threads and flutes. Spiral point machine taps also have a secondary angled flute to help direct the chips. Tom
Excellent, Mike! Yesterday I tapped 520 4-40 holes in some 6061 aluminum bar with a cordless drill. It took most of the day, but I finished up with the same tap that I started with, which is always a good thing. :) Tom
Tom good info I never thought of not tightening the chuck too much to let the tap slip. I use the hand drill way often. I set the clutch on the drill to avoid breaking the tap if it binds up. But I don't do anything above 1/4 because we don't have nice spiral point taps.
Knowing how to use and how to be in control of your power tools is the key to not breaking things. Some people say not to use a drill or a screw gun for certain applications, but I know how to control the trigger and feel how things are going before any accident happens.
2) You can save even more time by using a single tool which combines a drill point with a tap body. These are available in various quality levels, and I've even made my own from a helical fluted tap* by grinding the end on a drill sharpener and cylindrically grinding on a utility lathe but unless you do some fancy relief grinding on the OD it's only suitable for alu alloy *(not advisable, as others say below, for blind holes!)
A step ahead of the rest...Great video once again. I love the ease of it all for something most will tell you it is too hard to do or unsafe. To all the pro's out there, this video is for you. Peace :)
Nice job, Tom! A couple of thoughts to expand the discussion: 1) As you point out, any 3 phase motor will reverse instantly (electrical people call it "plug reversing"). It won't hurt such a motor when the reversing switch is thrown heedlessly from 'full ahead' to 'full astern'. You can achieve the same effect with a VFD, but make sure you use the VFD's internal reversing switch. Don't use an external switch like the one on the machine, unless someone who knows what they're doing rewires it with respect to the VFD) On a big heavy mill, it's not wise to do it in a high gear. On my Euro-built Cincinatti Toolmaster, specifically designed for power tapping, they say to use instant reverse in back gear only, presumably to save inertial loads in the gearbox. It might be worth pointing out that a single phase motor, if you reverse it 'on the fly', will generally keep happily going in the original direction. I don't know any safe way of instantly reversing a standard single phase motor. If you just turn off the motor, there will be a considerable variation in how far it coasts to a stop - probably not great for blind holes unless you are turning real slow.
You crafty devil, you. I discovered your videos a few days ago and have been learning from them ever since. My most recent tap break was a 3mm tap in a small run of Dalek ear cages. It didn't occur to me not to tighten the chuck except lightly by hand, and I'll try that for the next small batch. Thankyou for sharing.
It was set up with all the different taps already in quick change holders and it had a crank handle on top.. I’m supposing you’re doing it in a manual mill where you change tap and drill like you did. With this, you just drill, say 5 holes, then tap them at the tap stand. Even if they were 5 different taps, the holders just pop in and out.
I think the first time I saw it used was in a job shop in the mid 70's. Don't remember teaching it back then though, probably couldn't afford the broken taps with the limited budgets in the machining programs.
Hey Tom, I've been power tapping on my Bridgeport all the time. But what I like to do is after drilling the hole I pop in a countersink and give it a little relief to help the tap go into the hole. I feel that this helps when tapping harder materials like SS.
+Steve Billmire I've heard that too Steve, but never really noticed a difference. I normally counter-sink mine after the fact with a cordless drill to save time, although doing it before hand would create less of a burr on the threads. Tom
Tom, I like to use my cordless drill that way for electrical panel mounting holes. I often use "draps". As you probably know they are a drill pointed tap. They work quickly in one step but are limited to relatively thin materials. I recently powered up my Bridgeport knock-off mill with a VFD. The first operation I did was to power tap (16) 5/16-18 holes in (4) 1/4 thick steel angle brackets. It worked beautifully !
I power tap on tool steel at work all of the time and it works great. Ever since I was introduced to the spiral point tap I shudder at the thought of using a hand tap. It seems that everyone local sells hand taps, and yet spiral points are so much nicer to use.
Thanks, I'm glad you like them. Basically life got in the way of making the videos. Right now I don't even have a shop, because we have sold our house and are in the middle of a move. Once we are settled and the new shop is operational, I hope to start up the videos again. Stay tuned!
@@TomsTechniques Tom, you are the man! Love your videos, and hope to see you soon. That drill chuck you are using , Jacobs.. what model is it? if you can remember , thanks, wanting to buy one, that one looks solid , the good old "made in USA" most likely
@@TomsTechniques thanks for the reply, I didn't see a notification for your reply but with this pandemic a year is like another dimension so..yeah. well that's good to hear, I will be on the lookout, I subscribed when I left this comment.
Thanks for video 🐲a good thing is collecting all shards of metal in a bunch and forging it to make more metal. I got a metric tap and die set I need SAE(Standard) imperial set.
G'day Tom thanks for the power tapping video I have some small holes to tap into a stretcher frame so I might give it ago, glad you showed tapping though steel because that's what I will be tapping in thanks mate John
+Ralf Boyke Thanks. The cordless drill thing takes some practice to get the tap going straight. I just start them a bit and look at it from both directions, correcting if necessary. Tom
A lot of DeWalt drills (like the one he's using) have an adjustable torque limiting clutch in them as well, seems like that would be put to good use in this task.
5) On a big lathe there's too much inertia in the chuck and headstock for plug reversing to be a great idea, and in small lathes you tend to have single phase or a screwed-on chuck or both) One way to get around this is to make a tap holder (ideally using the biggest Jacobs Superchuck you can find on eBay - much quicker than collets) and prevent it from turning by fitting something like a go-kart steering wheel to it. In other words, the holder is free-spinning on the tailstock barrel (make sure to bush it with plastic or bronze) unless you're hanging onto the wheel. Because you can use both hands, you can resist a lot of torque, and when you do let go, there's no handle to hit you. If it's a big lathe, go for a tractor wheel!
Never thought of power tapping being unconventional, one major difference and you are so like me Is that I use a much slower speed in both lathe, mill and cordless drill. Main reason I get a better feel for whats happening along with quicker time to do something about. Logically faster will cut easier, touch wood never broke a tap yet in over two decades.
Yes, the marks will eventually get rubbed off but all it takes is a quick check with the calipers to know the size. It's good to be familiar with the diameters of the various taps. I don't know about you, but it's getting pretty hard to read those marks anyway. Tom
i power tap all the time on the mill or a ridged drill press set-up but for the hand drill only taps 5/16ths or bigger i have seen way too many guys breaking 1/4 inch taps off that way because they are not making sure the tap is straight or the let the drill drop a little part way through, Love your videos by the way
Keep 'em coming. Even with my slowest speed on my Index milling machine, it takes practice. Very heavy flywheel, so I almost need to reverse the direct when just starting. I have a tapping heads, but they mainly stay in the box unless I have a helper to tap a 100 hole jig plate. For hand taping, make up some 1" rod drilled to just clear the tap. Part 1/2" thick. You have a nice finger held guide for straight tapping. Hold against the work, and that tap will remain straight. (also the guide doubles as a nice stop for blind holes) Tom
Tom, I often turn the spindle off and let it coast a bit before starting the tap. That would help with slow to respond mills like yours. The tap starters is a good idea for hand tapping. I also do a lot of my tapping with a cordless drill. The two techniques could be combined for a nice square start and the speed of the drill. Thanks for watching. Tom
Yeah, good taps are key because they take less torque to drive. The hand drill is definitely handy, but it takes some care to get the tap started straight. Thanks, Tom
I like your Leland MI shirt, my folks spent every weekend on Lake Leelanau from 1970 until about 2010, at Leelanau Pines on the SW area of the lake. They both passed away recently. Beautiful country up there!
I've only been there once, but was impressed at how large the peninsula is. Very nice scenery as well. I vacation a bit farther North, on the other side of Lake Michigan. About two hours by boat or 3 1/2 hours by car. Tom
Thanks Jon, I appreciate your taking time to comment. I'm starting to get the hang of the video thing, but it's a LOT easier to do it live. Maybe I should just invite you all over to my shop. Tom
Any 3 phase motor will reverse like that, I use a rotary phase converter for mine. I haven't used a VFD for a while, but I'm pretty sure they can be set-up to work the same way. Tom
I'm the old grumpy teacher at the local JC....I let them start taps like this...... But then, get a feel of what they are doing... I tell stories of breaking 1" taps... And chiseling .... Fracturing them out!
3) As regards letting the tap slip: That's good advice, I think, for people dipping their toe, but once your tools and technique are dialled in it's not essential (and not doing it will, as others point out, save wearing the lettering off the shank!). As I mentioned below my Toolmaster turret mill was designed for power tapping (in the early 70s), and when it's switched to 'tapping' mode, the spindle runs in reverse unless a push-button is held in, on the end of the downfeed handle. (The manual one, intended for sensitive drilling). This means at the first hint of binding you simply slip your thumb off the button and the tap winds back out. When you hit the bottom stop (which on this machine is designed with a pretravel, and microadjustable) in tapping mode, the machine decides you must have gone to sleep at the switch, and reverses the spindle on its own initiative. With a setup similar to this I've had no breakage issues with HSS taps intended for machine tapping, when using ER collets tightened to the max. If I ever change mills, (unlikely!) I will feel the need to duplicate the setup, it's that fast and easy. I tend to use collets because the one limitation of this mill is a lack of headroom for the work envelope. (I bought myself a Shars snub-nosed ER32 holder, whose internals are buried back inside an NT40 body, hence about the same overhang as with an R8 spindle. Prior to this they were only available from very expensive labels like RegoFix. It has bought me enough spare headroom to save me from having to make a riser for my turret - still available from Cincinatti, BTW, for approximately as much as I paid for the mill with German DRO) Tom's chuck is a Jacobs ball bearing Superchuck, one of the best chucks ever made, and it's well suited to being used as a sensitive clutch (probably more so than the modern-day chuck bearing the same designation). Most other drill chucks won't hold a tap much over 1/2" without slipping, no matter how hard you close them.
Toms Techniques You're quite right, I should have added that qualification, Tom. My "auto-reverse on reaching the depth stop" setup (which does permit safely tapping blind holes provided sufficient allowance is made for chips) is not something I've encountered on any other turret mill or drilling machine you'd be likely to find in a home shop. Having said this I did (carefully) power tap blind holes on my previous mill which lacked this brilliant feature, by marking the tap flutes and reversing at the correct depth, leaving (as I still do) a generous allowance for chip buildup. (And using helical fluted high quality machine taps, which evacuate almost all the chip from the hole)
awesome vid... I have been criticized for doing this before.. but it is all in the technique. ... my favorite tapping fluid for steel: buttercut, it's animal fat.
I had to chuckle at this video because I do this all the time, but 1/2 inch is about as big as I like to go just because anything bigger I cant get my chuck to hold it without slipping. I do have a tapping chuck that works in my lathe or mill but in the mill it slows the job down. I just use regular taps but lots of cutting oil and only about 60 rpm, thanks
Yeah, a half inch tap is pushing it, but even if it slips, at least the tap is started straight and you can finish it up by hand. I often do the same with small taps because the chuck releases when reversed. Tom
I'm surprised people who work with these had no idea about this. I remember teaching myself these methods when I was an apprentice... it was almost common sense.
I’ve seen a lot of individuals use this technique. I was taught to never ever put a tap in a drill chuck, unless you don’t value your chuck and definitely never in an expensive keyless chuck like an Albrecht. If you want to power tap safely and correctly then get yourself a tapping head such as a tapmatic. Your taps, and spindle switch will thank you.
I've been using this technique on this machine since I bought it in the mid 80's and am still using the same chuck and switch. I suspect what you were taught was based more on theory than real world experience.
Need to be corrected...? But I reckon the mill is 3 phase, hence the instantaneous reversal. If you have a plain single phase mill, it will need to stop before Reverse will come into effect. ie, if you hit reverse while spinning in, it will keep going the same direction. Try it...!
At work we do it both on the drill press and with cordless drill on stainless steel, steel and aluminum in stainless is the hardest because you have to play with you drills because of the hardness of the metal you go one or two sizes over depending on the thickness
A good tapping fluid is the secret for stainless because it is so sticky. I use the old formula Tap Magic, but I'm sure there are other good candidates around as well. Tom
I can hear my shop teacher screaming in my head every time you flipped the spindle in the other direction. Not that they don't let us do this in school, except we always use a tapping head. Pretty cool though, although I would be too afraid to attempt it.
Thanks! Spiral point taps made in the U.S., Europe and Japan are all excellent quality. Look for names like Morse, Regal, Union-Butterfield, Reiff and Nestor, Cleveland, etc. Cost should not be a factor when choosing taps. A quality tap will cost more, but more than pay for itself in performance and be MUCH less likely to break and cause you grief than a cheap alternative. The best tap I've ever owned was made by Bendix. It is a 2-56, 2 flute and I've been using it since the 80's. It just keeps on going, with no sign of wear. They must have got everything from the steel to the geometry absolutely perfect. Tom
Thanks for the great videos. I have no way to disengage my spindle from the quill handles. How do you get the proper feed rate? Will it just pull the tap into the hole (and therfore spin the quill handles?)
Do you drill enough holes for a dedicated drill press? I just use my mill for any holes that need drilling. It's faster than taking the time to layout and center punch holes to be drilled on a drill press. If you do have use for one, I would recommend a 20", possibly with a geared head, depending on how large holes you need to drill. If you want new, Baleigh and Powermatic make good ones. In the used market, look for Clausing. They were well built and last forever. Don't waste your money on Chinese made hobby drill presses, with the possible exception of Grizzly. Tom
Tapping heads work great as well. You do have to drill all of your holes first then come back and tap them. But for multiple parts you can't beat them. I would say find a good German made one with V jaws not collets. The thing about a tapping head is they auto reverse with the quill stop. And they feed out at twice the RPM as they go in.
Power driving is a quick and easy way to tap. We do use that method quite a bit. Just not on parts that have a tight thread tolerance. It does tend to make a little looser thread than hand, CNC or a tapping head.
So I am very new at all of this but am very anxious to learn how to tap into steel hence watching this video. My question is that why doesnt the tap bit just make a bigger hole since the drill is spinning so fast. I know you said you slow it down but it would seem like you would need to bring down the press at absolute perfect speed. Thanks.
Because the tap is free to move on the Z axis. As soon as it touches the hole, the tap will start to screw in because that's what it was designed to do. If you try this, it is very important to use spiral point machine taps NOT hand taps and very lightly chucked until you get the hang of it. Tom
Hey Tom, just another one of your terrific demos. Evidently, it's not important to keep backing off when power tapping, like you would hand tapping, or isn't it really necessary. or Is that all because it's a spiral tip? Thanks
+Toms Techniques Any advice on cutting male quarter-20 threads? Having trouble even getting it started manually. This is for short, half inch lengths attached to shelf supports.
4) I entirely agree with Tom that this method was hardly ever taught in the days of trade training. I used to wonder why, and it occurred to me that it was partly because shop teachers were generally (at best) gifted practitioners from an earlier era, who had it drummed into them that it is ESSENTIAL when tapping to stop and reverse to break the chip. This is one of those pieces of learning which remain true to this day, but only in the original context. If human wrists were equipped with a slewing ring and a small hydraulic motor we would never have made this rule: the reason we have to reverse is because we have to stop, and the reason we have to stop (when tapping by hand) is due to design limitations. I discovered this in the early days of battery drills: I found I could do a much better job with very small holes in alu (under 1/8") using a battery drill and NOT stopping. Then it occurred to me to try in steel, and eventually (like Tom) found it worked up to sizes as big as I could hang onto the drill (once they got torquier) And at some point it was natural to apply this to milling machines and lathes.
The need to break the chip or not actually depends on what type of tap you are using, not whether you are capable of driving the tap without stopping. With hand taps for instance, the chips form in the flutes of the tap and if you don't break them every now and then they will become compacted and break the tap. To power tap, you need to use spiral point taps. They push the chip ahead of the tap where there is much more room and don't require the chips to be broken. Thanks for watching. Tom
Toms Techniques I don't think it's an "either/or" situation. Both of us (I think) are correct. Even using a spiral point tap (or, for blind holes, spiral flute), in certain tough materials, it is not advisable to stop and start rotation. This is because the process of chip-forming is harder to initiate than it is to continue, so it requires extra torque to re-start a chip. This is made worse because a suddenly applied force (when the teeth simultaneously hit a 'frozen' chip) increases stresses above the level of sustaining that same force. Another reason not to back off to break the chip, in tough materials, is that there is a relief (eccentricity) to the form of the thread, which means the tap travelling in reverse over the chip from the tooth behind it will try to mash the chip into the groove of the thread. Conversely using a hand tap for machine tapping can work in materials which are not too tough; I do it all the time (high quality, HSS ground thread hand taps) and virtually never break a tap. In tough materials, serial taps (made for tapping by hand) work well, but these are not generally available in the US. I don't disagree with anything Tom says, and in common sizes I have progressively replaced all my hand taps with spiral point or spiral flute. I understand he's trying to keep things simple, and I hope I'm not diluting his message by introducing nuances, but I would hate to think that people are unnecessarily replacing good hand taps in sizes they rarely use, or reverting to hand tapping in free-chipping materials for lack of a machine tap. And in the case of through-holes, chips rarely become compacted, even in the flutes of a hand tap.
Toms Techniques I always had a large collection of taps. They had noticeable differences that I never understood. Then after getting a Procunier head I learned that the ones you were using are often referred to as "gun taps," not because they are used in firearms manufacturing but because they are designed for power tapping and eject or "shoot" the chip down away from the flutes. Also, the tight spiral taps I was told are good for blind holes because the tight spiral pulls chips up and out. Thanks for all you do!
Hi Tom...as a novice, I have been running the mill (step pulley) in the slowest speed to give myself more time react/reverse. Do see any issues with that? Also you didn't address percentage of thread?
I'm not a machinist by any means, I'm an engineer who likes to be aware of machining practices. My question is this: Isn't the spindle's height usually controlled by a hand lever? If so, what allows the tap to travel through the part at just the right speed to prevent it from stripping the threads? Do you just release the hand lever and it's free to be pulled down by the tap as the tap spins? Also, wouldn't there be some likelihood of the tap stripping or damaging the threads as it comes to a sudden stop, and then jerks to a start in the reverse direction?
The quill is left free to float so the tap can pull itself in and out. Reversing the tap mid-cut is normal procedure for any tapping method. It doesn't hurt the thread at all. If you calculate how much force it would take to pull the thread after the tap is in a couple diameters, you'll see that there is no way that can happen. Even if the quill hits the mechanical stop by accident, it just causes the tap slip and pull out of the chuck. Tom
304 has very poor machining characteristics. You can tap it, but it requires a tapping fluid meant for stainless to reduce friction on the tap. It can be power tapped, but likely not in one pass. You may have to back it out a few times to clear the chips and allow more tapping fluid in the hole if the tap starts slipping in the chuck. Tom
It doesn't hurt the chuck. I've been using the same chuck on my mill for 30 years and it still works just fine. BTW, taps may be cheaper than chucks, but having broken ones removed sure isn't.
I power tap blind holes daily. You should always chamfer your drilled hole before tapping. Also look into spiral fluted modified bottom taps for blind holes. good video.
You know if there's something extra I should be aware of when I'm going to tap a blind hole in aluminium for heli coils - do I need a special tap - or could I go with any spiral fluted modified bottom tap?
Hi Tom...as a novice, I have been running the mill (step pulley) in the slowest speed to give myself more time react/reverse. Do see any issues with that? Also you didn't address percentage of thread which I might adjust depending on the build/strength required...thoughts?
I use it on everything. Once you get a feel for how tight the chuck needs to be, you'll never break a tap. You also need to be sure to use the appropriate tapping fluid for the material. Tom
I personally try to power tap or at the least use the drill press when I can and by hand turn the chuck. An old machinist told me about using transmission fluid as tapping lube for aluminium. I have to disagree about closer thread tolerances by hand tapping over power tapping. For a slew of reasons. I drill and tap thousands of parts on the vmc's a week. Every hole has to pass thread check gauges and holes are 1/8, 3/16 and 1/4. When tapping holes in thin material (ie. 1/4 or thinner) power tapping vs hand is superior in holding tolerance hands down. No pun intended. My .02
hand turning in the press is my favored way of doing this.Even to just get it started. once its 5 or 6 threads in just put the tap handle on and let loose
What kind of controls are you using to get that instant reverse on the mill, 3 phase? drum switch, or reversing a VFD on the fly? . I think that is pretty important to that setup vs stopping to reverse.
I never had a problem. The only time you really have to be careful with any chuck is when you get into taps that are under 1/4 inch. I've done thousands of holes and it's the really small ones you want to be sure you are using a fresh tap. I wouldn't attempt it with the really small stuff like a 4-40 or a 2-56. Especially in a blind hole and even more so if it's steel. Aluminum is a piece of cake compared to steel.
Thoroughly enjoy your instructions. I had just acquired spiral taps however these are three flute. I work with 7075 alum. and mild steel, will this be an issue power tapping or using in a tapmatic?
I wouldn't try power tapping with them because they may plug up with chips. They will be ok with a tapping head, but clear the chips more often than you would with a two flute. Tom
Hi Tom, sorry if this has been answered before but couldn't find it in the comments.. Is there anything you should be extra aware of with blind holes? (other than using a spiral point tap). Thanks for the video!
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Nice to see this tip. I've been doing this for twenty years or so and never had a problem. Sometimes, depending on the situation, I turn off the spindle, let it coast to get the tap started, then finish by hand. Thanks again for posting his video. I heard about it on the PM forum.
Thanks, I'm glad you enjoyed it.
There has been a fair amount of traffic from PM lately, so I figured there must have been some mention of my channel there.
Tom
I've used this a bit on a regular drill press. Clamp work down, drill hole, power tap down (turn switch on and off real fast to not go too far), then you have to hand crank back out.
You can also hand crank both directions, the drill press is just a jig to align the tap. Works great, I rarely use the tap wrenches.
I have been using a cordless drill with my hand tapper, I took off the handle and made an adapter to work with my cordless drill. It aligns the tap and the clutch on the drill can be set to the size of the tap, I start off on a lower setting and work my way up. The hand tapper I bought only came with fractional sizes to fit the taps but to my surprise they also fit most of the metric sizes as well. When I machined the adapter I made both sizes without removing it from the lathe chuck then I sawed it off. Well they must not have aligned the hole straight so I just put the whole thing in the lathe and trued it up. Worked great and it feels quite safe to use.
Tom, I sincerely appreciate the plethora of invaluable knowledge you so freely share. I have most of your videos saved and go back when I need to be sure. They are my measure twice before I cut guide.
Most hand taps are four-fluted and have long lead in angles on the cutting edge. Both of these features make them easy to start. They will also often be made of carbon steel rather than high speed steel and are cut rather than ground.
Machine taps are normally two or three-fluted, are always high speed steel and will have ground threads and flutes. Spiral point machine taps also have a secondary angled flute to help direct the chips.
Tom
Tried a 5/16 tap with my power drill.. 4 holes, all turned out excellent! Thanks Tom!
Excellent, Mike!
Yesterday I tapped 520 4-40 holes in some 6061 aluminum bar with a cordless drill. It took most of the day, but I finished up with the same tap that I started with, which is always a good thing. :)
Tom
Tom good info I never thought of not tightening the chuck too much to let the tap slip. I use the hand drill way often. I set the clutch on the drill to avoid breaking the tap if it binds up. But I don't do anything above 1/4 because we don't have nice spiral point taps.
Knowing how to use and how to be in control of your power tools is the key to not breaking things. Some people say not to use a drill or a screw gun for certain applications, but I know how to control the trigger and feel how things are going before any accident happens.
2)
You can save even more time by using a single tool which combines a drill point with a tap body. These are available in various quality levels, and I've even made my own from a helical fluted tap* by grinding the end on a drill sharpener and cylindrically grinding on a utility lathe but unless you do some fancy relief grinding on the OD it's only suitable for alu alloy
*(not advisable, as others say below, for blind holes!)
Tom that was fantastic straight to the point.we love it in the UK your videos keep them comming.
+vimaljks
That's good to hear. Thanks for watching.
Tom
My machining class actually taught us this last semester. Had to come here for a refresher since it's been so long.
Kudos to your instructor for teaching you something out of the norm.
A step ahead of the rest...Great video once again. I love the ease of it all for something most will tell you it is too hard to do or unsafe. To all the pro's out there, this video is for you. Peace :)
Nice job, Tom!
A couple of thoughts to expand the discussion:
1) As you point out, any 3 phase motor will reverse instantly (electrical people call it "plug reversing").
It won't hurt such a motor when the reversing switch is thrown heedlessly from 'full ahead' to 'full astern'. You can achieve the same effect with a VFD, but make sure you use the VFD's internal reversing switch.
Don't use an external switch like the one on the machine, unless someone who knows what they're doing rewires it with respect to the VFD)
On a big heavy mill, it's not wise to do it in a high gear. On my Euro-built Cincinatti Toolmaster, specifically designed for power tapping, they say to use instant reverse in back gear only, presumably to save inertial loads in the gearbox.
It might be worth pointing out that a single phase motor, if you reverse it 'on the fly', will generally keep happily going in the original direction. I don't know any safe way of instantly reversing a standard single phase motor. If you just turn off the motor, there will be a considerable variation in how far it coasts to a stop - probably not great for blind holes unless you are turning real slow.
You crafty devil, you. I discovered your videos a few days ago and have been learning from them ever since. My most recent tap break was a 3mm tap in a small run of Dalek ear cages. It didn't occur to me not to tighten the chuck except lightly by hand, and I'll try that for the next small batch. Thankyou for sharing.
Thanks, I'm glad you are using the videos.
Tom
We had a tap stand at work and I loved it. Just as fast as doing it in the mill and you have the feedback from doing it by hand.
Not sure how hand tapping can be as fast as power tapping, but you liked it. Did it by chance have a pneumatic tapping head on it. I've seen those.
It was set up with all the different taps already in quick change holders and it had a crank handle on top.. I’m supposing you’re doing it in a manual mill where you change tap and drill like you did. With this, you just drill, say 5 holes, then tap them at the tap stand. Even if they were 5 different taps, the holders just pop in and out.
It's nice to see "real world" examples in your videos, Tom. Nice job! We did learn to power tap in high school machine shop though. Late 80s.
I think the first time I saw it used was in a job shop in the mid 70's. Don't remember teaching it back then though, probably couldn't afford the broken taps with the limited budgets in the machining programs.
Hey Tom, I've been power tapping on my Bridgeport all the time. But what I like to do is after drilling the hole I pop in a countersink and give it a little relief to help the tap go into the hole. I feel that this helps when tapping harder materials like SS.
+Steve Billmire
I've heard that too Steve, but never really noticed a difference. I normally counter-sink mine after the fact with a cordless drill to save time, although doing it before hand would create less of a burr on the threads.
Tom
Tom, I like to use my cordless drill that way for electrical panel mounting holes. I often use "draps". As you probably know they are a drill pointed tap. They work quickly in one step but are limited to relatively thin materials. I recently powered up my Bridgeport knock-off mill with a VFD. The first operation I did was to power tap (16) 5/16-18 holes in (4) 1/4 thick steel angle brackets. It worked beautifully !
Good to hear Harry. Thanks for watching.
Tom
I power tap on tool steel at work all of the time and it works great. Ever since I was introduced to the spiral point tap I shudder at the thought of using a hand tap. It seems that everyone local sells hand taps, and yet spiral points are so much nicer to use.
+Chip Wright
Yeah, I'm surprised you can even buy a hand tap anymore.
Tom
I want to know more about tapping with a 3 to 4 foot tap! ;)
S
Why did you stop uploading? These videos are Gold 🪙!
Thanks, I'm glad you like them. Basically life got in the way of making the videos. Right now I don't even have a shop, because we have sold our house and are in the middle of a move. Once we are settled and the new shop is operational, I hope to start up the videos again. Stay tuned!
@@TomsTechniques Tom, you are the man! Love your videos, and hope to see you soon. That drill chuck you are using , Jacobs.. what model is it? if you can remember , thanks, wanting to buy one, that one looks solid , the good old "made in USA" most likely
@@TomsTechniques Please do, Tom. You are one of the best!
@@TomsTechniques thanks for the reply, I didn't see a notification for your reply but with this pandemic a year is like another dimension so..yeah.
well that's good to hear, I will be on the lookout, I subscribed when I left this comment.
Thanks for video 🐲a good thing is collecting all shards of metal in a bunch and forging it to make more metal. I got a metric tap and die set I need SAE(Standard) imperial set.
G'day Tom thanks for the power tapping video I have some small holes to tap into a stretcher frame so I might give it ago, glad you showed tapping though steel because that's what I will be tapping in thanks mate John
+John Kinnane
Be sure to use spiral point taps and lots of oil.
Tom,
Great stuff, thanks so much for sharing!!! I appreciate your taking the time to make, edit & post your videos.
Best Regards,
Jon
19 people looking for video on removing broken taps..
Those would be the ones who didn't pay attention to the pointers in the video.
I love the video I have used the cordless to tap hole with no problems for many yrs.. I come in peace.
I thought that might be the case, but many just assume that power tapping can't help but result in a broken tap.
Thanks for watching
!9 dislikes..lol Toms Techniques
lmao
Thanks for the information as it is something that I will now use, mainly for speed using the cordless drill and for accuracy using the mill.
+Ralf Boyke
Thanks.
The cordless drill thing takes some practice to get the tap going straight. I just start them a bit and look at it from both directions, correcting if necessary.
Tom
A lot of DeWalt drills (like the one he's using) have an adjustable torque limiting clutch in them as well, seems like that would be put to good use in this task.
It's not necessary on a hand drill because it's pretty easy to feel the torque on the tap to know when to back it out.
Tom
5) On a big lathe there's too much inertia in the chuck and headstock for plug reversing to be a great idea, and in small lathes you tend to have single phase or a screwed-on chuck or both)
One way to get around this is to make a tap holder (ideally using the biggest Jacobs Superchuck you can find on eBay - much quicker than collets) and prevent it from turning by fitting something like a go-kart steering wheel to it. In other words, the holder is free-spinning on the tailstock barrel (make sure to bush it with plastic or bronze) unless you're hanging onto the wheel. Because you can use both hands, you can resist a lot of torque, and when you do let go, there's no handle to hit you.
If it's a big lathe, go for a tractor wheel!
cool video.Thanks for taking the time to making the videos glad I found your channel.
Hello Tom I did this on my second day of working as a machinist trainee and I did well without breaking anything :)
Excellent
Thanks.
Yes, good quality spiral point taps make all the difference.
Tom
Never thought of power tapping being unconventional, one major difference and you are so like me Is that I use a much slower speed in both lathe, mill and cordless drill. Main reason I get a better feel for whats happening along with quicker time to do something about.
Logically faster will cut easier, touch wood never broke a tap yet in over two decades.
Yes, the marks will eventually get rubbed off but all it takes is a quick check with the calipers to know the size. It's good to be familiar with the diameters of the various taps. I don't know about you, but it's getting pretty hard to read those marks anyway.
Tom
i power tap all the time on the mill or a ridged drill press set-up but for the hand drill only taps 5/16ths or bigger i have seen way too many guys breaking 1/4 inch taps off that way because they are not making sure the tap is straight or the let the drill drop a little part way through, Love your videos by the way
i'm really jealous of your chuck and spindle travel
Norm McDonald's voice twin! Very easy to listen to, very trustworthy voice!
Keep 'em coming.
Even with my slowest speed on my Index milling machine, it takes practice. Very heavy flywheel, so I almost need to reverse the direct when just starting. I have a tapping heads, but they mainly stay in the box unless I have a helper to tap a 100 hole jig plate.
For hand taping, make up some 1" rod drilled to just clear the tap. Part 1/2" thick. You have a nice finger held guide for straight tapping. Hold against the work, and that tap will remain straight. (also the guide doubles as a nice stop for blind holes)
Tom
Tom,
I often turn the spindle off and let it coast a bit before starting the tap. That would help with slow to respond mills like yours.
The tap starters is a good idea for hand tapping. I also do a lot of my tapping with a cordless drill. The two techniques could be combined for a nice square start and the speed of the drill.
Thanks for watching.
Tom
Yeah, good taps are key because they take less torque to drive. The hand drill is definitely handy, but it takes some care to get the tap started straight.
Thanks,
Tom
I like your Leland MI shirt, my folks spent every weekend on Lake Leelanau from 1970 until about 2010, at Leelanau Pines on the SW area of the lake. They both passed away recently. Beautiful country up there!
I've only been there once, but was impressed at how large the peninsula is. Very nice scenery as well. I vacation a bit farther North, on the other side of Lake Michigan. About two hours by boat or 3 1/2 hours by car.
Tom
Never mind. You just answered it in the video! Thanks, I love your vids!
Thanks for this video! This may spare me a case of carpal tunnel! I have to tap a lot of blind holes, so thanks for addressing that too!
Lol. Thanks for watching.
Nowadays, they are referred to as "visually impaired" holes...
Thanks Jon, I appreciate your taking time to comment.
I'm starting to get the hang of the video thing, but it's a LOT easier to do it live. Maybe I should just invite you all over to my shop.
Tom
Any 3 phase motor will reverse like that, I use a rotary phase converter for mine. I haven't used a VFD for a while, but I'm pretty sure they can be set-up to work the same way.
Tom
Nice work, as I have to expect. I use the hand drill techniques often. I will have to investigate into better taps for the application.
I TAP LIKE THIS ALL THE TIME, BREAKING A TAP CAN BE PREVENTED BY USING CORRECT TAP DRILL SIZE AND ALWAYS CHAMPHER HOLE BEFORE TAPPING,
Yep! Without a lead-in to guide it, its tougher on the tap. Also make sure its a gun tap you use!
Can you do it on say 1/2 inch steel or is this something only for aluminum?
I'm the old grumpy teacher at the local JC....I let them start taps like this...... But then, get a feel of what they are doing... I tell stories of breaking 1" taps... And chiseling .... Fracturing them out!
@@DominicPaz did you watch the video? 7:20
You make that look way too easy Tom, thanks for sharing!
3) As regards letting the tap slip: That's good advice, I think, for people dipping their toe, but once your tools and technique are dialled in it's not essential
(and not doing it will, as others point out, save wearing the lettering off the shank!).
As I mentioned below my Toolmaster turret mill was designed for power tapping (in the early 70s), and when it's switched to 'tapping' mode, the spindle runs in reverse unless a push-button is held in, on the end of the downfeed handle. (The manual one, intended for sensitive drilling). This means at the first hint of binding you simply slip your thumb off the button and the tap winds back out. When you hit the bottom stop (which on this machine is designed with a pretravel, and microadjustable) in tapping mode, the machine decides you must have gone to sleep at the switch, and reverses the spindle on its own initiative.
With a setup similar to this I've had no breakage issues with HSS taps intended for machine tapping, when using ER collets tightened to the max. If I ever change mills, (unlikely!) I will feel the need to duplicate the setup, it's that fast and easy. I tend to use collets because the one limitation of this mill is a lack of headroom for the work envelope. (I bought myself a Shars snub-nosed ER32 holder, whose internals are buried back inside an NT40 body, hence about the same overhang as with an R8 spindle. Prior to this they were only available from very expensive labels like RegoFix. It has bought me enough spare headroom to save me from having to make a riser for my turret - still available from Cincinatti, BTW, for approximately as much as I paid for the mill with German DRO)
Tom's chuck is a Jacobs ball bearing Superchuck, one of the best chucks ever made, and it's well suited to being used as a sensitive clutch (probably more so than the modern-day chuck bearing the same designation). Most other drill chucks won't hold a tap much over 1/2" without slipping, no matter how hard you close them.
Unless you are tapping a blind hole...
Toms Techniques You're quite right, I should have added that qualification, Tom.
My "auto-reverse on reaching the depth stop" setup (which does permit safely tapping blind holes provided sufficient allowance is made for chips) is not something I've encountered on any other turret mill or drilling machine you'd be likely to find in a home shop.
Having said this I did (carefully) power tap blind holes on my previous mill which lacked this brilliant feature, by marking the tap flutes and reversing at the correct depth, leaving (as I still do) a generous allowance for chip buildup. (And using helical fluted high quality machine taps, which evacuate almost all the chip from the hole)
Real excited to see a 3 foot tap video Tom!
awesome vid... I have been criticized for doing this before.. but it is all in the technique. ... my favorite tapping fluid for steel: buttercut, it's animal fat.
no1wrench
Criticized by the "purists" no doubt. :) How can someone criticize something that saves so much time?
Do it all the time with my Bridgeport. Piece of cake.
I had to chuckle at this video because I do this all the time, but 1/2 inch is about as big as I like to go just because anything bigger I cant get my chuck to hold it without slipping. I do have a tapping chuck that works in my lathe or mill but in the mill it slows the job down. I just use regular taps but lots of cutting oil and only about 60 rpm, thanks
Yeah, a half inch tap is pushing it, but even if it slips, at least the tap is started straight and you can finish it up by hand. I often do the same with small taps because the chuck releases when reversed.
Tom
thanks for the link, i will get the nerve up to practice this soon
Brice Glagau
Just be sure to get spiral point taps and start out with them lightly gripped in the chuck until you get the timing down.
Tom
The secret is out, now everyone knows. ;)
Glad you liked it.
Tom
I'm surprised people who work with these had no idea about this. I remember teaching myself these methods when I was an apprentice... it was almost common sense.
Great bit changing tool! It works on water and your favourite meal!
I’ve seen a lot of individuals use this technique. I was taught to never ever put a tap in a drill chuck, unless you don’t value your chuck and definitely never in an expensive keyless chuck like an Albrecht. If you want to power tap safely and correctly then get yourself a tapping head such as a tapmatic. Your taps, and spindle switch will thank you.
I've been using this technique on this machine since I bought it in the mid 80's and am still using the same chuck and switch. I suspect what you were taught was based more on theory than real world experience.
Need to be corrected...? But I reckon the mill is 3 phase, hence the instantaneous reversal. If you have a plain single phase mill, it will need to stop before Reverse will come into effect. ie, if you hit reverse while spinning in, it will keep going the same direction. Try it...!
That is correct. A keyless chuck will grab the tap.
Tom
I went to a machining school, and they taught us to power tap.
At work we do it both on the drill press and with cordless drill on stainless steel, steel and aluminum in stainless is the hardest because you have to play with you drills because of the hardness of the metal you go one or two sizes over depending on the thickness
A good tapping fluid is the secret for stainless because it is so sticky. I use the old formula Tap Magic, but I'm sure there are other good candidates around as well.
Tom
Was taught this in first machine shop class at the local JC
I can hear my shop teacher screaming in my head every time you flipped the spindle in the other direction. Not that they don't let us do this in school, except we always use a tapping head. Pretty cool though, although I would be too afraid to attempt it.
Tapping heads work well, but involve a change of set-up. This way is much faster.
Tom
Hey Tom, I love your videos, straight and direct in teaching the technique. Can you suggest a brand of taps?
Thanks!
Spiral point taps made in the U.S., Europe and Japan are all excellent quality. Look for names like Morse, Regal, Union-Butterfield, Reiff and Nestor, Cleveland, etc. Cost should not be a factor when choosing taps. A quality tap will cost more, but more than pay for itself in performance and be MUCH less likely to break and cause you grief than a cheap alternative. The best tap I've ever owned was made by Bendix. It is a 2-56, 2 flute and I've been using it since the 80's. It just keeps on going, with no sign of wear. They must have got everything from the steel to the geometry absolutely perfect.
Tom
Very enjoyable. Thanks for posting,
Tom Australia,
Thanks for the great videos. I have no way to disengage my spindle from the quill handles. How do you get the proper feed rate? Will it just pull the tap into the hole (and therfore spin the quill handles?)
+Steve Clark
Yes, the thread on the tap just pulls it in. Just be sure the stop has adequate clearance so it doesn't bottom out.
Tom
G'day Tom from down under, I'm glad you enjoyed the video.
Tom USA
Hello Tom, Really enjoying your videos. Couldn't help but notice a few different northern Michigan t-shirts. Are you located in MI? Just wondering!
This is skill + experience!
Skill comes from experience.
Great Job ,very Helpful thank you
Great technique
Thx alot
May i ask you, please what kind of drill press you promote for a machine shop with medium duty work ?
Do you drill enough holes for a dedicated drill press? I just use my mill for any holes that need drilling. It's faster than taking the time to layout and center punch holes to be drilled on a drill press.
If you do have use for one, I would recommend a 20", possibly with a geared head, depending on how large holes you need to drill. If you want new, Baleigh and Powermatic make good ones. In the used market, look for Clausing. They were well built and last forever. Don't waste your money on Chinese made hobby drill presses, with the possible exception of Grizzly.
Tom
Absolutely amazing.
Tapping heads work great as well. You do have to drill all of your holes first then come back and tap them. But for multiple parts you can't beat them. I would say find a good German made one with V jaws not collets. The thing about a tapping head is they auto reverse with the quill stop. And they feed out at twice the RPM as they go in.
There are definitely better ways to tap for production. This is just a quick way to do one off parts at the same time they are drilled.
Tom
Power driving is a quick and easy way to tap. We do use that method quite a bit. Just not on parts that have a tight thread tolerance. It does tend to make a little looser thread than hand, CNC or a tapping head.
Great video Tom. What size are your cutting oil dispenser bottles and where did you get them.
Thanks. The bottles are 8 ounce and proably came from McMaster Carr.
@@TomsTechniques Thank you Tom. I don't know where you are moving to in Michigan. My wife's sisters live in Grand Marais.
Thank You for this video
So I am very new at all of this but am very anxious to learn how to tap into steel hence watching this video. My question is that why doesnt the tap bit just make a bigger hole since the drill is spinning so fast. I know you said you slow it down but it would seem like you would need to bring down the press at absolute perfect speed. Thanks.
Because the tap is free to move on the Z axis. As soon as it touches the hole, the tap will start to screw in because that's what it was designed to do. If you try this, it is very important to use spiral point machine taps NOT hand taps and very lightly chucked until you get the hang of it.
Tom
Hey Tom, just another one of your terrific demos. Evidently, it's not important to keep backing off when power tapping, like you would hand tapping, or isn't it really necessary. or Is that all because it's a spiral tip? Thanks
Yup. The spiral point makes it unnecessary to break the chip as with a hand tap.
Your the best, Thanks Tom
Makes a lot of sense, good info.
+Larry Marc-Aurele
Thanks Larry
+Toms Techniques Any advice on cutting male quarter-20 threads? Having trouble even getting it started manually. This is for short, half inch lengths attached to shelf supports.
+Larry Marc-Aurele
The easiest way to cut non critical threads for something like that would be with a die, or just make them out of 1/4-20 bolts.
Tom
Great Video, Thanks Tom
raise your hand if you flinched a bit when that tap went in the first time hehe
Including me the first time I saw it used. :)
4) I entirely agree with Tom that this method was hardly ever taught in the days of trade training. I used to wonder why, and it occurred to me that it was partly because shop teachers were generally (at best) gifted practitioners from an earlier era, who had it drummed into them that it is ESSENTIAL when tapping to stop and reverse to break the chip.
This is one of those pieces of learning which remain true to this day, but only in the original context. If human wrists were equipped with a slewing ring and a small hydraulic motor we would never have made this rule: the reason we have to reverse is because we have to stop, and the reason we have to stop (when tapping by hand) is due to design limitations. I discovered this in the early days of battery drills: I found I could do a much better job with very small holes in alu (under 1/8") using a battery drill and NOT stopping. Then it occurred to me to try in steel, and eventually (like Tom) found it worked up to sizes as big as I could hang onto the drill (once they got torquier) And at some point it was natural to apply this to milling machines and lathes.
Very impressive. I love videos that are no-nonsense and right to the point. Thanks.
The need to break the chip or not actually depends on what type of tap you are using, not whether you are capable of driving the tap without stopping. With hand taps for instance, the chips form in the flutes of the tap and if you don't break them every now and then they will become compacted and break the tap.
To power tap, you need to use spiral point taps. They push the chip ahead of the tap where there is much more room and don't require the chips to be broken.
Thanks for watching.
Tom
Toms Techniques
I don't think it's an "either/or" situation. Both of us (I think) are correct.
Even using a spiral point tap (or, for blind holes, spiral flute), in certain tough materials, it is not advisable to stop and start rotation.
This is because the process of chip-forming is harder to initiate than it is to continue, so it requires extra torque to re-start a chip. This is made worse because a suddenly applied force (when the teeth simultaneously hit a 'frozen' chip) increases stresses above the level of sustaining that same force.
Another reason not to back off to break the chip, in tough materials, is that there is a relief (eccentricity) to the form of the thread, which means the tap travelling in reverse over the chip from the tooth behind it will try to mash the chip into the groove of the thread.
Conversely using a hand tap for machine tapping can work in materials which are not too tough; I do it all the time (high quality, HSS ground thread hand taps) and virtually never break a tap. In tough materials, serial taps (made for tapping by hand) work well, but these are not generally available in the US.
I don't disagree with anything Tom says, and in common sizes I have progressively replaced all my hand taps with spiral point or spiral flute. I understand he's trying to keep things simple, and I hope I'm not diluting his message by introducing nuances, but I would hate to think that people are unnecessarily replacing good hand taps in sizes they rarely use, or reverting to hand tapping in free-chipping materials for lack of a machine tap. And in the case of through-holes, chips rarely become compacted, even in the flutes of a hand tap.
Toms Techniques I always had a large collection of taps. They had noticeable differences that I never understood. Then after getting a Procunier head I learned that the ones you were using are often referred to as "gun taps," not because they are used in firearms manufacturing but because they are designed for power tapping and eject or "shoot" the chip down away from the flutes. Also, the tight spiral taps I was told are good for blind holes because the tight spiral pulls chips up and out. Thanks for all you do!
Hi Tom...as a novice, I have been running the mill (step pulley) in the slowest speed to give myself more time react/reverse. Do see any issues with that? Also you didn't address percentage of thread?
I'm not a machinist by any means, I'm an engineer who likes to be aware of machining practices.
My question is this: Isn't the spindle's height usually controlled by a hand lever? If so, what allows the tap to travel through the part at just the right speed to prevent it from stripping the threads? Do you just release the hand lever and it's free to be pulled down by the tap as the tap spins?
Also, wouldn't there be some likelihood of the tap stripping or damaging the threads as it comes to a sudden stop, and then jerks to a start in the reverse direction?
The quill is left free to float so the tap can pull itself in and out. Reversing the tap mid-cut is normal procedure for any tapping method. It doesn't hurt the thread at all. If you calculate how much force it would take to pull the thread after the tap is in a couple diameters, you'll see that there is no way that can happen. Even if the quill hits the mechanical stop by accident, it just causes the tap slip and pull out of the chuck.
Tom
Wow, amazing technique! Is it possible to do this on 304 stainless steel as well? I feel 304 dulls the taper easily, even for high speed steel taper.
304 has very poor machining characteristics. You can tap it, but it requires a tapping fluid meant for stainless to reduce friction on the tap. It can be power tapped, but likely not in one pass. You may have to back it out a few times to clear the chips and allow more tapping fluid in the hole if the tap starts slipping in the chuck.
Tom
I've done this for years, and never heard of leaving the chuck loose. It may save the tap from breaking, but taps are a lot cheaper than drill chucks.
It doesn't hurt the chuck. I've been using the same chuck on my mill for 30 years and it still works just fine. BTW, taps may be cheaper than chucks, but having broken ones removed sure isn't.
I power tap blind holes daily. You should always chamfer your drilled hole before tapping. Also look into spiral fluted modified bottom taps for blind holes. good video.
Hi Tynan - why is it important to chamfer before tapping? (if you use this method)
ziikzaaak Easier on the tap and loads it up evenly reducing your chance of breaking off at the top of the hole. Also helps with chip removal.
Tynan Clum
Thanks Tynan :) I'm new to this tapping business - so I'm trying to learn..
You know if there's something extra I should be aware of when I'm going to tap a blind hole in aluminium for heli coils - do I need a special tap - or could I go with any spiral fluted modified bottom tap?
ziikzaaak I don't install many helicoils but heres a chart you can reference.
www.noblefix.com/helicoil/HeliCoil-Tapping-Chart.html
Hi Tom...as a novice, I have been running the mill (step pulley) in the slowest speed to give myself more time react/reverse. Do see any issues with that? Also you didn't address percentage of thread which I might adjust depending on the build/strength required...thoughts?
Easy is good. Thanks for commenting.
Tom
I use back gear to do this... seems more controlled because of the lower rpms, but perhaps too much torque?
The torque is regulated by how tight you make the chuck. Just use whatever speed you are comfortable with.
I do this on all the aluminum parts I build. I use a mini mil so it can go pretty slow
I use it on everything. Once you get a feel for how tight the chuck needs to be, you'll never break a tap. You also need to be sure to use the appropriate tapping fluid for the material.
Tom
I personally try to power tap or at the least use the drill press when I can and by hand turn the chuck. An old machinist told me about using transmission fluid as tapping lube for aluminium.
I have to disagree about closer thread tolerances by hand tapping over power tapping. For a slew of reasons. I drill and tap thousands of parts on the vmc's a week. Every hole has to pass thread check gauges and holes are 1/8, 3/16 and 1/4. When tapping holes in thin material (ie. 1/4 or thinner) power tapping vs hand is superior in holding tolerance hands down. No pun intended. My .02
hand turning in the press is my favored way of doing this.Even to just get it started. once its 5 or 6 threads in just put the tap handle on and let loose
Eric,
Hand tapping more precise than machine tapping? That didn't come from me. Are you referring to someones comment?
Tom
Yes to someone else's comment. But I don't mean it harshly. :)
I realize that. Just wondering where it was coming from.
Tom
Tom - Am I correct in assuming that this wouldn't work with a keyless chuck. I'd be worried about it grabbing too tight when starting the tap, yes?
Love it :-) makes life easier
Amazing. By hand with cordless drill in steel at 10:28
It's all about using the correct tap and starting it on axis with the hole.
What kind of controls are you using to get that instant reverse on the mill, 3 phase? drum switch, or reversing a VFD on the fly?
.
I think that is pretty important to that setup vs stopping to reverse.
Am I correct that you wouldn't want to try this with a keyless chuck since they self-tighten?
I never had a problem. The only time you really have to be careful with any chuck is when you get into taps that are under 1/4 inch. I've done thousands of holes and it's the really small ones you want to be sure you are using a fresh tap. I wouldn't attempt it with the really small stuff like a 4-40 or a 2-56. Especially in a blind hole and even more so if it's steel. Aluminum is a piece of cake compared to steel.
tapping clutch works too
Thoroughly enjoy your instructions. I had just acquired spiral taps however these are three flute. I work with 7075 alum. and mild steel, will this be an issue power tapping or using in a tapmatic?
I wouldn't try power tapping with them because they may plug up with chips. They will be ok with a tapping head, but clear the chips more often than you would with a two flute.
Tom
Toms Techniques Thanks Tom
Thanks Ray, but it actually is pretty easy as long as you follow the rules. I can't remember the last time I broke a tap.
Tom
Hi Tom, sorry if this has been answered before but couldn't find it in the comments.. Is there anything you should be extra aware of with blind holes? (other than using a spiral point tap).
Thanks for the video!
Just err on the light side when you chuck the tap. You can always tighten it if necessary.
Thanks for watching.
Tom
Toms Techniques Thanks Tom :)
So if your machine doesn’t reverse then is this technique not possible?
Correct. It's normally used on vertical milling machines.