DIY Power Drawbar for a Bridgeport Style Mill - Part II
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- Опубликовано: 18 сен 2024
- #bridgeport #diy #powerdrawbar
Well, things have progressed and I have tackled the most challenging part of this build. Namely, getting a pair of bores to be absolutely aligned in two separate castings so that the carriage supporting a pneumatic impact wrench can slide up and down on a pair of linear bearings. In this video I detail a method which I have used previously to make a George Thomas designed tapping and staking tool. That part worked out fine but there is one recalcitrant issue which I am still dealing with but for now things are going to plan.
Wonderfully clear explanation and execution of the bore. Thanks for sharing the approach. I will remember the techniques.
Being a Motorcycle enthusiast and a racer myself, I love the Burt Munro shirt!
Thanks. I love the movie and I must have watched it at least 10 times. Anthony Hopkins is a wonderful actor but he didn't quite nail the Kiwi accent. I might add that I actually bought that shirt in Invercargill at the E. Hayes and Sons hardware store where their is a public display of Burt Munro memorabilia and some of the replica bikes from the movie.
Regards,
Mark
@@Preso58one of my favorite movies! I've seen it a few times myself
Thanks for the video. I will be back for part III.
The next time you make a part like this, maybe you should both of them together and drill both holes at the same time that way you don’t have to worry about all this crazy set up. But you did a good job.👍
For the life of me, I cannot remember why I chose such a complicated setup. There were probably 10 ways that were better and simpler than what I did, but I got the result I wanted.
Regards,
Mark
Happy New Year Mark,
Bet your issue is the R8 collets sticking and not releasing.
Might I suggest that you add a large flange to the head of the drawbar head so that it runs up to a thrust bearing in the lower housing and pops the taper.
You would have to ensure a clearance when the spindle is fully retracted so you don’t induce a false up stop, and lock the spindle up when doing a tool/collet change.
Enjoyed the proper way to get centres correct for varying diameters, this method is used a lot in pre CNC mass/quantity production.
Keep the old school alive.
I cut an internal thread at the top of the spindle to hold a nut to retain the drawbar. This addresses the problem of having to lock the spindle to prevent if from getting pushed down.
@@EDesigns_FL Good idea, depends on the design of the quill.
I haven’t looked at the top of a Bridgeport for a long time.
Discussion and knowledge share is a good thing.
Thanks.
Yes, sticking tools are the issue. My next job it to inspect the inside of the spindle taper to see if anything is amiss there. Your solution sounds interesting. I am hoping I won't have to overcomplicate the device but something tells me it ain't going to be an easy road.
Regards,
Mark
@@Preso58 Hopefully episode 3 will bring fruit to the exercise or at least for the fruit bats.
Looking forward to seeing your solution.
@@Preso58 I have two mills with R8 tapers, and tooling has to be forced out of both of them. There is nothing wrong with the spindles. It just requires a little pressure to eject the tooling. Typically, this would be accomplished with a tap from a hammer. You might be able to accomplish it by installing end stops on the rails supporting your impact wrench. This will likely work most of the time, but you will encounter situations where you have to lock the spindle to prevent it from dropping. I prefer captured drawbars.
2021 is already better. (A low bar, for sure!) That sneak peak at the next episode was priceless. Every video ending leaves me smiling. Unlike some years I can think of...
Can't wait to see part 3. Wonderful castings.
Another great one, mate. I really appreciate when you leave in the issue you face as they are something that folks may likely encounter. Keep the videos coming!
William, unfortunately, when researching this build, no one reported that the tools hang up in the R8 taper, at least not in the videos I watched. I haven't given up yet. I need to inspect the inside of the spindle taper to see if there are any nicks or burrs in there and I also want to run some blued tapers in there to see if everything fits as it should.
Regards,
Mark
I don't think I've ever seen someone make drilling a couple of holes so complicated.
I know. But that's what us Asperger's types do!
Regards,
Mark
I really don't understand why your subscriber count is so low compared to the other machining channels. Your content is stellar with a large breadth of skills & topics, and your video quality is fantastic. I wish you much growth in 2021; you really deserve it. Thanks for sharing your projects with us- I'm sure I can speak for most subscribers when I say we all really appreciate it and wish you the best!
Thanks for that. It's reassuring to get positive feedback. I must say that I do sometimes wonder if I am doing something wrong or if I am not doing something in terms of getting any growth in the channel. One decision I made right from the get go was that I wasn't interested in monetising my content and I want to remain independent and thus not beholden to any sponsors. I wonder sometimes if RUclips regards my content to be of lesser value because I don't make them any money? Still, making videos keeps me off the streets and I am never short of things to do.
Thanks for the best wished.
Regards,
Mark
@@Preso58
You are absolutely correct - if you don’t make money for Google their algorithms will not recommend your videos.
Also, you don’t ask for likes and to subscribe to your channel at the beginning, few times in between and at the end like others do...
Thank you for teaching another useful trick - and happy new year to you, Mark!
Great video. High attention to detail. Can't wait to see it finished. Mahalo for sharing! : ) 🐒
I will be back with another glass of Blanton's and a cigar! HAPPY NEW YEAR to you and yours!
OK, I had to Google Blanton's! I'm not really a bourbon kind of guy. Bundaberg rum is my alcohol of choice. Too bad it make me a bit maudlin if I overindulge.
Regards,
Mark
Mark, Thanks for the detailed info on that fixturing method, it sure did the job..
Thanks, I was wondering if anyone would understand the nuances of how it worked. It all seemed so clear in my head but in reality it's not quite as straightforward.
Regards,
Mark
Nice technique and thanks for showing it. I learned something ... looking forward to #3. Happy new year.
Great workk...like. Greetings from Brazil
Celso Ari
Happy New Year and thanks for sharing!
Hello Mark,
Happy New Year to you and your family... This video will be added to one of my favorites, In my opinion you are showing engineering at its best. a logical approach to making the bore align without the use of DRO, Rotary table and as always an approach that does not accept near enough is good enough... I have a feeling some more casting may have taken place.
Take care
Paul,,
Yes, I did have to do another casting (I am embarrassed to say I totally forgot to do it at the same time as the others) but you will get to see it being done in a future video.
Regards,
Mark
Thanks Mark for the detailed lesson. I wish you the best in 2021. It’s going to awesome. 👍👍😎👍👍
That is great technique, Mark. The only one issue with it, though - it is overcomplicated, IMO. Why not to clamp two plates together and drill those holes at once ?
Exactly my thoughts. I know this as a "match plate" process. We use this for drilling and boring machine side frames where I work. Stack the two together and go.
Yes, that would absolutely work. Castings can be a little more complicated though. In my case I only had reference surfaces on one side and the fixture allowed me to use the reference surface on one part and then swap out to the other part and replicate the centre distance for the second part. If I were using accurate plate stock I would sandwich the parts and lay out all three holes and finish them together although there is still the issue of having different diameter bores in each part. Sigh! It's never straightforward.
Regards,
Preso
@@Preso58 Right. Anyway, nicely done!
This method, while complicated, was devised by George H. Thomas to ensures that not only the holes are aligned but also that they are perpendicular to the flat side of the cast AND the operation had to be performed using a lathe.
To your point, both castings could have been bolted to a plate that could be aligned parallel to the mill table then two holes drilled, bored and reamed in this “sandwich “ fixture.
However I for one appreciate the video for showing the technique.
The only issue I have with mine is: The butterfly
wrench’s socket doesn’t always line up perfectly
with the nut, so it’s better to use the 12 point
socket on it. The 12 point is far better than
the 6 for this application but it could still use
some work. If you chamfer the edge of the
Hex bar a bit more on the drawbar the socket
should ease down onto the hex easier.
I now have a short 12 point socket and it's much better than the six point long impact socket I was using up until recently. I will be adding the internal chamfer before the next video goes up.
Regards,
Mark
Great project Guy Lutard caliber fixturing. Offering up a no rotary table solution and pointing it out as a no rotary table solution really jogs the mind for ways to do that The toolmakers button for locating on the lathe faceplate (that even looked in balance) and the mill fixture all real good work. I drilled the faceplate from a sieg c-6 with a 10-24 coutersink drill and bolted it to a 4" rotary table It just clears the index plates on the chapest grizzly 4" rotary. So it's like a 10" rotary table those faceplates are cheap the last i looked But ya great design great video/audio really fine work Mark Thanks
Thanks for that. I actually have a 4" rotary table but I converted it to a CNC 4th axis for my little Sieg X3. I really must get a 6" rotary for the Bridgeport though. I recall reading a lot of those Guy Lautard bedside readers when they were kept at our local library. There is a lot of rich knowledge in those books. I must see if I can hunt them down again.
Regards,
Mark
Well, no idea what went wrong at the end there, seems like it's working as intended 😁. Making a fixture to align holes is a good way to go. You could essentially do that with a drill press (minus the boring part of course) in that fashion if you really needed to 😊. Thanks for sharing Mark, Happy New Year! 👍😁👍
I am afraid I probably made a mountain out of a mole hill there. There are probably lots of ways of getting those two sets of bores to line up. Many people have questioned why I didn't just clamp the plates together and drill them both at the same time but it's never that straightforward. The castings don't really have two flat parallel surfaces and the bosses get in the way plus, I needed two different diameter bores for the two parts. The parts do fit the way I wanted them though. The issue now is that the tools stay stuck in the spindle taper instead of just magically dropping out the way they seem to on just about every other YT video I have seen on the topic. Either everyone is using some creative editing or I have a dud spindle in my mill. I have spent the last day or two redesigning the assembly to lock the impact wrench down so it will push the tools out as it unwinds the drawbar. The video count is already blowing out from three to four. Just so you know, It was about 32C today and about 90% humidity so I could only stand it for an hour or two.
Regards,
Mark
@@Preso58 yikes, too hot for me 🥵. It does get that way here too on occasion but I'm pretty much camped in front of the ac at that point 🤣. Does the nut on your drawbar have a flange? If you could capture that nut or head to the spindle (would require a couple carefully placed drilled an tapped
holes directly into the spindle probably) with a concaved sleeve of sorts your problem would be solved 😊.
Great series, awesome t-shirt. Love that film. Happy New Year
Yes, it's one of my favourite films too. I still get a bit teary towards the end even after watching it at least a dozen times. Anthony Hopkins does such a wonderful job as Burt Munro. We were actually in Invercargill during the Burt Munro Challenge just before Covid went mad. I am definitely not a biker but it was wonderful to see the number of bikers that had come from all over the world to pay homage to such a unique character and his bike. If you ever get a chance to go to Invercargill, the E. Hayes and Sons hardware store in the main street has at least three replica bikes from the movie and some of Burt's personal collection of bike parts all on public display. They also have them most beautifully presented collections of classic cars, chainsaws, motor mowers, outboard motors and some truly stunning brand new Indian road bikes. Definitely worth a visit.
Regards,
Mark
Wow Mark i would love to go there some day, sounds great. I tripped over that film one day and was hooked. I've watched it a lot as well. The birds in your garden look amazing. Haha our garden is full of sparrows and starlings. New Zealand is definitely on my wish list. May be when i retire. Cheers
Rup
Well, cliff hangar for Part-III! Will be sitting on the edge of my chair until then.
Spoiler alert... there's going to be a fourth video in the series. I have had to redesign the top end of the assembly!
Regards,
Mark
Like your Burt shirt Mark.
I actually bought that when my wife and I were in Invercargill just before Covid went mad last year. Just by coincidence we were there during the Burt Munro Challenge weekend. I've never seen so many bikes and bikers all in one place.
Regards,
Mark
Great build. I see that my bet for the issue has already been reported by OMAD's Dad. Looking forward to your next episode.
Happy New Year to you and your family Mark. Have a great 2021!
Your mill is really looking good now, well done. Stay safe and well :)
Always interesting!
Looking like it's going well. I know I will want a PDB once I get my BP going. I have a lot of Tormach tooling so I wonder if anyone has made a PDB for that system. Looking forward to the next episode.
Brilliant! I have an idea what the to-be-resolved problem is, but I don't want to embarrass myself guessing publicly...ha.
Tom, one of the great lies perpetrated by RUclipsr's who build power drawbars is that the tools just magically drop out of the spindle when in reality, if you read the forums, Bridgeport users regularly resort to hammering on the end of the drawbar to remove the tools. As this build progressed it began to dawn on me that once I had this thing in place I no longer had access to the end of the drawbar and if the tool refused to come out I would have to remove it to whack the drawbar with something. I haven't given up yet but the next video may be less than triumphant. If I get it to work I will make a nice etched maker plate for it, if it's a complete fail, I won't bother! 😁😁😁
Regards,
Mark
@@Preso58 Might there be a way to incorporate a cam to push the drawbar downward as part of the actuation cycle?
@@Preso58
I am afraid you will need to complicate the design, add a thrust bearing and a cam/lock contraption for the driver to push the collet down a tiny bit. That is how the commercial models do it.
Some models have the socket that engages with the drawbar on a non-locking thread & spline so as the socket turns and encounters resistance it moves down a small distance (think automotive starter motor engaging with the flywheel mechanism).
Not easy to replicate, though.
This one seems to have an air cylinder to push the driver down:
www.airpowerdrawbar.com/parts_guide.php
I think this is doable in a home shop.
My power drawbar has only three parts: a step ladder, battery operated impact driver and rubber mallet :-)
Happy new year to you Mark.. great video again parts 1 and 2 now. I particularly like the cad presentation.
I need one those for my bridgeport. A couple years ago i checked and priced the Comercially made ones and back then they were like 795 and now they as re going for 990 discounted.. Way over priced !
Great video again.
Yes, buying a commercially made one was never an option for me. I have had to do a few mods on the design so there is going to be fourth video in the series.
Regards,
Mark
Another great video.
I couldn’t see the problem, but if I think about my mill with Morse taper tooling, I would need to force the tooling out somehow.
I wonder if a custom long thread drawbar could be used and the vertical travel on the air tool able to be locked in the down position, thereby using the thread on the drawbar to push out the tool.
So the action would be sort of like “down, lock, undo” and the reverse to fit a new tool.
I am still struggling to find out why the tools stick in the first place. R8 tapers are allegedly non locking but most Bridgeport users report that they usually have to tap the drawbar or lever on the end of the drawbar to release the taper. I am just about to go and have a good look at the inside of the spindle taper to see if there are any nicks or burrs but you are correct about locking the impact wrench and then operating the rotation. I have tried pulling down quite hard to simulate the same thing but so far without success. One way that does work is to just bang the impact wrench down a few times to loosen the taper but it seems a little barbaric!
Regards,
Mark
@@Preso58 also banging on it, kind of defeats the point a bit, as I assume the idea is for it to be a smooth single action release.
As I was trying to explain in my last ramble, if worst comes to worst, could the sideways motion that starts the air tool, also latch it down so it winds the collet out the bottom, rather than letting the draw bar rise?
If you manually clamp the air tool down (don’t start the spindle obviously), can you operate it both ways and have it eject and re-grab the collet?
Perhaps a switch on the handle that works a lock solenoid to drive a pin to hold it down, or even an air solenoid (or whatever they are called) given you already have air available.
I really don’t know, but sometimes somebody else’s left field idea might trigger an answer.
Cheers
Rohan.
G'day Mark. Love that shirt mate. Does it come in a "full figured man" size, LOL. Excellent build Mark. I love the handle extension you built for it. Definitely added the cheery on top. Cheers, Aaron.
PS: I'm back up in the mother country at the moment. Visiting my mum up on the Gold Coast ;-)
Yes, I saw via your instagram that you were back in the land of the free! 😁 Those shirts did come in all sizes. I got mine in Invercargill during the Burt Munro Challenge back in February last year. I have never seen so may bikers all in one place at one time. Some of those guys would make three of me!
Regards,
Mark
Hi Mark
Great videos
But what is the point having a DRO? if you don't trust it
I use mine all the time, and it's never let me down
Eddie Harper
Fair point but I haven't done a lot of work with the mill or the DRO yet and I am still getting to know the capabilities of both. So far the DRO seems to be holding tolerances of around .01mm and that's good enough for the work I do.
Regards,
Mark
G'day Mark, just a question and I may have missed something. Why can't the drive be engaged all the time and just free wheel when the draw bar it turning. So rather than have the drive slide up and down it is fixed and will drive the taper out rather than moving up if the taper sticks. The only issue is the thrust would be put back onto the drive motor, maybe a small mod with thrust bearings.
Cam (from a very wet camp in Torquay)
The spindle on these types of Mills move up and down in relation to the headstock. So the drawbar moves up and down with the spindle and the impact gun would not be able to be engaged all the time.
@@XS400Seca yes good point Ulrik, I guess it wouldn't really matter if the quill draw bar moves down. You could actually run it with the quill slightly down and locked and reingauge when you want to do a taper change. The big King Richie's I worked on many years ago had air cylinders to engage and hold the drive down while it released but there is possibly a simpler solution. I'll be interested to see what Mark comes up with.
Cam (still camping in wet and cold Torquay for the next 2 weeks)
Cam, I did see a design with a similar feature but I didn't think it would be necessary. I naively assumed (dangerous) that the hammering action of the wrench would knock the tools out of the taper. As it has turned out I have redesigned the top end of the assembly to incorporate a lock which keeps the impact wrench fixed while it is winding the drawbar out and the theory is that it will force the tools down instead of allowing the wrench to ride up. It's an evolving design and I am fairly confident the new mods will work without overcomplicating the design.
Regards,
Mark
Don't know if you've gotten a bigger rotary table yet, or what size your is, but I just bought my 8 inch from Vevor Australia for under $310. It's a damn good table for the price.
I now have a 10" table that was given to me by a friend.
Regards,
Mark
Burt Munro was a mans man. Have you seen the movie "the worlds fastest indian"?
Yes, it's one of my favourite movies. I guess I've watched it about 10 times. I am a sucker for a story about an underdog which is also why I loved "Ford vs Ferrari". I got that shirt in Invercargill early last year. Coincidently, we were there on the weekend of the Burt Munro Challenge.
Regards,
Mark
@@Preso58 yes sir, I meet Carol Shelbly before he passed even tho I'm a chevy guy (holden for you down under) he was a car nut worse than me. I was humbled but he told me things about a ford and a chevy v8 . crap I aint but 40 but that man is a god
Dear Mark
I have been thinking witch is dangerous !
Are the two tapers ring like precision gauge blocks . Do the two tapered faces have a laped like finish ?
Bead blasting one of the tapers might solve the problem .
Have no idea if this would work ( thinking this my problem )
Christopher, I have only one accessory that ejects from the spindle and all the others get stuck. They only need a slight tap to get them out but so far the power drawbar just rides up instead of pushing the tool out. The taper inside the spindle could be gummy or it may have nicks and burrs in it. I still need to tilt the head over so I can get a good look in there. In the meantime I have redesigned some parts of the assembly to keep the impact wrench locked in the down position so it will push the tools out. One thing I was very keen to do was to keep the design as simple as possible. I think the extra parts I need to fit are not too difficult to do and it should still be quick and easy to operate. There will now be a fourth video in this series which will hopefully show the more successful version.
Regards,
Mark
Great video. What CAD software did you use to make the visuals?
I use Autodesk inventor for most of my CAD. I also use Fusion360 occasionally. Both have the capability of creating animations and presentations but that's for the pro's. What I did for that video was to just export jpg's as still shots and then edit it together in my video editing software.
Regards,
Mark
Hey Mark,
that's good stuff. Are you perhaps planing something similar for your CNC mill - or maybe even planing on going with an ATC for that one?
BTW., there seems to be very little beyond those 2 initial videos on your cnc mill on your channel (I think those were the ones how I initially found your channel);
has there been anything else you've done with it since then or maybe even the initial mod/upgrade process documented somewhere.
- I happen to have a similar mill myself (a later version with a BL motor) and have been having some ideas for it for quite a while now - mainly involving the z-axis stiffening and addinf cnc controls .. maybe throw in some scraping and other adjustments while at it.
I've seen the outside z-axis spindle mod done on a cnc converted mill that was sold in Japan, but, unfortunately, without much more info beyond that.
I have not really done a lot more with the little mill. I did convert a small 4" rotary table to turn it into a 4th axis but I didn't do a video on that. I have done a few videos on drag engraving and using the 4th axis but other than that it is mostly used as a sort of accurate drilling tool. I have always been disappointed at the lack of rigidity and this seems to limit the amount of serious milling you can do on it, especially on steel. Maybe one day I will upgrade to something that can handle deeper cuts.
Regards,
Mark
I had to chuck my butterfly wrench up in the
Lathe to true up the part that gets inserted
into the mount, it’s just cast and was quite a
bit out of round.
Mine wasn't too bad. It does have a few little discrepancies here and there but so far it seems to be holding up to the torque quite well. I think I will be either adding a key or a second set screw before I powder coat everything.
Regards,
Mark
@@Preso58 I used 3 set screws on mine.
So you dont trust a precision DRO and how accurate it is....but a few minutes later you do trust a wiggler and your eyesight to accurately find a center ??? :) :) Happy new year !
I know it seems counterintuitive but I got there in the end! 😁
Regards,
Mark
I would not trust iGaging scales with with 0.0015/inch accuracy to align these holes either.
With this technique the alignment is very close to perfect.
@@rok1475 LOL
Nice work. I'd like to build one, but my R8 taper sticks all the time, not sure how to overcome that with this design.
My R8's stick also. I made a captured drawbar so that it can force the R8 down, and it has worked great.
And yet, according to Wikipedia, the R8 taper is supposed to be self releasing. I am still investigating what is causing the sticking issue. Hopefully I'll have some conclusions for the next video.
Regards,
Mark
I miss the "Animal Planet" intro. Looking forward to the next episode.
Why did you just not bolt them together for the boring operation? Also, why not over bore the top plate and let the sliding bearings be the index, if they are secure to the top plate then the 4 bolts on each should accurately position the uprights.?
Like any of these prototypes, there are lots of ways to get the same result. Just about everything I make is a stage one prototype. That means that if you were to do it over again you would probably streamline the production and make upgrades to the assembly. At the end of the day there are some lessons learned and compromises in the approach but the video series was intended to be a narrative on making a prototype rather than a "how to" or tutorial type of video. A while back I made a video on a demagnetising tool I made for the shop. ruclips.net/video/bKNigMT0qq4/видео.html The first one worked but it wasn't exactly much to look at. I did a second one and I was able to adopt all the lessons learned from the first one. ruclips.net/video/Ew4BwYTzCe8/видео.html
Regards,
Mark
Mark Hi, your video is very timely. I am about to embark on the same project with my Bridgeport. So question for you, I am a fellow Aussie and is there any chance of purchasing a set of the aluminium castings from you ?
Charles, unfortunately, I don't normally do castings to order but I will be making the drawings for the build available at no charge when the next video comes out. To be perfectly honest, you could make the entire build with fabricated parts by welding or just substituting plate stock for the castings. If you know someone who has a home foundry I could send you the STL files for the patterns. I just used castings because I enjoy the foundry work and it looks a bit different than some of the similar builds which have been CNC machined or fabricated.
Regards,
Mark
@@Preso58 No problem Mark. Looking forward to the drawings. I will do as you suggest & fabricate the parts.
Welcome to 2021.
Oosps
🤣
What's with this quarter inch business? I thought Aussie was metric...
Aussie is metric, Bridgeport is not.
Johann, I am old enough to have worked with both imperial and metric systems and personally, I cannot understand why the whole world hasn't gone metric. In my view it is both logical and simple but Bridgeport = USA so I have to keep a supply of imperial fasteners on hand for mounting accessories. Sad but true!
Regards,
Preso
@@Preso58 Thanks, Preso. I have the same problem with a Harley. Have to keep a whole imperial toolkit on the side just for that. All the best!
Awesome 😍💋 💝💖♥️❤️