Ball Adapters for My Lathes Live Centers
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- Опубликовано: 18 сен 2024
- This project was supposed to be quick, but was far from it and was about creating ball center adapters for my live centers as addressed in my video, "A Problem in Workholding"
Please Note: I am a beginning machinist and I do not pretend to know everything. Please always operate machinery in a safe manner and if you don't know, find a reliable source. DO NOT COPY ME. I make a lot of mistakes. I provide these videos for entertainment only.
Thank you for showing the whole process and including the theory, really good job.
You welcome. Thanks for watching.
Thank you for showing us how to put these things together. I think I will try to use "TIG" instead of a torch.
That might work out really well. Great idea.
Rather than saying "tangent to the minus 1 power" it is more correct to say "inverse tangent" or "arctangent" (my preference). Very informative video. May try it with brass wire or fluxless aluminum "solder" instead of silver solder.
Thanks. I made this video quite awhile back and am surprised that I said tangent^-1, I would normally say arc tangent.
I turned some 4130 a couple of years ago for stand-offs for a rotisserie to rotate my airplane fuselage. I got a terrible finish no matter what I tried. Finally dug out some old high sulpher cutting oil my dad got 50 years ago to thread water pipe. The 4130 cut like butter and I got a beautiful finish. I was using an old wore out 6 inch Craftsman 109 lathe, so size doesn't matter.
That's really interesting. I don't have an sulphured cutting oil, but will have to try that. I have found that a high feed (0.009"/rev+) rate combined with moderate depth of cut (0.025"+) can yield good results if the machine can handle it. Thanks for the hint.
My situation was a whole lot different than yours. I'm even more of a novice than you claim to be and I was using a old 6" Craftsman 109 lathe. Slow rpm, low power, manual feed, and 6" of stick out in a 4" 3 jaw chuck. I was trimming to length so no tail stock support and no steady rest, and the spindle id is 1/4" so all the stock was sticking out the chuck. I was using a hhs cutter. I reground the tool different shapes, tried different cutting fluids and finally dug out the old can of high sulpher oil. It worked like magic. It was on old can I inherited from my dad. He got it about 50 years ago to thread pipe. Unfortunately that was the last of that oil, I had to squeeze the can to get enough to finish the job and I haven't been able to find anything to replace it with. Kind of limited here as to what's available and anything haz-mat is impossible to get shipped. I've used tap-magic, hydrolic oil, mineral oil and water soluble cutting oil on other steel with good luck, but the high sulpher was the trick on the chrome moly.
Another nice video my friend! I was all set to give you some silver soldering tips and you figured it out on your own. Great job! I will give you a couple small tips, though. First I felt that the torch tip was large for the job because the force of the burning gas blew the ball off the tip. When I solder I turn down the pressure and use a small tip. I get the heat I need and the carbide or smaller material doesn't move. You gave yourself quite a soldering challange by making such a small radius for the ball to fit in. Commonly the radius you make is just shy of the ball's dia. This allows you to make a heavier cut without the fear of dislodging the ball. I really like your approach and narratives. Check your Machinist Handbook for the recomended SFM for that material. I think it likes a small radius tool, a positive rake tool, and higher RPM. Keep those videos comming! Great job!
I'll happily take all of the tips you care to offer. I really appreciate you taking the time to share your knowledge. I didn't show my first attempts, because I didn't want to deal with getting the camera in there while I was trying to figure things out. In my first attempt I coated both pieces with flux, assembled them and heated the whole thing. When the parts were glowing red, I tried to feed the silver solder, like you would when soldering copper pipe, but it just balled up and fell off. I made several attempts, but they were a miserable failure. I only tried the solder piece solution, because I had seen someone else do that for carbide brazing. I used the large torch tip, because I was concerned with having to spend too much time heating the part and losing the flux protection. I guessed poorly. I considered making a deeper hole for the ball to mount in, but was trying to have as much back relief as I could manage. If they solder joints end up being too weak, I will go there next. I will make sure to turn the parts at a slow rpm to start. Catastrophic failure could be ugly. Thanks for all of your help and support.
Flat bottom drills make the rocking world go round:)
Cheers.
soldering: put a very small amout of the flux in the ball seat. like 1/2 what will fit on an end of a regular pencil or less. the silver will stick where ever you put the flux. just a small amount. put the heat protector gell on the tapered part first. then put 1/2 ereassorful of flux in the seat. then put the ball on. then heat with downward aim of torch so ball dosent blow off. When the ball and seat are glowing enough to melt the solder, touch a small solder rod to the joint. the solder will be sucked into the joint where
the flux was.
Thanks for the really thorough tips and explanation. Very helpful. As you can tell I don't have a ton of experience in brazing.
The Y (opposite) value is prone to error when it register off the horizontal plane crossing Z (spindle) axis.
To sanity check : use (1) a straight edge and (2) a 20-degree angle wafer in between cone and straight edge.
Useful advise. Thanks.
A bit late to the party but I would have placed the tail stock in the head stcok and dialed it in and then set an indicator on the top slide and found the angle by running a zero to zero over the length of the unknow angle, the same way that you would set up the top slide for cutting a machine taper. Lock the top slide and machine the part. Relying on DROs and DTIs is prone to error as these are very sensitive to being placed absolutely perpendicular to the parts that you are making the measurements from. Great set of videos BTW. Thanks.
You make so very interesting points. Thanks.
Hi Dudley,
In GH Thomas’s book “The Model Engineers Workshop Manual” he describes in detail the issues with contact angles on the centres when offset taper turning, he also described a centre drill that produces a radiused hole that when used with a regular 60 deg centre offers a lot more support for the work piece, it’s a good reference manual and worth having if you can get one.
Cheers
I have been looking for that book, as another commenter recommended the same book. I have found one in England. When I get the cash, I'll get the book. Thanks for the referral and suggestions.
I’ll have to review all the old books my father gave me 20 years ago. They are geared to the unimax 3000 watch maker lathe. I sure didn’t understand most things about turning 20year ago.
A tip on simple way to copy a taper on the lathe accurately if the angle does need to be known, is something like this:
Set a sensitive indicator close to the tool tip and adjust its height carefully on the smallest radius available.
Position the tip against the angle to be copied.
Move the top slide back and forth and knock it s angle in place until the indicator changes the least amount during movement.
At this point You can figure in wear etc and tweak for that to get accurate.
Then turn the part, it will be more accurate than using the DRO:s fancy functions. An important thing that is easy to forget is
that tool height influences the angle as much as the indicator height. They need to be very close.
Thanks. I really appreciate you taking the time to share some ideas. I always learn so much from the comments - good or bad.
Interesting math lesson, but do you even need to know what the angle is, just set the compound to match the angle (using an indicator against the center)
So obvious, yet I did not even think of that. Brilliant suggestion, thanks.
Interesting stuff - I just made a rather small tailstock offset - not overly happy with it but planning to make a ball center anyways - probably going to make up a boring head approach. Like your idea for the ball bearing addition - may well go that route... tricky getting ball in place while heating! :)
Your lathe is super quiet - mine is noisy!
Just a suggestion: Don't make the tip anywhere near as tapered as I did. It turned out to not be strong enough and the part wobbled by 0.004-0.006". My lathe is a really nice tool. It certainly performs a lot better than I do. Let me know how your taper turns out. Cheers.
Hello, I was gritting my teeth for you on that silver soldering job!! The torch tip was just too big to do that without blowing the ball around. You were getting into the size for a jeweler's tip. Always like how you show your mind working while building. Take care. Doug
You make a good point. I was worried that the moderately large mass of steel would take too long to heat, and that, even with the flux, I would get some bad oxidation. In at least one case, I used the force of the flame and probably surface tension, to push/pull the ball into place. The biggest problem I had, was the flux. It was really sticky at first, then got hard, and finally melted and got sticky again. Clearly, more experience would have helped me. Thanks for taking the time to comment.
As a 35+ yr bookmaker I have another solution for you. Square up the tool post to the Chuck then measure the Ashleigh your vernier protractor off of the tool post to the desired angle. Easier and faster. I can do the math and have no problems doing it but some people might. As for the ball center us "old guys" were makeing those years ago simply by ball end milling a pocket in an insert for our live centers and silver soldering a ball bearing in it then Machineing the clearance on it afterwards and then put it to work
There is no substitute for experience. I rarely think of the post machining solution. After I read your post I thought, duh! It seemed like such an obvious solution not. Thanks. I liked your angle finding solution as well. I appreciate you taking the time to share your perspective.
Flat bottom drills are good for finishing holes, but I would not recommend trying to start a hole with one. The combination of no conical point to guide the start, and the flexibility of ordinary twist drills, made my first attempts using them into a painful lesson.
These days I counterbore with an endmill or boring bar whenever possible.
I wonder if it would be harder or easier to braze a carbide ball?
Did you test how concentric the balls ended up being, relative to the taper? I would not trust the soldering process to seat the ball evenly in the round socket.
You know they make Bell hole center drills for offset tailstock taper turning
Excellent point and because of the cutter relief, end mills don't really make flat bottomed holed either.
I think I have seen someone drill a ball bearing and insert a hardened pin. Then you could use appropriate grade of locktite to attach the pin. If it works you might be able to prepare several different sized balls with the same-sized pin if need be. I hope you were using borrowed pliers to hold the balls, LOL. Success would depend on how well the drill bits cut ball bearings. You might even be able to dispense with the live center and mount the pin & ball assy in a stationary drill chuck or whatever. Thanks for the excellent lesson!
I love your approach. Thanks for sharing a great idea. The ball bearings I was using were stainless, not chrome plated, so perhaps they would drill without too much of an issue. I should look into that.
Dudley Toolwright, The bearing-driller may have been Stefan Gotteswinter. If the chrome is a problem, you could grind a flat to drill on.
I saw a video, with some drilling into a ball shape. He chucked up a plumping compression fitting to hold the ball. He drill and tapped it but as small as yours ball is a pin would work.
It is fairly easy to drill ordinary steel ball bearing balls with a carbide drill. I was quite surprised at this the first time I tried it, they are at the upper HRC range of what these drills are made for. It is not the drilling that is the problem, but the centering. My trick is to grind a flat slightly smaller than the drill the ball to get the drill started. I held the balls in a C5 fixture. for both grinding and drilling. I would still solder or pressfit the ball though since these may get a little to hot for Loctite.
Hey dydley witch lathe do u got and are u happy with it. In the past did u make some sirous roughing cuts? Btw ur vids is great.
Thanks. I have this lathe:
acramachinery.com/product/1460te-precision-gap-bed-engine-lathe/.
I have taken large, for me, cuts before (0.300" diam. per pass .012"/rev) and it is a fantastic lathe.
The tip of your indicator you have on the live center should be parallel with the ways, and be dead on or extremely close to the center line of the lathe/ taper you are measuring. If it's even the slightest amount off center you will get an inaccurate reading. The same is true with cutting a taper. If your tool bit is not dead on center you will cut an incorrect taper. Just my opinion. Thanks for posting
Good observation. Thanks for the useful suggestion. I realized that the indicator needs to be perpendicular to the axis of the lathe, but I had not thought about the sensitivity of the measurement relative to where along the cone I was travelling. That was a really good observation. I was not overly careful about the height of the toolpost indicator. I think you might have found my mistake. Thanks!
Film thickness of the lube can theoretically make a significant change to the fit of the pin gage but not having pin gages I have never actually never checked. Should be a thou approximately depending on the viscosity.
Thanks for the tip. I had heard that this could be an issue, but have never measured it. Perhaps I should.
Hi! Your bar is perfect in dimensions for this job. Did you buy it for this project? It is obviously something you will enjoy, and it will last thousands of years if somebody else doesn’t dropp it or gives it a sharp shock of some sort. It really is top of the line. You have so much good gear.
I am not sure what bar you are talking about. I get a lot of my tools from EBay and sometimes get great deals from estate sales. I really do enjoy all of my tools. I am quite the addict. Every time I see a new tool, I can just imagine the possibilities. Thanks for the comments. They are appreciated.
Great video of the internal taper cuts! Just what I was thinking decorative, but functional, grooves. What type lube will you use on the ball when turning you tapers? Nice work overall but that one was darn near perfect! You ran them in the chuck to check concentricity, correct? You continue to display interesting projects. Love your work.
Thanks. Always appreciated.
Position your 20 degree angle blocks against that center taper and indicate along its opposite side. If angle is 20 degrees, indicator will show no change along the side. When setting compound angle, move toolpost center directly over compound pivot axis if possible.
Good to hear from you. I thought of that, but could not figure out how to get the angle block to stay in position for a measurement. Solution?
Dudley Toolwright I use a combination of supermagnets and masking tape.
Interesting approach. I never thought about adhesives. Thanks.
Good video. How about measuring the obtuse angle and subtracting 180?
Interesting approach. Thanks for the idea. I love that so many people out there are so willing to take the time to help others out. Cheers.
if you set up the flame so it comes from the top, the gas of the flame will help you with placing the ball i guess, if it comes from the side, it shoots away, at least that would be my theory on that.
maybe it would be also smarter to drill a small hole inside the ball cavity and fill it with solder, then dip everything in flux and assemble it before heating up, maybe the flux is strong enough to pull the solder up under the ball?
i never soldered myself but that are some ideas i just had watching this, maybe you can try some of it and it actually works :)
Thanks. I love suggestions and if one of them works, everyone wins. Thanks for taking the time.
It is really critical to get the radial indicator on center height, otherwise the indicator traces a hyperbolic curve rather the line you want. Now this is not the reason for your deviation because it will give you a reading of a higher angle than true rather than a lower, but it is worth noting.
If I wanted to duplicate a taper really accurately, I would set up the compound with an indicator and bump it until it indicates parallell, because even if you measure the taper really accurately, most compound protractor scales won't be accurate enough to really match an angle. Getting the indicator on center is still critical though.
Of course I made the comment on the protractor accuracy before I saw you angle block trick.... Nice trick.
Not a problem and thanks for the suggestions. I really appreciate you taking the time to share your ideas. everyone wins.
Hi, How do you ensure that you have no runout of the ball ?.
An excellent question that has been plaguing me and I don't have an answer at this time. I think the appropriate approach should have been to design some sort of fixture to hold the ball in place for soldering. Another approach is to turn the balls now to be concentric (it is a stainless steel ball bearing). Thanks for the great observation.
Yes, turning or grinding, a good old handmade thumbs up, All the best
Hi, I think I have found the perfect solution, If you look at Edge Presion (youtube name) Peter have the tools to grind you a carbide ball, I was thinking of something like a ball then a smaller diameter shank and then the diameter of the stock, theese you could use as a dead centers in both ends (I would avoid the live center for accuracy reasons) hope you get the ide otherwise I can send you a drawing of what I mean. Just remembered what looks like what I mean www.ebay.co.uk/itm/Edge-Finder-Electronic-Optical-Edge-Finder-with-LED-and-Beep-for-CNC-Lathe-I1N6/183181122574?epid=1787356172&hash=item2aa6721c0e:g:~b8AAOSwaZFa1Eed
👍👍👍
Thanks.
But, by your calculation it wasn’t a trigonometry problem, it was an assumption problem, and you know what happens when you assume, correct? You make an ASS out of U and end up with the two useless letters of “M” & “E”. LOL, You’re videos are awesome, and very informative, I’m glad I subscribed, great job.
Thanks and too true you are.
like your style - subbed
Very kind. Thanks.
Too kind and really appreciated.
Never seen anyone spend so much time and effort on such a simple job. I use two N02 MT soft shanks, centre dronn and silver solder ball bearings in,. I was NOT impressed wth him using a nice pair of pliers to try holding his ball in a flame. Go to the back of the class lad.
Fair enough, thanks for the tips!
you must take into account the slope angle, that we're the error lies, the answer is 20 degrees, son. stop. Anglais is always longer the line in a 90, then listen from the smaller baseline, was wet the distance went wrong.
Thanks.
all comes down to the mass and rigidity of machine. Abom does 4130 all day long with mirror finish but he is using old american made iron machines not imports
Adam is definitely a pro and does use huge machines at his place of work, but my machine is a very heavy 14" throw lathe. It is an ACRA Heavy 14 that weighs about 3500 pounds. As a matter of fact, Adam uses an ACRA at his job. Rigidity could be an issue for me, but I think it is more likely a feeds and speeds problem. Adam has a ton of experience, that I don't, so he probably knows the right setting for every insert and situation. Thanks for the input. I really appreciate the help.
At 6:35 you are not going to get the desired result. Here's why:
Theoretically if the tip of your plunger had been a true point, you'd get correct readings. But the tip is a round surface, perhaps 1/8" or larger (my Mitutoyo 2915 is 0.196"). Imagine magnifying the surfaces sufficiently to see how they actually contact. Regardless of whether the tip is round or tapered - actual condition of the tip when magnified sufficiently - the same kind of errors are inherent. I'll call them parallax until someone comes up with a better name.
Indicators are designed to intersect the surface to be measured solely perpendicular to the centerline of the plunger.
But no matter how you measure the slope with a round or tapered tip, you won't get a true reading because you are measuring relative to some unknown surface on the round tip - not along its true centerline/endpoint.
Solution, use your compound to move the indicator perpendicular to the sloping surface.
See the video by Joe Pie on the subject of cosine error:
ruclips.net/video/dsWSxpwCPUg/видео.html
Thanks. You are the second person to point out that my indicator was probably not following a line parallel to the axis of center. It seems so obvious in hind site. Thanks for taking the time to point out my silly mistake. I appreciate it.
I wonder if the rule or razor blade trick would be good enough to find the center?
I had the same issues with that material and was able to overcome them with the following inserts from MSC 67512756 & 67595777.
Thanks for the suggestions. I will check them out.
forgot to mention faster feed is needed, my lathe likes .009 IPR.
Excellent, thanks. I also have found that higher feed rates can sometimes improve surface finish.
Yes, .030 DOC, 1400 RPM, 010 IPR, does it for my lathe and .050 DOC not an issue.
why didn't you just press the balls in? you're relieving stresses heating the part like that, changing its geometry.
Excellent point. Brazing might have been a bad choice on many levels.
nice
thanks.
Like my father you complicate and take the long approach,,, I know a much simple way
Interesting. I would love to hear about a better approach. Thx.
center drill work piece (60 degrees) center drill ball (60 degrees) put drilled ball in work piece put live center in hole drilled in ball you will get full contact in work piece
Interesting approach. How hard is it to center drill a ball bearing? Do you use carbide? Thanks for the idea. Simple and elegant.
dudley i have not drilled a ball bearing, your video gave me the ball bearing idea because i have turned morse tapers with offset tail stock and i know i did not have full contact on live center, but I will give it a try thanx
No problem. I like the idea a lot and might just give it a try. Thanks again.
Waiting for that plastic bottle to melt, lol
I noticed when I was editing that the camera made the bottle look like it was really close. In truth it was not. It was also full of water. Good observation though and thanks.
Dudley Toolwright
Had a thought, why not put the bb down and have the heavier part on top. As the silver solder melts it will drop down but center the bb.
your indicator stay on centerline at times ,
Yea, a problem for sure.