188 1 Pinion VS 3 Pinions on a 6 Jaw Chuck
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- Опубликовано: 10 фев 2025
- 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.
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I'd be curious to see two more tests. #1. If you use all three pinions and dial it in with the set-tru, do you get the same repeatability?
#2. Dial it in using the master pinion, then check the runout using each of the other pinions (Still only one pinions, just not the master)
You got it. Great suggestions!
There’s no real “master”. It’s just labeled so,that you know which is which, so that you can use the same one each time. It shouldn’t matter which one that is.
If you walk the pinions and then zero using the set-tru, is walking the pinions repeatable and the single pinion tighten off by the 1.2 thou?
So, is the problem that for repeatability you need to always use the same method rather than mix methods? Or is the single pinion method always better?
My thoughts, exactly.. Sitting here watching and talking to the computer the whole time. LOL.
Ditto. Please test after setting the set-tru with 3 pinion
Was wondering the same thing. Do you get a better run out if you use the same method that you adjusted the set thru with.
I will definitely have to investigate this. Look for a follow up video. You guy made some really excellent points.
This is basically true but you can never expect as good results with the 3 pinion method. Unless you make sure to go with the same pinion last every time, then it might be close
Mind blown, I would have vehemently agreed with you prior to this. Thank you as always, I live vicariously through you some days.
Thanks. I feel much the same way with a bunch of other RUclipsrs.
I have a small bench top lathe with a Buck 4 inch 6 jaw AjustTru chuck with a single pinion (yes, the chuck cost more than the lathe). It is repeatable to about 0.0004" from 1/8" to 3/4" diameter (3/4" is the largest precision ground piece I have). I've often wondered if Buck chose a single pinion design for cost or because that produces greater repeatability. I think I now know - it's a better design.
Perhaps, I have the same style Buck Adjust-a-Tru, 5" size, made in USA, purchased brand new about 20 years ago. The chuck has only one pinion. The chuck may be adjusted to run true on any given diameter of (truly round) round stock within less than 0.0005" and it will repeat that level of accuracy on any same diameter rod. This is close enough for my class of work. However, the chuck has NEVER repeated on different sizes of round stock. That is to say if I change diameters I have to re-true the setting.
I entered into a lengthy discussion about this on the Practical Machinist Forum and the consensus was it is the scroll. I discussed this with Buck and they told me that they do not make many manual chucks anymore and they could care less. Seeing Shars tool respond here is refreshing.
The chuck jaws will grab and dig if tightened fully. I have never used any form of cheater or augmentation, must be uneven force from scroll. I just have to be extremely diligent. I'm afraid that the serrations on Dudley's chuck will scar up any material other than heat treated steel or carbide.
I have wondered that same thing. I am working on a follow up video, looking into the suggestions that people have put forward. I think you might be surprised at the results.
Robert, if you look at your Bison, there is a registration mark on the lead pinion "0". Tighten this pinion first and you should have better success and accuracy when clamping. In fact you may want to use this pinion only in your next test
Actually the correct terminology is Master Pinion
This is the comment I was looking for. I wonder what makes the master pinion the master? Are the jaws ground at factory? I always mark the pinion after cutting or grinding jaws and try to use it only.
Thanks for the info. It now makes me wonder if I was completely wrong being discouraged when the Shars 6-jaw chuck only had a single pinion. It seems like your chuck had all of the necessary parts. By the way, the resale on your chuck was excellent, but I could have saved a lot of money and not bought a different chuck. I really thought that 3 pinions would be a huge improvement in gripping strength.
Nice to see Shars here, kudos for the product support “out in the wild” 👍
My first reaction was how envious I am of the triple-rack of tool holders (and the tools in them) in the background 😁
The tool holders are the result of reinvesting years of meager RUclips earnings into fairly inexpensive holder. I noticed recently that the prices have gone way up. Apparently, it was too good to last.
Very interesting test! Thanks, Robert 😁. From what I understand, the nominating or "0" pinion is the last pinon tightened when the jaws were ground at the factory. The 40+ year machinist at work has it labeled on his giant 3-jaw for repeatability 😊.
Very interesting, thanks!! I have a follow up video coming very soon.
How fascinating! Thanks so much for doing this video. This is what I really live for, when you find old manuals that seem to imply modern SOP is wrong. I've been stuck on the fact that all of the most basic lathe manuals teach one to face from the center out and to generally do turning operations in the direction of the tail stock. I was always taught to do as you described, walk my way along the chuck tightening each opinion. A part that I was particularly nervous about, I might do more than one circuit! But it's hard to think of a more authoritative source then Buck Chuck themselves. I only have Coleman's, but I'm going to replicate this test myself. I think it would be great if we could get people with a significant number of Chuck models to test this; more data makes for better conclusions. I'm excited.
I am excited as well and will have to do a follow up video to test the ton of suggestions I have gotten from the comments.
That was very interesting Robert , I always taught to tighten a Jacob's style Chuck in the drill press on the three positions wander if this would have the same effect ? Could use brake cleaner on the Chuck jaws .
You often mention your work place it seems to be a very interesting establishment is it possible to do a
workshop tour .
Christopher from Down Under
Thanks. It might be difficult to give a tour of the Studios I work in. There is a strict "No Photos" policy, but I can ask. I would also have to ask each production for permission to shoot any of their sets.
Just like with everything in a machine shop, consistency is the key to repeatability. Either use 1 pinion all the time, or use 3 pinions all the time. Curious: if you tighten with all 3 pinions, then dial in the chuck to read zero, then run the same experiment. Will the 3 pinion method repeat as well as the 1 pinion method?
My 3 jaw only has 1 pinion and it repeats within .0002" consistently.
Thanks for the suggestion. I have just tested your suggestion and the results will be out shortly.
Interesting results there.
Thanks, Tom. It seems that there are so many suggestions that I am going to have to do a follow up video to investigate them.
@@DudleyToolwright Looking forward to it. Curious minds want to know.
Interesting video.
Just adapted a 5" 3 jaw chuck to my standard 4" mini lathe. Then the protective guard had to be removed and the protection against starting the lathe having the chuck key sitting in the chuck is lost....
Why tampering with the chuck centering feature? (I loosen the 3 bolts and use a knocker for centering.)
Sorry to be picking on You but You surely see the reason at time 04:40...
Confusing result, really.
Chuck things up, measure and start turning....
You are definitely not picking on me. I am always open to constructive criticism. I am only interested in the truth, my ego can take it.
@@DudleyToolwright Thanks. You've launched so many interesting videos and it's very seldom I feel any reson for criticism. Several skilled Tubers now and the receives "remarks"....
Having access to and using in the past, 2 Adam Booth sized lathes I did the mistake of starting the lathe with the chuck key in the chuck. The lathe started very slowly so the chuck fell down in the tray. Then the words from the metall works teacher started ringing in my ears. He showed us the marks in the wall 30 feet away, from a flying chuck key. Having no routine I really have to use discipline....
Hey this suprised me to. You are definitely correct about the commenters.
Yep, they are the best. They have given me a bunch of great suggestions for further investigations.
Great information. I wouldn’t have guessed. Thanks much. Cheers, Will
Thanks. It seems counterintuitive.
@@DudleyToolwright I agree and I’m so glad you “put it to the test.”
And there will usually one pinion better than the other two
usually it's marked as the master pinion
I will test this as well. Thanks for the suggestion.
fascinating I would not have believed it had you not done your tests. It would have to be a devotion in the pinion to the ring gear that causing it to bind up inside
I was surprised as well.
There is always some clearance between moving parts. If you use ONE pinion you will always come back to the same spot. If you move all three pinions, you will have no idea where you will end up. This is also true on a three jaw chuck. Always use the same pinion EVERY time. Adjust for that pinion. If you change diameter of the part, you should reset your true. This especially important as the chuck gets older as the scroll and the jaws wear. Three jaw chucks SEEM to lose their true faster over time than a six jaw. I do not do any accurate work with a three jaw because I can't trust them to repeat as they get worn.
Excellent tips, thanks.
What dial indicator mount are you using on your tool rest?
That is a home made one. I have a pair of video on what I did there:
ruclips.net/video/0YtSy4pNW3Q/видео.html
ruclips.net/video/QkZcGkyC668/видео.html
You can also buy one factory made these days.
My adjustable Buck chuck is the same. Repeatedly is spot on. But also my chuck only has one pinion. I think chucks with 3 or so pinions are there to use the one facing you, so your not spinning it looking for the pinion.
Interesting. I am really starting to wonder. You might have a really good point.
Perhaps all 3 pinions are for loosening the chuck, but only one for tightening.
I agree that it seems counterintuitive. Of course, the quality of the chuck matters. It’s interesting that Buck, and others, make chucks with one pinion, two, or three. Some of the most accurate chucks come with two, or even one. Buck points out that you should always use one pinion - the same one each time, for greatest accuracy, and both for greater tightening.
I would think that for cheaper chucks, the fewer the pinions, the lower the price. But my 8” Buck was pretty damn expensive, even the adjust tru back was over $500. So I don’t think Buck did two to save money. These chucks, the Buck or Bison, plus Rolm and others have highly accurately ground parts that fit precisely. But the jaws themselves are looser, or they would jam.
One thing to mention is that good scroll chucks need to be greased with a high quality chuck grease. I use Chuck-EZ, which used to be made by Kitigowa. This and the one from Rolm, are heavily moly’d greases. Cheap scroll chucks are usually oiled, which is a bad idea. People don’t get what’s going on inside a chuck. Oiling one will damage it after some time as the oil ends up on the inside rim of the casting from centripetal force. Then when it stops, the oil drips to the downwards side of the chuck. When you tighten, or loosen it, it’s dry, and some of the oil will leak out through the pinion on the bottom. That’s one reason some chucks wear so quickly. If the chuck is used properly, chips will never get inside.
Wonderful tips, thanks. I have been greasing my chucks with Moly grease, but it came oiled. I have a follow up video with more surprising results.
i wonder if you only use 1 pinion but not the original will it be off or maintain its accuracy
Excellent suggestion. I am going to test that.
Very interesting 👍👍😎👍👍
Thanks for the visit
I’m not experienced/knowledgeable enough to offer an explanation or even comment 🥴, but very cool.
I don't have one either at this point.
Thanks for sharing 👍
Thank you too
a car wheel has individual nuts, a chuck has one scroll being turned no matter from which pinion. good question though.
Thanks for the info. I was specifically wondering why some chucks have one pinion and others have three. Coincidence, convenience, or are three better. but more expensive?
@@DudleyToolwright the strange thing is that many 3 jaw chucks with 3 pinions, including mine have one of the 3 that are better for concentricity than the other 2. mine is even marked thus with no marks at the other 2. I have discussed this with guys on machining websites and many have found the same to be true.
Your scroll is shifting little inside…when you thight in different spots he shift little and you lose repetability…
Interesting explanation. Thanks for sharing your insights.
Well that shows that you need to trust in proof not blind faith in what you assume to be an obvious assumption. You just did a Science.
Thanks. It makes me wonder about other assumptions I have.
Who wooda thought!
Definitely not me.
you did set your chuck on zero with the 1 pignon method, if you set your chuck on zero with the 3 pignon method, you wil have (i think) the best result with the 3 pignon method and the 1 pignon method will be worse then. (i think) :-)
I'm going to test that. Excellent sugestion.
@@DudleyToolwright am really curious, let us know the result (if you want).
greetings from the netherlands, ben.
Great video, I was wondering if you have a link to the carbide blank that you used. I have some experimentation that I would like to conduct and the carbide that you where using would be a great addition to my setup.
Thanks,
Craig.
I don't remember exactly where I got the blank, but here is what I used:
allindustrial.com/micro-100-sr-500-6-1-2-diameter-x-6-length-round-solid-carbide-blank/
@@DudleyToolwright Thank you so much!