RANT: 5C Collets Chuck, D1-4 Cam-Lock

I also agree with Ray, I stay away from direct mount chucks. My primary use chuck is a Bison Set-Tru so no worries there & my 3 jaw chuck is plain back with a backplate which I use as a "tap-tru". The only exception is my 4-jaw chuck that is a direct mount but of course it doesn't matter on an independent 4-jaw. I opted for the direct mount on the 4-jaw to reduce overhang & transport weight.

I'm a strong believer when it comes to items that mean the most, such as accuracy in chucks, I don't cheap out on them & buy quality. Generally even the expensive high quality chucks don't guarantee very low runout like on scroll chucks so I can't imagine most direct mount chucks to give lower than .002" TIR unless your lucky. Not sure about the TIR claims are on no adjustable collet chucks as I have never looked but I never trust the TIR claims on a Chinese import chuck. You get what you pay for in this case.

Hopefully you can fix yours as planned & if you do please share.
 
This is the only and last direct mount chuck that I'll ever own. It's not a big deal to grind the bore, it's just irritating to have to do it.:angry:
 
Oh my, I ordered that with my new lathe! I reckon I'll find out soon enough. I hope you guys have a fix for it. Then again I could get lucky.











Thanks for the heads up.
Bob
 
rc63 said:
Oh my, I ordered that with my new lathe! I reckon I'll find out soon enough. I hope you guys have a fix for it. Then again I could get lucky.

Thanks for the heads up.
Bob
Click to expand...

I would not worry too much about what you ordered. This rant is only about one particular brand of chuck, and is not meant to indite all of the collet chucks of the general style. There are some very good ones out there, I just went really cheap and I knew better.
 
Point taken Jim. Although I never thought about checking TRO in the first place. Now I know. Working with cnc machines, Things like that never dawn
us button pushers. Last time I turned cranks was over 20 yrs ago. Then I was put on cnc's. Been that way ever since. Always wanted to do manual ever since as well. At 50 i finally have the chance to build my own home shop and continue where I left off those 20 yrs ago.









Bob
 
This is a timely discussion for me. I'm working up to making a 5C chuck for my Storebro lathe. Your comments will help me in the design process.
 
I have Pratt Burned D1-3 direct mount 3 jaw and also a direct mount 4 jaw and both have virtually no run out (measuring from the bore). These were their top-o-the-line chucks in the day rated for 3000 rpm - quite impressive since they are from the 60's. I think if you spend the money then you get the quality. This is the biggest reason I don't go Chinese on anything that can't easily be fixed or trued up.

Paul.
 
ULMA DOCTOR, I have a South Bend with the same thread and bought one of the mentioned collet closers. It would not repeat and I made the backing plate and it was machined in place. I bored out the spindle nose and it did make it better but not perfect. THEN I found out the inside was full of small chips and never was cleaned out after machining leading the plate that the collet screws into to be crooked. Accuracy is about .001-.0015 about 1" out. Not stellar but works.
 
BTW: When you're checking the RO on a 5C-type chuck, reading off the body or nose is not a useful measurement. Reading off the inner taper and concentricity thereof is what's important for it to run true. Same goes for Jacobs type chucks. -Don't even waste your time reading off the body... For those, mount a known shaft and read 1" from the nose.

Once a 5C chuck has been centered on it's backplate so that readings from the inner tapered cone are true, then you can check with straight shafts. If you have a known shaft placed in a 5C chuck and if the readings off the shaft get out of whack as you read further down the shaft then, you need to make corrections somewhere in the backplate interface. A skim pass on the backplate or the back of the chuck itself will usually clear that up. Sometimes, surface grinding the back of the chuck is effective. Each time the backplate is adjusted, the chuck must be recentered on the backplate before you check shaft linearity again.

FWIW, I don't have high-dollar chucks -and all my chucks are reliable and very well behaved. A friend brought me 3 chucks that he was convinced were junk. The weren't worn-out at all. I re-fitted all of them (and balanced them too) and he was blown away they could be "salvaged". -No salvaging was necessary; only proper fitting and adjustment.


Ray
 
Excellent thread top to bottom!

What are your thoughts on used equipment of this type?

Certainly harder to find but perhaps the chances of getting a really good unit used is as good as the chances you take buying brand new.

Industry generally seems to buy high quality stuff because they can't afford to go cheap. A lot of this stuff hits the open market eventually. Some of it may be utterly worn out but plenty still have a lifetime of hobbyist use in them.


To me it would seem that buying a half used up Hardinge chuck would be a better route than playing Chinese roulette. Even for more money.


Maybe not, but that's my thinking anyway.


Jim, I too hope Chinese QA permeates their military industrial complex and I chuckled when I read what you wrote.


Why do you make so much sense all the time Ray??? Great stuff!


Great thread everyone.
 
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