Source for good quality 4" 3-jaw chuck (import)

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crazybrit

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Can anyone recommend a source for a decent quality 4" 3-jaw self-centering (scroll) chuck that is ideally around $100.

I'll be mating it to a 4 inch 2-1/4"/8 threaded backplate adapter that I already have.

The chuck that originally came with the lathe as new was a 4" Bison but it was missing on mine and a new Bison would be 2x what I paid for the lathe. I'm reluctant to buy used off eBay due to wear issues. No luck looking locally on CL.

I've had to return one Chinese chuck already, the machining on the jaws was awful.

I've had fairly good luck with Shars in the past and the description on this sounds encouraging

www.shars.com

4" 3 jaw Self Centering Scroll Lathe Chucks Solid Jaws

www.shars.com www.shars.com

  • Each chuck has gone through rigorous accuracy and repeatability inspection by clamping and jamming multiple random testing rods or rings
  • Accuracy is maintained for the entire clamping range
  • A serialized set of jaws are then finished, ground, and lapped on their designated chuck body which will be the same chuck body on the final assembly to achieve a greater accuracy
  • Before assembling the jaws to its designated chuck body, the jaws finish machining is performed on a close tolerance state of the art CNC machine from Japan
 
3 jaw chucks are not inherently accurate, if you can get one in the sub .003" range you are doing pretty good
you may wish to look at good used chucks, before buying new- just for giggles

you can make a poor mans set true, by slightly enlarging the mounting bolt holes in the backplate and truing the chuck to the backplate, while indicating on a suitable standard held within the chuck jaws.
once you hit desired/best runout simply lock the backing plate bolts down and you will get the best runout possible with the intended chuck.
don't expect sub tenths of runout with a 3 jaw, and you'll be a lot happier :grin:
 
Ulma Doctor said:
3 jaw chucks are not inherently accurate, if you can get one in the sub .003" range you are doing pretty good
Click to expand...

I understand all this.

The general advice I've read is new is better than used unless you can fully evaluate used.

The Shars is spec's at .003, now whether production QA meets this is an open question.
 
Ulma Doctor said:
you can make a poor mans set true, by slightly enlarging the mounting bolt holes in the backplate and truing the chuck to the backplate, while indicating on a suitable standard held within the chuck jaws.
once you hit desired/best runout simply lock the backing plate bolts down and you will get the best runout possible with the intended chuck.
Click to expand...

What the Doc said is absolutely true . It's a simple process to true in a not so perfect chuck . No-one on here can speculate what a buyer WILL get out of any imported chuck regardless of their specs , so if you're looking on a budget go with the Shars .
 
crazybrit said:
I simply asked if anyone had a specific suggestion on a supplier. Clearly you don't. Got it.
Click to expand...

Dude, the Doc gave you sound advice, as did mmcldl. A 3 jaw scroll chuck is a first operations device and anything you turn in it the first time will be on the dead centerline of the spindle, regardless of the degree of run out. As long as you don't take it out of the chuck the work will be accurate. If you try to turn an already turned piece in a 3 jaw chuck for a second operation it will run out, period, and it doesn't matter if it is a cheap chuck or an expensive one. It is possible to center that turned work piece by knocking the chuck into alignment on its backplate as Doc told you or you can spend big bucks for an adjust-tru chuck.

I suggest you leave your snarkiness at the door.
 
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I agree with the given advice. If you want an accurate 4" three jaw chuck for 2nd ops try to find this little guy used. It is amazing, but new it will cost you about $1k.

I have looked high and low for cheaper versions with no success.

W8KDRfW.jpg
 
I buy a lot from Shars and have been quite happy with their quality. Seems to be a step above other import suppliers and 3 steps above eBay import tools. I wouldn't hesitate to buy from them for a lathe chuck. That being said don't expect the quality of a Buck chuck. If something is wrong, they'll stand behind their products and make it right.

Plan on truing up the backplate when you install the chuck. This will definitely help your runout.
 
If you are looking for a cheap chuck, you will get what you pay for. Even if you have a low TIR at one point, the scroll consistency across the clamping range and grind of the jaws will most likely be poor at the price point you are looking at. If it is an inexpensive lathe, then most likely you will be limited by many other factors that will effect the accuracy of the cut. I would agree that Shar's tends to have a bit better quality products these days then the generic Chinese chucks/products for sale. You will want to do a skim cut on the back plate and mount the chuck. If it is out few thousandth, you can cut the register by a few thousandth an lightly tap the chuck to adjust the TIR and then fully tighten the mounting bolts. Chances are at this price range the TIR will vary with the position of the jaws, so the results may be a mixed bag at the end of the day.

Unless you are dealing with something like a 7x14 lathe, you may be able to go to a 5" 3J scroll which is better built. Shar's carries a better quality "CS chuck" line which is not that much more with 2 piece jaws and a claimed TIR of 0.00012" or better for their 5". Overall a much nicer built chuck, the 5" runs $220 which is inexpensive in comparison to say a Bison. Otherwise you can hunt eBay for a name brand NOS 4-5" and see what shows up.
www.shars.com

CS53 5" 3 Jaw Cast Steel Self Centering Scroll Lathe Chuck

www.shars.com www.shars.com
 
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