Which chuck? Opinions requested

[hman]

As others have pointed out, a 4-jaw chuck can hold a workpiece as true/concentric as you have the patience to make it.
-BUT-
If the faces of the jaws are not parallel to the axis of rotation, the diameter of the workipece may only be true/concentric at the one particular distance out where you adjusted it. So if the jaws themselves are not "square with the world," it's definitely worthwhile to replace the chuck.

 

[Razzle]

It seems like the majority opinion is for a quality 3 jaw scroll chuck. That sounds reasonable. I will start looking at the choices mentioned so far. Thanks for the assist.

Sent from my Pixel 4a using Tapatalk

 

[Buffalo21]

I have 3 Bisons, 2 piece jaws, work well for me

 

[mikey]

So, I would suggest a 3 jaw from a good maker - Pratt Burnered International from England, Rohm from Germany, Yuasa from Japan, Samchully from Korea are all top shelf and there are others. Song from Japan and Bison are also good. The best chucks are forged steel, have published minimal run out numbers and the most accurate pinion will be marked.

@Razzle, I may be doing you a disservice by mentioning these chuck makers. I'm not lying; they are amongst the best chucks available but you best be sitting down when you look at new ones.

I think the most reasonable new ones are probably Bison chucks but if you can find a good example of the above chucks that is used but in good shape then that is probably the best route for a hobby guy to take. Good chucks last a long time when not abused, and I'm talking decades here, so if I was a hobby guy on a budget I would be looking at used chucks on eBay. I've noticed that even among high end chuck makers the global economy has led to them cutting corners - Rohm has had some issues of late and Pratt Burnerd America has some chucks made in China - so I prefer the older chucks anyway.

The question then becomes, "how do I find a decent chuck on eBay?" While there are no guarantees, there are some things to look for that will enhance your chances of finding a good one, in no particular order:

• Dirt, grease, chips and surface rust will clean up. Ignore this stuff. The chuck may look ugly as hell but if the bones are good then look deeper.
• Wear, contact damage will not clean up. Walk away. You can tell when a chuck is worn. Look really closely at the machining on each jaw; if it looks unused then it probably didn't see a lot of use. If the wear pattern is worse at the front of the jaws then it saw a lot of use and is possibly bell-mouthed; walk away. On a camlock chuck, look at the studs to see if there are signs of heavy use. Look at the openings of the pinions used to tighten the chuck; if they are pristine, that is a low mileage chuck.
• Many higher end chucks have two piece jaws held on by two socket head cap screws. These are nice because you can make soft jaws at need or buy replacements if you damage them. On the other hand, many high end chucks also use reversible jaws that are more expensive to machine with precision; Rohm does this a lot.
• Forged chucks will usually have an inscription denoting that somewhere on the chuck. If you don't see it, it is likely cast steel or semi-steel. The advantage of forged chucks is that they can handle much higher speeds and are typically balanced better; Rohm is particularly good about this. Forged chucks also tend to be made differently from cast chucks and reflect a higher end design. I have two Rohm chucks; one is cast, one is forged. Both are nicely made but the forged one is definitely of a higher quality and design.
• Look at the chuck register where it would meet your spindle register. It must be totally undamaged and show no signs of wear. If it does, don't buy it. If it is a plain back chuck and you have to mount it to a back plate then this is less of a concern.
• Make sure everything that should be there, is there. Many used chucks are sold without jaws or have screws missing. This will cost you to rectify; I would walk away from an incomplete chuck.
• If possible, make sure the chuck key comes with the chuck. Not a disaster if it doesn't but you'll have to find or make one to use the chuck; a nuisance.
• Look for obvious signs of damage. If the chuck was dropped on a concrete floor then it may show a bent edge. Unless it was an especially good deal, I avoid these. Sometimes a cast chuck can crack and that crack may not be visible in a photo so be careful here.
• Look for chucks that the seller is taking best offers for. Email him and ask what his rock bottom price would be. Quite often, this will get you a better deal than you might guess.

That's all I can think of off the top of my head. Good luck!

 

[talvare]

I have read through all of the replies here and there is some good advice. But, I went back and re-read your original post, and the way I'm interpreting your question is that you have two unsatisfactory chucks that you are attempting to replace with one good chuck. If that's the case and this new chuck is to be used as the only chuck for all of your needs, then I don't see a reasonable option other than a 4-jaw chuck. You simply can not do all of the work holding in a 3-jaw chuck that you can with a 4-jaw chuck. And, as has been mentioned here by others, it's unlikely that you will be able to achieve the same level of accuracy with a 3-jaw that you can with a 4-jaw. I have a 3-jaw, two 4-jaws and a 6-jaw chuck for my lathe and I have finally gotten to where the 8" 4-jaw is my go-to chuck. I have gotten to where I can dial in round stock to within .0005" with a couple of minutes. It just takes practice. Just my two cents.

Ted