Need help with Lathe chuck please.

[macardoso]

Great info guys! Thanks so much! Yeah I have been thinking about a 4 jaw independent. From what I've read, they are the way to go. That's actually what I have been looking for online, but none had the correct threading. So...an adapter plate, anything I should be looking for, to make sure the plate/chuck are comparable? And again, I am very thankful for you guys quick responses! This is my first time joining a forum, and it is great! Just forgive me, if I am not too savvy on technology. I'm just an old guy, with a phone smarter than himself.

Any adapter plate you buy will need a skim cut to true it up on your lathe. I would buy the chuck and the backplate from the same place so you know they match. Sometimes the hole patterns will be different when purchased from different locations.

What size chuck do you want?

 

[Nogoingback]

As others have mentioned, you'll need an adapter plate. Aftermarket chucks sold as "plain back" or flat back chucks are used
with adapter plates. You will need to machine the adapter on the lathe to ensure that the chuck fits properly in many cases, though
some companies may supply both the chuck and back plate together. An independent 4 jaw is a great way to start since they can
be adjusted accurately, and you can chuck up square stock as well as round. It just takes a bit more time to set up than a three
jaw, though as you gain experience, you'll get better at it.

Here are a couple of vids:

 

[benmychree]

A 3 jaw chuck is what I normally keep on my 19" Regal, it is a Buck Adjust Tru; it is nearly 30 years old now, and runs true enough for most work without adjustment, when I need something closer, I easily adjust it to run true. I only use the 4 jaw when I need it for large diameter work, or square or irregular work. You are correct in avoiding used chucks, they would be a "pig in a poke" and likely as worn as what you have.
Buying a flat back chuck and a semi finished backplate is the way to go if you cannot find one that is pre threaded for your lathe and likely if you bought a flat back and semi finished backplate, the end result would likely run truer than a pre finished one. I'd advise, get the 3 jaw first and the 4 jaw second, likely you will find that you will use the 3 jaw much more than the 4 jaw, as most people do. Speaking for myself, I'd avoid Chinese chucks, Taiwan OK and European even better; THERE IS A DIFFERENCE!

 

[SubtleHustle]

Any adapter plate you buy will need a skim cut to true it up on your lathe. I would buy the chuck and the backplate from the same place so you know they match. Sometimes the hole patterns will be different when purchased from different locations.

What size chuck do you want?

Looking for a 6" 4 jaw independent

 

[SubtleHustle]

As others have mentioned, you'll need an adapter plate. Aftermarket chucks sold as "plain back" or flat back chucks are used
with adapter plates. You will need to machine the adapter on the lathe to ensure that the chuck fits properly in many cases, though
some companies may supply both the chuck and back plate together. An independent 4 jaw is a great way to start since they can
be adjusted accurately, and you can chuck up square stock as well as round. It just takes a bit more time to set up than a three
jaw, though as you gain experience, you'll get better at it.

Here are a couple of vids:

Thanks for the video links, I'm sure they will help!

 

[macardoso]

Looking for a 6" 4 jaw independent

CDCO: Part numbers 26412 + 25454
Total price: $140 (you will need to drill and tap the mounting holes)

Shars: Part number 202-5431
Total Price: $130 (Ready to mount, currently out of stock, call them, they will give you a lead time, usually quick)

Small Tools doesn't have a 6" w/ 1.5-8

JTS Machinery: PartNumbers 0604F0 + 7-871-062
Total Price: $254 (That back plate costs more than the chuck )

 

[SubtleHustle]

You're awesome Macardoso! Thanks

 

[BaronJ]

If you think you need a new independent four chuck, then the one you have must be in a really bad way !

I would be interested in what is wrong with it.

 

[ericc]

Hi BaronJ. I think he has a bad 3 jaw chuck. When I bought my SB 9, it had no chuck. Somebody gave me a 4 jaw chuck with no back plate and a broken screw (missing threads). I fixed the screw with a TIG welder, and I made a back plate blacksmith style. It took a while, but once I had the back plate, I could attach the chuck and make a plug gauge, which I measured with three wires. That will allow me to make a real back plate. It would have been a lot simpler to just buy an import chuck and back plate for 1-1/2" x 8 spindle thread. Some assembly required: you will have to cut the register to fit. The fit doesn't matter so much with a 4 jaw chuck.

By the way, is there any way that one could salvage a three jaw chuck by bodging some soft jaws.? You would have to do this for each workpiece, but it would allow one to proceed without having to buy a new chuck.

 

[hman]

Regarding backplates and their preparation -
All a backplate really has to fit is the OD of the chuck and the thread pattern of the spindle. When you get the backplate, you mount it on the spindle about as tightly as you would the chuck. Then machine the diameter of the raised "register" to a close sliding fit with the recess in the back of the chuck. Then a skim cut from the register outward, to get a true surface perpendicular to the spindle. This "customizes" the backplate for your lathe. Threaded backplates should not be moved between lathes.

Once the above is done, you can either use transfer screws (if the chuck's mounting holes are threaded, typical of a 3-jaw) or a close fitting center punch from the front of the chuck (if it has counterbored clearance holes on its face, typical of a 4-jaw). Drill the backplate and/or tap as appropriate.

The above is mainly for threaded-on backplates. I've not dealt with other "flavors" of mounts.