Chucks for heavy ten?

Halcohead · Aug 11, 2005

I need to get some chucks for my heavy ten (basic three jaw scroll and 4 jaw independent is all I need). I'm wondering what sizes I should get, and also where I should look for them. I'm not interested in machining a backing plate for a new one.

Someone's offered me a Cushman 9" 3 jaw scroll chuck with a 2 1/2-8 thread on its backing plate. I'm wondering if this will be a bit large for a lathe with a mere 10" swing. Also, I don't know how much these things go for, but the guy wants $75 for it. Is it worth that much?

steelhead · Aug 11, 2005

I would say if its in good shape its worth more then that. I would also say it is too large for your lathe though.

aametalmaster · Aug 11, 2005

I have a 6" 3 jaw and a 6" 4 jaw for my 10K 10". Plus the same chucks in 4", you can never have enough. Some times i have parts in all 4 chucks at the same time...Bob

aametalmaster · Aug 11, 2005

Which spindle do you have?, Threaded?...Bob

Bob-O · Aug 11, 2005

For my heavy 10 with the 2 1/4" threaded spindle, I have a 4" 3 jaw, 4" 4 jaw, a 6" 3 jaw, and a 6" 4 jaw. In practice thou, most of the work I do is 5C collet work.

As a point of information, my old 1964 South Bend catalog lists 5" & 6" 3 jaw chucks, and 6" & 7-1/2" 4 jaw chucks for the 10" lathe.

Hope this helps.
Bob

aametalmaster · Aug 12, 2005

A 7 1/2" 4 jaw would be nice for some work. Guess i should start looking...Bob

Halcohead · Aug 12, 2005

I have the 1 3/8" thru hole on my spindle, with what I believe to be a 2 1/4-8 spindle thread. I already have a spin 5C collet chuck. No 4 jaw, YET. I honestly think i'll use the 3jaw for cutting a 1 1/16" or 1 1/8" nub on the end of larger parts and then still use the collet chuck. The 3jaw just doesn't strike me as accurate enough if I ever plan to re-chuck the part. If anyone has a 4 jaw 6" or larger they'd like to sell me, I'm all ears.

peterh5322 · Aug 12, 2005

"The 3 jaw just doesn't strike me as accurate enough if I ever plan to re-chuck the part."

A scroll chuck is generally accurate for one diameter.

If the same area being re-chucked, it should repeat.

However, don't expect the chuck to repeat to any other diameter.

All of my scroll chucks are set-true, or have been converted to set-true.

With set-true, any work piece of any diameter can be set to zero TIR,

Halcohead · Aug 12, 2005

Hmm, this chuck is not set-thru, and I wasn't planning on getting a set-thru. However, what does it take to convert to set-thru, and is it easier to adjust a set-thru than a 4-jaw chuck?

Are those chucks that attach directly to 5C collet closers worth the time? ONe of those looks tempting for the stuff too large for a collet but too small to justify a full fledged large chuck.

peterh5322 · Aug 12, 2005

"Hmm, this chuck is not set-thru, and I wasn't planning on getting a set-thru. However, what does it take to convert to set-thru, and is it easier to adjust a set-thru than a 4-jaw chuck?"

Several approches are possible, but most involve a back plate with a loose fitting internal shoulder projecting deeply into the chuck's body, and against which the radial adjusting screws bear.

One loosens the axial plate attachment bolts, slightly, then adjusts the radial adjusting screws for zero TIR, and then tightens the radial attachment screws and rechecks for zero TIR.

"Are those chucks that attach directly to 5C collet closers worth the time? One of those looks tempting for the stuff too large for a collet but too small to justify a full fledged large chuck."

Useful where the spindle is natively 5C, such as Hardinge and others.

Obviously, less useful on spindles which have to be adapted to 5C in the first place.

Jon_Spear · Aug 13, 2005

It is more important to get a 4-jaw chuck, rather than try to make a set-tru 3-jaw chuck.

There have been some threads about how much more valuable and versatile a 4-jaw is than a 3-jaw. It holds the part more securely, and you can quickly true up your piece with an indicator once you learn how. here is one guy's detailed explanation:
http://www.cartertools.com/fourjaw.html It really isn't that complicated. You can get 4-jaw chucks on eBay for cheaper than many 3-jaw chucks.

I have the same lathe as you. I made a back plate for a chuck that I got on eBay. That is a good learning project, one that helped me become more confident. If you have a chance to stop by the Sunset District, I can show you how I did it.

One thing you can do to true up a piece in a 3-jaw chuck is to use shims, cut from thin pieces of sheet metal, or from pieces of paper. You still need to set up your dial test indicator.

I think the right diameter chuck for the 10-inch lathe is 6-inches or 5-inches. The other one is a bit big, even though it has the correct thread on the backplate.

-Jon

Halcohead · Aug 13, 2005

Jon, I agree, 4 jaw independents are more useful. I'm just trying to find both, so I figured I'd ask about this one. I'll call you when I have time to drop by the sunset.

I already have an 8" 4 jaw independant chuck for my 13" south bend. It's the same chuck that shipped with the lathe way back in 1911. Should I just make a new backing plate for that one (funny, the spindle on the 13" is smaller than the spindle on the 10)? I also have a 7" 3 jaw that I could convert, should the need arise.

peterh5322 · Aug 13, 2005

"I think the right diameter chuck for the 10-inch lathe is 6-inches or 5-inches. The other one is a bit big, even though it has the correct thread on the backplate."

6" is now obsolete.

A true 6", such as made by Cushman for the Monarch 10EE, is very a nice, all-steel chuck.

The current standard is 6.25", made from semi-steel, and is dramatically larger and heavier, while not being nearly as strong as an all-steel chuck.

For a small 10" machine, 5" would be my choice.

For a large 10" machine, such as a 10EE, 6" would be my choice.

As independent chucks generally weigh significanly less than scroll chucks, I usually oufit my machines with an independent chuck one size larger than its own scroll chuck.

So, 5" scroll and 6" independent for a small 10", and 6" scroll and 8" independent for a large 10".

My 9 x 18 Hardinge has 5" chucks (integral screw mount, made for Hardinge by Pratt Bernerd); my 10 x 20 Monarchs have 6" (scroll) and 8" (independent) all-steel chucks, as supplied by Monarch; my 10 x 20 Logan, has a 4" (scroll), 6.25" (scroll) and 6" (independent). My fave for the Logan is the 4".

I wish more 5" chucks were available.

JRouche · Aug 17, 2005

I use two 4-jaw chucks. One is a 6" cushman (614c) and the other is a 8" cushman (814c). IMO cushman makes some of the finest 4-jaw lathe chucks. The 8" seems abit large at first but once you get used to the additional mass it's just right. I actually prefer the 8". JRouche

Oh yeah, I have a 10L with 2-1/4"x8tpi spindle.

ztarum · Aug 18, 2005

I recently purchased a Rohm Hi-Tru scroll chuck (6.25"). I'm very impressed with the quality. I think it is nicer than my Buck Forkardt. The body is of forged steel. Good for 4600 RPM. The 6.25" is probably a little big for a 10L. Rohm also makes a 5", but in cast iron only. This is not really a problems since the maximum speed is still 4000 RPM. These chuck aren't cheap, but they are definitely top notch.

On another note, I used to have an older (6") Buck on my 10L. I sold that chuck along with the lathe, but I was happy with the chuck and thought it was a pretty good fit for the machine. If you can find a good used Buck Adjust-Tru, that might be a good way to go.

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