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K1UM
02-07-2009, 10:44 AM
Hi all

I need a 4 jaw independent chuck for a steam engine project I am making.

I have a 7x10 mini lathe and according to the info in the “little Machine Shop” it seems that a 5” diameter chuck should fit on the lathe. The cost is about the same as a 4" diam. Is there a down side to buying the 5” jaw chuck for this lathe over the 4”?? What am I missing??

Many thanks

Ken K1UM

SGW
02-07-2009, 02:11 PM
It seems to me as though you should be okay with a 5" chuck, but I think it's difficult to make a definitive statement about it. "Fit" and "be in proportion to the rest of the lathe" are two different things, and the latter is hard to quantify.

For example, I could probably fit an 8" chuck on my 10K, but I think a 6" chuck is actually a more appropriate size. Others might disagree.

One thing that might come into play is clearance for the cross slide; will the cross slide go under a 4" chuck, but not a 5" chuck? The cross slide doesn't necessarily HAVE to fit under the chuck, but it might be worth thinking about.

Dunc
02-07-2009, 02:32 PM
Looking at the same question myself. Thinking that 11 lbs for the 5 in diameter chuck is adding quite a bit of metal vs a more reasonable - imo - 7 lbs for the smaller one. But, there is that extra inch of capacity...

Aside: pls post back with your choice & how it works out.

danlb
02-07-2009, 03:15 PM
A 4 inch chuck on a 7 x 10 lathe is a nice compromise. Yes, it's heavier, but mine's had no problems spinning it. The controller uses a soft start, so it spins up slowly anyway.

A larger chuck usually has a larger bore, which may be nice.

With a 5 inch chuck your jaws will protrude an inch when holding a piece that is about 2 or 3 inches diameter. They will hit the ways much sooner than you think that they will.

The end result is that a larger chuck will not always let you work on larger pieces. It will do a better job when holding a large piece from the inside.

I leave my 4 inch, 4 jaw independent on my 7x12 lathe most of the time.

Dan

K1UM
02-09-2009, 08:03 AM
Thanks for the guidence.... I have decided to go with the 4 jaw chuck from the Little Machine Shop...

Ken

K1UM
02-09-2009, 07:54 PM
Chris at Little Machine Shop told me that 5" chuck is simply too big for 7x10 HF lathe!!

Liger Zero
02-09-2009, 07:56 PM
Good to know, I am pondering a 4-jaw too.

Yankee1
02-09-2009, 10:51 PM
Hi Ken
I suggest that you take a look at Varmint Al's web-site.
http://www.varmintal.com/alath.htm
When you get there click on 4 Jaw Chucks at the top of the page.
You will find useful information there.
Chuck

Yankee1
02-09-2009, 11:18 PM
Hi Again
http://www.mini-lathe.com/Mini_lathe/Chucks/chucks.htm#4-Inch%203-Jaw%20Chuck

I believe you will find just about all you want to know about chucks and backing plates for your 7 series lathes here.
Chuck

K1UM
02-10-2009, 10:02 AM
Great, Thanks