Suggestions For A 4 Jaw Chuck

[BriancCc]

I picked up a Clausing 100 and it lacks a 4 jaw chuck. It is a 1 1/2" 8tpi. What size should I get 6" or 8"? How do you guys suggest I go about getting one? Used off Ebay? New off Ebay? Grizzly?

If I get an 8" do I need to get an 8" backing plate or can it be just larger that the bolt circle?

 

[Paul in OKC]

Depending on what you want to spend.........You should be able to get a chuck with that thread on it. Determine the size needed wither by through hole, or by how large a piece you will need to hold with the jaws reversed. I would probably go with the 8", myself. Here is a 6" http://www.shars.com/products/toolh..._category=4+Jaw+Lathe+Chucks&mounting=1-1/2-8. There are others, in a price range from $115-ish, but a backing plate will run another $50-60.

 

[intjonmiller]

I have been very impressed with Shars tools. My Logan came with a very good condition 4-jaw and a beat up 3-jaw. I got a 4-jaw scroll chuck from Shars for about $180 or so, including shipping, and including a 1 1/2 - 8 tpi threaded back plate. They had a number of options for that spindle configuration.

 

[BriancCc]

Thanks Jon and Paul. The through hole is like 7/8" and I don't have specific work pieces that plan on needing to hold.

 

[intjonmiller]

That is a typical spindle bore for 1 1/2 - 8 tpi. I think mine is "25/32". Enough to handle 3/4" stock.

 

[Wreck™Wreck]

This is a Bison 8" that I changed to on a 15" X 48" Romi lathe today, excellent chucks and this one is less then a year old. My employer makes me do all of the 4 jaw work so I will be Spongebob Squareparts for the next several days.
Chuck size is entirely dependent on the size of work that you intend to do and what your machine is capable of, an 8" chuck on a 1 1/2" threaded spindle nose seems a bit much but what do I know?

This particular lathe is 2"+ through the spindle with an A taper nose. The only thing that I do not like about this chuck is that it has VERY coarse threads on the jaw screws, 6TPI so knocking out that last .001" is annoying.

These aluminum parts are 2 1/2" X 1 1/2" X 8" long with a 7/8" through hole off center and .985-.986" X 1.063" deep bearing bores on each end, concentricity and parallesim between the bores is .003", this is 5 hours of setup and 1 hour of machining, very very tedious. I put nylon pads under the jaws because the parts will be clear anodized after machining

 

[BriancCc]

Wreck,

Thanks for the info.

That job looks serious! Do you chuck it, do the through hole and bearing on one end then flip it around? How many of these are you going to have to do in this batch?

 

[4GSR]

Wreck brought a good point when using four jaw chucks.

Four jaw chucks are made for work holding with a tight grip without your work piece moving on you. The jaws will mark up the surface of what ever it is that you chuck on. For most work, this is not a problem. To prevent this or reduce the chance of marking the surface, you usually put some kind of "soft" material between the work piece and the jaws. Aluminum and thick brass shim stock is what I use. Wreck mentioned using nylon pads under the jaws for aluminum.

Ken

 

[Wreck™Wreck]

Wreck,

Thanks for the info.

That job looks serious! Do you chuck it, do the through hole and bearing on one end then flip it around? How many of these are you going to have to do in this batch?

Drill and ream 7/8" half way through then bore, flip and repeat, this sort of thing must be carefully indicated. If you do alot of square and rectangular lathe work buy a 2" travel indicator, I hold one in a tool block on a qctp,

Each end takes 15-20 min. to set up and 20 min. to machine, the pic is 1 of 2 parts, there are 6 others with a different bore size.

 

[Christian Poulsen]

Just model preference here but I always have liked Buck Chucks...I know the subject is 4 jaws but for smaller rounds (Let's say around 3" and under and depending on the lathe and stock (specs of a steel work pc.)...and down to small odd sizes (non collet sizes), I have become hooked on bucking 3 jaws...
...you can slap the rough stock in it and do your thing on that side of the part, then turn the part around, indicate, and loosen/tighten the 4 adjusting set screws ("buck") dead on easily to what you have turned on that 1st side...
But yes, as for holding power and still adjusting; A 4 jaw should be 1st for a metal lathe...
....and as said by others in this thread: Go as big as the swing of your lathe allows and also what the motor will handle.

http://www.buckchuckusa.com/products/manual-chucks-atsc-3-jaw.html

Ha, I see many manufacturers have those spring loaded chuck wrenches to make sure we don't leave the wrench in the chuck (I know it's probably not good to say but I always took those out as I found pushing on a spring irritating while I tightened (Disclaimer (lol): But don't do as I say)