9X20 Chuck

[Zeb123]

When I bought my lathe, all I got was the 4" 3 jaw chuck with on set of jaws. I am thinking of buying a 4 jaw independent jaw chuck. Would a 6" be too big? The manual says that a 71/4" 4 jaw chuck came with the lathe but I cannot seem to find one on line. Also any suggestions on brands would be nice as I am a noob.
Thanks

 

[mikey]

Zeb, a rough rule of thumb is to use a chuck about half the swing of the lathe. A 4 - 5" chuck would be about right. A big chuck doesn't give you much more capacity and it weighs more.

 

[Ulma Doctor]

another problem with a big chuck on a relatively small swing,
the stick out of the jaws when turning sizable work and trying to grip the od of the part.
if the jaws stick out too far, there is potential for collision with the ways

 

[stioc]

This is the 9x20 lathe I have which also came with a 4-jaw 7-1/4" chuck - and it works great:
https://www.grizzly.com/products/Grizzly-9-x-19-Bench-Lathe/G4000

If you look at the part nos in the back of the manual you can order almost any part for it right from Grizzly.

 

[mikey]

Here is something from Logan Actuator on their Logan lathes: http://www.lathe.com/faq/#_Toc95180284

What is the right size chuck for this lathe?
2.13.. Logan supplied a 5” 3-jaw chuck and a 6” 4-jaw chuck for their 10” lathes. Logan supplied a 6” 3-jaw chuck and a 6” 4-jaw chuck for their 11” lathes. Larger chucks were available, but they are impractical on these lathes because the jaws would hit the bed when the chucks were opened. Larger chucks are also heavier, so they put a strain on the spindle and spindle bearings. In general, use the smallest possible quality chuck for the job.

Your choice, of course, but I use a 6", 3 jaw and a 6.5", 4 jaw on my Emco 11" lathe. I can use the jaws up to their safe maximum extension without hitting anything.

 

[darkzero]

Aside from the jaws hitting the bed ways (what good is a chuck if you can't use it with the jaws opened up all the way), I like having my primary chuck smaller. Spins up & down fast, less weight to lug around.

Seems like the norm is to have a scroll chuck smaller than the 4 jaw. Of course this depends on the work you do. Lathes these days usually come with a 3 jaw one size smaller than the 4-jaw, except when you get into a certain size lathe & both chucks are the same size.

My 12x36 came with a 6.25" 3-jaw & an 8" 4-jaw. I felt these sizes were perfect for my lathe. So when I replaced them I stuck with 6.25" 6-jaw & 3-jaw and for my 4 jaw I also got 8" again but I went with a direct mount. That eliminated the additional weight & stick out from the adapter like on my original 4-jaw.

I primarily use my scroll chucks. I break out the 4-jaw when I need to hold something larger or of course when I need the independent jaws. I vote for the larger 4-jaw as long as the jaws clear but if I primarily used a 4-jaw and didn't need the extra capacity I would have choosen the smaller size.

 

[mikey]

Actually, I think if I owned a 12" lathe I would go with an 8", 4 jaw, too. That 1" of additional swing makes a big difference in jaw clearance. For a 9" lathe, I would personally limit my chuck to 5" or so. As @Ulma Doctor said, you really can't use much more capacity without something hitting.

 

[darkzero]

Yup, although I really didn't want a 10" because of the weight I think I recall checking to see if a 10" would fit my lathe with the jaws fully extended. 8" is perfect for my lathe for a 4-jaw. No way I would buy a chuck where the jaws wouldn't clear the ways. Not clearing the cross slide on the other hand I don't care as much.

When I had an 8x14 I put a 5" chuck on it mainly cause the chuck had a big through hole & helped me chuck up larger diameters that I couldn't pass through the spindle. That was bordeline too big for that lathe but it was fine for the most part. I've seen people put 6.25" chucks on those 8x14s.

 

[Aaron_W]

Also any suggestions on brands would be nice as I am a noob.
Thanks

I've bought quite a bit from Little Machine Shop. It is mostly no name import stuff but everything I've bought has been decent quality with good quality control (none of the customary Chinese sand and flypaper glue lubricant) and their prices are pretty reasonable.

They cater to the owners of smaller machines up to about 10-11" lathes and medium size mills.

https://littlemachineshop.com/default.php


If you get into name brand chucks like Bison you can easily spend as much as that lathe costs new.

 

[C-Bag]

My used 9x20 came with a 4" 3jaw, 5" 3jaw and a 6 1/2" 4jaw. I've just been trying to use the 4jaw and it is tricky to use because of clearance. 99% of the time the 5" 3jaw is what's in use for me. I'll bet a 5" 4jaw would be less scary for clearance.