What is meant by #1, #2, #3... jaws?

[Mike Goetzke]

I've been trying to turn for almost 2-years now and been too embarrassed to ask the subject question. All my chucks are made by Hurricane and their dovetail jaws come in small, medium, large, extra large (I think). I did make a chart of the sizes close and open for ID and OD but would like to speak in turner's language.

Thanks,

Mike

[Bill Jobe]

Mike, I think it refers to the size, both inside and out that a particular pair offered by the same brand offers.
I just bought a Grizzly lathe and intend to by a Oneway Sronghd . It comes with #2 jaws and one member suggested getting the #3s for bigger parts.

[John Keeton]

I am not sure that chuck jaw sizing is universal enough to permit one to "speak in turner's language." I have Nova chucks, and the #2 jaws are approx. 50 mm/2" OD when closed. Typically, the larger the number, the larger the jaws. If you are interested, I am sure one could find the manuals online and get that information. I know the Teknatool (Nova) manual is available.

[Bob Bouis]

I could tell you but this is a family friendly forum.

Actually I think it's just a marketing gimmick. Collect 'em all.

[Michael Mills]

I think it just depends on the manufacturer and even the chuck.
As John said, the Nova comes with 2" jaws. I also have one Hurricane chuck, the 100, and it came with 2-3/8 standard. If you go to the Hurricane 125 it comes with 2-3/4 as standard.
You may not be able to go just by the size stated either. For example the Nova 35mm spigot jaws are very very different from the Nova 35mm bowl jaws.

[Mike Goetzke]

Thanks for the replies. Glad and sad I asked . I just see reference to "I used a #3 jaw set" in the forums and at the club. I have both Hurricane HTC100 and HTS125 chucks so I have all sizes covered but was wondering how to classify my jaws with the #X convention but guess there isn't one.

Thanks,

Mike

[Peter Fabricius]

Hi Mike,
Here is the scoop for the Oneway Chucks. I may actually have contributed to this issue in the discussions we have had about various projects.
If you look at the base plate for any jaw you see that there are three basic positions that a jaw can be milled on the base. #1 jaws are flush with the inside diameter of the base... #2 jaws are set in the middle of the base (default on a Stronghold and Talon new chuck)... #3 jaws are set on the outside diameter of the base..
Then there are the #4 and 5 jaws, usually Aluminum, but the base for these is just larger and go out beyond the body in the closed position. Just larger jaws.
The Turners jargon therefore really just refers to these three sizes of jaws. My preferred set is the #1 Spigot jaws that are about 1.5 inches long. They grab max of 1.75" and close down just ynder 3/8".
Hope this helps, now walk the talk and understand when the jargon!!! LOL
Peter F.