Longworth Type Lathe Chuck

[leehljp]

https://www.ptreeusa.com/edirect_032...&utm_id=TURN62

Looks Good to me. Great price!

I have this type:
https://www.amazon.com/NOVA-COLE-JAW...%2C117&sr=8-30

But I wonder how they work by comparison?

[mpc]

I have no experience with Longworth style chucks... but my gut reaction makes me question how tightly you can actually get them to grip the workpiece. With the Nova setup, the Nova chuck's tightening mechanism (two rods on some Nova chucks, a T-handled gear drive for other Nova chuck models) is used so you can crank the pie-shaped Cole jaw grip as tight as you want/need. I have the Nova Cole jaw setup and it has worked well for me. Two comments on the Nova Cole jaw setup:
1: the length of the stock gripping rubber pieces is small so it may not work well on workpieces that curve inwards at the lip unless longer optional screws+rubber sleeves are substituted. Some folks use dowels as spacers below the stock rubber tips.
2: The first time you thread the screws with the rubber pieces into the pie-shaped pieces you'll find the screws fit tightly... very tightly on my Nova Cole jaw set. Not a problem really but it does make you wonder "am I cross-threading this?" when it happens. This occurs only on the first use of a screw hole; once "broken in" subsequent uses are much easier.

On both the Peachtree Longworth example and the Nova chuck the rubber grippers change diameter as you tighten their mounting screws... so you need to be consistent on how tight you make all of them to keep your workpiece centered. Peachtree's close-up picture of the grippers makes this easy to see. Unless you are horribly inconsistent in how tight you make each gripper, the workpiece won't be too un-centered however.

Installing the Nova Cole jaws onto a Nova chuck takes a few minutes... lots of screws. The Longworth chuck looks like it would install quicker.

mpc

[leehljp]

I had not given the "consistent tightening" across all grippers than much thought. Although I do tighten mine close to consistent automatically, I have not mentally tried to be as consistent as possible. since you mentioned it, I can easily see that almost ANY inconsistency can cause problems. Thanks for the response.