Old chuck jaw refreshing

[Alcap]

I’ve been following your thread , I also have a 3 jaw chuck that doesn’t hold stock true , about .006“ runout . I’m trying to understand how after grinding it still has .0035” runout ? Maybe because the scroll is worn ? I’m thinking about grinding my jaws too .

 

[ErichKeane]

I’ve been following your thread , I also have a 3 jaw chuck that doesn’t hold stock true , about .006“ runout . I’m trying to understand how after grinding it still has .0035” runout ? Maybe because the scroll is worn ? I’m thinking about grinding my jaws too .

A big problem with scroll chucks is how they touch the scroll. The interface between the scroll and the jaw teeth is inconsistent, since it is designed to work across a fairly sizable range of sizes (the teeth on the jaw are 'dome' shaped). Since each diameter interfaces slightly differently, you're always going to get at least some difference.

 

[jwmay]

I don't know if continuing to grind would have made it any better. I didn't think I was going to succeed actually. .0035" is still not great, but the chuck holds work securely now, which was my primary goal.
Some things to keep in mind though:
1: I used a budget rotary tool with stone in a very janky setup...NOT a toolpost grinder.
2: The chuck jaw ways allow the jaws to tilt away from the chuck body, which afaik, cannot be changed.
3: What Keane said. Lol
4: I haven't tried to do this with the chuck that THIS thread is about. So we still have yet to see if I can get lucky twice. HA! I'll grind the snot out of it, because I don't care about the result. In fact, I should have started with it.

 

[Tozguy]

I used a budget rotary tool with stone in a very janky setup...NOT a toolpost grinder.

Looks fine to me. It gets the job done.

 

[John_Dennis]

I watched Tubal Cains tool post grinder inventory video and noticed that a Craftsman Electric Die Grinder is machined to be clamped in a fixture. This fixture is no longer available but does not look difficult to make. Dumore also makes a similar Die Grinder that was also marketed under the Dayton brand. I bought a Craftsman industrial die grinder which was probably made by Black and Decker on ebay and will be making a fixture to grind my 3 jaw.

 

[jwmay]

This fixture is no longer available but does not look difficult to make.

I had one of these in my watchlist on EBay just last week, but somebody wanted it more than I did.

 

[jwmay]

Just an update: After a few days of using this chuck, I found that two of the three jaws are extremely loose in the scroll. I put a smaller diameter piece in the chuck, and it looked as bad as it ever had. I took the chuck off and remounted a newer one. I don't think I was as successful as I'd hoped, or as my preliminary measuring would indicate. So...I don't know. Cheap lesson I guess. For my part, I wouldn't recommend it. I'll wait for the sting to wear off, and I'll probably buy a new chuck.