[4]

The Fabled and Legendary Universal-Independent 3-Jaw Chuck?

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

MrWhoopee

H-M Supporter - Silver Member
H-M Supporter - Silver Member ($10)
Joined
Jan 20, 2018
Messages
559
While looking at an old ad on CL, I noticed this..

1541438017503.png
1541438065097.png

1541438108942.png
It would appear that this is a scroll-type 3-jaw chuck with independently adjustable jaws. Why do we not see these anymore? The ad says that this is a 1906 vintage lathe. Might be worth the price of admission for the chuck alone.

https://sacramento.craigslist.org/tls/d/metal-lathe/6733822339.html

1541437606307.png

1541437740565.png
 

cjtoombs

Active User
Registered
Joined
May 10, 2012
Messages
663
Probably because adjusting a 3 jaw independently to set something up would be a PITA. They still make 4 jaw combination chucks (scroll and independent), which seems much more useful than a 3 jaw of the same type. I would love to have one, but they tend to be quite expensive.
 

francist

Active User
H-M Supporter - Gold Member ($25)
Joined
Sep 5, 2013
Messages
1,190
It probably isn't! My take on it is that it's not necessarily for centering purposes, but rather to grip an odd-shaped part repeatedly with speed. I guess you'd still want it centered to a degree, but not like a set-tru would accomplish. I could be totally off base though.

-frank
 

Ulma Doctor

Infinitely Curious
H-M Supporter - Gold Member ($25)
Joined
Feb 2, 2013
Messages
275
i have looked at the CL ad for this lathe more than a few times now......o_O
 

682bear

Active Member
Registered
Joined
Nov 28, 2016
Messages
273
I have 2 of these chucks... an 8 inch Union and a 9 inch Rohm, for my South Bend 14 1/2.

The first time you try to get them centered, it is a real pain... but after doing it a few times, it becomes very easy... I can get a part indicated within a half thousandth in less than 2 minutes now.

Both of mine have a lot of wear in the scroll, so I have to indicate everything that I chuck up... It tends to repeat within about .010, so I get a lot of experience adjusting the jaws.

Now, I actually prefer these chucks over a standard 3 jaw or a 4 jaw...

I would still love to have a set-tru chuck, but these work well enough that I can't justify paying the price for a set-tru.

-Bear
 

mksj

Active User
H-M Supporter - Gold Member ($25)
Joined
Jun 12, 2014
Messages
2,092
A number of individuals use the Bison 4 jaw 8" combination chuck, the repeatability of the scroll is about 0.001", the independent jaws allow you to take out any remaining TIR quickly. Very easy to remove and reinsert stock, and get it spot on as far as runout, you also can adjust for the non-uniformity of stock or the piece you are working on. The jaws are 0.2" at the tips so it hold smaller round stock munch better than a 3 jaw, although I usually use a collet chuck. I use my collet chuck probably 50% of the time, combo 40% and 3 jaw set-true 10%. A set-true will not necessarily hold its tolerance over a wide range of diameters, I usually set up mine with some 1" stock. SThe combo cost is similar to a 6J Set-True type. If you consider you would not need a 4J independent and a 3J scroll set-true, it is a less expensive alternative. I purchase my 3J first, and then the combo, but almost never use my 3J anymore.
 
[6]
[5] [7]
Top