View Full Version : 3-Jaw vs 4-Jaw Chuck
03-23-2002, 05:10 AM
Now this is one that totally screws up my thought processes.I read where when using a 3 jaw chuck that you had to watch out for your knuckles.What is the deal here ,are they manufactured differently and if so why can't a 3-jaw be made to have the same sort of clearance that a 4-jaw has...........
03-23-2002, 10:55 AM
Dick, the difference is in the design of the jaws
As you can see, the jaws on the 3 jaw chuck protrude, limiting how close you can safely work.
The 4 jaw chuck has more gripping area and has no protruding edges when in use.
I hope this answer is not as confusing to you as it seems to me.
03-23-2002, 04:23 PM
Seems clear to me ,wonder why they made that like that,it even looks dumb,,,,,,,,,,,,,,,,,,,but Im sure there was a reason but I'm not going to buy one thanx for the answer
03-23-2002, 08:49 PM
I'm sure that someone more knowledgable than myself can correct some of my errors, but from some of the 15-30 year old woodturning books that I inherited, it appears that what you're looking at above is sort of a natural evolution of chucks. From what I can tell, 3 and 4 jaw "engineer's" chucks similar to the 3-jaw chuck above were quite commonly used by woodworkers until sometime in the 70's when 4-jaw scroll chucks started to appear for woodworkers. Having tried both, the 3-jaw is stashed with the rest of my antique tools.
The old chucks will take a chunk out of your hand if you brush up against them while they're turning. The scroll chucks, speaking from experience, are much easier on the skin. The wide jaws hold the workpiece much better and usually have interchangable jaws. They also cost considerably more. IMHO, they are almost indispensable. You'd be amazed, though, what you can do with just a screw chuck and homemade jam-chuck on a 3" faceplate.
03-24-2002, 06:34 AM
What you said in your last sentence ,I'll just have to take your word for that lolLOL but I'm sure you are right
03-25-2002, 03:21 PM
Just a little explanation:
Screw chuck: A chuck with a fairly large, coarse threaded screw at the center that holds the piece mounted. It can be use with or without the tailstock
Jam Chuck: a rounded (usually homemade) knob (convex) or divot (concave) shape that is sized to support the piece when it is "jammed" against it by the tailstock. Usually it will be lined with some materials to help hold the part by friction, such as sandpaper or carpet foam
3" Face plate: A three inch plate that is threaded onto the lathe. It has several holes where screws can be used to attach the wood to the faceplate.
Hope that helps a little.
"If it is worth doing, it's worth overdoing"
03-31-2002, 12:33 PM
I saw the humor:o)