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4 Jaw Chuck Help

6K views 14 replies 12 participants last post by  BillWhite 
#1 · (Edited by Moderator)
This is my first post I recently purchased my first lathe lot from a yard sale (a bunch of tools 15-20, an 1/2 HP Craftsmen lathe, and a 3/4 HP Duracraft lathe, craftsmen bowl rest, 2 face plates and a 4 jaw chuck). I made out very well at an estate sale in which they just wanted a bunch of tools gone. Needless to say I'm a novice and that's being generous, I've made some rolling pins, captive rings/ rings, a few "magic wands", nothing spectacular but i'm learning.

I am not sure if I am doing something wrong, or if there is an issue with the chuck (I believe it to be on my end) When it comes to centering the blank on the chuck. I have tried to find a video on youtube on how to center a 4 jaw chuck, but they all seem to be on how to use a self centering chuck. I plan to someday purchase a newer lathe and at that point would upgrade to a better chuck. However for right now I am really eager to try turning something with the chuck.

If there are any tips/ tricks or links that could help me please let me know!

Thanks a bunch!
Sandy
 
#2 ·
http://littlemachineshop.com/Reference/Centering4-JawChuck.pdf

Most woodworking 4-jaws are self-centering If yours isn't, it might be for metalworking in which case it's probably a heavier chunk of metal than your lathe needs to be turning, with jaws that aren't made for gripping wood. But if it is indeed a woodworking chuck, or you're determined to use it even if its for metal, then the pdf in the link above should get you going.
 
#4 · (Edited by Moderator)
This will work on spindle or bowl blanks except might have to turn a recess or tenon on bowl blank between centers first. . Mark center in one end of wood (draw an X) take an awl and make a hole in center of X. Place wood in chuck loosely bring up tailstock and put live center point in hole, then tighten chuck.

We have posted this video here before but might help you/
 
#6 ·
I would think about a self-centering chuck. Check out your head stock size and threads. Buy a smaller chuck like a Nova G3 for around $125. Get the threaded insert that fits your lathe. Then, when you upgrade lathes, if you do, you only have to get a new threaded insert ($20-25).
 
#9 ·
Grizzly once sold a big heavy version of this chuck with revisable jaws. Jaws were flat on both sides. If have old style or this current style buy a new chuck. Both are knuckle busters you can really compress wood when tightening. 3-jaw chucks not really safe for woodturning!

http://www.grizzly.com/products/3-4-Jaw-Chuck-1-x-8-TPI/H7605

Even though jaws and chuck body numbered have to make sure jaws go back into same slots when reversing jaws or will not close all the way.

If have one of these or similar scroll chucks, procedure outlined above will work. A lot of turners just eye ball it but I still draw the X and make hole with awl so live center has a place to go.

http://www.grizzly.com/products/4-Jaw-Wood-Chuck-3-4-x-16-TPI/H6264

Self centering does not always mean wood will be perfectly centered once jaws are tighten even if turn a tenon or recess for jaws. Wood not made perfectly machined from birth. When mounting wood on a lathe whether turning between centers with spur drive or chuck in or on headstock and live center in tailstock get wood as close as you can then turn it perfectly round!
 
#11 ·
Sandy, if you are using a 4-jaw independent adjustable jaw chuck, might be easier to install spindle or bowl blank in the chuck off the lathe where can see jaws better. Whether hold outside of wood (compression) or fit into a recess (expansion) adjust jaws close to actual size of the blank. Then snug up jaws moving in or out depending upon method need to hold blank. Then mount on lathe and bring up tailstock for support and tighten down wood in chuck.

Only word of caution unless end of blank is perfectly square make sure wood is not touching chuck body face.
 
#12 ·
4 jaw independent chucks are used a lot in metal working where you mount a piece in it and then use a precision indicator to get it perfectly concentric with a hole of feature in the piece.I have one that is made to be used on the wood lathe and it never has gotten out of the drawer, but it could be used to do some neat eccentric work. The best ways to use it is to mark the center on a piece of wood and poke a hole in with an awl. then back all the jaws away so they don't contact the piece and put the block in the 4 jaw chuck and bring up the tail stock with live center in it and drive the cent in the awl mark and hold pressure on it while you bring up each of the jaws to the edges of the piece and clamp them down. then you can turn you piece and it should be center on the mark you laid out.

I'd suggest a 4 jaw scroll chuck with angled jaws for wood working. But, don't get a chuck that used two pins to tighten it- get one that uses a T handle so you have one hand free when loading it. It makes it a Whole lot easier.
Here is the model # for a Grizzly 3 3/4" chuck for wood and for a 1"-8 spindle: H6265. Once you buy it and you need to use it on a different threaded spindle, call the technical department for the part number of that back bushing and you can get one for about $14. You will not be disappointed!!!!!!!!!!
I have a 1"-8, a 3/4"-16 and 1 1/2" -8 bushings. I can turn a piece on one lathe, leave it in the chuck, switch the bushing and mount it on another lathe and it is right on.

...............Jim
 
#13 ·
My situation is similar to Sandy's in that I got a Dunlap/Sears vintage 1940's lathe model 101.06242 with a bunch older tools. I have never done any turning so I joined my local turning club to get educated on turning.

The chuck I have now is for metal turning. My spindle is 3/4, 16tpi, the max. blank diameter is 9". I was all set to order a Grizzly chuck until a club member recommended not getting a Grizzly. Since I want to keep my investment down until I get serious about turning, can someone recommend a good quality chuck new or used that will work for turning bowls, spindles and pens?

Thanks in advance for your suggestions,
Ken
 
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