Am i Expecting too much out of a Chinese 4 JaW?

Dman1114

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Hi all....


I've been having issues with a 4 jaw chuck... i can't seem to get anything to come close to dialed in. Grizzly replaced the chuck for me and admitted that it was defective. well i got the new one in and Im getting the same results.


The Jaws are not parallel to each other. so it only tightens down on the from teeth. I try to dial in a piece 2" round aluminum right in front of the jaws then go out 3 or 4 inches and its way off.
Here is a photo of the jaws. there is no gap at the front, the back has a .012 gap. this doesn't seem right. Am i expecting too much out of the chuck i would think that they should clamp down even. I think that it may work using a steady rest but the work I'm doing is too short.

Would a bison chuck look like this? I like my machine just a few bugs i gotta get worked out.

kinda hard to tell from the pic... but there is clear daylight on the back side.
BDCF4699-83F6-4AFF-B4EE-7715345965E7_zps6ztqhh67.jpg

BDCF4699-83F6-4AFF-B4EE-7715345965E7_zps6ztqhh67.jpg
 
Seems to be common. Alot of folks end up grinding them. You will need to indicate a part in at the chuck and further out if it's longer. You cant compare a bison to a cheap chuck I dont believe.
 
Dman1114, I'm going to post my Chinese 4-jaw adventure in a little bit. I's a pretty comprehensive write up on how I fixed mine. Stay tuned.
 
Mine was the same way . I re-ground the jaws and that fixed it right up.
 
Mine was the same way . I re-ground the jaws and that fixed it right up.


I think that would take car of this too...

I just don't have the ability, tooling or know how to do it.
 
Reading the other post about fixing a 4 jaw reminded my that I had more to do as well. I had to re-face the backplate to get the jaw to fit square for example, and it needs more work to get it in balance although the balance is "good enough" for now, I know it's not where it could be. The faceplate that came with the lathe needs work too, it won't even mount on the lathe.
 
Every man and women on this site has the ability. Pick up a die grinder or dremel tool. All it takes is a little "will" to get new skills. And some money
 
I think that would take car of this too...

I just don't have the ability, tooling or know how to do it.

I reground my first chuck on my Atlas lathe about 45 years ago, and I didn't know how to do it either. But I had a Dremel, and some stones for it. I knew that I had to hold on to the Dremel some way, and feed the stone into the chuck jaws, at that point that's about all I knew. I built a mount for the Dremel to go in the tool post. I checked the clearances and started grinding. It took me a while to figure out the feed and speed that worked, but I got the job done. I recently reground a 5C collet chuck, that one was the second one in 45 years. I used a HF air die grinder, and built a mount for it to go in the tool post. This one went a little easier, having had a few years of machining experience, I actually knew what I was doing this time. The way to get the experience is to just do it, but be safe.
 
Well I guess what's the worst that can happen....

I might learn something!!!!
As far as I'm concerned the chuck is useless. ....

I've got a couple of good did grinders from when I used to bang rivets on airplanes....

I also got me a dremmel too.

Just gotta find me the right stones and I think I will be golden


I think all I'm lacking is the confidence. But I may be getting over that so looks like I'll be giving them jaws A new makeover.

Never really did a precision grinding.

can someone point me in the right direction as far as what type of stone I might need???


Thanks guys
 
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