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

[Dman1114]

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.

 

[chuckorlando]

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.

 

[JimDawson]

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.

 

[MikeWi]

Mine was the same way . I re-ground the jaws and that fixed it right up.

 

[JimDawson]

See this post http://www.hobby-machinist.com/show...uck-Adventures?p=234042&viewfull=1#post234042

 

[Dman1114]

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.

 

[MikeWi]

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.

 

[chuckorlando]

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

 

[JimDawson]

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.

 

[Dman1114]

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