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

If you have to buy some stones, I would go with a medium hard, 80-120 grit, and the most important...rated for your grinder speed. I would also buy a diamond dressing tool, just to make life easy. Take a look here to see how I did it. http://www.hobby-machinist.com/show...-D1-4-Cam-Lock?p=211905&viewfull=1#post211905

I would load the jaws something like this http://www.hobby-machinist.com/show...chuck-grinding?p=208594&viewfull=1#post208594 With a 4-jaw it is not critical to have the jaws exactly in a perfect ''circle'' like you would with a 3-jaw scroll chuck. You could grind only one at a time, because all you want to do is get them parallel with the lathe centerline. I would check the jaw track alignment like I did. You could do this right on the lathe, it is not necessary to to it on a mill like I did. Just mount up a dial indicator on the cross slide or tool holder.

Good luck.
 
Confidence stops more projects and ideas then skill will ever produce. On the buggy forums we get alot of guys who see the custom fab work others are doing. They tend to all say the same things.... If I knew how, if I had the skill, I wish I could, etc, etc.... I always tell them the same thing " only diffrance between you and them is they were not scared to cut it up". It's metal and we deal in metal.

The best thing is grinding takes very little so it's hard to ruin a jaw long as your awake.

Oh and I get intemidated all the time. Sometimes I even drag my feet so as to prolong that uncomfortable place where I have no clue. But it all ends the same, it has to get done. And no one I could pay to do it, is any smarter then me
Dman1114 said:
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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Whats the worse that can happen? well, we are talking about a independent 4 jaw (I hope). I am one that doesnt refuse free junk, however I was given a four jaw bell mouthed,
fork mouthed but there is hope. With a true test piece even my eyes see daylight, mainly the rear like .010. I feeler gauged it. Took that jaw out and wisked it on the side with
a standard bench grinder #80 grit. Put jaw back in tighten it & grind until perfectly flat. And one by one, ground until I got a perfect contact. Probably my jaw flats were ok, it was
(call it) dovetails are worn, not too much you can do about that. Whats happening is applying pressure cocks the jaw so now even contact is lost, bell-mouthed so called. You may
loose a little of the ring sights, I dont care about those, just getting a little more mileage.. If I get questioned? all I can say It works for me. 3 jaw scroll is a hole different deal.
Oh I talking about inside jaws not outside. Outside don't care.

sam


I'm probably going ta get the dunce-cap award for this one Old school getter done
 
chuckorlando said:
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
Click to expand...


It takes a little more than that Chuck. First, the jaws need to be preloaded from the OD of the jaws. This puts them all in the same position and the won't move during grinding. It's the only way to get the grind straight. The grinder itself must be held somehow, not hand held. The whole length of the jaw needs grinding so you might need a long shaft diegrinder. It depends on how far they are opened when preloading. Preloading is done with a ring chucked on its ID. That's it in a nutshell. It takes time and patience to get it right.

Now, as to the OPs problem. Unless you can't wait, send it back again. This time tell them to check it there. Obviously they didn't.

"Billy G"
 
I never said everyone knows how to do it. I said they have the ability to do it. And they do
 
They are taking this chuck back for the 2nd time.... They told me they were gonna make sure the next one is right. If i get it back again and it is AFU Im going to fab me up a mount for my long nose die grinder and I'm gonna fix it myself.
 
The tone and experience in this thread should be enough to move it to the beginners section as a motivator. Seems like these fixes are related to way scraping. I have used blue dye marker and hand tools for many successful efforts accross the years when I simply did not have proper machine tools. Kudos!
 
chuckorlando said:
I never said everyone knows how to do it. I said they have the ability to do it. And they do
Click to expand...

Agree. I get a little hesitant sometimes but I try to remind myself that if I really hose it up then 1) it was broke in the first place so what 2) can buy another one or 3) if its that important, pay someone to fix it.
 
I just got in another chinese 4 jaw From Grizzly. This is the third chuck from them and its no different. The jaws are not parallel. Not sure what is going on here. But when i put a piece in the chuck i would think that the jaws should make contact from to back. Only the Front of the jaws makes contact. ... Gonna call them tomorrow and see WTF is going on. They told me they would check it out and make sure i got a good one....

kinda messed up how a company thinks... they would rather pay shipping on a chuck (probably not cheep) back and fourth 2 times now than just credit me the price of it toward a bison.

If this don't pan out i will be fixing it myself.
 
Some bias toward the front of the jaw is not a bad thing. As you tighten the jaws, there is some spring in the system they will tend to contact more and more surface the tighter they get. Bell-mouth on the other hand would be a bad thing.

EDIT:

It is important that the centerline of the jaws point directly at the tailstock center. That's where mine was way off.
 
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