3 Jaw Chuck Jaw Alignment Issues

[iron man]

Thanks for the info everyone. After some grinding, below is as close as I could get the jaws. I am sure now I will need to grid all three as described by Iron Man in order to actually get them accurate. @ iron man, if you could post some setup pictures that would be great, I am not quite sure I understand what your doing with the keystock. I do have a dremel, and various stones and diamond bits, I will just have to come up with something to hold it.

Thanks


View attachment 48241

I will set that up and take some pic's right now. be back in a while.. Ray

 

[Ray C]

Looks a lot better!

I have seen (but never tried myself) where folks will take a rotary-type device like a drill that mounts on the toolpost. They insert a grinding bit and move it into the small opening of the chuck jaws. It grinds all three of them at the same time. To do this, the rear/inner part of the jaws must be clamped down on something (preferrably something that is accurately round) to hold them in the proper position while being ground. This is where things get tricky because when you clamp something back in the jaws, they to angle inward a bit.

Hope that made sense -and again, I've not done this myself but gather many folks have.

Hopefully someone whose done this successfully can elaborate on the procedure.

Ray

Thanks for the info everyone. After some grinding, below is as close as I could get the jaws. I am sure now I will need to grid all three as described by Iron Man in order to actually get them accurate. @ iron man, if you could post some setup pictures that would be great, I am not quite sure I understand what your doing with the keystock. I do have a dremel, and various stones and diamond bits, I will just have to come up with something to hold it.

Thanks


View attachment 48241

 

[iron man]

Here is one of the first simple dremal holders I made it worked real well. Ray

 

[Tom Griffin]

The way to true up the jaws on a chuck is to bore a ring and grip it by the bore with the outside of the jaws. Then indicate the bore of the ring until it runs true. This will ensure that when the inside of the jaws are ground, they will be concentric with the outside of the jaws. This technique will also pre-load the jaws so they don't move while grinding and allows you to grind the entire length of the jaws in one set-up. Before any grinding is done on the jaws, indicate the outside of the chuck to be sure it is concentric with the spindle. And before doing any of this stuff, take it back to the store and tell them you want it replaced. If they sell junk like that, they should expect that some of it is going to get returned.

Tom

 

[iron man]

Here is the keystock stuck in the jaws I left one out for the picture these are to long cut some no longer than the jaw. When you squeeze down on them this will put the correct pressure on the jaw You must pre-load the inside and the outside just like it is when it is being used just leave enough of the jaw exposed to grind this will allow you to grind the entire length of the jaw.. Ray

 

[iron man]

Here is a little better shot to give you an idea on how to do it. TAKE your time have the chuck and your feed really slow and on your last few passes do not feed in anymore let it grind until there is no more to grind. This chuck was out abot 5 thousands after it was ground it come out perfect..I have used this setup on several chucks with all the same results and this is the simplest way to hold the jaws. To do the out side just put a hose clamp around the chuck and put some outward tension on the jaws then grind them.. Ray

 

[iron man]

The way to true up the jaws on a chuck is to bore a ring and grip it by the bore with the outside of the jaws. Then indicate the bore of the ring until it runs true. This will ensure that when the inside of the jaws are ground, they will be concentric with the outside of the jaws. This technique will also pre-load the jaws so they don't move while grinding and allows you to grind the entire length of the jaws in one set-up. Before any grinding is done on the jaws, indicate the outside of the chuck to be sure it is concentric with the spindle. And before doing any of this stuff, take it back to the store and tell them you want it replaced. If they sell junk like that, they should expect that some of it is going to get returned.

Tom

If you grip it from the outside of the jaws you will put outward pressure on the jaws which will pre load them in the wrong direction when doing an internal bore they must have pressure on them like they are clamping down on something like it would be used when you are going to turn something. The same goes for the outside of the jaws you must push out against something like a ring or hose clamp to put pressure on the jaws just as they would when your grabbing the inside of something they idea is to get the jaws to (tip) in the right direction under pressure. I have tried clamping onto a ring as you have described and the chuck was just as bad when I got done as when I started.. Ray

 

[iron man]

Here is another way to do it or look at it just make sure the chuck clamps down on all three equally not two like what is pictured.. Ray

 

[Tom Griffin]

If you grip it from the outside of the jaws you will put outward pressure on the jaws which will pre load them in the wrong direction when doing an internal bore they must have pressure on them like they are clamping down on something like it would be used when you are going to turn something. The same goes for the outside of the jaws you must push out against something like a ring or hose clamp to put pressure on the jaws just as they would when your grabbing the inside of something they idea is to get the jaws to (tip) in the right direction under pressure. I have tried clamping onto a ring as you have described and the chuck was just as bad when I got done as when I started.. Ray

Ray,

The scroll is meant to work in both directions so it doesn't matter which way you pre-load the jaws. The important thing is to keep the inside and outside concentric. Otherwise the chuck may work well clamping on the inside of the jaws but will run out when using the outside. If you had trouble doing it this way, the scroll in your chuck was probably worn out.

Tom

 

[Syn3rgy]

The newbie is confused, should I be trying the ring or key stock method? @iron man thanks for the pictures by the way I now understand what you were describing.

I did indeed try to call HF to see about a replacement but ended up having to leave a message and they have yet to call back. I'll try again tomorrow, but I figured it might be a good thing to learn about anyways, and I couldn't make it any more useless than it already was.