Chuck Crack Repair

[yukon_rose]

I have an 8" Craftsman chuck with a crack in it. I've included a photo below.

Is it possible or even necessary to repair it?

If you think I should repair it, do I braze it or do something else?

Gary

 

[macardoso]

I'd be a bit concerned about spinning that sucker up and having it come flying apart.

Is it a nice chuck, or are you due to replace it with a new one?

 

[yukon_rose]

I'd be a bit concerned about spinning that sucker up and having it come flying apart.

Is it a nice chuck, or are you due to replace it with a new one?

It is quite nice but the crack goes completely through. it doesn't enter the jaw race area at all.

Gary

 

[macardoso]

It is quite nice but the crack goes completely through. it doesn't enter the jaw race area at all.

Gary

Personally, I'd pick up a $200 import 4 jaw and not risk injury. That's just me. Some people are much more willing to try a repair and see what happens.

 

[FOMOGO]

I would be inclined to drill the end of the crack to keep it from spreading, and just run it. If you have the skill set V'ing it out and brazing after drilling would be the proper way to go about it, or you could fill the V with JB-weld epoxy (use the original, not the quick set) and sand smooth if brazing isn't an option for you. Mike

 

[Flyinfool]

That crack looks like it happened from dropping it (or some other hard impact), That looks like concrete tracks in the metal near the crack. My first thought is it still round?
IF you are going to try to repair it, You have to be sure that your stop drill is all the way past the crack, the crack is often longer that what is visible to the naked eye. Drilling a stop hole before the end of the crack does nothing to help stop it.

Since there is a good chance it is no longer round, plan on having to do some machining to make it round again. I would then make sure that I only used it for low rpm work in the future. If it bent enough to crack there that means it also flexed somewhere else, Cast Iron does not like to be flexed. There could be other invisible damage.

It may be a good candidate for setting up as a chuck for a rotary table.

 

[SLK001]

I wouldn't worry about it. The crack is on a non-structural web, so the chuck isn't compromised. That whole web could break off and not hurt the operation of the chuck (but aesthetics would suck). However, keep an eye on it to make sure it doesn't spread. Drilling the end of the crack and then filling the hole with J-B Weld is a good idea.

 

[Flyinfool]

True the piece could come off and not affect operation of the chuck. But if it does come off, it would not fall off sitting still, it would be at speed and become a bullet.

Since you mentioned Brazing in the OP I assume you have that ability. If you are going to repair it, I would first completely disassemble, then stop drill it, then grind a V groove at least 3/4 of the way thru the material, overfill it with braze. then grind a groove on the back side till the braze from the front is showing and fill the backside with braze. This will completely remove the crack, and its stress risers, so that it can not try to propagate in the future. Machine it back to smooth and round to reduce vibration and make it pretty.

JB Weld is great stuff and I use a lot of it, In this case JB weld would only be a cosmetic fix, It is not near strong enough to join cast iron, and there is no way to get it into the actual crack, it would just be a cosmetic patch for the stop drill hole.

 

[yukon_rose]

Since you mentioned Brazing in the OP I assume you have that ability.

I know how to do it but I lack the facility to heat the casting up uniformly and cool it down slowly. So the stop drill hole & JB Weld sounds like a winner.

Gary

 

[Flyinfool]

I have used the oven in the kitchen for heating parts. Clean all the oils off of it first. Just be good at ducking flying frying pans.............. Or do it when the Wife ain't home.