Craftsman 4 jaw chuck screws

[cbrims]

I've got a Craftsman 4 jaw, 8" chuck that has a broken adjustment screw for one of the jaws. I've received some good tips on how what to do about making a new one since I can't find a source for a replacement screw or donor chuck.

My issue is getting the plug out that holds the screw in, and specifically how to get it out. I've tried using a drift pin/punch to try to get the plug out but it wouldn't move. The one plug was flush with the back of the chuck and the others were slightly pushed in so I tapped the back of the plug with a small hammer and it became pushed in like the others so I know it's not frozen in place. I'm stumped as to how to get it out.

I also figure I should take out all the screws and really clean the chuck, there are some chips and grime in the recesses.

1 image is the rear of the chuck where the plug was pushed in, the other image is the front of the chuck showing 1 of the 2 fingers on the plug that keeps the screw in.

 

[mikey]

I'm winging it here but if this were my chuck, I would make a two-pronged punch from brass. It looks like the plug is a slight press fit so it should come out with some gentle persuasion but the force on each finger has to be equal or the thing will cock/tip and get stuck.

 

[cbrims]

I'll try to make a 2 pronged punch and see if I can come up with a design that will both fit and not fold over on first hit. I was having to angle the punch fairly steeply to get any purchase on one prong. Was hoping someone had taken one of these apart before.

Edit: What if I gently drilled a hole into the back of this plug and tapped the hole then pulled it out using a thrown together puller? I don't see a reason the plug can't have a hole through it from the back as it's main purpose is to fix that screw in place.

 

[mikey]

I'll try to make a 2 pronged punch and see if I can come up with a design that will both fit and not fold over on first hit. I was having to angle the punch fairly steeply to get any purchase on one prong. Was hoping someone had taken one of these apart before.

Edit: What if I gently drilled a hole into the back of this plug and tapped the hole then pulled it out using a thrown together puller? I don't see a reason the plug can't have a hole through it from the back as it's main purpose is to fix that screw in place.

Yeah, I thought about pulling it and that would be another option. Also, what about slipping in a flat piece of metal that will sit on both prongs of the stud and tapping in the middle of the flat piece? Might be worth a try before drilling the stud.

 

[cbrims]

Yeah, I thought about pulling it and that would be another option. Also, what about slipping in a flat piece of metal that will sit on both prongs of the stud and tapping in the middle of the flat piece? Might be worth a try before drilling the stud.

I'll give that a shot but the rails that the jaws ride on overlap quite a lot and there's not much of those 2 prongs that I'd be able to get purchase on; to get the punches on those 2 fingers I had to tilt it over a ways. Maybe if I make a triangular cut I'll be able to slip some flat stock in there. I'll try a straight cut piece of steel and see if there's enough meat for me to hammer on gently.

I added an image more or less straight down showing comparatively how much metal is there. It might be enough, I'll see how it works out.

 

[mikey]

Yeah, not much metal to get a purchase on. I hope you can at least push it out far enough to maybe put something like a hose clamp or similar thing on the back side that will allow you to use some pulling force to get it out.