Need Help!- To Clean Threads or Just Force Past the garbage?

[JWB_Machining]

Hey,

So I am trying to put a set of step jaws on my 4" Kurt vise, for what I plan to do I have to put one jaw on the back side of the backstop of my vise. (A lil vocab help would be appreciated). I have yet to put a jaw on this part of my vise and the threaded holes that you screw the mounting screws into seem to have some debris in them. I know the screws are good because I'm able to screw them into other holes on my vise. When I try n screw them in my back stop though I hit a point where they become hard to turn. I'm having this problem in both holes at different depths. I was thinking of just forcing them through this point but that's never a good idea, especially if you plan on removing the screws. I was wondering if anyone had any advice on cleaning out the threads, so far I've tried blowing air through the holes when they're blind and not blind, I've put a lil magnet in there and pulled some chips out and I've run some Q-Tips in n out, I've taken plenty of junk out but Still not that annoying chip/debris that's stopping my screws. Also once I get this remedied is it recommended to leave extra mounting screws in all the mounting holes so that they don't become filled with junk? Thanks for whatever advice you can give.

[stevo1]

Can you blow out the chips and rechase the threads with a tap? The other thing we use to do if it was just some gunk in the threads was put a stiff cone shape wire brush with a small shaft on it into a cordless drill and run that in and out/forward and reverse. These wire brushes can be ordered from just about any supplier and there cheap.

Stevo

[Geof]

Forcing is not a good idea.

Check that your bolts are not too long; I did make this mistake one time, not checking that is.

The solution I have implemented is to grind a little notch in the end of the bolts; turn the first two thread into a single flute tap. The idea is to have a blunt start to the first thread so that any debris in the hole gets swept ahead of the bolt not squeegeed into the thread by the chamfer on the leading threads of the bolt.

It works like a charm and if you put a bit of grease on the bolts the debris tends to stick in the 'flute' and gets carried out when the bolt is removed.

[JWB_Machining]

Thanks I'm a get lunch then try those ideas out, I don't think it can be that the bolt is too long cause it's through hole that goes through the backstop. I like that 'flute' idea though.

But you guys both missed my one question, is it good to leave extra mounting screws in all the mounting holes even if they're not holding jaws on? Or will this create some undesired effect in which case I could use rubber stoppers? I just figure it'd be good to plug the holes up somehow so more chips n such don't get in there.

[Geof]

Plugging holes to keep chips out is a good idea; I always think about doing every time I have to blow out the chips that have lodged in empty bolt holes.

[JWB_Machining]

Well I didn't have the cone shaped wire brush but I did get part of a regular wire brush in there, it worked great. Don't worry Geof, I'm defiantely remembering that flute idea for a rainy day.