question Removal of self-tapping rivets?

[andym]

I need to remove this brass plate from the Abbot loader's guard as the guard is rusting behind it and needs to be blasted and painted:

 

 

My initial intention was just to drill out the rivets from the back, but they aren't normal rivets. They appear to be those self-tapping things and are incredibly hard, nothing I've tried will touch them. This is the rear view:

 

 

The only thing I can think of is to find some sort of thin-walled counterbore tool with a hole in the centre so I can remove the metal from round the rivets but I'd appreciate any other suggestions!

 

Andy

[ruxy]

They will be taper spline type, think dentistry. Small pencil die-grinder , mine does abt. 80,0000 rpm free , burr & stone - you may need a selection to try to get under the skin. Aim to remove the core & leave splines , 20/20 vision helps , work from front & rear..

[Richard Farrant]

They are called Drive Screws. As you can get the from behind, the easiest way is to get a block of hard wood, drill a hole the size of the head, hold this against the instruction plate, with head in hole to support and simply punch back out. Used these for fitting rebuild plates to engine blocks.

[ruxy]

You could grind a slot for screwdriver , try and wind out but you would need to be lucky if not slow helix type.

 

Alternative :-

 

Place a washer over the head , secure with - whatever.

This protects the plate then cut the head off with a small Dremel or die-grinder cutter.

Lever the plate carefully off and grind flush remains of pin.

Re-secure to one side with original pins insitu but ground flush , you can hide the odd one.

You could make a accurate drill jig from gauge plate , drill out original pins with a spot-weld type quality stub dril or TiN coated type..

Edited September 8, 2015 by ruxy
spelin

[timbo]

Dremel with cutting disc - if you're careful you should have enough control to remove the head without damaging the plate - worked on my batt box lids....

[andym]

Thanks all - some good ideas and very quick response too! I think I'll try knocking them back out (I'd considered that) and if not, time to invest in a Dremel!

 

Andy

[Richard Farrant]

Thanks all - some good ideas and very quick response too! I think I'll try knocking them back out (I'd considered that) and if not, time to invest in a Dremel!

 

Andy

 

Andy

Once you have knocked them back a little way, a good pair of pliers gripping the head and a slight twist and they usually come out.

[utt61]

I've always knocked them out from behind with a pin punch in the manner Richard suggests. Never (yet) had a problem.

[ruxy]

Never (yet) had need to remove them - where there has been access from the rear. Then - you don't know the exact type you are up against, pitch /start , some of the fine thread pin type have barbs for grip where security is the intention. You will not wind out a very fine spline type with a long start into steel or cast iron.

[andym]

Thanks again, all!

 

Andy

[andym]

I thought I'd follow this up as I hate threads that just finish in mid-air.

 

I tried knocking the drive screws out from behind but they weren't interested so I carefully took the heads off with a Dremel, luckily with minimal damage to the plate. Now that I had a stub sticking out there wasn't enough to grip but I could knock them back and forth enough to loosen them off and eventually drive them out completely.

 

 

 

 

Once again thanks to all for the helpful suggestions.

 

Andy