Most of those type of fasteners are of the spiral flute design. Usually clockwise. So in theory they need to be turned anticlockwise. I have a set of damaged nut / bolt removers which would, if you could get a small enough one, do the job. Those pins are usually made from a hard material.

Steve.

Edited By Steviegtr on 27/09/2020 17:39:19

Or try to put a ultra thin Dremel cutting disc slot across each one and use a screwdriver on them.

Guess whether a RH or LH spiral.

Some careful tapping with a wedge with a similar profile to a wood chisel between the head and the plate, not just in one place, but at several positions. Then as the head starts to lift, a blunter wedge and finally they should be high enough to turn. I would expect them to have a right handed helix.

Gentle tapping in all directions will normally loosen them. A very small chisel is ideal for applying the tapping and pliers to unscrew them. plan B, grind 2 flats on opposite sides and mole wrench to unscrew.

Good luck Noel

My Warco 16B mill had nothing as sophisticated as hammer drive rivets holding the index marks. Just aluminium round head rivets seemingly banged in skew-whiff by the youngest apprentice. They were the worst feature on an otherwise well finished machine. When I decided to replace them they popped out easily with a small chisel. i drilled the holes deeper, tapped 7 BA, or M2.5 in new money, and retained the markers with small screws.

Looks much better.

The best tool I've found is a pair of well made toe nail clippers with edges that are truly flush and straight. The curved ones don't work as well. The edges can be gently worked under the head of the screw and will wedge the screw right out. With some care, drive screws can be removed without marking up the surface. If the flat sides of the edges are polished, and most clippers are, they won't mark.

I replace those things with screws or, on thin material like machinery cabinets, aluminum pop rivets.

Pete

Edited By Peter Krogh on 27/09/2020 22:01:08

Chas

I have no idea whether this is a definitive list, but it looks a useful place to start: **LINK**

https://www.rivetsonline.com/drive-screws#1

I remember, when my dad worked for GKN in the early 1960s, there was a wide variety available.

MichaelG.

I found them easy to remove from vintage cast iron car engine blocks by filing flats on the edges and gripping with a mole wrench to twist them out.

Russell

And to complete the information, they are right hand thread

Brian

Michael G,

Thanks for this info, just what I needed. I stand in awe of your internet searching capabilities

Chas