Thread: Spot Weld Removal Tools

I recently sharpened a standard HSS jobber drill to a spot weld drill profile in order to remove a floor pan from a Defender firewall, I drilled a least 90 holes and the drill was still going fine at the end of it. No resharpening. I used an 8mm drill and was careful not to go any further than needed to seperate the panels. If you are wearing drills out, I suspect you are drilling with too much speed. I doubt that the hardness of the weld is any greater than the original material, unless you panels are made of a high tensile steel.

Cheers, Mick.

Originally Posted by Killer

I recently sharpened a standard HSS jobber drill to a spot weld drill profile in order to remove a floor pan from a Defender firewall, I drilled a least 90 holes and the drill was still going fine at the end of it. No resharpening. I used an 8mm drill and was careful not to go any further than needed to seperate the panels. If you are wearing drills out, I suspect you are drilling with too much speed. I doubt that the hardness of the weld is any greater than the original material, unless you panels are made of a high tensile steel.

Cheers, Mick.

Most steel panels on modern cars are made of what is called HSLA or high strength light alloy steel. It is sensitive to heating and should not be welded with oxy-acetylene.

Originally Posted by Killer

I used an 8mm drill and was careful not to go any further than needed to seperate the panels. If you are wearing drills out, I suspect you are drilling with too much speed.Cheers, Mick.

Most handymen drill too slowly. Workshop formula for speed using HSS in mild steel is 9000/drill diameter in millimetres. So 1100 rpm is about right for 8 mm. Squirt a bit of light oil into the cut. Dexron is good. EP diff oil for stainless if nothing better is around. Tool steels need to be run at the efficient speed. HSS and CoHSS can be run red without damage just don't quench a red hot drill with water. Tungsten carbide and ceramics don't cut efficiently unless hot.

Originally Posted by Brian Hjelm

Most handymen drill too slowly. Workshop formula for speed using HSS in mild steel is 9000/drill diameter in millimetres. So 1100 rpm is about right for 8 mm. Squirt a bit of light oil into the cut. Dexron is good. EP diff oil for stainless if nothing better is around. Tool steels need to be run at the efficient speed. HSS and CoHSS can be run red without damage just don't quench a red hot drill with water. Tungsten carbide and ceramics don't cut efficiently unless hot.

Thanks Brian, they say you should learn something new every day, this is mine for today