General Spot Weld Cutting

[goodfellow]

Don't know if this is of interest, but I thought I'd post a quick and efficient method of cutting spot welds with out having to resort to those expensive mini-holesaw based cutters that seem to get dull very quickly, and are hard to maneuver in tight spaces.

I start with a standard 5/16" drill bit and then grind it to a 138º angle. My vintage Drill Doctor grinder only grinds 118º and 138º profiles, but more modern grinders are capable of more shallow angles up to 145º. The shallower the better, because the drill will cut a wider swath with less penetration than a narrowly ground standard bit.





setting the bit in the Drill Doctor grinder --



The finished bit!! The Drill Doctor will resharpen this bit in a few seconds. I usually get about 40 or so good cuts  from one freshly sharpened bit.



The shallow angle allows me to cut through a spot weld almost entirely and only leave a small dimple in the underlying metal panel.



To start the drill I use a heavy duty ACME automatic center punch. This works well and is extremely fast.



Next I load a spotweld cutter air chisel in my air hammer and seperate the cut spotwelds with just a little bit of persuasion. The cutter in the pic is a Snap-On version, but I've also had great results with Ajax cutters from Harry Epstein.





With just a little practice and this method will leave little trace of any spotwelds on the underlying panels