Spot weld cutters

We use the Blair spot weld cutter's too, 3/8 dia. is what you want, the one's we use, are cutter number 13214, of course you have to buy the arbor separtely and the center pin's too. We also do use the Harbor Freight cutter's.........they come individually ( one complete cutter to a pack) they work great, but the only down side is the center pin is kinda soft, and will bend some letting the cutter wobble around while your using it. You can use the blair center pin's in the HF cutter's, I don't have the part number for them,as soon as I find it I will post it. I have never boke a HF cutter as of this
day, don't know why....... but have not. The shank on the HF cutter is 7mm. The trick is is to have a very sharp center punch to mark the weld for drilling, and also keeping the center pin sharp on the cutter, so they don't run out of the center punch mark. There are all kind's of extension's available to purchase for extending these cutter's to reach down in recessed area's. We been doing this stuff for a long time and can be frusterating at time's, but take a break and think about it, relax, and it will come apart one panel at a time. Good luck!!