Spot weld drills

[Lindsay36551]

Hey all, I just ordered 10 spotweld removal drills(cobalt) how many welds are usually good for?
I will be spraying oil to cool as I go.

[njjeeper]

The answer directly depends on the quality of the cutters you bought. Good ones are expensive and if you bought 10 I suspect they are the cheapo Harbor Freight type. On the last set of VW Beetle rockers I drilled out I was getting 5 or 6 good cuts out of the HF bits. They dull fast and break easy, even with WD40. A Blue-Point(sold by snap-on) single bit is about 50 bucks. They last a good long time as long as you dont burn it up.

[rickf]

Cobalt is just a coating and is a marketing tool. They will not last you all that long but a lot depends on how you use them. Cutting oit is different from WD-40 and other penetrants so get cutting oil. Slow to medium speed on the drill. If they are the cutters that cut around the weld they will last longer than the ones that cut the entire weld.

These are good quality bits and last a fair amount of time based on above use.

http://shop.blairequipment.com/ProductD ... IUQAvD_BwE

Here are the good ones TJ is talking about, they are carbide bits. I don't think you spent 600.00 in bits!

http://shop.blairequipment.com/8mm-Carb ... /11308.htm

[Lindsay36551]

Thanks so much for the correct info!
I will be sending those back!
I need the cutter that goes around the weld ! time to check out the site you gave me and also youtube!

[rickf]

The cutter that goes around the weld is good for removing the panel but when it comes time to put the new panel on you will have to grind off that center spot that is left behind. I think that is better for the novice than trying to use a carbide bit and judge whether you are maybe not deep enough and then drill all the way through. Just when you grind off the weld do not try to do it too fast and heat it up too much. If you push hard you will find that the grinder will grind into the good metal on the downward side of the direction of the grinding wheel. Use a coarse grit and light pressure. That will keep the heat down and give better control.

[Flyingvan911]

I used a spot weld bit to drill all the way through for my rear fender tops. I pulled the old pieces off. I then straightened everything and put the new panel in place. I used the old holes to weld the panels together. It was a bit tight inside the wheel well but the panels are solidly in place.

[rickf]

If you are going to do that a cheap 3/8 drill will work but getting to the rear of the panel is not possible in some places and filling a 3/8 hole without blowing through can be tricky.