Spotweld drills

I'm looking at the Eastwood.com spotweld drills, many to choose from, cheap tp expensive. They offer a set of 5 drills, from 1/4" to 1/2" for about 119.00 see
Colbalt Spot Weld Cutter kit 1/4 5/16 3/8 1/2


Item #50192.

http://www.eastwood.com/colbalt-spot-weld-cutter-kit-1-4-5-16-3-8-1-2.html

This item has a Limited lifetime manufacturer's warranty; and others with no warranty. Does anyone have any experiance with these colbalt cutters? Is this a good deal?
What type/style/make of bit lasts the longest and do the best job?
I'm working on a 57 GMC panel with forward floor panel, forward floor panel support, and lower door hinge support componentsthat have to be repaired/replaced.

 

send a pm to jagfixer1949 he can probably help.

 

Back in the day, I had good luck just using brad point drill bits

 

lisle tool company has my business there.

 

Yeah, just grind your own on a wornout 5/16 drill. The point doesn't need to be anywhere near as sharp as the one in the picture, so long as its higher than the lips on the flutes.

 

One thing about the "hole saw" type of spot weld cutter is that they leave the "body" of the spot weld behind. You will have to sand or grind it down before fitting the new panel.

It is an extra step, and it risks warping the unsupported edge. Be careful.

Cobalt bits are good and hard, which is what you want, because most sharpeners, or sharpening techniques can't reproduce that tip profile.

Whatever you use, don't overdrive it and heat it up. Use oil, if it is practical.

 

If you have a grinder, you can make your own.

 

I never had good luck with the "hole saw" type, they always seem to shatter and break at the wrong time, like when I'm working with them, but for a long time, they were what was available. Blair makes a nice unit that's the solid type, has the pilot bit to keep it aligned and leaves no welded ring behind, no grinding afterward...and they're MADE IN THE USA!

http://www.blairequipment.com/Spotweld_Cutters/Spotweld_Cutters.html

Eric

 

Don't I know you?

 

Thank you all for your response(s) and input! I will look at the mentioned types....., I would like to order 100 bits @ $1.00. a piece if they will do the job or 1 bit for $100.00that would last through the job, come with a limited lifetime warranty....
I take it there is no experiance with the bits in question...?
http://www.eastwood.com/colbalt-spot...6-3-8-1-2.html

I have never had much luck sharpening drill bits to the conventional shape, I realize that I would probably save some money but right now with the limited time I have to spend out in the Puget Sound Elements (I have no garage or proper floor to work on just a board on the gravel in my drive) I'd rather spend the money being productive vs. making tools when I could be using the tools.
Thanks again for the help!

 

How about 25 more replies from about a month ago?

http://www.jalopyjournal.com/forum/showthread.php?t=469314&highlight=spotweld+cutter

 

Thanksa lot; there was a lot of good info there!