What is your favorite brand and style of spot-weld drill?

[95avblm3]

I am to the point on my project Turning a "Boxster" in to a longhood! where I need to start cutting and welding some sheetmetal. If anyone is still following that thread (sorry for dragging on so long about what to do) I have good news... I have a plan!

So I thought I would pose a question. Please understand, I did a quick search and didn't find the answer... I have also been wrenching on other cars today and wasn't really focused on digging too deep to find the answer, so to the search patrol, please cut me some slack today?

What is your preferred style and brand of spot weld drill?

I have a small set from Northern Tool that sort of looks like a hole saw with a centering pin. I struggled to make a dimple with a punch that the centering pin would stay in and in the process of messing around with it, broke the teeth off of the saw part. Call it user error, call it cheap NT crap, it flat out didn't work.

Dismayed, I retreated to my family room to watch the marathon of Wheeler Dealers I DVR'd over Christmas. If anyone has seen the episode with the Nissan Skyline, Edd China used a different kind of spot weld drill. His looked more like a regular drill bit with extra "teeth" at the top of the flutes. I'm not sure what this type is called, but it seemed to work real well. Of course, everything probably works real well when you have the magic of editing.

Back to the question at hand, what do you use. Thanks in advance for your responses.

Cheers!

[sailchef]

I got two of these from Harbor frieight. Never punched. Just drilled. $3-4 each I think. They are not super expensive high tech bits but worked fine for me. The centering pin is spring loaded.



I think its more technique than anything else. Just drill the little buggers. I doubt you can center punch a weld. The welding meterial is to hard. Maybe you can, I don't know. I never did.

[wildcat077]

These are a charm ... the technical name is a spotface,they come in different diameters and you can use different sized pilots.Since the cutting surface is flat,you only remove the metal to the depth you need ...

Cheers !
Phil

[95avblm3]

Originally Posted by sailchef

I got two of these from Harbor frieight. Never punched. Just drilled. $3-4 each I think. They are not super expensive high tech bits but worked fine for me. The centering pin is spring loaded.



I think its more technique than anything else. Just drill the little buggers. I doubt you can center punch a weld. The welding meterial is to hard. Maybe you can, I don't know. I never did.

These look identical to the ones I got from Northern Tool... Perhaps I was over thinking it but they just wanted to run all over the place. Thanks for the post!

[95avblm3]

Originally Posted by wildcat077

These are a charm ... the technical name is a spotface,they come in different diameters and you can use different sized pilots.Since the cutting surface is flat,you only remove the metal to the depth you need ...

Cheers !
Phil

Thanks Phil! These look pretty nice. I may go look for some and give them a shot.

[timmy2]

I picked some up from Eastwood a few years ago. Not cheap but it works.
Spotweld Drill 3/8" Pro

[jhelgesen]

I prefer to use tool makers carbide "die drills" in 3/16 or 1/4 dia. Center punch the weld and drill until the panel is loose.

[r-mm]

+1 on HF. I always use a countersink or small drill to make a pilot hole or the spot weld cutter dances around like crazy. I've never been able to flip the cutter over (supposedly reversible) but they last a remarkably long time for a cheap object.

[Rotmilky]

I've used the ones from HF and Northern tool shown above. They worked great on flat surfaces, but if I was drilling a spot weld that wasn't flat and smooth, I'd break the teeth off. I've broken maybe 5-6 sides. So a total of 3 cutters I've mangled (since there are two cutting surfaces) Maybe I'm a bit ham fisted. Anyway, I came across Rotabroach cutters somewhere and bought a set. The cutting teeth are much thicker. I haven't managed to break them off. Maybe that's a good sign? If I can't break it...then no one can. Anyway, they have a spring loaded centering tip just like the HF jobs and basically are a similar design as the HF jobs except for the beefy teeth.

Anyway, here is the set I bought, although I didn't get them there:
Amazon.com: Blair Equipment 11090N Rotabroach Cutter Kit: Home Improvement

[NY65912]

I've had good luck with the Eastwood bits. They're probably relabeled Chinese bits anyway.

[sailchef]

When i used the HF drill bits I was using a cordless variable speed drill. Just place the drill head over the weld and press down lightly, the center punch will retract ( its spring loaded) start out very slow with light preasure until you scratch a ring around the weld. once the teeth have a path to follow you can increase the spead. when the teeth go thru the top panel you can feel the bit give a little and you stop drilling before going thru the next panel. you need to keep everything flat , level, and it takes a little elbow greese to hold the bit steady for the first few revolutions, but once there is a track inscribed for the teeth to follow you can just rip thru them.

[not_hans_stuck]

+1 on Eastwoods...

[timmy2]

Eastwood does have their stuff made in China but.. Better quality than HF.
I bought their intergrip panel holders for $20 a set, then found HF has ones that look the same for about $5 a set on sale and bought them. Not even close in quality. The difference in usability was like night and day.
Bottom line, You get what you pay for.

[95avblm3]

Originally Posted by Rotmilky

I've used the ones from HF and Northern tool shown above. They worked great on flat surfaces, but if I was drilling a spot weld that wasn't flat and smooth, I'd break the teeth off. I've broken maybe 5-6 sides. So a total of 3 cutters I've mangled (since there are two cutting surfaces) Maybe I'm a bit ham fisted. Anyway, I came across Rotabroach cutters somewhere and bought a set. The cutting teeth are much thicker. I haven't managed to break them off. Maybe that's a good sign? If I can't break it...then no one can. Anyway, they have a spring loaded centering tip just like the HF jobs and basically are a similar design as the HF jobs except for the beefy teeth.

Anyway, here is the set I bought, although I didn't get them there:
Amazon.com: Blair Equipment 11090N Rotabroach Cutter Kit: Home Improvement

I had the same problem. I was trying to drill out the driver side battery box and the flange was slightly bent due to prior, unresolved accident damage. I broke teeth off. This kit on Amazon looks pretty interesting and really isn't priced too bad, I don't think. thanks for the post!

[95avblm3]

Thanks everyone for all of your posts. Here is what I have gathered so far, either from your posts or my experience:

1) The reversible bits like the one shown in the post by sailchef from HF or NT work okay on a perfectly flat surface. Hit a non-flat surface or drop one and they are toast. They are cheap though and you get what you pay for.
2) Eastwood is priced higher but seems to have higher quality. This seems to hold true on other things. My welder is a 220V Eastwood... I chose it because I got it on sale. It has worked great so far and far superior to my brother's HF.
3) The are alternative spot weld drilling options to the ones mentioned above in no.1. It sounds like some of the other options laid out here my be better for me since I am dealing with wrinkly, not rusty spotwelds.
4) For any of these to work well, it sounds like in most cases, either a pilot drill or good center punch is required.

I'm looking to pick up new sheetmetal soon, so I will be working on drilling out these spotwelds.

Thanks again for the input!