spot weld tool recommendations

[911 tweaks]

I am tired of using the blair spin on barrel shaped cutters that always loose a tooth and the bit becomes useless...what are you all using for bits & possibly a drill tool set up to quickly & effeciently drill out spot welds on porsche panels...thx in advance for all of your help here...bob

[Bob Kontak]

This guy drills out the spot welds.

You will also have better luck in the paint and body work forum.

http://forums.pelicanparts.com/paint-bodywork-discussion-forum/506621-project-911r-something.html

[Tom '74 911]

I just asked Fishcop (John) the same question in his thread in the Paint & Bodywork forum. He said he started with the bits you mention, then switched to a specific spot weld cutting tool bit that he used in his drill. I've been looking at spot weld specific drills and they look to be the ticket as you can set the drill depth to drill through just the top layer... They aren't cheap ($250-$500), but my guess is that this is the type of tool that would make drilling spot welds so much easier than fighting with the bits you're using. Like this one on my wish list:

[r-mm]

On my alfa i used a really cheap, probably harbor freight hole saw style, started with a center punch or small pilot hole. Key is getting the drill normal to the surface being drilled so it doesn't walk. Maybe i had good luck but if you treat it like a saw not a drill, ie dont just plunge hard, i have found them to be remarkably durable, and even if you break a few they're double sided and very cheap to replace. Grab a half dozen. Im pretty sure i used one bit and got literally dozens of old, irregular 70s alfa spot welds drilled out nice and cleanly. If the geometry you're dealing with prevents getting the drill normal to the work, this advice won't help.

[1990C4S]

Step drill.

[Daves911L]

Spot welds are tedious, but the results are worth it. As often as not, I use the blair cutters and have good luck. Its is just a matter of patience an having good centering. Rather than center punch, I dimple each one with a very small drill bit first so the center pin won't walk. They wear out and you do occasionally break a tooth, and you must consider them expendable.

I have one of the fancy "Spottool" guns like Tom posted. It works very well, but takes time to set up correctly and you must have the ability to access both sides of the panel. For certain situations its a dream, but its usefulness is limited.

There is always the good old grind-it-down-and-peel-it technique too. If you are sacrificing the top panel, thats as fast and simple as anything.

DG

[Festive_Zombie]

My favourite is the SnapOn, went through a bunch of the type you are using. Only ever needed one of these! Center punch first to get best results.

I also recommend a dab of cutting fluid on each weld.

SWDK438, Cutter, Spot Weld, 3/8"

[Fishcop]

I'll chime in

The problem with those cheaper 3/8 bit is that they are too big a diameter compared to the welds Porsche use. You end up with big Swiss cheese holes that are a pain to plug-weld later.

You want to cut the bare minimum around the weld... about 6mm

[Festive_Zombie]

They come in various sizes on the 914 the smaller bit would not always get enough metal out to pop the weld...

[sballard]

I tried the spotweld cutters, but eventually switched to the drill bits. Drill bits were faster, removed less material, and were easier to get into tight places.