Easy Way to Grind Off Spot Welds
- #1
Hi folks - what's the best way to separate spot welds? 
Cheers
C.T.
- #2
Drill them out, I reckon. I've been drilling hundreds of the buggers out on this MGB I'm rebuilding. I've got a nifty little thing with a spring, but you can use an ordinary bit if you're careful.
Hitch
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- #3
Proper spot weld drills are available, but i use a standard hss bit, but grind the edges so they are quite shallow.
malcolm
& Clementine the Cat
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- #4
Depends what you are doing - for removing a panel to replace I tend to grind through them and pop them off with a screwdriver:
- #5
Malcolm
One panel seems OK and only part of the other panel needs replacing.
I'm looking for a tidy way to leave one panel intact whilst cutting out the rotten bits of the bad panel and butt and plug weld a patch.
So how do you avoid removing too much metal when grinding? Use a 110mm fairly thick disk on edge?
Drilling: Would you drill part the way through or ALL the way through?
Hitch
Do you mean: grind the drill so that the drill point is a very shallow angle (flatter)?
Cheers.
C.T.
malcolm
& Clementine the Cat
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- #6
I tend to use a thickish disk on the edge or corner. The top layer heats up to bright red before it grinds through. Stop then and there's no damage to the other panel. You get a feel for it after doing one of two, and it's quite quick. Around 150 spot welds in that floor panel!
- #7
With the spot weld cutters (about a fiver from eg Machine Mart), you can set the cut depth. It just cuts a ring around the weld in the old metal. You grind the welds off when you remove the old panel.
zardoz
Old school Socialist
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- #8
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zipcut.jpg
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- #9
i used to use those a few years back
then all of a sudden i could'nt get then as the local shops stated to only sell the small mag cutters 
now i know where i can get them again 
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JS-MM29007.jpg
- #10
Ah, thems the things I was talking about, didn't know they was called zipcutters!
- #11
?
keep the drill speed slow or you strip the threads that the cutter attaches to,found out the hard way.
Hitch
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- #12
Yes, rather than using the standard 60degree angle, i tend to sharpen so its about 20-30 degrees.
Some freehand drill sharpening skils are needed though, i doubt any jigs will let it go that shallow. Sharpening at a low angle is a trick for drilling sheet metal, saves big burrs or snatching 
- #13
Thanks folks - whilst looking for other stuff I found:
I'll have to experiment.
Cheers C.T.
- #14
keep the drill speed slow or you strip the threads that the cutter attaches to,found out the hard way.
i use an old black & decker 2 speed drill
the low speed (900 rpm) is just right for using the zipp cutter 
- #15
The Screwfix type work well.
- #17
i always used a slocom (sp?) drill, the ones that are used in the dead end of a lathe for centre drilling, they do a great job
john
ps, if anyone doesn't know what one is, i'll go a take a pic tomorrow
- #18
is it tomorrow yet....
sorry.....
but its xmas
awemawson
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- #19
As im currently restoring my car ive tried them all.
So took it back, thinking it was a faulty, got another one and tried again, this time done 20 spot welds then all teeth snapped.... so temper flaring it got launched into the nearby field
Chris
Having had to dig all sorts of horrors out of animals feet PLEASE DON'T DO THIS. Be a bit more considerate.
colnerov
Member
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- #20
Different times back then. 
Source: https://www.mig-welding.co.uk/forum/threads/best-way-to-separate-spot-welds.4035/
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