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Spot Weld Drill Bit

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Any reason not to buy the $5 harbor freight bit over another brand?

 

Price ranges from $30-$40 down to the $5 bits. Will the more expensive bits last a bunch more than the inexpensive ones? Are they one-size fits all or does anyone know what size I should get?

 

For scope of work, I'll be disassembling a lot of the car. The rear bulkhead/firewall (hopefully not but maybe), rear shock towers, RR quarter panel (which I believe is completely riveted & bondo'd, not welded so no big deal), rocker panels, floors, parts of the front frame rails, nose, etc. 

 

Thanks. 

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I have no experience with them, but a friend bought a spot weld bit at NAPA that has a point in the middle, instead of a drill.  You apparently punch the spot weld and that indexes the bit, which cuts around the weld, without putting a hole in the metal you are leaving.  Is the bit you are considering like that, or is it a drill bit with a cutter?

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I was specifically asking about this one. Generally they all have either adjustable or fixed center points, presumably so the bit doesn't walk all over the metal. Or, should I just spend the $$ on a pneumatic like this

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I have used that HF one for probably 50 welds. Still going strong. I always use a little cutting fluid to help preserve it.

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I got to harbor freight for all of my consumable tool needs. Although I have not used that one in particular, the myriads of other drill bits / flap disks/grinding disks / cut off wheels etc I've used stand up just fine. Its only when I really abuse them do they burn up on me...which would probably be true of any other tool.

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Honestly, I'm not a fan, except in specific situations.  A cobalt bit that's quite a bit smaller is my tool of choice.

And then I adjust the holes as needed for re- welding.  

Yes, they work.  Yes, they leave a nice hole for plug welding.  They're just liable to head off in random directions when you're least expecting it.

And you still have to grind off the hardened nib without pooching the base panel.

 

I do my damnedest to NOT have to save one side or the other, trim off almost all of the mating panel,

then peel off the strip.  That seems to do the least damage to the donor panel.

 

But I've gotten lazy in my old age...

 

t

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Honestly, I'm not a fan, except in specific situations.  A cobalt bit that's quite a bit smaller is my tool of choice.

And then I adjust the holes as needed for re- welding.  

Yes, they work.  Yes, they leave a nice hole for plug welding.  They're just liable to head off in random directions when you're least expecting it.

And you still have to grind off the hardened nib without pooching the base panel.

 

I do my damnedest to NOT have to save one side or the other, trim off almost all of the mating panel,

then peel off the strip.  That seems to do the least damage to the donor panel.

 

But I've gotten lazy in my old age...

 

t

 

So  do you punch a small dent/imprint first so the bit doesn't walk or do you live dangerously and just have at it?

 

I've never had an issue by putting a piece of copper behind a hole I'm trying to plug weld. Have any other tips?

 

Side note... My PO was so thoughtful of future owners that he used 1/8" aluminum rivets for most of his handiwork. They pop right off with a hammer and a Craftsman flat blade screwdriver. Everything else is either grinder or BMW OEM spot welds. 

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I have to admit, I seldom center- punch.  The smaller bit will 'usually' nestle in there.

The biggest hassle is that the spot weld itself is hardened so much more than the base metal...

 

Lazy, lazy, lazy....

 

t

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Buy cheap - buy twice.

 

Depending how many points you plan to drill, but my advice is: go matco or comparable. I've got a very similar tool bought 15 years ago, and I love it. You just need to pull the handle instead of pressing your entire body mass towards the car. It works loudly, yes- pff. But very convenient.

 

Hen

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When I did both rockers, floorpans and other areas I just used drill bits, 1/4 and 9/32. I just look for the bits that have a flatter tip, think I used Dewalt bits from Lowes. Only used 3 for the whole job. Have used spot cutters in past and they leave alot of work for you to grind, were as a carefully drilled out spotweld leaves little behind except a nicely prepped area for spot/plug welding. Good luck which ever route you choose.

From Galaxy S6

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post-46789-0-49149000-1451075943_thumb.j

 

This is how my car looks....almost.  (I have done some work since !)

 

But, I have found by far the easiest AND least expensive way of removing spot welds, is to use a thin cutting wheel and cut ALL the metal away, leaving JUST the spot welds in place.  Then cut a cross in them with the same disc and then grind it off.

 

I went through tons of spot weld drill bits, before deciding this was the best way.  I am almost at the stage of reskinning the roof and I won't be touching it with a drill bit !!!

 

Obviously, you will come across areas where ONLY a spot weld cutter will fit.  For this I use a "DORMER" 8mm drill bit.

Edited by 1Eighteen

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