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Posted by: obscurity Apr 15 2010, 08:09 AM

I have been drilling spot welds as I work on my car and it occured to me that there may be a better way (or maybe I am being to picky). I am curious what everyone else uses.

I have been using a spot weld cutter. It looks like a short drill bit with a pilot point and little cutters along the edge. It will cut through the top layer or steel but not the back layer (usually). They will cut about 10 welds before being hoplessly dull. When I was buying them at $5/bit it was fine but that company went out of business and the ones I find now are $25/bit. Are these the right tools to use or should I be just using a drill bit allthe way through the weld.

Any help or tool suggestions would be appreciated.

Thanks,
John W.

Posted by: ConeDodger Apr 15 2010, 08:12 AM

That is what I use... They run about $15/bit at an autobody supply near me.

Posted by: tat2dphreak Apr 15 2010, 08:37 AM

a decent one will drill more than 10 spots... or should. remember the welding metal is usually softer than the metal around it... the metal around it will dull the blade faster.

I have one that I've used for quite a few spots(I've lost count) and it still works... I can't remember what I paid, tho I remember thinking it wasn't cheap for a single bit.... then I ended up needing it more than I thought I would.

Posted by: sean_v8_914 Apr 15 2010, 08:46 AM

harbor freight spot weld drill I use has done 3 suspension consoles, 3-4 battery trays and 2 trunks. they try to walk if your technique is off, this breaks the pilot tip. I drill a small 1/8 pilot dimple. start teh "circle" cut slow then lay into it once the "cut track" is about 1/16-1/8 deep

Posted by: 993inNC Apr 15 2010, 08:46 AM

I just did my floor pans recently and used a standard bit (sorry don't recall the size). I drilled until the bit got dull and then ran it through the bit sharpener, worked like a champ. The only issue is you can't drill quite as deep and I used a chisels to get under the pan and pop the last fringes of metal holding on. One bit, worked it down to a nub

Posted by: dion9146 Apr 15 2010, 08:54 AM

Yep, exactly what I used too, but I only used it on one suspension console and it worked like a charm. I started using a regular drill bit, but this was much easier to use and less damaging to the metal underneath.

Posted by: rjames Apr 15 2010, 09:00 AM

Would cutting fluid help with keeping the bits from getting dull?

Posted by: jasons Apr 15 2010, 09:11 AM

You know, I found using an air chisel CAREFULLY worked better than a spot weld bit. Or, using a small cut off wheel to grind down the spot weld, then pop it with the air chisel. Once you get the seam lifted up a little, the air chisel just pops it away, leaving a minimal amount of weld to clean up.

I must stress the word CAREFULLY. You can do a lot of damage with the chisel if you aren't careful.

BTW, if you are dulling them, maybe you are turning them too fast. Also, a touch of oil on the bit before you drill might help too.

Posted by: jim_hoyland Apr 15 2010, 09:15 AM

What size is recommended for say removing the spot welds for a bumper backdate project ( '75 914 )


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Posted by: Bleyseng Apr 15 2010, 09:20 AM

Are you finally going to jump to the "darkside" of early chrome bumpers?

Posted by: McMark Apr 15 2010, 09:30 AM

I buy a huge box of cheap drill bits and use those. When one gets dull I toss it and grab another. http://cgi.ebay.com/115-Titanium-Power-Drill-Bit-Set-Cordless-Tools-Bits-NR_W0QQitemZ170472586128QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item27b0f53b90#ht_943wt_941

Posted by: Porcharu Apr 15 2010, 09:42 AM

I use the solid type spot weld cutters. These are much better and last much longer than the 'tiny hole saw type'. I got 5 for about $12 on ebay.

Posted by: obscurity Apr 15 2010, 10:51 AM

The kind I have been using us the solid type. I have actually never seen the two piece version. I can't actually find them on Harbour freight but I will check e-bay.

john

Posted by: Larouex Apr 15 2010, 11:01 AM

Everyone of those cheap, HF buys will leave you pissed off and unhappy with the cleanliness of the job. I tried them all and have done 100's of them with my Wurth bits. I recommend them highly.

https://shoponline.wurthusa.com/wurthusa/servlet/CyberVendor/category/G4216046/catalog/group.jsp/

Cheers,
Larouex

Posted by: rick 918-S Apr 15 2010, 11:04 AM

I don't drill spot welds unless I absolutely have to. I grind them an slip a sharpened flat blade screw driver between the pieces and pop them. This wrecks the piece I am discarding and leaves the piece I want to clean up and save from being swiss cheesed full of holes from drilling too deep or making a bunch of thin spots that blow through when trying to reattach the new piece.

Posted by: strawman Apr 15 2010, 11:05 AM

If you're going to be tossing the piece you're removing, just grind down the spot in the outer/upper metal piece and then use a cold chisel to knock it loose -- much faster than a spot weld cutter. I use a round-head bit in an air die grinder.

If you plan to re-use the piece you're removing, then using a good quality spot welder cutter is essential. I used to use the el cheapo Harbor Freight ones, but they seem to be made out of powdered iron and break at the most inopportune times. Regardless of the cutter you end up using, I'll echo the advice above about drilling a small pilot indentation and spinning the cutter at a relatively slow speed.

Best of luck!

Posted by: SirAndy Apr 15 2010, 12:10 PM

The guys at the body shop have some special drill bits they use with a air-drill. Those last forever without going dull and the air-drill makes for very quick drilling.

I watched them remove whole panels in just minutes ...
Andy

PS: I have to ask what brand the drill bits are. I bet they are not cheap ...

Posted by: 1968Cayman Apr 15 2010, 04:23 PM

In the past I used a spot weld removal tool; if you're doing several cars or several panels that can become expensive.

Now I used DeWalt Pilot-Tip bits. They don't run like other bits and you can usually buy a complete set for $17- and use at least four of the bits to drill welds (all of the pilot-tipped ones if you don't mind the larger holes).

Posted by: roadster fan Apr 16 2010, 12:21 AM

Just my .02 but I have drilled hundreds of spot welds with the smallest size of these (5/16" i think) from the set I have and it is as good as new. Cut steel like butter! Blair Rotabroach.





Jim

Posted by: Richard Casto Apr 16 2010, 11:11 AM

When drilling, I use a 3/8" Blair Rotabroach. If you do not use cutting oil they will dull within a handful of uses. But if you use cutting oil they last quite a long time.

As much as I love the Rotabroach, I also grind down the spot weld and pop apart and sometimes just drill straight through using a regular drill. It just depends upon the situation.

Posted by: charliew Apr 16 2010, 12:38 PM

My experience with the hole saw spotweld cutter is it leaves the center still stuck to the bottom piece and you still gotta grind the saved piece clean, but it doesusually cut faster. Also it seems to me like a spot weld is harder than the surrounding metal, a dimple makes it stay in the exact spot you want to cut. I also use the cutters that are reversable with cutting oil but I also use a carbide cutter in a air tool sometimes also. I always end up using a chisel either by hand or in the air tool to peel the top piece off though. I don't remember ever not needing to go back with at least a sanding disk to clean the saved piece up. Be sure and really hold on to a grinder or sander when you are in a tight spot, your nose is not metal.

Posted by: ghuff Apr 16 2010, 01:16 PM

So far mine have survived a bunch of spotwelds on the 914 so far with no sign of dulling.

Warning, unless you can get straight onto the spot eld, you may end up going through, it is very easy to do so at an angle.

Posted by: obscurity Apr 18 2010, 10:55 AM

OK I bought one of the hole saw type cutters from harbor Freight (I know HF sucks but I want to give one a try before I sepend real money)

Where can you buy wurth brand cutters? The Wurth page looks to be for commercial accounts only. Is there somewhere else or do I just represent myself as a business.

Thanks,
John

Posted by: charliew Apr 18 2010, 10:58 AM

You can try being a business but you may need a tax id #. I would try a online body tool place or eastwood .

http://www.autobodytoolmart.com/search/search.aspx?keywords=spotweld+cutter

Posted by: Porcharu Apr 18 2010, 01:15 PM

Cool! I have never seen the tiny ones like those before. I have a good selection of bigger ones (say 5/8" - 1-1/2") They cut 1/4" steel like it's plywood and leave a nice machined edge.
One more thing to put on the wish list.
Steve

Posted by: sixnotfour Dec 25 2019, 06:38 AM

https://www.amazon.com/drill-remover-cutter-cobalt-BERGEN/dp/B01M9GUVX8

Posted by: Superhawk996 Dec 25 2019, 08:36 AM

Yes.

In addition, many times when a bit goes dull early (and 10 is early) the bit is being spun to fast and/or too much pressure is being applied.

This creates excessive heat at the tip of the cutting edge and it rapidly goes dull. The bits are made of High Speed Steel (HSS) which is just common tool steel and isn't particularly tolerant to being overheated. Carbide rotatry broaches cut faster and will be more tolerant of heat but they are way more $$.

Slow the drill down and don't push as hard. Once it gets dull the natural tendency is to try to speed up and/or push harder, this just dulls even quicker. Change to a new bit and SLOW DOWN!

Posted by: IronHillRestorations Dec 25 2019, 08:45 AM

+1 on Blair Rotobroach. I use a punch to index the center of the spot weld, and as others have said a little cutting fluid or oil, and be sure to set the depth stop. Some locations require grinding out the spot weld, for which I use a carbide burr

Posted by: cary Dec 25 2019, 09:29 AM

https://www.blairequipment.com/spotweld-cutters

https://www.airgas.com/product/Tools-and-Hardware/MRO-&-Plant-Maintenance/Magnetic-Drill-Cutters-&-Cutter-Accessories/p/HOU14005?fo_c=306&fo_k=8f33a3e74d36d2ea81d13871358e0873&fo_s=cstmc&s_kwcid=AL!10136!3!381309882230!!!g!813912737400!&utm_arg=SEM:Google:GSN_-_General_-_Tools_and_Hardware- Magnetic_Drill_Cutters_and_Cutter_Accessories::pla:pla:Airgas:tools_hardware::HO
U14005::PLA&gclid=Cj0KCQiArozwBRDOARIsAHo2s7vpOg-kJ-5WcBV_L61xR4ChehNXTTkRygFUNMp4K27ah1RBfblZYCoaAib8EALw_wcB

Ditto on what Perry said. I use a Rotabroach when needed.
Primary technique, die cutter wheel and wood chisel. Peel it back like a sardine can.

I can go all day on one bit. But I use Hougen dipping sauce in each spot weld.
https://www.airgas.com/product/Tools-and-Hardware/MRO-&-Plant-Maintenance/Lubrication-Equipment/Lubricants/p/HOU11746-24?fo_c=306&fo_k=b4af57c26419b50c748b2827914d4198&fo_s=cstmc&s_kwcid=AL!10136!3!381309882890!!!g!813860527163!&utm_arg=SEM:Google:GSN_-_Brands_-_Tools_and_Hardware-Lubrication_Equipment::pla:pla:Airgas:tools_hardware::HOU11746-24::PLA& amp;gclid=Cj0KCQiArozwBRDOARIsAHo2s7tKJgbNBt8sJO7pbZ8yzLsv_F6MaBg0T_Fa9zEIUvW6HO
JHX-AwR-0aAsBREALw_wcB
I get my replacement cutting heads thru AirGas.
Most important info. Keep head perpendicular to the spot weld. And let the tool do the work work. No pushing.
Oh yeah, your going to break a few on the after lunch or beer break welds. Two stacked on top of each.

Posted by: porschetub Dec 25 2019, 01:30 PM

Best to buy these by price,I payed $35nzd for a quality one and it did a huge amount of work,I used tried and true Triflex paste drill lube on most of the cuts.
Used this bit on my 66 one year only Beetle rustoration,did one floorpan ,1 heater channel and the whole upper section under the rear window,did some work on my 74 camper also,by that time it was getting a little dull.

Posted by: draganc Dec 25 2019, 03:30 PM

I have used HF and quality spot weld drill bits and didn’t really like any of them.

My buddy, who is working in a body shop, got me a narrow small belt sander with
60 grid paper and it works like a charm. Takes less then 30sec per spot.

I have a 3m but I’m sure any other quality tool will work.

Posted by: 76-914 Dec 26 2019, 01:43 PM

I remember you telling me that years ago. After I had been a bit aggressive with the spot weld bit. Good tip as always.

Posted by: Literati914 Dec 28 2019, 02:50 PM

I've used the HF bit w/cutting oil and it's work fairly well - my only complaint is that it left behind a hole that was bigger than I wanted, for re-using a panel and also you still have to clean up the welded center with a grinder.

..I like this - are you using this sander to go completely thru, down to the base metal ? Nothing else required?

Posted by: GTSandberg Jan 2 2020, 07:26 AM

also prefer to use a small belt sander. Grind away until the metal turns blue around the actual spot. Then it is thin enough to just pry away with a screwdriver or similar.

Posted by: djway Jan 3 2020, 01:25 AM

For the 914 I have on the rotisserie I had to dissect near 2 cars lower half to get what I needed to remove and replace.
I scuff the area to see the recessed areas of the spot welds then I use the spot weld cutters, mini hole saws, with a waxy lubricant or drill bits, depending on the angle of attack. The drill bits were faster. Drill in through top layer then use a HF painters putty knife to split the little hangerons. I have split hundreds of spots with the same blade so far. I also use the large spot weld splitter bars where more muscle is needed and whacked it with a big ass hammer.
I had them all sitting there and switched around as necessary.

Posted by: bkrantz Jan 3 2020, 09:30 PM

I have noticed that with the Blair cutter, the 3 bits that came in the kit seemed to dull quickly, but the first replacement bit has stayed sharp after drilling many more spot welds.

Posted by: bbrock Jan 3 2020, 09:36 PM

Hmm. That's interesting. My first set of Blair bits in the kit lasted a LONG time keeping the drill speed slow and liberally using a Blair lubrication stick. I did go through two sets over the course of my build but didn't notice any difference between the original set and replacements. In the long run, the Blair bits were quite a bit cheaper per spot weld than the HF bits.