Core support spot welds

[97nismo]

So I have been rebuilding my car after a minor fender bender and the top of my core support took a big part of the damage....it has a thousand spot welds and the angle grinder ain't working or the drill bits....any suggestions? I can't locate mini holesaw bits which I have heard works

 

[engineboy]

They actually sell spot weld drill bits. They are for doing that exact thing and work great, just need to find a place that sells them.

I know tool trucks carry them, I imagine any body shop supply place would have them.

Here ya go.

http://www.eastwood.com/welders/spot-weld-cutters.html

 

[Thunderbisciut]

I use a Blair 11082 spot weld cutter kit. Comes with the mandrel, 2 tips, and 3 cutters for about 40 or so. I've only used it for about 15 to 20 holes so far, but the cutter shows no signs of dulling.

I also use a 3" cutoff tool. Much quicker than an angle grinder. Just position it over the weld, and gently go back and forth over it. You don't need a lot of pressure at all.

Manufacturer's site.

 

[97nismo]

Yea problem is the replacement part I have needs to drilled out too...didn't want to wait...wanted to pick a bit up at lowes or something

 

[73surffisher]

The one pictured above can be picked up at napa , , , put some type of lubricant on the spot weld , , , ,if you use a center punch first it (put a punch in the center of the spot weld) will keep the cutter from wondering around when you start to cut

 

[metaleltr]

Yea problem is the replacement part I have needs to drilled out too...didn't want to wait...wanted to pick a bit up at lowes or something

You may have an auto body supply locally where you could walk in and pick it up. Also this may be an option if you have a local oriely auto parts

http://www.oreillyauto.com/site/c/d....oap?ck=Search_N2191_-1_-1&pt=N2191&ppt=C1958

http://www.oreillyauto.com/site/c/d....oap?ck=Search_N1977_-1_-1&pt=N1977&ppt=C0063

 

[alwaysFlOoReD]

This is the bit I prefer. I bought it at KMSTools (western Canada only), and it works much better than the one first shown in this thread.





Sorry for the focus. Hope you get the idea,

Richard

 

[Beaumont67]

This is the bit I prefer. I bought it at KMSTools (western Canada only), and it works much better than the one first shown in this thread.



Sorry for the focus. Hope you get the idea,

Richard

^^^^ Thanks OoReD - if I only ordered one cutter bit, should it be 5/16" or 3/8" ??
- thks for your help

 

[twertsy]

Spend the money and get the Rotabroach. Also get the "BOELUBE" in the picture. Cuts through spot welds like butter. I do it every day and haven't replaced a bit from Rotabroach in over a year.

 

[chipper]

HF sells that spot weld cutter you could also use step drill bit if you had one handy but the cutter is the right tool for the job

 

[twertsy]

HF sells that spot weld cutter you could also use step drill bit if you had one handy but the cutter is the right tool for the job

After snapping the teeth off of 5 HF spot weld bits over the course of 3 days, I went with the ones I posted above.

 

[97nismo]

Well hopefully I can find something that will work out...heading to a local body shop

 

[rsanter]

How does an angle grinder not work for that.
An angle grinder and a die grinder with a carbide bit are my prefered methods

Bob

 

[97nismo]

i think its because of the area of the spot welds. I actually am removing a top portion off a good support and welding it on just the part where mine is busted. If i was removing the entire core it would work fine...i cant justify a 500 core support but somehow i can justify a 100 dollar snap on ratchet lol

 

[metaleltr]

^^^^ Thanks OoReD - if I only ordered one cutter bit, should it be 5/16" or 3/8" ??
- thks for your help

3/8 it will make sure you can cut out the entire weld, and it is just as easy to plug weld the larger hole

 

[MBfreak]

I have done a fair bit of spotweld removing, I rebuilt a MB 230 SL where front and rear wheel arches are spotwelded with Teotonic amounts of spotwelds.
I used a "hole saw" type of tool, as shown in the thread.
Some tips.
Cut away as much as you can of the part to be removed , leaving just a flat strip.
Lightly sanblast the spotweld surfaces, this bring out every single spotweld.
Centerpunch each spot LIGHTLY-
Starting from a free end of the strip drill thru most of the top metal and then tilt the tool to go thru the top metal on around 50% of the circumference. Repeat all over, tedious but no way around it.
When you have a decent length of strip done, take a hefty pair of pliers and roll off the strip, by letting it spin up on the plier, a bit like you would do to open a tin can of sardines.
The spots will be sitting on the stationaru part of the job, with one end sticking up.
Take a high quality chisel, sharpen it to a knife edge.
Chop off each spot weld circular remains.
Do this with care and the base metal will not be distorted.
Clean up the surface with a grinding disc, then straighten out any bent/distorted area carefully.
Apply spotweld primer, spotwels back and caulk the seams real careful.

This is a great method , but probably only applicable to major replacements where there are no parts left in place .

The MB230 SL (W113) is all welded panels, so replacements are a major exercise in bodywork!

Ola

 

[JeepsAreBuilt]

^^^^ Thanks OoReD - if I only ordered one cutter bit, should it be 5/16" or 3/8" ??
- thks for your help

5/16" or 8mm.... the 3/8" works too, but will cut a bigger hole to weld back up if you needed to.

You can also use a regular drill bit to break spot welds.. and the panel not being replace would be ready for plug welds.. just make sure the replacement panel is not being drilled out in the same spot. And, also that you have enough access to mig weld it. If planned correctly, this can save you time and money(on spot weld bits).

 

[wrench]

After snapping the teeth off of 5 HF spot weld bits over the course of 3 days, I went with the ones I posted above.

I have had really good luck with the Harbor freight cutters.I run them slow and get lots of use out of them.You must be abusing them if you broke that many.I have even used the HF cutters on a Blair mandril. If you use a 3/8 bit you are going to have a hard time making neat plug welds on that core support.5/16 should be plenty big. When I am doing visible plug welds on the top of a core support,I do the weld,and tap it lightly with a body hammer while it is still red,it flattens the plug out nice and neat.

 

[twertsy]

I have had really good luck with the Harbor freight cutters.I run them slow and get lots of use out of them.You must be abusing them if you broke that many.I have even used the HF cutters on a Blair mandril. If you use a 3/8 bit you are going to have a hard time making neat plug welds on that core support.5/16 should be plenty big. When I am doing visible plug welds on the top of a core support,I do the weld,and tap it lightly with a body hammer while it is still red,it flattens the plug out nice and neat.

Wrench, you would be correct in that I was going at them a bit hard. After slowing down (as you suggested), they did last a bit longer, but still wore out much quicker when compared to the Rotabroach. Also, I can't stress the "Boelube" enough. It's like a powder lubricant that you dip your bit in before cutting. The stuff is amazing. I believe it was developed by Boeing for machining / cutting aircraft grade materials. I use it for absolutely everything cutting/drilling/milling metal.

 

[97nismo]

So I got me a spot weld drill bit and man did it work....took out 26 welds in 10 minutes but....that was the life of the bit it dulled quick and turned blue but it was only 15 bux so I am super pleased thanks for the help guys

 

[metaleltr]

If it was dull after that you were drilling way too fast, slow down and use steady pressure you should be able to drill twice or three times that may welds, the holes saw cutters usually break before they cut many welds

 

[Blake150]

Make sure you take good measurements and square out your new upper tie bar. You can use a tram bar from the strut tower to the opposing side of the support and repeat on the other side. That way when you build it you won't have any supprizes.

 

[Chris_Hamilton]

So I got me a spot weld drill bit and man did it work....took out 26 welds in 10 minutes but....that was the life of the bit it dulled quick and turned blue but it was only 15 bux so I am super pleased thanks for the help guys

Maybe I can help. As a Autobody Tech I learned a long time ago the when you are disassembling something and replacing it (like your radiator core support) the fastest and cheapest way to remove the spot welds are to simply grind them. A thick 3M wheel in a die grinder works best. Locate the spot weld, grind with medium pressure until the metal starts to turn blue.(this means the top layer is getting thin) Repeat until you have all the spot welds needed to be removed done. Then take a thin chisel or something you can hammer on ( I have found a gasket scraper works great) and start to separate the 2 layers of metal. If you do it right you'll see the outline of the spot weld as you wedge the tool between the 2 layers. And you'll have little to no marking of the bottom layer. A few taps with a hammer is all you need to separate the 2 layers.

Keep in mind this only works on something you are replacing. If you are removing something and planning on reusing it, you need a spot weld cutter of some type. (the end mill type seems to last much longer than the hole saw type). But for replacing you only need a die grinder, a 3 inch diameter, thick cut-off wheel. (3M #1991) and a 1/4 -5/16 drill bit for making your new plug weld holes. Always drill and plug weld as many holes as you removed. And try and stay away from ever making 3/8" holes as the are unnecessary for anything but multi layer structural type plug welds (unibody frame rails) A 3/8" hole is much harder to plug than a 1/4"- 5/16" hole (which duplicates the size of most factory spot welds).

Hope this helps.

 

[b-body-bob]

I bought the expensive Blair kit on a recommendation, but found later that the HF $4 a pop spot weld cutters work just as well for me. I'm not doing it professionally but I've cut a helluva bunch of spot welds working on cars as a hobby (R&R of an inner and outer cowl, inner fender, rear crossmember, etc.

I like to use a 5/16 hole when using new panels. I found 1/4" isn't always enough given my level of welding skill. Nothing like finishing the nth plug weld and hearing the nth-1 weld pop loose. I started using bigger holes and the problem went away.

 

[metaleltr]

1/4 is too small to plug weld, the industry standard for replacement panels is 5/16 or 8mm,

This is the standard that the ICAR welding qualification test is done to

 

[97nismo]

I used the 8mm bit and it worked very good...actually when I bought the car the passenger radiator bracket was always off a little causing the radiator to sit a little low...after welding the new top back on it lines up so nice now.

 

[bodyguy16]

Spend the money and get the Rotabroach. Also get the "BOELUBE" in the picture. Cuts through spot welds like butter. I do it every day and haven't replaced a bit from Rotabroach in over a year.

I 2nd this ...the lube is very important I personally use the blair lube cause its provided at work.

 

[Chris_Hamilton]

1/4 is too small to plug weld, the industry standard for replacement panels is 5/16 or 8mm,

This is the standard that the ICAR welding qualification test is done to

1/4" is not too small, many factory spot welds are 1/4" (or metric equivalent of 6.5mm). ICAR recommends 5/16 for structural plug welds. Smaller is perfectly acceptable in many instances involving non structural parts.

 

[97nismo]

Uploaded some pics

 

[97nismo]

After pic

 

[97nismo]

During pic