So, bought a Blair spot weld cutter for some body work. First spot weld OK, second one broke the teeth on the bit. Turned the bit over to use other side and that lasted only one spot weld. Went back to regular drill bits and finished up the job. What the heck did I do wrong with the Blair bit as I was really disappointed in performance?
Blair Spot Welder Cutter
- Thread starter bfr57
- Start date
Ilikeike
ALLIANCE MEMBER
I didn’t like those reversible ones either. These Blair’s worked great https://www.amazon.com/dp/B002XML5HK/?tag=atomicindus08-20
I used a drill, the Blair cutters, grinder, hammer and homemade chisel on welds when I did my mini tub job. Just depended on the position I was in.
I used a drill, the Blair cutters, grinder, hammer and homemade chisel on welds when I did my mini tub job. Just depended on the position I was in.
evintho
Well-known member
I just replaced the floors on my '54 Ford and had to drill out a zillion spot welds. Went to HF and bought their cheap $5 spot weld cutter. It's dual sided. Worked fine until about the 15th spot weld then I noticed a tooth broke. Flipped it over and drilled out another 30 spot welds......then a tooth broke. Back to HF and bought two more. Finished the job and now I have a spare cutter and a half. Total spent...$15.
Suggestion: if you go this route, they're so cheap....buy a couple at a time.
Suggestion: if you go this route, they're so cheap....buy a couple at a time.
finn
Well-known member
The Blair I have has outlasted a dozen of the HF type cutters.
HMCFab9
Well-known member
Most of those double sided hole saw type spotweld cutters ****! Unless you are really careful, they break quickly.
There are better options available
There are better options available
emeraldcoupe
Well-known member
the HF cheap ones work great believe it or not. I just used it again yesterday to cut about a dozen.
metaleltr
Well-known member
Run slow on a cordless drill. Use an 1/8” drill bit to dimple the center of the spot weld to prevent the cutter from walking.
neophyte
Well-known member
Running the bit really fast might actually be safer and help prevent bit breakage.
Cobalt bits for instance are supposed to be run at higher drill speeds, since heat isn’t really an issue for cobalt alloyed steel, but brittleness is.
This is specifically out of the speed recommendation in the Precision Twist Drill catalog.
Higher speed is also usually recommended for carbide tipped bits.
There seem to be several different types of Blair bits, although Nlair recommends slower 500RPM speeds.
FJ 432
Well-known member
I've had success with HF as well. The only problems I've had is self inflicted and go to far.
speed bump
Well-known member
I bought the hf cutter and it was unimpressive so I put a blair cutter on the hf mandrel and it has done well. Spin it slow and feed it gently.
Twenty+ years ago when I was doing collision work the shops would buy the blair two sided bits for us. If you don't work slow and keep the bit flat, the teeth will break. I used an air drill with a regulator on a slow speed and they would last. I also had a Blue Point spot weld drill. Nowadays, it seems that the mini belt grinder is the way to go. Just grind the metal away.
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dnschmidt
Well-known member
THIS ^^^^ Spot weld bits are a thing of the past. With the new high strength steels like boron steel they're useless. These belt files will remove 100 spot welds before you need a new belt and the belts cost $2.00 each. Astro makes good ones.
kabinenroller
Well-known member
That is the ticket! My suggestions exactly. I have a few HF spot weld cutters, they have lasted well if used correctly.
Jazz1
Well-known member
I used SH Industries spot weld cutter to remove floor pans in my ‘68 Firebird. I gave 15 year old #1 son the job of cutting all those spot welds. Bit was getting tired so boy started putting a 1/8” pilot hole at each weld to complete the job. Floor pan removal of those cars is a tedious job, a billion spot welds
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sweetk30
Well-known member
yep them 2 sided bits are good . just dont go crazy . light pressure and kiss kiss kiss tends to be the ticket . i also center punch them first to help hold center before starting .
Vinny
Well-known member
How fast can those mini belt grinders get through a spot weld?
My HF is so stupid they took 5 of them back with heavy wear and broken teeth. Damn glad I looked at the one in my hand a little closer before checking out. Threw the 5 **** ones on the bottom shelf so no one else would get screwed. I'm sure they were back on the peg by the next day...
