Well, I bought my first spot weld cutter (hole saw type) from NAPA thinking they would have a good one ... It lasted 3 holes per side!! I've been really bummed ... and dreading the multiple spot welds to go.

Anyhow, now I want to find a good hobby'ist one ... I know MartinSR is fond of the specialized drill. Can't afford it though.

What are opinions of Motor Guard JMC001 or Blair RotaBroach 11,000 Series. The nice things here, is they seem to be getting into tool steels. I think mine from NAPA was mild-steel at best.

I'd be willing to spend $30-40 if I could do lots of spot welds. I can't spend another $12, and do 6 spot welds:-(

Any help, please? I'm really discouraged by what I see.
Thanks, Neal

the ones I use seem to be made from a carbide. but I do break them sometimes. but they are always sharp and cut good. sorry i cant help you with the brand i got tham at an auto body supply joint i dont know who makes them.

Neal, Martin and I have the same spot weld drill, its the cat meow but for the guy doing one car in a lifetime graemlins/clonk.gif
http://206.117.149.144/acb2/showdetl.cfm?DID=6&Product_ID=30&CATID=3
Just buy the bits for the drill!!
They range from 15 to 30 bucks will last darn near forever!!
http://www.dentfix.com/acb2/showdetl.cfm?DID=6&Product_ID=23&CATID=3

Then install them in an angle drill or regular drill...Eric

Well, I ordered one of their "zip bits" today. The guy at DentFix says they are the same thing as their spot weld annilator, just longer to fit a normal drill.

Could other questions ... Is it best to use some cutting or tapping fluid when using these? Will that help it last longer.

What kind of speeds should they be. I think my normal electric drill is 1300RPM. Does that sound reasonable?

Thanks, Neal

I use NO cutting fluid what so ever.

I believe the DF15 spot weld drill runs at 2800rpm, I also have an air regular on the drill to slow it down at times. I dont see a problem with 1300rpm, but I would talk to Jeff at Dentfix to be for sure.

Something to note, when I get to an area my drill wont work I have an angle drill setup so I can remove those welds. Ive found its best to center punch the weld or drill a VERY small pilot hole(1/8) to prevent the bit from walking. I only do this when I cant use my DF15 as the clamp holds it in place.

Thanks for the help Eric ... after wasting $30 on NAPA one's for 6 welds, and spending another $30 today for another drill. I am completely obsessed with getting this one to last at least 50-60 spot welds.

The guy I talked with at Dent Fix didn't seem terribly knowledgable ... cause he kept saying hold on, and then hear him asking someone in the background. Sounds like 1300rpm and some cutting fluid (Marvel Mystery) will probably help.

I'm also thinking of rigging up a drill bushing fixture with some Vise-Grips. I figure the other part to making them last is keep it as perpendicular as possible.

I'm also planning on drilling the pilot holes ... through I was considering a hair smaller than 1/8". Does 1/8" really work for you pretty good?

Biggest thing is I think I'm going to stick with my Dewalt 3/8" taper bit on one's that don't have to be perfect. $6-8/bit is a whole lot cheaper!!

Spending $30 for a drill bit definitely gets the wheels turning:) Any other suggestions will greatly be appreciated. I'm bound and determined to keep this a fun hobby, and not break the piggy bank!

Thanks, Neal

I have the one from Westco Autobody. It looks like a small hole saw with a plunger type center pin. I think it cost in the $20 range and has replaceable cutters. The trick I found was to cut slow. As with any drill bit, over speed causes heat and that's what destroys the cutter. I've got dozens of cuts with this one and it still works fine.

Cam

Neal, I still say avoid the cutting fluid. If you fail to FULLY remove that fluid from the weld zone then weld over that stuff you could have some major welding issues!!

Ive never used fluid be it my DF15 or just a drill with those cheap arse holesaw bits.

If you cant get more then 50-60 welds out of that bit you are doing something wrong.
Ive had mine since mid July of last year and still on the SAME bit!!

1/8 bit is fine for a pilot hole all you are doing is providing a recess in the metal to prevent the bit from walking. Also DONT drill all the way trhou the panel with either the 1/8 bit or that spot weld bit. It does nothing more then create more work later.

Right here:

www.eastwoodcompany.com (http://www.eastwoodcompany.com)

The most important thing you can do to add life to the bit is hold the drill straight and apply even pressure. That is one of the reasons my spot weld driller works so well. A bit will last hundreds and hundreds if not thousands of welds. I can take the clamp off the driller and hold it like a regular drill to drill welds as well. But when I do, I can see that it is much harder on the bit. Holding it straight and steady is the key.

Neal, By the way, I havn't used the little hole saw style one for years. There are much better ways to drill spot welds. But I have to tell you, I drilled thousands of spot welds with one of those for many years. Yes, I broke the little saws once in a while and they do leave that metal there you have to grind off. But they are really pretty hard to beat for the money. I feel they are probably the best way to go for the home hobbiest.

I think the problems you had were with the not holding it straight or hitting edges of metal, that will break them every time. Did yours break or did it wear out? I found them to be very good, but the one you bought at NAPA may be a poor quality.

It also depends on what you were drilling like a factory resistance weld or if there were some other material there like a mig weld or something like that.

The hole saw one that I had just seemed very poor. It may have been made from HSS, at best.

Right now I am replacing my front floor pans, and was drilling welds along the rocker to slip the floor pan underneath. Since the top of the rocker is about the easiest to get at ... I was able to concentrate on a straight perpendicular cut.

The teeth on the saw just wore away!! After my 1st hole, the teeth (all the way around) wore to about 1/2 ... After that drilling was near impossible, and by the 3rd hole all teeth had worn to nothing (just a cylinder left). No teeth ever broke off.

Since then I have looked online, and seen that there are one's available make of tool steel. I think these would do much better.

Oh well, usually have good stuff at NAPA .. not this time. Neal

I second or Third, that the spot weld cutting should not wear out in one or two holes.. more like one or two hundred or more.
I like the 1/8 pilot hole or hard center punched
weld as a guild for the cutter tool...


you can get them at you local Body shop supply house...or Eastwood... the madrel and a few replacable cutters...

THe other nice thing about the Dent Fix bits is they can be resharpened. Any good machine shop with a tool grinder can sharpen. I just had one done and its ready for another 50 holes :D