Weld grinder

[Aunt Phil]

This little darling goes about 22 pounds and is sweet with a 6 or 8 x 1 1/2 wheel on the arbor.  It also works very nicely with a 1/4 thick disk for cutting cracks out, and will when necessary carry a 3/16 rubber wheel for removing carbide.

You'll notice the tool clearly predates any thought of OSHA.  I have been asked to put it back in the truck on a couple jobs. 

[kxxr]

I didn't take a very good picture but this Skil tool is very similar.

I only photographed the name plate because I thought it would be easy to look up more information. It wasn't. I never did find out much about it. It is, without a doubt, one of the more dangerous looking tools I've seen in a while. Interesting to note the 6 fold difference in RPMs listed on each tool. How come that is??

[Aunt Phil]

That little Skill is generally known as a toenail filer or fingernail grinder. 

Normally it's used with thin snagging wheels a/k/a cutoff wheels in tight spots or to cut out cracks and defects. 

These tools predate the common availability of compressed air and air tools, and are by comparison FAT, heavy and nasty to run.  The smaller ones like your Skill also had short working lives generally because the bearings simply couldn't stand the workload.

Speed difference~
Well into the 70s grinding and abrasive speeds were normally quoted in Feet Per Minute. 
A 3000 rpm spindle carrying an 8" wheel grinds at 75,360 fpm when the wheel is new.  By the time the wheel is down to 6" it's only cutting at 56,520 fpm, barely 2/3 of the machine's design workload, and a pathetic use of a grinder, so yo put a new wheel on and go back to making money.

Your Skill spins a 2.5" wheel at 17,500 rppm delivering 137,375 fpm, an appropriate speed for cutting and snagging, but way faster than you could ever hold and turn a 6" wheel because of gyro effect.  A 6" wheel spinning near 6,500 rpm would deliver about the same feet per minute, but few men could hold it and use it.

The gyro thing can get very nasty, particularly in places where there isn't much room for the grinder to get clear of the wheel if something goes south.  If you get the chance to mount a 9" wheel on a standard angle grinder normally used with a 7" wheel give it a try.  Changing the attitude of the grinder becomes more work than hanging onto the grinder.

[kxxr]

The physics of danger. Very interesting and well stated. I only sensed that such machine would be more than a 'handful', and I left it lying on the pawn shop shelf.

[Lewill2]

The other thing you have to be careful of is the speed rating on the grinding and/or cutting disks that you use with each tool. The larger disks are usually rated for lower RPM's due to the surface speed of the larger circumference.

[radguy]

This is what I think of when I see a grinders without wheel guards.



Yes that is bone and a permanent aluminum tattoo.

Dan

[rusty]

I exploded a cutting wheel once, it was almost a full minute before pieces stopped ricocheting around the shop. I found pieces *inside* the closed drawer of my toolbox! Also exploded a lightbulb, and embedded several pieces in a plaster wall. I still can't believe none of them hit me...

(The little moral of that one was don't use a grinding wheel as a cutoff wheel in a flexible piece of material...)

(Tho, i have exploded the little cutoff wheels a few times , I have come to the conclusion that the air cutoff tools are a lot more dangerous than most people goive them credit for)

[Uncle Buck]

I exploded a cutting wheel once, it was almost a full minute before pieces stopped ricocheting around the shop. I found pieces *inside* the closed drawer of my toolbox! Also exploded a lightbulb, and embedded several pieces in a plaster wall. I still can't believe none of them hit me...

(The little moral of that one was don't use a grinding wheel as a cutoff wheel in a flexible piece of material...)

(Tho, i have exploded the little cutoff wheels a few times , I have come to the conclusion that the air cutoff tools are a lot more dangerous than most people goive them credit for)

Yes, very true. Unfortunately most never heed the warnings!

[ron darner]

Bradford was not the only manufacturer of such grinders.  I have one which I have not identified; the hexagonal cross-section through the motor makes me think Black & Decker, but that's only a guess, since I haven't been able to read the plates.  Not even 100% certain that they're nameplates...

[Papaw]

Ron, those look more like access plates to get to the brushes, don't they?

[ron darner]

No; the sort of "warts" directly beneath the two plates are the brush housings; they're 90 degrees apart from the plates.  I had to go out and actully look at the unit itself to be 100 % certain - but if you enlarge, especially on the lower photo, you can even see the slot for removing the brush holder cap.  I have not take ANYthing apart on this one, so can't say what's under the plates.  Haven't even plugged it in, either.  Switch (one of those "push-push" through-the-handle types like on older trouble lights) is stuck, and I don't know whether it's on or off!  A quick check of continuity with my meter will tell me, though.

[64longstep/Brian]

I exploded a cutting wheel once, it was almost a full minute before pieces stopped ricocheting around the shop. I found pieces *inside* the closed drawer of my toolbox!

I have lost count on how many that I have exploded... Not fun...

[Aunt Phil]

No; the sort of "warts" directly beneath the two plates are the brush housings; they're 90 degrees apart from the plates.  I had to go out and actully look at the unit itself to be 100 % certain - but if you enlarge, especially on the lower photo, you can even see the slot for removing the brush holder cap.  I have not take ANYthing apart on this one, so can't say what's under the plates.  Haven't even plugged it in, either.  Switch (one of those "push-push" through-the-handle types like on older trouble lights) is stuck, and I don't know whether it's on or off!  A quick check of continuity with my meter will tell me, though.

The well known Aw Crap did he switch it off before he lost it or will it be headed for me, where the hell is the cord switch.  They sure did beat holding the trigger pulled though if you were the guy running it.

Generally those are stuck for want of a few drops of Marvel Mystery Oil and a couple days time.  When you get it apart the plunger is usually operating a cheap toggle switch.  Good luck finding a direct replacement.

[Dustin21]

I exploded a cutting wheel once, it was almost a full minute before pieces stopped ricocheting around the shop. I found pieces *inside* the closed drawer of my toolbox!

I have lost count on how many that I have exploded... Not fun...

had to  dig a fragment out of my leg once    that was seriously not fun...

[scottg]

  I caught a bit of the edge of a zipdisk last year.  It had the guard in place too.
Did I ever mention I hate exhaust work?  Cramped quarters and an angle grinder do not make for fun.
Well it bit me on the index finger between the 1st and second knuckle.
I was going to try and keep going, till I got a look at it.
  So I tried to sneak in the house and get to the bathroom,  but the old lady caught me. Guess I was leaving a blood trail.
   I got in the bathroom under the lights, and crap no way I was getting away without stitches. Easy view of the bone for about an inch.

  I packed it in gauze and headed for the local clinic.
Stupid move. The town "doctor" took a look and said "I can't do anything with this". "You'll have to go to Yreka". 
So he wrapped it better, and threw me out.
I had to drive myself 75 miles.  I was driving like a bat at the end because I figured the day shift at the hospital would be going off at 5, and I wanted to beat that. It turned out the day shift lasted until 6 anyway. 
I got the attending.  A smart easy going  dude named Pearlberg.
He gingerly opened it up for a look. I had severed the nerve so, hell you could peel it open and have a look at the -other- side of the bone no sweat.  It was almost a fillet job.

He looked it over good and said, "What are you doing here? A cut like this your aunt Zelda could have stitched up". 
So he sewed a few stitches, no anesthetic necessary,  (5 or 6  I  'spose) and sent me on my way.

grinders
yours Scott