The Stovebolt Site Forums The Shop Area The Electrical Bay Rebuild that Generator

So you got that generator sitting on the bench and manage to pull it
all apart without bending, warping, tearing or other wise destroying
anything. Next step is the growler for the armature and if it passes
that, off to the lathe to turn the commutator.
If you're replacing the two terminals and or the coils then the next
challenge you face is the pole piece screws. Those can be a real
butch to get out without a pole screwdriver, although a milling machine,
drill press or hydraulic press can work sometimes. If you're lucky enough
to get this far along then blasting and repainting the field frame gets you
almost to home plate.
Now if you don't feel the need to disassemble the field frame assembly
then you need to decide how you're going to treat the assembly. The
rare case would be where all that is needed is to blow out the dust before
reassembly. But....in most case's it will be loaded with old grease and dirt.
If it laid out back of the barn in the mud the insides could be caked with it
or you might find that a mud dauber claimed some space inside for it's
nursery in among'st the brushes and coil windings.
Cleaning a dirty frame without damaging the coils could present a real
problem. You can't use a solvent for the grease cuz it might damage the
varnish, shorting out the coil. If it's just mud then water should get it cleaned
up, but.....getting water under the wrapping tape could take forever to dry out
and then you never know if you've got it all out.
This is a delema that I face every time I do a generator or starter. If anyone
has a practical solution to this clean up part of the rebuild.......please post
your ideas......Ken W?????? I and a bunch of others I'm sure, would like
to hear your method.
So the reassembly phase is pretty straight forward from here on out so it
really doesn't warrant any further discussion.
Denny Graham
Sandwich, IL

Water-based solvents like Fast Orange in a recirculating bath parts washer are pretty insulation-safe, although I've cleaned up dozens, if not hundreds of generator and starter housings with a quick dip and scrub in a bucket of gasoline back in the bad old days when I was 10 feet tall and bulletproof, without damaging the insulation of the coils. Electrical insulating varnish is pretty tough stuff. A quick work-over with a heat gun or a little while in a warm oven dries the housing out while you're doing other stuff like turning the commutator, undercutting mica, changing bushings, etc. Unless we were dealing with a very scarce item, it was a lot simpler and more profitable to use good-quality rebuilt starters and generators, but that was also back in the dark ages when parts were made to be rebuilt and enough of them were on the road to make it worthwhile to do so.

Denny,
here is what I face but keep in mind 99% of the restorations I do the coils all come out and get replaced. On the rare occasion that I am trying to save the coils I consider a couple of things, are they the old plastic coated type or some sort of cloth type. If I were going to leave them in I would certainly try and remove as much of the crud as possible without any chemical, liquid etc first. The plastic coated type are bad about having cracks in them between the case and the coil that you cant always see and the cloth wrapped coils that have had a coating on them at one point are bad about rotting between the case and coil due to moisture. So long story short I use an electrical cleaner that dries fast. Even a brake cleaner. Visual inspection of the coils while in the case are only going to show you whats going on where you can see and not behind the coils. That being said if you check continuity between the A terminal and F terminal to the generator case and have none your usually ok......making sure brushes etc. are not going to ground and the armature is out.
Getting pole shoe screws out without the handy dandy pole shoe screw removal tool can be a royal pain. I would post a picture of mine if I could figure out how. The correct slotted head screws are no longer made. There are a couple of suppliers that make the slotted head screws and you may see them on ebay but they are not correct and do not fit down into the counter sunk hole in the case. You end up with a few thousandths sticking up and I wont use them. I am in constant search of NOS ones because even with the correct tool to remove them they dont always come out like they are supposed to and I end up with my fair share of damaged ones.
One more thing and Im done.....LOL...Most all of the generator field coils for any of the Chevys from the 20s-60s are still available in aftermarket and NOS is always still good as well.
Ken

Thanks guys, I knew I could count on some reliable suggestions based on experience.
I've used my Bridgeport mill in the past Ken, to replace starter coils which I got from you.
I made the pole screwdriver from some hex stock which I had around the shop, turned the
end so I could chuck up in a mill collet. That made for a nice solid setup. That works, but it
puts quite a load on the quill feed so I'm in the process of building a pole screwdriver based on
the one that Delco pictures in all their manuals. This time I've got a piece of 4140 that I'm making
the driver bit from, I'll harden it after it's machined. I can justify building the rig because I've got some
starters around here that I also need to redo and I've rebuilt a few for buddies.
It's much easier to replace and solder the posts in the generators if the coils are out on the bench,
and as you posted, you never know what the condition of the tape is on the back side of the coils till
they are out on the bench, so I'll probably pull the coils from the two I'm working on now.
Any chance I can buy a suitable tape locally to re-rap the coils in the two generators that I've got
apart now????? I've used some 1/2" glass tap on other electrical projects and I have several electrical
supply houses near by.
Both pairs of coils check out at 3.6 ohms with no shorts to the frame. If I pull them I'd kind of
like to redo the tape. My original generator that I'm replacing also checks out at 3.6 ohms and
isn't shorted to the frame either, but the tape was torn loose when the bearing went to ell and I
think the varnish may have been compromised between a few loops.
Thanks again for the response guys, I appreciate it.
Denny Graham
Sandwich, IL

Denny, the pole shoe vise we used back in the 1950's resembled a big C clamp with a V-shaped fixed jaw to hold the housing. The jackscrew was used to push the screwdriver bit tight into the pole shoe screw, and there was a hole in the bit for a cross bar similar to a vise handle. It would be pretty simple to fabricate something similar from a 10" C clamp, a big piece of angle iron, and some air-hardening drill rod to make the screwdriver bit. Weld the angle iron to the fixed C Clamp jaw. Hold the clamp in a big vise and secure the starter/generator housing that way.
Jerry

The field coil wrapping material comes in large rolls of either cotton or a paper material. Both made specifically for wrapping generator or starter coils. I personally use the paper.
I think I also read where you were looking at the metal oilers on another post. Gits still makes them but they are very expensive. They do not still make them like they did originally back in the day. The original oiler caps said Gits Bros on them and purist search and pay a pretty penny for those. Last I saw they just had a G on the top. Replacement / reproduction ones are around but again they are expensive even for me. I suppose we should just be lucky they are around, for years aftermarket had none of these and only sold the plastic ones.
Ken

Something like this Weidenhoff out of Chicago back in the day Jerry? Not sure exactly which
design I'm going to use yet, but part of my enjoyment is building tools for the shop, even if
they are rarely used tools. http://www.pbase.com/dennygraham/image/167743557

Think I might stop by the local starter/alternator shop and see if they'll sell me a roll of tape.
Yes, the "Gits" oiler's are out of the the world price wise, even the repos are nuts. I'd just
like to have a dozen or so to keep in stock, often times I find them smashed from people
dropping the unit. I see the two rebuild kits that I got from you a few months back include them, thanks for that.
Your rebuild package is great and I'd recommend them to anyone rebuilding a starter or generator.
Thanks Ken.
Denny G
Sandwich, IL

It's a similar concept, but instead of using a lever arm to put pressure on the screwdriver bit, ours used an ACME jackscrew like a C clamp. It had interchangeable bits for Phillips, straight screw slots, and square drives. We didn't use it often, but it was very effective when we did.
Jerry

The old cotton coil wrap on about every original <>60 year old generator or starter
that I've had apart had seen better days. Kind of reminded me of what the mummy's
looked like when they opened the tome. If I'm going to the trouble to pull the coils
when I do a rebuild, and if the coil checks out OK electrically, then I may just as well
re-wrap them with fresh tape.
After doing a little research on the coil wrap, I've pretty much settled in on
1/2 inch SCOTCH 27 Glass Cloth Rubber Adhesive Electrical Tape, good to 266°F.
Its a woven insulating glass cloth tape; is high temperature resistance; has high mechanical strength.
It's specifically designed to be a heat-stable insulation for furnace and oven controls, motor leads
and switches.
And.....we used it for coils and coil leads when I worked at the FERMI Accelerator Lab.
So if it's good enough for particle accelerator magnets, then I think it will serve the
purpose in an old Stovebolt generator or starter just fine and dandy.
Now....the only problem is getting that roll of tape thru the hole in the doughnut 40 or 50
times!!!!!!!

Denny Graham
Sandwich, IL

OKEY DOKEY!!!! Screwdriver is done and works great. The geometry is the
same as the old Delco-Remy ones that are in their old service manuals. I couldn't
believe how easy the screws came out of this generator, in spite of how badly rusted
it was, probably from sitting out in the weather for many years.
The screw driver:
http://www.pbase.com/dennygraham/image/167786552
Screws out:
http://www.pbase.com/dennygraham/image/167786553

Now to pop the terminals and tag off....into the blaster, fresh paint, re-wrap the coils, stamp
a new tag and it should look like it came from the factory......and you old timers here know
how I like my stuff to look just like it came from the factory.

Got a couple of starters I need to redo this summer also.
Like to thank the guys again for the cores they gifted me and Ken Warner of Classic Generator
for his excellent rebuild kit's.
Denny Graham
Sandwich, IL

Dang DG! That contraption looks to be stout enough to push the screw right through the housing. Did you do that on purpose just in case the screw wouldn't budge?
There was a guy around here who specialized in pulling the idiot off-road mudders out of the swamps. His motto was, "I'll pull you out, or pull you apart."
Carl

Carl, the whole concept is to keep the driver blade bottomed out in the slot tight enough that the only thing the screw can do is turn- - - -no way for the driver to cam itself out of the slot and bollux it up. Once the slot is damaged, about the only option then is to drill it out. Some of those screws can be TIGHT! We used a smaller-scale but similar tool to remove stubborn screws for access panels on airplanes back when I was in the USAF.
Jerry

Right on Jerry. With all that leverage, the blade would bust off before it jumped out of the slot.
Had a bunch of the 1.250 x 2 rectangular tubing around Carl, and been using it up for all my
projects. The stiffer the better and this made for a real nice rigid setup. Machined all the
pivot points in the mill so there isn't any slop in it either.
For some reason I just can't quit making tools to get the job done. Doesn't leave any time
to....get the job done. I remember something my brother once said of my dad after he passed away.
"He spent all is time getting ready, not enough time on the projects themselves."
Must be where I get it from.
DG

An old-school German gunsmith I once knew had a similar obsession with sharp tools. Now, it's essential to have razor-sharp chisels, gouges, etc. when doing something like making a custom gunstock from a hunk of well-cured hardwood, and the fancier the grain, the more important it is to be able to make precise cuts, but this guy went a little overboard. "First ve sharpen der knife- - - - -den ve cut der vood!" The problem was that he spent far too much time on "der knife" to be very effective at getting the project done! When he finally got finished, I will admit that he did some very impressive whittling, however!
Jerry

Well when I get done "whittling" away at Old Blue.......I won't have an impressive Stovebolt,
but.....she'll be a dependable old gal, still built just like her engineers designed her 68 years ago.
dg

I dig the art of making tools, man. I get what you have created. I made a tool to hold the pinion yoke to allow torquing down the pinion nut to collapse the crush collar to set the bearing preload. It is made up of a long handle and ragged scrap metal bits welded to it and drill for the threaded holes in the yoke. It works like a champ and hangs on the wall for easy access, should a herd of zombies get the sneak on me. Its a little on the medieval side, in appearance.

Got me a generator back on Old Blue and after 8 months of not drivin' her.....I'm sure
glad the old gal is back to work.
Had one 'ell of a time handling that generator one handed, especially since me one
hand is the one that is connected to that broken wrist, which will never heal right thanks
to the quack that treated me.
So....I called me old stovebolt buddy, WelderDave to give me a hand from the top side,
holding the mass up whilest I put the bolts in from the bottom side. But......then had a
temper flare up before Dave got here and got it all bolted up just as he was pulling into the drive.
Although the armature was shot, I still wanted to see if I could save the burned coils from
my original generator. I pealed back all the burned tape and re-wrapped it after verifying
that there weren't any shorted or open coil loops. http://www.pbase.com/dennygraham/image/167798390
dg