Ttalk Tech

Ttalk Tech

Holcombe Armature Kit Installation

(All images are thumbnails)

[Please note: Since publishing this web page I have learned that Jim Holcombe, NEMGTR Member #6603 passed away just about a year ago. BK, 2/28/05]

A fellow T-typer, James Holcombe of Atlanta, GA,owns a company called Holcombe Armature. They specialize in electric motors and rewind armatures. It seems that a couple of years ago Mr. Holcombe decided to produce a kit to allow us to redo the innards of our dynamos. The kits go for the very reasonable price of about $50. Santa Claus brought one of the kits for Lazarus. It’s no secret that keeping a tight fan belt raises havoc with the bearings and bushing inside of the generator. I speak from experience. The Holcombe kit contains a rewound armature, a new pair of brushes, a new front bearing, a new rear bushing and a set of instructions for DIY'ers.

Installation of the kit was reasonably straight forward. The surprise was in discovering that the bearing at the pulley end is retained by some long rivets that have to be punched out. They were no longer usable after being removed. They are an odd size and it will take some hunting to find an equivalent. The instructions mentioned the use of nuts and bolts. That's what I ended up doing.  More about that below.  I also discovered that my cooling fan’s hole had become egg shaped so I bought a new one.

The reassembly instructions are a bit over simplified.  They read, "Re-assemble the unit using replacement armature." The only tricky part was getting the new brushes to slip onto the commutator when putting it all together. Reinstalled the generator with a new NAPA 25-22392 fan belt to replace the Dayco BP-36, and fired it up. Works fine.

What about the things that were learned?  You can read the Holcombe Installation instructions from a .pdf file by clicking here.  They do tend to oversimplify the task a bit.

Disassembly was reasonably straight forward.  Take out the through bolts , give a couple of taps with a rubber mallet and it's opened .  Now wrap some rubber around the armature and clamp it in a vice while you loosen the nut and it all comes apart .

It was my experience that the bronze bushing was not in a mood to come out easily.  A 1/4 inch chisel was too wide, so I ground an edge onto a screw and used it.  By the time I was finished the bushing was in a lot of little pieces.

(The following was suggested by Bob Jeffers on 2/19/09:

I had occasion this morning to have to remove the rear bushing from one of our "T" series generators. I used a 3/8 - 16 NPT. tap, threading it in from the armature side about 3/8 in. Then with a 1/4" drift from the tachometer side and a hammer the bushing came out as slick as you please.

I forgot to put the dimensions of the bushing in the above note. Just in case some hardware store has one.
Must press into a 0.710" hole, so about 0.713" O.D.
The armature shaft measures 0.587" so bearing S/B about 0.590" I.D. when installed.
I think that indicates that the shaft is a metric size. Closest would be 15 mm.)

Can't say as how I like their installation technique of using a screwdriver for a guide to install the new one. I used a driver and it went in fine.  BTW, I soaked the bushing in light oil for a day before I installed it.

The pulley end was a bit of a learning experience.  The retainer rivets are not something that you'll find at your neighborhood Home Depot.  I ended up replacing them with 8-32 pan head screws with nyloc nuts. The pan heads are thin enough to fit under the fan and, with the screws cut to length, the nylocs will clear the armature.

There are a number of components on the armature shaft that will determine how it goes together at the pulley end. At the inside there is a split ring that fits into a groove in the shaft.  There is a cap that goes over the ring . The inner race of the bearing will locate against the end of this cap.  You'll find that you have to give some thought to how far over the split ring you press this cap. The order of assembly from this point out is plus one more spacer that goes onto the shaft before the pulley goes on . Here's where I ran into a snag. I discovered why the center hole of my fan was oval-shaped. It was free to rotate around the shaft.  It was not being located by the woodruff key.(I know, the blades go the other way.  I just slipped it on for the photo.) After a few measurements and a look through the bench goodie box I was able to come up with a washer that was just thick enough to bring the new fan onto the key.

The rest is, as they say, the reverse of disassembly.  That's once you get the knack of slipping the new brushes onto the commutator.  The late David DuBois  long advocated, and wrote about, the desirability of using the proper fan belt for our cars.  The NAPA 25-22392 belt was what I used for the reinstallation. See below for a link to David's article on belt tension.

All in all it was a fairly easy task and at a very reasonable cost. With the usual disclaimers, you could contact : Holcombe Armature Co., 905 Rockmart Rd., Villa Rica GA 30180, (770)-459-5544.

To see the late David DuBois' pdf article on fan belt tension click here



edited 6/1/2020
cellphone - 508-317-9412 (text okay)