Generator shaft repair

[Byron Warwick]

I run a late model generator with the fan attached on my '34 pickup. it has a 1953-54 flat 8BA. The generator armature shaft is worn where it fits to the front bearing. Is there a repair for this area of the shaft? I had thought of building up the shaft and then machine it down. However I was warned about heat so close to the windings. Is there a source of new armatures? Thanks in advance, Byron.

[super flat]

Build it up with j b weld then machine it. Gary

[Byron Warwick]

If the steel shaft has worn, why won't the JB wear even sooner? Byron.

[flatheadernie]

The jb weld is to center the shaft in the bearing, you will neen a new bearing most likely, then when you assemble the gen pulley tight thats is the reason for the wear! the fit to shaft is easy hand fit not tight. ernie n tx

[flatheadernie]

need, the bearing has been spinning on the shaft, tight fit pulley to bearing to sholder on shaft is key . e

[JonC]

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There is a product for fixing shafts that are worn under a seal so they leak. It is a thin sleeve of stainless steel that is used to repair the shafts, you may be able to find it in McMaster Carr, or the other thought is to take it to a machine shop and have them sleeve it.

[flatheadfan]

Byron-

Armatures, especially 8BA are a common occurrence on epay. However, if you still can't come up with one you might want to give some serious consideration for a Redi-Sleeve. These things come in a multitude of sizes and can be slid on the shaft using a common 100 watt light bulb for heating. Most auto parts store such as NAPA or Carquest can get them.

Tom

[Charlie ny]

Byron,
Perhaps JB weld will work....I hope so.
Redi Sleeves have about a .005 wall and are fine for running a
seal on because the seal has lots of give to it. A bearing doesn't give at
all so tread lightly.
If however you post a photo of your armature I'm sure many
of us horders will have a replacement. If you choose to post a photo lay
a 12" ruler along side the armature so we get the right one.
OMO,
Charlie ny

[Karl Wolf]

I like Charlie NY's idea... I will further that, with another armature, you won't be thinking about pushing the car when far from home...
Karl

[flatheadfan]

Byron-

I have been re-thinking my previous answer and I think the solution to your quandary may be easy. I have taken apart a lot of generators over the years and have found many that have difficult to take off front plates. When I eventually get the plate off I have seen the shaft portion of the armature where the bearing sits has been "staked" with a center punch. This raises the armature shaft surface. As a result, the lower shell of the ball bearing cannot rotate on the shaft. When this is done all the rotational motion is being done by the bearings (as it should be). If you are experiencing wear on the shaft it probably indicates a bearing problem that forced the armature shaft to act as the main bearing surface, which it was not intended to do.

After "staking" the armature shaft, slide the (new) bearing on the shaft (now assembled on the the front plate). If every thing is as it should be the bearing will need to be nudged into place with a socket and a few light taps with your favorite hammer.

I have seen enough of this "staking" that I have often wondered if it may have been part of a factory manufacturing process or at least a common repair in the past. At any rate. give it a try. If it doesn't work just file down the "staking" and go to your plan "B."

Hope this helps.

Tom

[Byron Warwick]

Tom and other Barners: Thanks for your replies.I was prepared to use the JB weld on the shaft and hope it would get a good grip using the scarring on the worn shafts for extra grip. However "flatheadfans" idea is also appealing. Tom, would you use several peens of the centre punch to raise up the shaft? I noted that the bearing slides into the end plate before it then slides onto the shaft. But that is no problem. Byron.

[Charlie ny]

If you use FHF's idea which sounds pracatical to make up .005 or so be sure
to use locktite to help 'steady things'.
Charlie ny

[KiWinUS]

Originally Posted by Byron Warwick

Tom and other Barners: Thanks for your replies.I was prepared to use the JB weld on the shaft and hope it would get a good grip using the scarring on the worn shafts for extra grip. However "flatheadfans" idea is also appealing. Tom, would you use several peens of the centre punch to raise up the shaft? I noted that the bearing slides into the end plate before it then slides onto the shaft. But that is no problem. Byron.

I have a never used remanufactured armature for a 36 genny & it has been staked where the bearing sits , I was quite supprised to see this when I opened up its box . I would also do a Charlie NY suggests & loc-tite it.
Cheers
Tony

[flatheadfan]

Bryron-

If I was in your situation, dealing with a worn armature shaft, I would center punch about 7-10 dimples in the bearing seat on the armature shaft and then attempt to slide the bearing on the shaft. It should slide on with some effort but not enough effort that the bearing would be damaged from being forced on. If needed put some more dimples in the shaft or file down some of the dimples that you originally put in whatever it takes to get the tight fit you need. Once you are satisfied with the fit place the bearing with the baffle plates and two felt washers into the end plate. As you probably know, everything is held into the end plate with a snap ring. Once this is done slip the entire plate on to the armature shaft and use a socket and hammer to complete the job. That should do it!

Hope this helps.

Tom

[B-O-B]

Checkout your local electrical too/motor repair shops or machine shop to find one that can KNURL the shaft better than peening/staking used this all the time when running a electric motor repair shop. The armature or shaft is centered in a lathe & this tool will make hatch crossmarks to hold the bearing.
To find out more on KNURLING try GOOGLE

[Fordestes]

There is one listed on e-pay for 25.00 N.O.S, I p.m. the info. to you on on a couple I had on watch.
Good luck,
fordestes

[Ronnie]

https://jdparts.deere.com/partsmkt/d..._Compounds.htm

R

[FlatheadTed]

I like bobs idea ,another opshion is to make up a shim using somthing like a tin can .fold up the ends with little cuts in it all round ,Or weld the shaft t using running water & hose to cool the amiture .

[Byron Warwick]

Thanks for all your help, Byron.

[Rich Overton]

In response to JONC, The sleeves JONC mentions are called "Red-i sleeves" from Federal Mogul National seals or "Speedi- sleeves" from Chicago Rawhide Seals. Most any Automotive or truck parts distributor should have them available. Not sure about how small they make them though.

Rich O.

[JM 35 Sedan]

I believe B-O-B has the best idea. Knurl the worn section of the shaft to uniformly raise that area enough to give something close to the original press fit for the ball bearing. We used a controlled staking operation (4 stakes placed symmetrically around the shaft at a controlled height) to hold lamination stacks on armature shafts (high volume universal electric motor manufacturing). These same stakes did not work that well to hold commutators and ball bearings in place because they caused stress concentrations in the areas where they contacted the commutator and ball bearing ID's. A knurl would spread the press fit load more evenly around the ID of these same parts. If you know someone who has a lathe and a knurling tool he could fix that shaft in no time for you. A light coating of Loctite on the knurl prior to pressing the bearing in place is also a good suggestion.

[JonC]

I may have been in error suggesting the thin sleeves, the problem is they (the sleeve) will deform to the shafts discrepency. Without seeing where the worn area is or how wide this area is it may not be the best approach. I would not use a prick punch and stake the shaft this will not produce a uniform condition and may lead to concentricity issues increasing vibration and shortening the life of a bearing. If repair is needed rather than replacement I would take it to a machine shop and have them turn the shaft down to accept the sleeve or make a new sleeve to install and remachine to the original size. This may cost more than the replacement and you need to determine that yourself.

[Mike51Merc]

I always say that we live in a disposable society today where nobody fixes stuff anymore. I try to take stuff apart and fix whatever is broken whenever I can.

That being said, I beleive some things are better replaced then repaired. I think an armature shaft is one of them. They're readily available and relatively cheap compared to the "fix-it" suggestions above. Plus, you'll have the confidence of a new part and not wonder whether the fix will hold out.

Edit: You mention your old shaft is scarred. You probably should figure out why it scarred before fixing anything else.