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uute
10-17-2008, 10:30 PM
Screwin around with a power tool armature (belt sander).

5/16" shaft kind of "flatted" itself on one side in roller bearing. Best option?? :

turn down for hardened sleeve, then A) shrink on, b) locktight on?

or

try to tig it up and turn/grind back to size (Windings on, will I kill them).

uute

I believe I can get a replacement after I destroy it, but I definitely need the practice!

uute
10-18-2008, 01:00 AM
Pics:

http://img.photobucket.com/albums/v300/uute/IMG_0331.jpg

http://img.photobucket.com/albums/v300/uute/IMG_0332.jpg

Step one - raise a burr on the little spline while removing the fan.

Then I made a bush to push onto the spline and run in a steady during clean-up. See 1st pic via link.

Now: weld it or sleeve it??

Richard-TX
10-18-2008, 01:04 AM
DO not weld it. Welding will distort the shaft. Turn it and press on a sleeve. Use Loctite red if if makes you feel any better.

Carld
10-18-2008, 09:26 AM
5/16" shaft is kind of small to sleeve. How much undersize is the worn side?

I would look into the plastic metal used to build up shafts, etc. before I would try to sleeve it. There are some of the build up products that are so hard you have to grind them or turn them with ceramic inserts.

radioman
10-18-2008, 10:23 AM
Liquid Plastic metal is a good choice. Belzona is one of the trade names. They have several grades available. They also have small pouches available so you will not have to purchace a large container. Just mix the 2 components together and apply. Once hardened it machines like metal. Been using this product for years at work.

http://www.belzona.com/prod1k.aspx

Dennis

Lew Hartswick
10-18-2008, 11:07 AM
Liquid Plastic metal is a good choice. Belzona is one of the trade names. They have several grades available. They also have small pouches available so you will not have to purchace a large container. Just mix the 2 components together and apply. Once hardened it machines like metal. Been using this product for years at work.

http://www.belzona.com/prod1k.aspx

Dennis
Hey! If the web site info is to be believed that is "SOME" material.
I haven't heard of it till now.
I didn't see on the web site any details of the small packaging you
mentioned. What have you been using it for and where did you
get it? What sort of minimum order is necessary? etc.
...lew...

paulx
10-18-2008, 11:22 AM
I think welding would be best and easiest.Distortion is a problem when welding on the middle of a shaft but not the end.The armature winding has to be protected from heat of course.

radioman
10-18-2008, 11:27 AM
Hello Lew, I have been using this product at work where a breakdown occurs resulting in the stopping of production and the time delivery of larger pieces of stock required for proper fix is several days. We apply this stuff quickly as some harden real quick. Then machine it back to size. Millwrights then reinstall part and we are back into production. At the same time, a sketch is made and the proper replacement sleeve or shaft is made ready for planned shutdowns. My employer orders the belzona in and we keep several grades in the shop for use. As for the cost, I have not checked the Purchase order on the computer for the price. If you re look on the Belzona site you will see the small pouch I mentioned in the 2000 series of products. If you send a note in the contact section to Belzona asking who might have a supply in your area, I am sure you will get a response. Break downs where I work are measured in cost by minutes not hours. I work for a Pulp and Paper mill. Newsprint machine spits out paper at 1350Meters a minute, and the pulp side of the operation I am not sure of. You can see production is huge. the following link is my employers website.

http://www.hspp.ca/

Locate the Virtual tour on the left hand side and click on. Then each page after viewing scroll down and click on the Yellow hard Hat to view the mill.

Trust me, the Belzona product works very well.

Dennis

uute
10-18-2008, 01:54 PM
Hi Carld,

The groove is about .030" deep, all on one side covering about 1/2 circumference.

My best laid plans are already coming up short. :| The armature is short enough that my steady rest would have to sit over the gap where there is no way to clamp it down.

radioman, paul & Lew,

I'll consider the plastic metal, but will likely try to build it up w/ the TIG using a bit of 7014 electrode metal as filler (all I have on hand that might get somewhat hard).

Still thinking of best way to turn/grind the end. May just have to grip laminations in 4 jaw. Might be OK for grinding?
uute

Carld
10-18-2008, 05:55 PM
If the shaft has centers in both ends I would use the plastic metal. I have used the Belzona and it is great but expensive. Most any plastic metal would work under the bearing.

If you tig it the weld will pull the shaft to the side you weld it on and it will be hard to make it run true. The only way is to turn it undersize and weld all the way around and then turn to size. If you weld it you can't depend on the center on the end you weld to be concentric with the other end. Welding causes all kinds of problems, especially on something that small not to even mention the heat that will get into the comutator area.

radioman
10-18-2008, 06:20 PM
Hi every one, the other option is to have the shaft spray welded. Hope folks liked the ink to my employer.

Dennis

radish1us
10-18-2008, 06:40 PM
I'll consider the plastic metal, but will likely try to build it up w/ the TIG using a bit of 7014 electrode metal as filler (all I have on hand that might get somewhat hard).



You want to weld it, OK, don't bother wasting your time doing that, go order a new one !

Once you weld it, it's stuffed, you got your mind set on welding it, so go for it, then go order a new one.

R W
10-18-2008, 06:40 PM
I would consult somone who is familar with spray welding as suggested above. (by radioman)

Carld
10-18-2008, 07:37 PM
Any welding process will induce heat into the shaft and the comutator. As radish said, you will order a new armature after you weld on it.

speedy
10-18-2008, 09:09 PM
Just a belt sander? I would refit using plastic metal and shim packers(if possible).
A few years back my son and I were rebuilding an old 60's Vespa 150 scooter. the main output shaft bearing was shot and unobtainable. We found the nearest size available from the local bearing house; correct I.D, incorrect O.D (so smaller balls)and a couple of mm short on the width.
I packed the bearing up in the housing and shimmed the O.D as firm as possible with 3 spacers. Dissassembled the arrangement, thoroughly prept with cleaner activater and reassembled using Loctite liquid metal.
Now the HP output of that old Vespa (5 HP?) is probably more than a belt sander so I think that you would be OK with filler.
The old Vespa? That was probably 7 years back and maybe it is still functioning ??

Just reread your post. If you have machined it already then I would sleeve it and use Loctite or Omni if need be. I'm all for spending less where possible. Especially on a low(ish) $ item

J Tiers
10-18-2008, 11:17 PM
The belzona stuff IS good.

One bearing seat on my TP grinder is built up with it, and it is still working fine many years later.

Old employer fixed a number of wallered-out shafts with it...... they worked for years until the place was dismantled after work went south of the border (to Arkansas).

Carld
10-18-2008, 11:58 PM
The Ford factory in Lou. Ky uses lots of Belzona repairing shafts, etc. but for his use something cheaper will work.

uute
10-19-2008, 04:00 AM
see new thread - PoorMan Grinder