Re: (ET) ugh - bent / broke flange of blade hub

I'm guessing I have the first design, since the flange was starting to come off by itself. You said that kind can be straightened, re-assembled, then "staked". What do you mean by "staked"? It looks like I should be able to straighten it. I was considering doing a little spot weld, but of course that would throw it out of balance.

For some reason I didn't think the split-bearing puller would fit above the collar. Kind of stupid to not try it. After reading your email I finally tried it, and sure enough it fits. Not sure there's enough room between it and the bottom of the housing to be able to grab it with the 3-arm puller, but I'll give it a shot.

All of the descriptions I've seen for taking these motors apart talk about threading a bolt into the armature shaft - yours is the first mention I've seen of not doing that. What do you do instead?

From: RJ Kanary <rjkanary consolidated net>
Sent: Sunday, May 29, 2016 6:03 PM
To: Briggs, Michael; et
Subject: Re: (ET) ugh - bent / broke flange of blade hub

One design of hub is fabricated from two pieces, then furnace brazed together. Using a puller on the flange will remove the flange ONLY. :(

The other design seems to be machined from a solid piece of material.Using a puller on the flange will remove the flange in PIECES. :(

The first type can be straightened, re-assembled then staked, and will last a lifetime without being re-brazed, whereas the second type is now a paperweight. Yes, experience speaking, here. <G>

ANY force to remove either type must be applied to the collar, period. A bearing splitter used on an arbor press is the best thing I have seen to achieve separation without damage.

A stout piece of material that fits into the bolt hole but not screwed into the threads will be needed to apply force to the armature shaft. Using a bolt to do so could risk damage to the threads. The armature shaft is very soft.

Heating the collar may well be needed, but must be precisely directed,and performed with great care.

Safety equipment is a MUST.

After disassembly, thorough corrosion removal on all the parts, followed by anti-seize application will save you or the next guy a ton of grief. <VBG>

On 5/29/2016 5:14 PM, Briggs, Michael wrote:

I decided to start rebuilding another one of my deck motors - and it didn't go so well. With the first one I did, I didn't have a split bearing puller, so I made my own version from some old composite decking to use when pulling the blade hub off (I cut out a donut and cut that in half, and screwed it together to hold it onto the blade hub). It worked nicely.

For some reason, I decided to buy an actual split bearing puller - shouldn't have done that. It doesn't seem to spread the force out all the way around the blade hub flange as well as my composite donut puller does - and the result was that the flange bent and even cracked. D'oh.

So, how can I go about getting this flange off now that the flange is compromised? I could try using my composite donut, but since part of the flange is already bent and broken away, I'm not sure how well it will work (I'll try it anyway). Assuming that doesn't work - can I pry it down from above without damaging anything? (maybe put two long screwdrivers going opposite directions up above the blade hub, and use them as levers to try to pry it downward)

Any other thoughts?

And hopefully somebody sells used blade hubs....

Thanks,

Mike

Michael S. Briggs, PhD

UNH Physics Department

(603) 862-2828
_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak

Virus-free. www.avast.com