MTFCA Forum

This isn't going to be easy to admit.......

I've been working on a junk 1918 engine for close to 18 months now. When I say junk, I mean JUNK as the serial number had been roughly chiseled off years ago. To make a long story short, everything needed replacement in addition to rebuilding.

I've had the flywheel on and off quite a few times in order to set my magnet clearances, so the transmission drum assembly sat on the bench for awhile. When it came time to place it back on the main shaft, it was tight. So tight I had to "urge" it down with a copper hammer, thinking it would loosen up when it seated. Not so. Oh, it turned but took more effort than when I first installed it. Here comes the stupid part....

I spend several hours building a 3 arm puller to remove the drums. I began pulling and it moved, then froze. I applied a tiny bit more force and heard a pop. Quick examination showed that one of my puller arms broke a piece off the slow speed drum flange about 3/8" long. The drum surface itself was NOT injured but now I have a nice chunk missing from the flange. I was (and still am) pretty upset , since that drum was a very good used one obtained from Dave Huson.

Now, the question: Could I successfully run the drum if I carefully dress the broken portion to avoid hurting the linings, or should I just cuss a bit more and buy another replacement? I considered brazing, welding, etc. but that flange is very thin and I'm sure the heat would probably warp the drum.

Oh, what caused my brand new transmission bushings to suddenly get "tight"? In two words, assembly grease. The bushings were bored to a .003" fit if I recall, and the original grease hardened a bit while the drums were sitting on the bench (about two months). That grease is very soft, but it didn't take much to gum up the works! Next time, plain oil................

Would using a drum with a chunk out of it cause a out of balance issue? Don’t think you have cornered the market on making mistakes. Welcome to the worlds biggest club.

Pictures ??
A sign of intelligence is admitting the woopsies and learning.

Better to replace the drum with a good one. See attached. If the drum breaks and locks your transmission, you will be in big trouble. The picture below shows what will happen.
Norm

...carefully dress the broken portion to avoid hurting the linings...

Been there, done that. It did not end well. Get another drum.

George, you have me a little confused, which is not hard to do. You say you broke a piece out of the flange on the low speed drum. I have never seen a low speed drum with a flange. Might you mean the reverse drum? I have seen quite a few reveres drums with chunks out of the flange, still in use, or at least having been in use until parted out. Definitely check the drum for further cracking, and perhaps spin it in a lathe to check run out, but such damage may not necessarily preclude further use.

Allan from down under.

Allan, I apologize........it IS the reverse drum. I also forgot to mention that close examination shows that the broken out area does NOT go down to the drum surface and there's no damage to the drum itself. My only concern was balance and whether the edges of the break out might chew on the band linings..........and especially if running it might change the break into a crack. Steve's comment is spot on really, and much thanks to everyone who responded.

Anyway, after a full day (and night) of self abuse , I think I'll start asking around about a replacement drum. After all, I'm getting pretty good at taking it apart!

George,

Just finished cleaning, inspecting, polishing, and installing a new bushing in one for you.

Sent email with my phone number. Going to bed now but leave a voice mail if you still need it.

All the Best,

Hank

May I offer that my own stupidity no longer amazes or surprises me.
Sorry for your troubles.
Rich