Is this low-speed drum OK to use?

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Model T Ford Forum: Forum 2012: Is this low-speed drum OK to use?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Bamford, Edmonton AB on Wednesday, August 01, 2012 - 06:41 pm:

I'm gathering the parts to refurbish my '24 Speedster transmission (previous thread "Lots of broken/worn transmission parts after 2,000 miles — Why?") and having trouble finding a good used low-speed drum. Lang's is quoting two months for an exchange drum and that does not suit my Labour Day weekend travel plans.

I received this drum today from a fellow in Calgary... thickness looks OK and there are no cracks but the circumference is quite pitted. I chucked it in the lathe and gave it a good sanding so there are no high points/sharpness, but I am unsure if the pitting itself will be a problem. The optimist in me would like to believe the pits will hold oil and thus help reduce band wear and heating. My pessimistic side sees me tearing this engine down yet again for another drum replacement.

FWIW, I am changing out my Kevlar bands for Guinn wood bands this time around. The photos show my drum after sandblasting and after a sandpaper polishing. So, does this drum look OK to use?




Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Wednesday, August 01, 2012 - 07:01 pm:

I would use it just like that. Don't remove any more metal.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Wednesday, August 01, 2012 - 07:02 pm:

OK is a relative term, unfortunately.

I would say that it could be used as is, but it might chatter and engage roughly, but it would work. It also might be hard on your bands.

My best advice is to take it to a machine shop and have them resurface it; just taking off enough metal to get rid of the pitting and make a nice, smooth surface. Taking off too much metal can certainly be a problem!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Wednesday, August 01, 2012 - 07:04 pm:

Then again, the drums in my '24 Touring are in only slightly better shape and I've had no issues with them.

I also realized that I may have sparked quite a controversy here by talking about resurfacing the drum!

We'll see what happens...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Wednesday, August 01, 2012 - 07:16 pm:

Oh, and I forgot to mention an important factor in determining whether a part is useable or not, and it's this: How much you are going to drive your car.

If you plan on doing some major cross-country touring, you would want everything to be pretty immaculate.

However, if you're like me and drive your T maybe 200 miles a year, you can get away with tired bushings, worn bearings, rough drums, etc, especially if you are like me and are extremely devoted to maintaing your car. Not to mention I plan on doing a full mechanical restoration a few years in the future, so many of these parts just have to last until then.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Wednesday, August 01, 2012 - 07:16 pm:

Pits on the drum is nothing to fix that, you should be looking at the hub, and gear, I can see some pitting! More Pictures!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Perigo - Linton, IN on Wednesday, August 01, 2012 - 07:27 pm:

I used very fine sand paper with the drums in a lathe until they felt like velvet. The pits were still there and no issues with wooden bands,

The key is a slick surface!

Mike


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Wednesday, August 01, 2012 - 08:14 pm:

I think if it were mine, I would set it up in the lathe and kiss it with a flat file and then polish it with emery cloth. It looks like it has a thick rim comparatively for a low speed drum, but I agree with Royce, I wouldn't machine it pretty.

Konhke does bring up a point, what does the gear look like?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Wednesday, August 01, 2012 - 08:37 pm:

I too agree with Herm...The drum looks OK but the gear looks rough. I would look for a nicer gear and drill the rivets and re rivet it in place of the gear shown. Not a big job but will likely give you better service.JMHO


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Bamford, Edmonton AB on Wednesday, August 01, 2012 - 08:46 pm:

Thanks for the comments and suggestions. Here are so additional pictures. The hub faces need a bit of clean-up too — turn flat or just smooth out?






Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, August 01, 2012 - 09:01 pm:

That gear might be noisy. The drum could be sanded in a lathe. I don't think you should take off much. The pits will actually hold oil, but you should get off any rough edges which would tear into the bands. I wouldn't recommend taking it smooth, because it would get thinner. Just smooth it out.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stephen D Heatherly on Wednesday, August 01, 2012 - 09:09 pm:

The pits are not a big deal if you are going to use wood bands. As Norman said lightly sand the drum but, do not turn the drum down in a lathe as it will weaken it. The gear shows a little wear but, it would probably be ok. Have you considered having the drums magnafluxed to make sure they are not cracked? There are forum members who have extra drums for sale.

Stephen


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Wednesday, August 01, 2012 - 09:10 pm:

Pits on the drum = LOTS of tiny oil reservoirs........as long as it's smooth....... :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stephen D Heatherly on Wednesday, August 01, 2012 - 09:13 pm:

Looking at the first two pictures you posted I now see a little more gear pitting than I would be comfortable with. That gear would probably be noisy. You may want to find a different drum.

Stephen


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Wednesday, August 01, 2012 - 10:09 pm:

Let me just warn you all now that I'm WAY over thinking this!

Now I've always wondered that maybe pits on the drum are not a bad thing, as long as they are smooth. Perhaps it keeps oil on the bands when they are engaged, kind of like those aftermarket Oillite drums, or whatever they are called, that have the big oil groove in them. I've smoothed out some drums before using the lathe and file method, and it works beautifully.

I do feel that a possible problem with not turning down the drum (which I would cap at five thousandths) is that if the drum has a bit of pitting, the metal on the surface that appears fine may have microscopic pitting anyway, and the metal is still weakened, even without turning it down. Has anyone ever put the surface of pitted drum under a powerful microscope?

That's enough about drum surfaces for now!

I would also say that that gear does look a bit worn, perhaps a little too much. It would certainly work, but it would probably be noisy. I would also consider installing a new bushing. A little effort now can go a long way!

In the end, though, I'm sure that there are as many different opinions out there as there are T owners!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Danial - Veneta OR US Earth Solar System on Wednesday, August 01, 2012 - 10:31 pm:

That gear might make a bit of noise. I build and rebuild gear boxes for conveyors in industry and I have had customers bring in gear boxes with the complaint that they are making one helluva racket.

(Industrial noise levels are monitored by OSHA.)

Upon opening and inspection, there have been times when I have found one tiny divot or chip on a pinion gear (high speed or input end) and it was that that was making all the noise.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Dupree on Wednesday, August 01, 2012 - 10:38 pm:

I got suckered into using a drum like that under the theory that wooden bands can make anything shift smooth. Yes, we polished the surface of the drum until it looked smooth (except for the rust pits). My experience was that rough drums will result in grabbing/rough band operation REGARDLESS of whether you have the magic wooden bands on it.

Pitch that drum and get something that has a LOT smoother drum surface, and smoother gear teeth.

Ron Dupree


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Wednesday, August 01, 2012 - 11:06 pm:

The drum will work. A drum that is smooth with nice teeth would be better. On the other hand the rim of that drum seems exceptionally thick which is good. The gear teeth show signs of past corrosion, they may or may not be noisy. Any time you mix used parts from one transmission in another, you run the risk of gear noise.

If you really want a noisy transmission combine parts from several transmissions and rebush them all.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Wednesday, August 01, 2012 - 11:08 pm:

I just reread your post,if it were mine I would stay with the kevlar bands.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Thursday, August 02, 2012 - 06:32 am:

You can rivet that drum to a different hub if you think the hub is better on one than the other. Use the best parts you have. After riveting the hub into a different drum of course you have to machine the rivet heads flush. Just don't machine the outside.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Thursday, August 02, 2012 - 07:24 am:

Those pits are minor enough to polish out with some use.

Every other consideration appears to be minor as well.

The low drum is the center meat of the drum sandwich and runs hotter from more use and abuse.

The early brake drums also get a lot of abuse.

Which drum is the most difficult to find in good condition is a toss up between the Low and Brake Drums.

The one item that gets most people in trouble when rebuilding a transmission is the clearance between the bushing and shaft. Too much is better than too little.

The new bushing material seems to expand when hot and never shrink when cold for some reason.

An old bushing with a .004 or .005 difference in diameter between the bushing and shaft might be a little noisier, but they will work much better.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Bamford, Edmonton AB on Thursday, August 02, 2012 - 09:20 am:

This is all very helpful. Thank you. We're considering riveting the hub that came out of my transmission to the good replacement drum. This hub has good thrust surfaces and bushing clearance. Point taken about machining/countersinking the rivets to/below the surface.

If we were to use the replacement drum and worn hub (with new bushing), I can see also machining the thrust surfaces slightly to eliminate the bit of ridging. They will doubtless become a few thou shallower and my feeling is that won't be a problem later. Is this correct?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, August 02, 2012 - 12:03 pm:

If I were going to the work of riveting the hub to another drum, I would buy a new drum. In fact, you can purchase a new drum and send your old hub to the company which will rivet it for you. That way, you will be sure to get a good job. If you are going to use the old drum, why not just go with the old gear too?
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Thursday, August 02, 2012 - 12:13 pm:

Ted Dumas on Wednesday, August 01, 2012 - 11:08 pm:
"I just reread your post,if it were mine I would stay with the kevlar bands."

Huh?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Huson, Berthoud, Co. on Thursday, August 02, 2012 - 01:33 pm:

Chris Banford:

I was glad to see James Golden suggest using the original bushings. I almost never find a bushing in a trani drum that has too much wear. Even Ford stated that you could use up to five thousands clearance. I almost never find that much and I deal in many, many drums. The idea that the bushing have to be changed on all drums is not right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Allen Vitko on Thursday, August 02, 2012 - 02:06 pm:

I would agree with Herm, the gear is going to get most of the torque.
I likely have better ones that need to find a new home.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Thursday, August 02, 2012 - 02:33 pm:

My opinion. That gear is well into marginal. I would change it. The drum, looks like a good one. I would spend about fifteen minutes with about three feet of 180 emery tape to take the sharpness out of the pits. But no more. I have not ever had a drum machined down and do not expect I ever will unless new material has been added to the surface.
I also agree with Dave H. Model T transmissions like to run loose. The bushings should not be replaced unless they are really loose or otherwise damaged.
Drive carefully, and enjoy, W2


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