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View Full Version : Thumler's Tumbler Model B Drive Belt Life - Poor


Bayou
11-17-2013, 07:29 PM
I'm only getting about 20 tumbling hours on each Thumler's Model B drive belt. These are new drive belts made and sold for this tumbler - not a cheap knockoff or copy.

I see no reason why these belts don't last longer - there is nothing out of alignment - the motor and axel pulleys are aligned. The bushings are appropriately lubed, there's no sway in the drum as it tumbles, and the belt channel in the drive pulley is smooth - no burs. I run the drum at 13 pounds which is 2 pounds under its 15 pound capacity.

These belts aren't cheap $5 - $6 apiece plus shipping - and I'm getting tired of popping for them.

Let's hear it - what kind of belt life are you getting from your Thumler's tumbler Model B drive belt?

Any suggestions on why I'm not getting a longer belt life here? I appreciate the comments -

Bayou

hiller
11-17-2013, 07:50 PM
I burn belts only if I overload. Belt should also have slack and not be tight. I have been using a big oring left over from a turbo 350 trans rebuild I did several years ago. It's been on for years with no problems. I think those new clear belts sold for the thumbler aren't as durable as the old black ones. If you are wet tumbling weight is very important. I think the heavier the load the shorter belt life.

plattincreek
11-17-2013, 09:28 PM
I used to have a Thumlers tumbler and may have a couple of the belts. Send me your mailing info. and I will send them to you. Rich hartdonnel@aol.com

AFBerryfarmer
11-17-2013, 09:59 PM
I have a Thumbles Tumbler. I have been running on the same belt since I got it about thirteen months ago now. I've tumbled well over 50k pieces of brass with it. Everything from 30-06 to .380.
I hope it doesn't give out on me for writing this. :mad: I've even forgotten about it when running some brass in the evenings and went to bed. When I go out to the garage in the morning I've wanted to kick myself for leaving it run all night.

sigman2
11-17-2013, 10:05 PM
I gave my Thumler's Model B to my son-in-law about two years ago. It is still running on the original belt from 1982. I bought a spare which is still in the wrapper.

Are you oiling your plastic shaft bushings? No oil on the belt. If you're using dry media I can't see how you can overload it. It's made for polishing rocks with the drum full of water.

Bayou
11-18-2013, 04:41 AM
I used to have a Thumlers tumbler and may have a couple of the belts. Send me your mailing info. and I will send them to you. Rich hartdonnel@aol.com

Thanks for your kind and generous offer of the extra belts, Rich. They are needed. Email sent to you -

Bayou

Bayou
11-18-2013, 04:44 AM
Are you oiling your plastic shaft bushings? No oil on the belt. If you're using dry media I can't see how you can overload it. It's made for polishing rocks with the drum full of water.

Thanks for the response. I do have lube on each bushing and am careful not to get any on the drive belt. I'm at a loss for the constant belt breakage, and may contact the factory to see what they say.

Bayou

milprileb
11-18-2013, 07:54 AM
Well something is amiss and others have given you clues what to look for like over loading the drum , lube , etc etc and I am sure you are looking at that .

I just want to say that I got tired of belts wearing out quicker with the clear versions from the maker. Not excessive but they just don't last as long . I was told a trip to a sewing machine shop would yield belts that can be substituted and will work.

Next belt that goes , I will take it and match at sewing machine shop and give it a go.

For what it is worth... good luck

milprileb
11-18-2013, 08:03 AM
Well something is amiss and others have given you clues what to look for like over loading the drum , lube , etc etc and I am sure you are looking at that .

I just want to say that I got tired of belts wearing out quicker with the clear versions from the maker. Not excessive but they just don't last as long . I was told a trip to a sewing machine shop would yield belts that can be substituted and will work.

Next belt that goes , I will take it and match at sewing machine shop and give it a go.

For what it is worth... good luck

1rosta
11-18-2013, 11:54 AM
I found the extra belt from my wife's vacuum works perfect and last longer than the belts that came with tumbler.

Bayou
11-18-2013, 12:31 PM
Thanks, All

Here's a follow up report:

I just got of the phone with the owner of Tru-Square Metal Products. Very nice - he said he would mail me out a new drive axle to try and fix the problem.

I'm wondering o-ring belts are better than the clear belts that go with the unit. I don't see any o-rings big enough at the hardware store, however.

Another poster mentioned a vacuum cleaner belt. I tried the one that was mentioned, but it was too fat and a bit small in inside diameter so that the motor would not turn because the belt was too tight.

So, I measured the corrdct replacement belt. If I measured correctly, a standard AS 568 o-ring, number .343, has just about the same measurement for inside diameter (3 3/4"), outside diameter (4 1/8") and cross section (3/16").

I've ordered a couple just to try them out. I was told to use a ring composed of ethylene propylene rather than rubber or neoprene since the E-P material won't stretch.

I hope my luck changes. All I want to do is tumble without breaking belts!

Bayou

milprileb
11-18-2013, 03:40 PM
Good luck Bayou, pls post a note if your solution is better.

cfullgraf
11-18-2013, 04:17 PM
Bayou,

In industry, we used round urethane drive belting that we bought on spools, cut the belt to length and used heat to splice them together. They even make V-belt cross section material for low power transmission applications of the same material.

If your broken belts are broken at what looks like a splice, i'd say they were not made well. But, you might be able to fab up a one from the broken pieces.

Search on round belt welding kits to see what they include, the most notable piece is a pencil style soldering iron with a wide flat tip. The other main pieces is a alignment gizmo but we are not talking rocket science here.

You would have to place two belts together as you may lose enough length welding one back together that it may be too short.

Food for thought to get by.

Bayou
11-18-2013, 06:52 PM
Thanks so much for the information, guys. It's always reassuring to know there are more experienced folks around who are willing to share advice.

Bayou

Scott in Michigan
11-19-2013, 11:40 AM
Take a new belt to Wal-Mart and match it up with a vacuum belt for diameter. If the belt is a bit fatter you can still use it, but rubber will flake off. They still last a very long time.

meplat
11-19-2013, 12:26 PM
Out of curiousity, are you using the "high speed" version of the motor? If so, I wonder if that might affect belt life.

I broke an original belt (1990's vintage) after a few weeks run, but since then, the "spare" (also '90's) which came with the tumbler seems to be holding its own and doesn't generate the "black powder" around the drive the first one did

:D

Bayou
11-19-2013, 06:34 PM
meplat -

Yes, I am using the Thumler's Model B, high speed. I've heard from numerous others who are getting much better belt life than myself even with the high speed model. Surely, 15 - 20 tumbling hours per belt is insufficient.

So, another thing to try is to switch from the clear belt that comes with the unit to the same size o-ring and see how that does.

Even if o-rings don't wind up lasting any longer, they only cost about 75 cents apiece rather than $5 apiece.

Tru-Square said they will mail me a new drive axle as well. Perhaps that will correct this problem. They seemed cooperative over the phone.

Bayou