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Flat belt repair

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Fwurth pointed out the same as I've found: the mechanical splices on an original belt just cannot stand up to drivebelt loads. Add the safety consideration of flying metal, and endless quickly becomes more attractive.

The Case Threshing manual shows 8" X 5 ply for 50HP. Of course, threshing is a fairly continuous load with potential for added abuse with a slugged cylinder.

I think I've seen more like 3HP per inch per ply, but may be my imagination.

The new materials, of course, more load per ply. This also equates to less forgiving on equipment from an overzealous throttle hand though.

Just from the small area shown, I'd think your belt deserves a proper repair, but probably semi-retired to some lighter loads.
The rule of thumb for rubber/canvas power transmission belts was: Hp=WSP/2400
Where W=width in inches, S=speed in feet per minute, P= number of plies. This was for new belting running on a 12” diameter or larger pulley. For pulley diameters less than 12” correction factors were applied, to reduce the horsepower rating. For a small pulley diameter of 10 “, the multiplying factor was 0.9; for 8”, 0.8; for 6”, 0.7; for 4”, 0.6; for 3”, 0.5. Other allowances were made for angle of wrap and nature of load.

So a 7” 4 ply belt running 2700 feet per minute on 36” pulleys would be good for 31.5 hp when new.
 
Hi Harvey,

Wow! I knew we had over loaded the belt a time or two. The 31.5Hp rating surprises me. Notice that I did NOT say it is wrong, I had no idea the rating would be that low.

I wonder how many times we have abused the belt in the 60Hp - 80Hp range. I said we have been up to the 140Hp range with the Blue Brake. Now I am wondering if we borrowed a bigger belt for that run. Perhaps in the future when someone askes us what it would take to get us to bring the Brake to their event, we will require them to provide a drive belt for the big dogs.

Later,
Jerry Christiansen
 

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Hi Harvey,

Wow! I knew we had over loaded the belt a time or two. The 31.5Hp rating surprises me. Notice that I did NOT say it is wrong, I had no idea the rating would be that low.

I wonder how many times we have abused the belt in the 60Hp - 80Hp range. I said we have been up to the 140Hp range with the Blue Brake. Now I am wondering if we borrowed a bigger belt for that run. Perhaps in the future when someone askes us what it would take to get us to bring the Brake to their event, we will require them to provide a drive belt for the big dogs.

Later,
Jerry Christiansen
At 140 hp that belt would have over 1100 pounds of tension due to torque alone, plus whatever tension placed on it initially. Makes you think....
 

G Willikers

Subscriber
Last Subscription Date
06/03/2020
Mr Christiansen
I saw your belt break last summer, or saw a belt break. That was a "big dog" on the brake also.
Actually, you stayed very calm and composed and no unmentionable language was heard. Was that because, as you say, the wife owns everything and you don't have a pup in the race?;)
 
Hi Mr. Wilikers,,

That was my favorite black belt that broke that day. I guess means there are two things I own, the cap my wife gave me for Christmas and the black belt. One is now broken and the other is nearly worn out.

As far as staying calm and not using magic words, several items went through my mind.
1) The belt fell down between the brake and the engine. Often broken belts do this because half of the belt is headed each direction, so the belt falls down.
2) Nobody got hurt. No one was close to the belt or either pulley.
3) The engine had a working governor so engine rpm was maintained and the engine was undamaged.
4) The engineer was on the job and closed the throtle
5) I figured that the folks at the Crosby show would have a belt we could borrow.

I work hard to keep magic words out of my vocabulary. We have all dealt with people whose speech is over populated with magic words. For some, if you removed the magic words their lips would move but no sound would come out. I get tired of that very quickly. Perhaps my previous life had something to do with that. My mother had something to do with that.

Later,
Jerry Christiansen
 

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Hi Mr. Wilikers,,

That was my favorite black belt that broke that day. I guess means there are two things I own, the cap my wife gave me for Christmas and the black belt. One is now broken and the other is nearly worn out.

As far as staying calm and not using magic words, several items went through my mind.
1) The belt fell down between the brake and the engine. Often broken belts do this because half of the belt is headed each direction, so the belt falls down.
2) Nobody got hurt. No one was close to the belt or either pulley.
3) The engine had a working governor so engine rpm was maintained and the engine was undamaged.
4) The engineer was on the job and closed the throtle
5) I figured that the folks at the Crosby show would have a belt we could borrow.

I work hard to keep magic words out of my vocabulary. We have all dealt with people whose speech is over populated with magic words. For some, if you removed the magic words their lips would move but no sound would come out. I get tired of that very quickly. Perhaps my previous life had something to do with that. My mother had something to do with that.

Later,
Jerry Christiansen
Folks,
Mulhern Belting (Mulhernbelting.com) is a trusted supplier for this class of belting. On their website, do a keyword search for “power transmission”. Several of their products will be listed. In particular, their part no’s 4-3004, 4-3005, 4-3006, 4-3008 would be good candidates for this service. Their working tension range of 140 to 210 pounds per inch of width could safely handle 100+ horsepower at 2700 fpm in a reasonably narrow belt (8-10”). Mulhern probably won’t sell directly to you but they will put you in touch with a distributor in your area. I still have some of their material in stock, but not enough to fabricate for this project. This belting material should eventually age to look like our existing belts. Hope this is useful.....Harvey
 
Hi Harvey,

The exact length of belt is not critical in this case. It is nice having a steam engine a good 50 - 60 feet away, so a 120 foot belt is a nice length.
I looked around the website you sent. I think we had a belt similar to the 4-30005 for the Red Brake at Rollag.
You can see what a 110 Case did to it here. We can't fault the belt for this failure.

Thanks again,
Jerry Christiansen
 
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Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Hi Harvey,

The exact length of belt is not critical in this case. It is nice having a steam engine a good 50 - 60 feet away, so a 120 foot belt is a nice length.
I looked around the website you sent. I think we had a belt similar to the 4-30005 for the Red Brake at Rollag.
You can see what a 110 Case did to it here. We can't fault the belt for this failure.

Thanks again,
Jerry Christiansen
That belt did stretch a bit before it failed. Was that brake mounted on concrete?
 

GreasyIron

Subscriber
Last Subscription Date
12/28/2019
That belt did stretch a bit before it failed. Was that brake mounted on concrete?
Jerry would have much better details, but without watching the video, I think that was the red brake that lives on a concrete pad at Rollag. The blue brake is Jerry's portable, but I believe generally staked well when in use.

Those part numbers were most interesting Harvey. I have a blower belt I recreated from material that looks very much like that; it was from one of the shops that used to advertise here, or maybe still does. A little bright, even after some use, but with a little threshing dust during or after a rack you wouldn't really know.

When I broke down and redid the whole set, including the blower, I went with some thinner stuff. That was much cheaper at the time. Maroon on one side, and black on the other. Hideously bright at first sight, but once ran in dust once, I actually liked the look better than the yellow. However, the thickness is noticeably thinner - not that by 3feet away anybody cares. And, even though thinner, very little stretch against hand tension - sometimes a bit tough to decide which notch on a tension idler it goes so quickly between loose and tight. I'm not sure whether or not that could be spliced in layers, mine are using clippers (smaller than for original belts), but I suspect any industrial uses needing endless would go with a single taper and hot seal.
 
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Hi all,

First of all I need to apologize to Harvey and any others that aren't familiar with the two Prony Brakes I am involved with.

The Red Brake is permanently in place on the Rollag Show grounds.

red brake.jpg
The diameter of brake wheel and the belt pulley are both about 42 inches. The brake wheel is 10 inches wide, the belt pulley is at least that wide. The dial scale that is capable of measuring 1600 pounds is covered by the blue tarp. The chain case allows 540 rpm and 1000 rpm PTO shafts to be hooked up and keep the wheels tuning about 250 rpm. The brake is attached to the concrete pad it sits on. The 110 Case that broke the belt was running this brake. During the 2019 Rollag show, I got to run Kory Anderson's 150 Case on this brake.

This is the second portable brake I built for my wife.
Blue brake 2.jpg

The two pulleys both have a 36 inch diameter. The brake wheel is 7 inches wide.
Notice the chain on the concrete to the right of the brake. We usually park a tractor with its left rear wheel on top of the chain. Then the chain is attached to the axle of the tractor with a chain binder to tighten the chain. Really the binder allows the chain can to be loosened when we get ready to pack up.

Blue Brake 3.jpg

From this shot looking down the belt I am going to guess the belt pulley is 12 inches wide.

Later,
Jerry Christiansen
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Hi Harvey,
I was operating the Red Brake at that time and yes, the belt did stretch just a wee bit. Once I calmed down enough to walk a straight line again I paced off that the rear wheel of the engine was 13 feet behind the block that was set before the excitement. You can use that to make your own guess as to how far things were stretched at the breaking point. If the belt broke at 1/3 of that distance then each run of the belt stretched 4 feet........PD
 

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Jerry would have much better details, but without watching the video, I think that was the red brake that lives on a concrete pad at Rollag. The blue brake is Jerry's portable, but I believe generally staked well when in use.

Those part numbers were most interesting Harvey. I have a blower belt I recreated from material that looks very much like that; it was from one of the shops that used to advertise here, or maybe still does. A little bright, even after some use, but with a little threshing dust during or after a rack you wouldn't really know.

When I broke down and redid the whole set, including the blower, I went with some thinner stuff. That was much cheaper at the time. Maroon on one side, and black on the other. Hideously bright at first sight, but once ran in dust once, I actually liked the look better than the yellow. However, the thickness is noticeably thinner - not that by 3feet away anybody cares. And, even though thinner, very little stretch against hand tension - sometimes a bit tough to decide which notch on a tension idler it goes so quickly between loose and tight. I'm not sure whether or not that could be spliced in layers, mine are using clippers (smaller than for original belts), but I suspect any industrial uses needing endless would go with a single taper and hot seal.
Hi Harvey,
I was operating the Red Brake at that time and yes, the belt did stretch just a wee bit. Once I calmed down enough to walk a straight line again I paced off that the rear wheel of the engine was 13 feet behind the block that was set before the excitement. You can use that to make your own guess as to how far things were stretched at the breaking point. If the belt broke at 1/3 of that distance then each run of the belt stretched 4 feet........PD
A maneuver known as “post tensioning”. Best done after an engine has warmed up the brake.
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Hi Harvey,
The bad part of typing is one can't always tell if something was said tongue-in-cheek or not. After putting in a long day here I'm not sure. If that were the case then yes, it should also be done gradually.
What I didn't say very well was that in that video the engine moved 13 feet backward from on the block to where the engineer got it stopped.:wave:................PD
 

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Hi Harvey,
The bad part of typing is one can't always tell if something was said tongue-in-cheek or not. After putting in a long day here I'm not sure. If that were the case then yes, it should also be done gradually.
What I didn't say very well was that in that video the engine moved 13 feet backward from on the block to where the engineer got it stopped.:wave:................PD
 

Harvey Teal

Subscriber
Last Subscription Date
07/22/2019
Pete, my comment was definitely tongue-in-cheek...Over the years I have repaired belts and machinery in the aftermath of belt failures. But I confess that I have never been present during an actual belt failure under those conditions. Glad nobody was injured....Harvey
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Thanks Harvey,
I was hoping that would be your intent. We were very fortunate in a couple of ways. The belt snapped back toward the engine and not toward the brake as there were more people closer to the brake. It was also good that no one or nothing was directly behind the engine so it didn't back over anything.
Jerry: Sorry for the detour in the thread as the repair information is well needed. I hope to see you again in June at the University of Rollag!......PD
 

Russ Hamm

Subscriber
Age
61
Last Subscription Date
10/12/2024
My endless belts are all just about shot by now, its time to replace them. Seems like even when we find
a good looking used one its not long before delamination starts showing. Last year we had one that started
to show a problem just as the crowd was gathered for threshing, one of the hands brought it to my attention
and I ALMOST decided to run it but caught myself and we changed it out. Actually...…..crowds like belting
up as part of the show, so no matter the schedule safety should be first in such matters. I may be wrong, but
last time I priced a new drive belt it was 4-500 dollars, and something that would outlast a threshing show
with proper care. (not sure about the price) Us collectors will usually spend that much on a small part of our
collection, im convincing myself to buy one now before it gets higher as I type. :unsure:
Even if it meant selling one tractor it would be worth it, I suppose. We bought one very long wide drive belt some
years ago and its still nice, but we need a narrower one now and then for the smaller thresher setups and such.
 
Actually...…..crowds like belting up as part of the show, . . . .
Crowds seem to like under power de-belting demonstrations, too. Those are often followed up with re-belting demonstrations.
Most times the belt falls down between the two pulleys on the de-belting. I have seen a couple videos on Utube where the belt takes off toward one pulley, usually the driving pulley.

Later,
Jerry Christiansen
 
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