Tiller belt length

[Sutty 97]

I am trying to fit my tiller that has not been fitted for 30 years, maybe more. The belt will not go on, no way no how and I think it must have shrunk, or the rubber has lost compliance, so I cannot get it on. It is the only belt I have that's close to this length, so it has to be the right one. My problem is now two fold. My model does not have a lever arm for the spring belt tensioner, and I know when I last used it it did not need the spring. It was so tight, back then, that it was a real pig to get on the big rear pulley anyway, now it seems impossible. Anyway, there is no lever arm on the attach-o-matic pulley and idler that mounts there to apply the spring to.

 

Second, because my model seems to be somewhat unrecognised on here, it's a Belgium machine, I worry that if I get the standard length it will be slightly too long, requiring the spring loaded idler, which I do not have. Is there anywhere to look up what belt length is needed on my specific machine for my tiller?

 

It's a C-140 8 speed, and has serial number 151391. Yes, I know there is no C-140 8 speed in the USA. See below. Everyone seemed very pleased to see one.
 

 

Also below is the tiller:

 

 

By the way, it's very late here now, so I won't check back in until tomorrow, so don't think I'm being rude if I don't reply further tonight to any suggestions.

 

Thanks in advance.

 

Regards

 

Sutty

Edited 17 hours ago by Sutty

[gwest_ca-(File Mod) 12,276]

Click on the fuzzy picture

 

[Sutty 97]

Thank you for the exploded view, and the belt description. I'd read the belt was 139" x 1/2" elsewhere on this site, but was worried it won't be tight enough, without a spring tensioner. However, I have just discovered why I do not have a spring tensioner lever.

 

 

 

I think it's fairly clear that it was badly welded, and at some point it has snapped off. The fact that it has paint on the flat metal portion, behind the front weld area, suggests there was no weld there and it was somewhat open. I will have to see what I can come up with. Maybe I can weld something on?

 

Excuse my ignorance, but just in case I get it wrong, can I assume that the 139" will be the inside running length or shall we say, inside circumference?

 

Thanks again.

[peter lena 9,899]

@Sutty  glaringly  obvious to me ?  those , chinese fish oil " lubricated " sealed bearings , are  known for failure  , and excessissive belt wear  , also long  unsupported , spring  tension enhanced , set up  , insures belt bounce . look up some related pictures of the set ups , might  find some help , pete 

[gwest_ca-(File Mod) 12,276]

Belts we use are measured on the outside circumference.

Belts shrink with age so a new old belt will measure a bit short.

 

Industrial belts are measured at the internal cord location which allows shaft speeds to be accurately determined.

A or 1/2" wide belts add 2" to get the outside circumference.

B or 5/8" wide belts add 3" to get the outside circumference.

[Sutty 97]

Thanks Peter, but I'm not sure I follow your post about fish oil. I've looked up a bunch of pictures, and have now clearly identified the issue, the belt tensioner arm has snapped off on my attachment. I have the pulleys off it now, and have a piece of appropriate steel to weld in place. I'm not entirely clear why part number 88 in the picture above has an offset. Many of the photographs I've seen are just flat bar. It doesn't look like I will foul anything with just flat bar, but I need to take a closer look before I can be sure. Can anyone tell me the length of the flat bar for the spring arm? From pictures I could guess, but easier with a measurement from someone, if maybe someone could measure one. Thanks.

 

Thanks gwest for the belt detail. My belt, that I had used before, is 135.625 outside, which explains why it is too short, when it should be 139 outside. It must have shrunk a lot, or was a little shorter to begin with, to make up for not having any tensioner mechanism. Last time I used it, all those years ago, it was super tight. Now it's just a tad beyond that.

 

The following product should be okay then, for when I get my spring arm welded on to my attachment?

 

https://bepltd.com/products/spa3482cr-advance-continental-advance-wrapped-wedge-belt

 

 

[gwest_ca-(File Mod) 12,276]

I do not know if that belt would work. My metric math says it should work. Datum length 3482mm is 137.08" + 2" for an A (1/2" wide belt = 139"

 

Notice the Datum length is the industrial spec I mentioned. That is measured where the cords that give a belt it's strength are located in the pulley grooves.

An industrial pulley may measure 6" OD but will be stamped 5.2. The 5.2 is the diameter where the cords will run.

When shaft speeds are designed these are the figures used in applications where pulley diameters determine shaft speeds. Very accurate.

 

If a belt bends backwards over a flat pulley an ideal belt will have the cords located about center of the belt. They can bend both ways placing less stress on the rubber.

Most belts have the cords closer to the wide back of the belt allowing it to bend around V-pulleys easier than flat pulleys. The Gates green belts are ideal for both bends and there are others.

[Sutty 97]

It's tricky because mainly I don't know anything about belts. I do know that many sites have A136 or A138, but no A137, which is the 139" outer that's needed. If I do find an A137, it often looks worryingly poor quality, like some no name eBay item. The one I linked, like all I've seen, has the cords near the flat side. It is the classic profile shown below.

 

[Sutty 97]

I can't find those Gates green A137 over here. I think I'll just have to try the one I linked. Do you happen to know the length of the tensioning arm, from where it is shown broken off in my picture?

[Razorback 1,337]

27 minutes ago, Sutty said:

I can't find those Gates green A137 over here. I think I'll just have to try the one I linked. Do you happen to know the length of the tensioning arm, from where it is shown broken off in my picture?

I hope these pics help. The top of that measuring tape is inches, bottom is centimeters. Mine uses an A139 belt.

 

Edited 2 hours ago by Razorback
added soem text

[gwest_ca-(File Mod) 12,276]

You can see in your illustrations how a reverse bend would severely stress the rubber on the inside of the belt.

The green belts do not come in the A & B sizes and do not see a direct replacement for 1599.

Some applications called for a 141" belt which may work for you since the spring tensioner appears to have a lot of travel.

Sorry have never had one so do not know dimensions of the idler.

See Toro still has the 141" 110265 but expensive.

 

[Sutty 97]

Thanks for the pictures Razorback, I will cut it to the length you show there and drill accordingly.

 

Yes gwest, thanks, I can see how that would stress it more, it would be stretched a lot on the outside curve. Having said that, I'm doing a couple of small areas, and it will be worth it for £40, if it lasts out the job.

 

My welding skills are appalling, but I think in this case they will be good enough. The other side is the same quality, or lack thereof.

 

 

[Razorback 1,337]

@Sutty I’m not sure if it matters much, but in my second picture, can you tell that there is a compound bend in that flat stock? Where the vise-grip is clamped is in the middle of the two bends. I think the top end where the spring attaches ends up in line with the outside of the pulley. I’ll get another pic ….

Edited 40 minutes ago by Razorback

[Sutty 97]

Yes, thanks, I mentioned it up the thread. Part 88 in the drawing, clearly shows it, but many photos of other people's didn't seem to have it. I checked mine, and it shouldn't interfere with anything, so I've left it flat like many of the photos of other people's. If it does need it, it won't be difficult to add it, and will lose hardly anything off the length. 

 

I've finished it now, and painted it with red oxide primer, which I'll have to run it with until I can get hold of some Wheel Horse red.

 

Good enough, I think. Just need the belt now.