Belt cutting machines always slightly narrower than "belt width"?

[Cumberland Highpower]

You can get spacers made in just about every configuration.  +/-.  

I have a handful of Randall 132's. Older machines, but work just fine.  They had spacers in exact lengths, undersize, oversize, etc.  I tend to use single spacers that are 1/16" under that way the straps come out exact as 1" 1-1/4" 1-1/2" etc.   

Some spacers are also meant to cut straps oversized to compensate for what's lost from an edging machine.  

Spacers are also intended to be stacked.  For example, you can use a 1/4" spacer with a 1-3/16 spacer to get your 1-1/2" strap. (The missing 1/16" is the width of the cutting blade).   When you're calculating what spacers to use, you take the desired strap width and subtract 1/16" to get your total stack.

What's the make on your strap cutter? Looks metric to me.  Could also be your spacers are metric 28mm, etc?  

It also looks to me you're stacking spacers (At least 2 of them) that are each 1/16" under and you're stacking tolerances as a result.  The 1/16" under on each spacer is the width of a blade.  You can correct for that by either using just a single spacer that is 1/16" under actual width of your straps, or you can ADD a thin spacer to your spacer stack that's like  1/16" or 1/8" or whatever you need to make up for the loss if that's all you have to work with.  

You can as a last resort have a machine shop make you some up or cut some down.  I had a relative cut some down for me on a surface grinder.

Hope that makes sense?

Edited March 14 by Cumberland Highpower

[TomE]

I see the discrepancies when repairing tack made in Asia, which is the majority of manufactured tack.  The hardware matches inches but the straps are narrower making them loose on the hardware and promoting wear.  For economical repairs (matching the client's expectations for inexpensive tack) I have to fudge the width when splicing a new end on a strap.  I always check the setting on my plough gauge with a scrap of leather to ensure I'm getting accurate widths.  I realize this is a bit off topic.

[nstarleather]

12 hours ago, Cumberland Highpower said:

You can get spacers made in just about every configuration.  +/-.  

I have a handful of Randall 132's. Older machines, but work just fine.  They had spacers in exact lengths, undersize, oversize, etc.  I tend to use single spacers that are 1/16" under that way the straps come out exact as 1" 1-1/4" 1-1/2" etc.   

Some spacers are also meant to cut straps oversized to compensate for what's lost from an edging machine.  

Spacers are also intended to be stacked.  For example, you can use a 1/4" spacer with a 1-3/16 spacer to get your 1-1/2" strap. (The missing 1/16" is the width of the cutting blade).   When you're calculating what spacers to use, you take the desired strap width and subtract 1/16" to get your total stack.

What's the make on your strap cutter? Looks metric to me.  Could also be your spacers are metric 28mm, etc?  

It also looks to me you're stacking spacers (At least 2 of them) that are each 1/16" under and you're stacking tolerances as a result.  The 1/16" under on each spacer is the width of a blade.  You can correct for that by either using just a single spacer that is 1/16" under actual width of your straps, or you can ADD a thin spacer to your spacer stack that's like  1/16" or 1/8" or whatever you need to make up for the loss if that's all you have to work with.  

You can as a last resort have a machine shop make you some up or cut some down.  I had a relative cut some down for me on a surface grinder.

Hope that makes sense?

So the machine is ancient… like older than me. I’m 43…

Which is why I guess the machine is probably Italian or American because that’s what was around back then.  I doubt it’s metric just because of the spacers I have seemed to correspond to inches and fractions of inches.

 

What you say about the tolerance is adding up makes sense, I think I’m going to see if I have a 1.5” spacer, and if it lines up with one 1 inch spacer and two 1/4”

we sold a lot of belts last year, so I’m not terribly worried. I was just curious, as if it was normal or not… apparently there’s a lot of variation in machines.

[Cumberland Highpower]

33 minutes ago, nstarleather said:

So the machine is ancient… like older than me. I’m 43…

 

That just means you have a good machine! If it's been here for 40+ years it will probably be around another 40?

I'd rather have a 40 year old Italian or US made machine than a "new" Chinese machine anyway!  We have exactly ONE machine here made in China, a hot foil embosser.   Every time I look at it or use it, I feel like tossing it in the scrap pile...Poor casting, machining, assembly, etc.  No heat treated parts, etc.  I bought it at an auction so I wasn't into it for much....

Edited March 14 by Cumberland Highpower

[Tigweldor]

You could always add some hardened steel shim washers between blade and spacer to increase width of cut.

They are absolutely flat and of even thickness.

They come in many different thicknesses - ranging from a few thou to most any thickness and size you may desire.

Here just an example - for a 1inch diameter shaft, you would use a 26mm inside diameter shim of desired thickness :

https://www.metricmcc.com/precision-shim-ring#4

Of course there are other suppliers - just check the internet or go to your nearest engine rebuilder/transmission(not supposed to say tranny any more) shop and ask them who they buy shims from.

 

Greetings

Hans