Matching V-belts in a set

One of my lathes, an Okuma LS, uses a set of 3 V-belts for the main drive. One of the belts shows possibly excessive wear. Must these be replaced as a matched set? Or is it enough that the 3 belts simply be all the same brand/model/size/perhaps age?

Markings on one show: Dayco Super Blue Ribbon BP79.

Thanks fellas. All comments welcome.

I was in the same boat when I had to replace the 3 belts on my lathe. I talked to the applications engineer at Gates and he said 'matched sets' is an outdated concept. All the belts will stretch to be the same size now. He said to put them on, tension the loosest belt until correct tension then run it for like 24 hours (I think he was thinking this was for like an air compressor). He said they will stretch to size. Even when they have a listing for a "set" they just throw however many off the shelf of the same size in a box.

This was for the Gates Hi-Power II or something like that.

Im sure they will tell you the belts will stretch and even out. Last time I tried to buy a matched set I was basically laughed at, out of the 3 I got 1 was really loose and still remains loose to this day. I started buying banded vbelts so if you need 3 matched, it all comes as 1 belt. They are a little more spendy but have worked great for me on a few projects.

Thanks fellas. I will just order 3 of the same brand.

We had 3 and 4 belt combos that were made as a unit


Dave

King size serpentine belt!

Blazemaster said:

Im sure they will tell you the belts will stretch and even out. Last time I tried to buy a matched set I was basically laughed at, out of the 3 I got 1 was really loose and still remains loose to this day. I started buying banded vbelts so if you need 3 matched, it all comes as 1 belt. They are a little more spendy but have worked great for me on a few projects.View attachment 328970

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winger said:

We had 3 and 4 belt combos that were made as a unit


Dave

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See post 2
Then did you check the grooves of the poelies were the same???

Peter

Blazemaster said:

Im sure they will tell you the belts will stretch and even out. Last time I tried to buy a matched set I was basically laughed at, out of the 3 I got 1 was really loose and still remains loose to this day. I started buying banded vbelts so if you need 3 matched, it all comes as 1 belt. They are a little more spendy but have worked great for me on a few projects.View attachment 328970

Click to expand...

What is your preferred place for getting those? My Daewoo needs all new belts... all 12 of them. I'm sure a banded 8x5L is gonna cost a fortune, but so will individual.

Peter from Holland said:

See post 2
Then did you check the grooves of the poelies were the same???

Peter

Click to expand...

Didn't really matter, it was what the machines came with. About a 12 dia driving a 60" flywheel.
Dave

winger said:

Didn't really matter, it was what the machines came with. About a 12 dia driving a 60" flywheel.
Dave

Click to expand...

The bigger the drive the less the absolute differences in lenght matter
Peter

Jaxian said:

I was in the same boat when I had to replace the 3 belts on my lathe. I talked to the applications engineer at Gates and he said 'matched sets' is an outdated concept. All the belts will stretch to be the same size now. He said to put them on, tension the loosest belt until correct tension then run it for like 24 hours (I think he was thinking this was for like an air compressor). He said they will stretch to size. Even when they have a listing for a "set" they just throw however many off the shelf of the same size in a box.

This was for the Gates Hi-Power II or something like that.

Click to expand...

That was my experience when I went to replace my 4 belt set on my Colchester. I guess I'm just old school.

I also have a Okuma LS 540x1500. I ordered a matched set for it about 15 years ago from Grainger. They were a truly matched set back then. Still going strong with those belts. I think it was about $60-$75 for the matched set.

Matched belts are still a thing. There are a few MFGs that make special lines of belts that are all inside tolerance so those no longer need to be "matched" but there's plenty of places you can get them as a matched set. McMaster is one. Most of these online guys do it too: https://www.vbelts4less.com/faqs

Business model
Peter

Necro thread, but happy it came up as my manual lathe is running on 2 C-section belts atm as the first two disintegrated.

Thinking a banded set of 4 is the way to go. After all alignment is checked.

Speaking of which, in my searching I found SKF sells a jig to check pulley alignment. Jig is little more than an aluminum widget with a laser pointer on it. $3800 USD. LOL.

d6stringer said:

Matched belts are still a thing. There are a few MFGs that make special lines of belts that are all inside tolerance so those no longer need to be "matched" but there's plenty of places you can get them as a matched set. McMaster is one. Most of these online guys do it too: https://www.vbelts4less.com/faqs

Click to expand...

Thank you for that. I need 8+4 belts for my Daewoo A-20 and wanted a matching set/banded.

Blazemaster said:

View attachment 328970

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Just a note when trying to run one of these banded vee belts....
As for as multi-vee pulleys, they can have different vee spacings.
There are "V" belt pulleys, there are "L" belt pulleys, there are "A"
belt pulleys, (and "B" and J rib" and on and on").
But be aware the 3 that I first mention look almost the same.
Yes "V" is a series of belt, not the same as "L" and "A".
Anyhow, if you were to buy a commercially available pulley
(or sheave or whatever), for multiple belts, there are 3 different
spacings available for the seemingly same size belt. And to
add complication, they sell a combination "A/B" pulley (multi-
vee) that is actually the spacing of the "B" series of belts
(Because "B" is larger, and it has to be). This to reduce
inventory. (Just like phasing out match sets of belts).
I bought a 5 belt pulley for my 17" Colchester lathe, to
get a taper lock series, and get away from the shaft and
key type that had fretted tight to the motor shaft.
I ordered an "A/B" unit, spacing too large to match the
headstock pulley. So I got out the CAD models from
their web site (B&B mfg, as I recall). I downloaded models
of their "A/B" pulley, their "L" pulley, and their "V" pulley.
I also double checked the CAD models from Browning
and McMaster Carr. They all seemed to be 99% the same.
Anyhow, it turns out, I needed a 5 belt "V" pulley. NOT
the others mentioned. The "L" spacing between the vee's
was about 1/16" more. The "A/B" (really a "B") spacing
was about 1/8" more. This was a small problem for matching
multiple separate belts on pulleys, but mismatched pulleys
would be a NOT-GO for banded belts.
So I know this was a babbit hole of pulleys, but just thought
I would mention it, in case you start ordering belts and nothing
is fitting up. I am an engineer, and I really feel like I should have
known this stuff about pulleys and belts. But I am smarter now
having went through finding the answers to replacing my lathe
motor pulley. Live and learn, and hope I helped someone here.

-Doozer