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V-belt pulley angle

Joined
Jan 25, 2005
Location
New Egypt, NJ
Does anyone know what the correct angle is for a v-belt pulley? I'm assuming the angle is standard, and that width and depth are the only variables for the different cross sections for belts. Is this the sort of thing tha would be in a machinery's handbook?
 
i just went thru this with a belt engineer at goodyear and one at browning, and guess what..

no definitive answer, but both concur that it appears to them that all v belts share the same angle. only depth and width are the variables

i promptly forgot the angle that we came up with but i think it was 37 degrees

if anyone has a better answer i too would like to know and the source of the info.

bob gayle
 
also i might add i checked on the following sections

letter sizes such as A, B, C

automotive such as gates 7000, 9000 series

and power belts, such as 5L etc

all have the same angle

hope this helps

bob g
 
Per the Machiners's Handbook, 20th edition:
Light duty V-belt Sheeve dimentions
2L
Effective Outside Diameter in inchs
Under 1.5-- 32 deg. width at full dia .240
1.5-1.99-- 34 deg. """"""""""""""""" .243
2.0-2.5-- 36 deg. """"""""""""""""" .246
over 2.5-- 38 deg. """"""""""""""""" .250
depth o f groove .250

3L
Effective Outside Diameter in inchs
Under 2.2-- 32deg. width at full dia .360
2.2-3.19-- 34 deg. """"""""""""""""" .364
3.2-4.2-- 36 deg. """"""""""""""""" .368
over 4.2--38 deg. """"""""""""""""" .372
depth of groove .406

4L
Effective Outside Diameter in inchs
Under 2.65-- 30 deg. width at full dia .485
2.65-3.24-- 32 deg. """"""""""""""""" .490
3.25-5.65-- 34 deg. """"""""""""""""" .494
over 5.65-- 38 deg. """"""""""""""""" .503
depth of groove .490

5L
Effective Outside Diameter in inchs
Under 3.95-- 30 deg. width at full dia .624
3.95-4.94-- 32 deg. """"""""""""""""" .630
4.95-7.35-- 34 deg. """"""""""""""""" .637
Over 7.35-- 38 deg. """"""""""""""""" .650
Depth of groove .580

groove angle is included angle

Smitty
 
Interesting that belt engineers couldn't come up with a defininte answer. I just had a similar SNAFU regarding connecting rod orientation in Benz engine and Benz engineers... they finally took apart a new engine from Germany to get the answer! Anyway, thank you Smitty, I just printed your info, and will tack it on my wall next to my tap drill chart. However, I now have a related question: What relation to sizes such as "5L" have to sizes such as "B"? When I bought a belt for the drive on my lathe, I asked for a 5L, as informed by someone on this site. The counterman said they don't carry 5L, but a "B" section belt is the same thing. Works fine in the lathe, so I assume that's true. What's the deal with this?
 
"What relation to sizes such as "5L" have to sizes such as "B"? When I bought a belt for the drive on my lathe, I asked for a 5L, as informed by someone on this site. The counterman said they don't carry 5L, but a "B" section belt is the same thing. Works fine in the lathe, so I assume that's true. What's the deal with this?"

4L is equivalent to A/AX (with exceptions), and
5L is equivalent to B/BX (with exceptions), etcetera.

However, the L suffix indicates light duty, and not matched as to length, whereas the A/B prefix, etcetera, indicates heavy duty, and matched as to length, according to the RMA (Rubber Manufacturer's Association) standards for "ganged" belts.

(There is no heavy duty belt which corresponds to a 3L, which is quite popular in early Hardinge Brothers products).

However, if you do need matched lengths of 3L, 4L or 5L belts, and RMA belts (A/AX, B/BX) are not an option, be aware that belts are cut from a master belt, and the master belt number, and the position from within that master belt which an L belt was cut are encoded on the edge of the belt, near the manufacturer's logo.

If you need three matched length 3L belts, as for a Hardinge TL or TM/UM, you may notice that matched sets of Browning "Matchmaker" belts, the HB OEM belt, are no longer available.

However, by carefully selecting from retail 3L belts of the same manufacturer and "trade size", and matching the master belt and position codes, you can obtain a pretty well matched set.
 
From the Machinery's Handbook:
Table 7
Standard Multiple V-belt Dimentions
A) width= 1/2
depth= 5/16

B) width= 21/32
depth= 13/32

C) width= 7/8
depth= 17/32

D) width= 1 1/4
depth= 3/4

E) width= 1 1/2
depth= 29/32

FWIW the section in the Machinery"s Handbook that I have has 17 pages on v-belts and sheaves (pullys). The book is a 1975 printing so things may have changed.
Smitty
 
I make custom pulleys mostly for serpentine
automobile belts, but I have made a few v-belt
pulleys as per sample as people want smaller
or larger dia ones, the average angle when checked on the ones that came off cars was
38 degrees included.
 
Thanks again for the info. Very glad to know about matching lengths; I always thought you had to buy a matched pair, but I gather 2 individual "A" or "B" section belts off the shelf (of the same length) would be matching length. Gotta get me a machinery's handbook!
 
My 13 in SB double belt motor pulley is 28 degrees with a belt spacing of .587. Try finding that in Machinery's Handbook.
 
30-42 degrees depending on the size of belt and the pulley dia. The larger dia the pulley the more degree on the angle. I have some pics but i won't post them..Bob
AUDEL Millwrights and Mechanics Guide 4th edition
 
matched belts used to come tagged in pairs.
goodyear for example now claim all the belts are matched.
i prefer to find belts that have a close batch number.
belts run together should be run a little loose with little load for a few minutes,then re-adjusted.
4L and 5L belts are measured on the outside circumferance,A and B series are sized by pitch diameter.
 








 
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