View Full Version : v-belt styles

08-03-2006, 03:47 PM
I just replaced the v-belts on my Rockwell since I already had the spindle out. Question came up whether to use the notched "cogged looking" belts, or a solid belt. It had the notched/cogged belts on it, but the guy at the belt place strongly recommended going with a solid, which I did. Over the years, I’ve heard “evidence” of the superiority of one over the other MANY times one way or the other and it seems to be one of those things that everybody just repeats whatever they heard from “some expert”. So I figured I would ask YOU experts... ;)

So I’ve heard it holds better, it runs smoother, it lasts longer in “x” conditions, and on and on. And, at various points and from different “experts”, I’ve heard each “better” point represented as applying to either! I’ve come to the conclusion, right or wrong, that it does not matter as long as you get a “good quality” belt and not a cheap-as-it-can-be-made no name version. The only real thing I can see “logically) is that I expect the notched/cogged belts can fit a smaller radius turn on a pulley (without degrading life span or performance) and maybe work better in the face of excess liquid environments where the groves might act like rain grooves/sipes in a tire.

Assuming the same “quality” with only the notch/solid variable, what is the real difference? And more specifically, is one or the other better for a dual belt spindle in a mid sized lathe? I bought “best quality” solid belts that are “matched size” from an industrial supplier; was that a mistake? Should I have insisted on notched?

Also, given that it's going to be in an oily environment, which these belts are specifically designed for, is there anything that should be done maintenance wise to keep them working well for years to come?

08-03-2006, 07:06 PM
The cogged belts are better than the solid for smaller diameter sheaves but let me tell you about my belt fun ...

I needed matched belts for my lathe and without them, the shorter belt will flop around and cause imbalance. Attempting to to the "right" thing, I picked up a pair of Goodyear Matchmaker belts. Matchmaker make me a wish ... take these POS belts back to where they came from :eek: They had significant thickening in width near the seam area.

Next, bought a pair of (I think) Browning belts, supposedly well made and by design, a close match. They differed by quite a bit, leaving one flopping.

Finally, went to a local VIP auto store, picked out 2 Goodyear replacement belts that seemd to match fairly well (carried 2 cylinders and tape with me). They have been running for months, silently and vibration free (as Vee belts go).

They were also the cheapest of the 3 sources.

With all due respect to the belt makers, my lathe has short belts which exacerbate the matching problem but that's no excuse for VERY sloppy width control. Den

A.K. Boomer
08-03-2006, 10:11 PM
A good cogged belt is better in many ways but like you said esp. under small pulley circumstances, they are easier on an electric motor and get more power to the aplication, they produce less internal heat and this increases longevity, they have less V-surface deformity so they keep a uniform platform for the pulley to grip yet unit pressure is still kept high because the slight gaps , a typical belt uses the inner part of the vee on small pulleys because the belt gets compressed on the inside and stretched on the outside on small diameter stuff, relief grooves keep the belt V uniform --- added bennie like you said of giving foreign matter a place to go,,, one draw back --- all the flex gets located in one area so this is the area that first shows cracking but because belts run cooler and this internal area is closer to the outer parimeter the distance it has to travel is reduced so belts generally outlast the others and save energy while doing it..... serpentine cogs are about as good as you get for power savings, this is a factor and is why all auto man. have at least gone to serp.
Cogged belts also handle misalinement problems better, and because some of the energy it takes to keep a belt in good radius with the pulleys is equated directly into the tension of the belt when its installed (i.e. getting over the vector force it takes to conform the belt to the pulley) cogged belts take a little less tension to get the same job done which is very healthy for alternator bearings, power steering bearings water pump bearings, (providing these units dont have automatic tensioners) Mill head and lathe motor and drive bearings and so on... iv always ran my belts as loose as posible for this reason (without slipping or slapping) big fan of the cogged belt...

08-04-2006, 03:44 AM
Ever tried a link belt? Pricey maybe, but worth it. Because they are built up from links, they are inherently matched, as long as you buy enough links at one time to make up your belts, and make your belts from equal numbers of links.

I'm a convert, especially after having the same problems you speak of. Uneven, lumpy belts, cord exposed in some spots and not in others, fat splice ares, etc.

08-04-2006, 10:15 PM
I work in the belting industry, not v belts though. The companies state that the manufacturing process is so exact that matched belts are not necessary anymore. Mark with chalk, cut with axe, charge customer. Works forTHEM.

08-05-2006, 02:45 AM
Thanks for the info guys.

On the linked belt being inherently matched, I don't buy that. But then again, I have a hard time accepting that they run smoother too, though I've not done any tests/experiments. But as for matched, I'm sure there is some tolerance in the acceptable size of links. And if there is tolerance, there is the inevitable opportunity for tolerances to "stack up" the "wrong way" to cause problems. I find it far easier to accept that ALL normal belts are now close enough that “matched” is no longer required (which it seems is questionable based on Mark’s post) than that 2 belts (each built from over 25 links) taken from a box will be “inherently matched”. I have no evidence one way or the other, and I may be completely off base, but that is my intuitive response. Am I missing something?

J Tiers
08-05-2006, 09:18 AM
One issue which those screaming about matched belts do not always consider, is matched PULLEYS.

Fairly small differences between the pulley grooves, due to wear, etc, can make a large difference in the needed belt.

Small and large here are on a small scale, of course.... pretty much nothing in our range of pulley sizes is going to make a 0.5" difference in required belts, it's going to be smaller. Much smaller. But it is small differences that affect which belt takes the power.

Then again, matched belts are usually for high power applications. Some of those have SHAFTS which are comparable the diameter of the PULLEYS on HSM miniature micro-machines (like 12" lathes, etc).

At the size of the pulley that fits one of those shafts, the appropriate sized belts ARE matched at the typical circumference differences... even if you can measure a "significant" difference.

08-05-2006, 10:23 AM
... At the size of the pulley that fits one of those shafts, the appropriate sized belts ARE matched at the typical circumference differences... even if you can measure a "significant" difference.

Very true. Another factor that goes hand in hand with this is belt tension. On small(er) machines, we don't want belt tension like the alternator or ac belts in our cars. With lighter tension applied, the belt variation leads to flopping around of the looser one and various resonances that develop from that.

And when you're sitting in the middle of $80-ish worth of new belts, some squeeking, some vibrating, you'll know what SCREAMING IS :D :D , especially when a $18 pair fixes the problem and the others are non-returnable. And, for the record, these are on precision machined, dual belt steel sheaves, around 4" diameter, 28" belt length.

08-05-2006, 02:38 PM
FWIW, in my case, the belts are 50" and pulleys are about ~3" diameter. But it can take some pretty good tightening I think (no spec, just guessing, but it took some pretty good tightening just to get the idler mounted! :eek:). In any case, I specified "matched" belts, and whatever I was given seem to run very smooth at ~$7 each...

08-05-2006, 10:35 PM
I was so disappointed in the brand new Gates belt that I put on my Rockwell mill, so I decided to try the linked belt by Fenner. What a difference! A couple years later I'd forgotten all about it, so I went through the same excersize with my table saw. The old ratty belt was replaced with a new Gates belt. I couldn't believe how much vibration there was. I picked up a linked Fenner belt from McMaster-Carr and had it on the next day, and the saw just hums now. The belt on my Delta surface grinder is looking ratty too. I'm not going to repeat my past mistake.


08-07-2006, 10:40 PM
I am looking for a source for small v-belts for my Edelstaal lathe.http://tinyurl.com/qraak
The literature refers to a "Gates narrow width polyurethane 60 degree V-belts" The unit requires 2 belts, one wide (6mm top) and one narrow (3mm top). Each are 44.2 cm in length.
Any help with sources is greatly appreciated.

08-08-2006, 03:05 AM
On the link belts- my recently completed countertop saw project requires two belts, and I used the link belts ( bought from Lee Valley, I forget what they call them) and the belts matched right away and run smoothly. I also replaced the pair on our table saw, and there hasn't been any problem since. Most of the funny noises went away with this belt change. One caveat with this use- the link belt has a higher profile than the standard vee belts, and the belts will rub the bottom of the saw table if the blade is cranked all the way up.

Every change I have made from a standard vee belt to a link belt has been an improvement, and where more than one belt is run side by side I've never had an issue with mis-match.