How much vibration is normal in the belt of a contractor saw? The saw/belt is about eight years old but has rarely been used. The belt appears to be in excellent condition, but the up/down vibration of the belt as it comes of the pulley appears to be bit excessive. How much is too much?
Best, Christopher
Can you balance a nickel on edge? If not, check the tension or how much the belt deflects when firmly pressed with one finger--you can actually measure this accurately using a cricket guage. There are many other things that can cause vibration, loose bolts, pitch buildup/damage on blade, damaged pulley, bent shaft, change in natural frequencies, etc. Inspect everything, time for a tuneup.
What is the recommended delfection tolerance?
If a saw is stored for extended periods of time, should the belt be removed to avoid uneven stretching?
Best, Christopher
I bought a saw that sat for many months. The belt had taken the shape of the pulleys... it had a memory kink, if you will. It has a heavy vibration at slow down, which I suspect is caused by the kinks in the belt.
Once I replece the belt with a new, round one, or one of those "link" belts, I bet it runs smooth as butta.
Typically a contractors saw belt thightness is not measured in deflection because the weight of the motor provides the tension. As the belts stretches or shrinks the tension is going to be different. Industrial belts, the type normally used on this type saw are pretty bad about taking a set and creating vibration.
To remedy this situation either up grade the belt to an "automotive" belt which is designed to fun at much faster rpm's with much less vibration or go with a link belt. The link belt is going to be considerable more expensive but will work the best.
As far as the automotive belt is concerned you want one that has the notches on the inner side of the belt. The notches run from side to side. The notches permit the belt to bend around a tighter/smaller radius pulley.
Don't confuse this with the serpintine automitice belts that have 8-10 groves on the inside perimeter of the belt.
Yeah, I think I'll do that. I don't use it much and it sits for long periods, so I'm guessing it has a memory kink. Thanks!
Best, Christopher
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I hear folks claim that but I've never seen it in 40 years or so--once a tool runs for a few minutes at most any belt I've ever had has had no apparent belt "memory kink".
Go to the Gates Rubber or other major belt manufactuer's site for tips/guidelins on v-belt tensioning/applications. I also personally don't think there's any significant difference between an "industrial" belt as opposed to "automotive" for small-sized belts (4L, typically) as used on woodworking equipment. Electric motor rpm of 3450 vs 2-3000 typical cruise rpm for automotive applications is pretty much overlapping. Somewhat higher torque loadings, but most belt spec's far exceed those anyway.
I suppose _perhaps_ some of the more recent Chiwanese stuff may use some really inexpensive belt that has some of these problems but certainly everything I've ever had it's never been an issue.
I'd look at whether the pulleys are truly concentric machined pulleys or cheap cast-zinc hardware store varieties, whether they're really tight on the shafts (motor and driven) and aligned properly as primary culprits.
If it is a saw w/ more than a single drive belt, be sure to get matched pairs/triplets depending on number required. These days Gates adds a suffix number at the time of manufacture that indicates those that are within a specified tolerance instead of the old "hunt and measure" days or buying actual sets.
$0.02, imo, etc., etc., ...
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Mine must be a pretty cheap belt. I marked the kinks, and they are still in it, after running the saw many times.
I'm not saying it *is* the issue, just saying it's something to check out before you go taking the saw apart.
I have not yet had a chance to pick up a new belt, but I did remove the old belt for inspection. Major kinks from the two pulleys, apparently due to sitting idle for long periods with little use. Thanks again for the assistance.
Best, Christopher
Christopher Glaeser wrote: ...
OK, ya' got me curious...can you find a vendor/manufacturer name on that puppy?
The PM-66 is 30 or so and has never had a new set and certainly has sat far more in those years than run and there's certainly no indication of any problem w/ them. Same w/ jointer, bandsaw, etc., etc., etc., ...
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The belt is CAT NO 49-034.
I purchased this Delta about ten years ago and is rarely used. In hind sight, if I had removed the belt when not in use, I expect it would be running just fine. There are no visible signs of age or wear, just two strong kinks. I'll confirm when I pick up a new belt (which will be removed when not in use).
Best, Christopher
I still dunno'....one would think 30 years would have done it if were going to do so. I just don't see the same problem.
Go figure...
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I think it certainly could have something to do the with manufacture/material of different belts and their intended purpose.
Someone else mention automotive belts being designed for tighter turns and faster speeds.
Just thinking out loud here, but I could see a belt that is reinforced with steel being more prone to developing kinks than one reinforced with fiberglass, for example.
Yes, please report back with the results.
I'm a believer in Gates which is, afaiaa(ware) what everything in the shop is (as is most everything on everything from the passenger cars to the largest tractors/combine/field equipment (JD-branded stuff is also afaik). Replacements for shop stuff are replacement-sized at NAPA which carries Gates as well as store brand (which I don't know what theirs is; I tend to pay the extra dollar there altho tend to use housebrand for most anything else--seems as good as any other).
I don't know who Delta or others use; it could be a problem there of trying to hold down cost too much, perhaps. I also don't have a piece of ww'ing stationary equipment that's much under 30, either... :) In fact, thinking, the Model 66 is the last new piece I have--the more recently acquired shaper is an old Walker-Turner from an ODU cabinet shop auction and the big jointer I found at a TVA surplus sale (held at a TN nuclear site but they had hauled stuff in from all over the TVA system plus a lot of other federal sites including a bunch of military shops) is unknown vintage but has to be WW-II era at newest. It does have lubricated bearings (not sealed, but not poured, either, so isn't truly ancient).
Heed the advice given elsewhere in responses to your question and invest in a link belt. It makes a world of difference - less vibration, less noise, better cut (IMHO). HFT sells them and sent out a 15% off coupon that makes them the best buy!
Ditto, except most of my belts are 50 or so years old. I put a new belt on my jointer when I built a new cabinet for my Tsaw/Jointer and needed a different length belt. I went to an auto parts store for a fan belt and when he asked what car it was for, and I told him, he said I needed a machine rated belt, and sold me a bit heavier belt? I wasn't too concerned. The new belt certainly was stiffer than all my old belts. They tend to loosen up bit after billions of revolutions....
On Fri, 06 Nov 2009 13:19:12 -0600, the infamous dpb scrawled the following:
Do an experiment. Gauge the vibrations from one of your current machines which uses belts. Now put on a link belt. I'll bet the vibration level is lower with the link belt on it.
-- "To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical." -- Thomas Jefferson
Larry Jaques wrote: ...
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I've have seen 'em tried on quality sheaves and heavy gear and I'm sure it won't make enough difference on anything I have to make it worth the time (and especially the expense; they're d-d proud of those puppies from what I've seen.
If one has a lightweight contractor saw w/ the pot metal cast out-of-true pulleys or the like, perhaps it'll cover up/mask some of the inherent problems.
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I replaced the original kinked belt with a new v-link. The blade now sings. Sweeter than pie. Thanks.
Best, Christopher
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