[87kevin]

I have an excello mill similar to a bridgeport that I am currently close to finishing a retrofit on. I've got the spindle working great - it is a cat40 spindle belt driven by a 3hp motor/vfd. There is a 2 speed gearbox but no vari-speed head or anything like that. It has a 1-1 pulley ratio, 3.75" pulleys and an HTD timing belt. Above 2k rpms, it gets quite loud in a whining belt noise kind of way. I'm sure this is quite normal, and I wouldnt care except that I'm trying to run this thing in my garage.

Any way to quiet down the belt noise? Smaller pulleys to reduce belt speed? Change to a v or smooth belt system? I dont want to drop a bunch of cash on new pulleys if it wont make a difference. Or is this just how it has to be with a belt driven spindle setup?

Thanks,
Kevin

[87kevin]

Somebody has to know whether or not v belts or flat belts are quieter than timing belts?

[underthetire]

V belts are a lot less noisy, however at 3 hp you may want to do double v belt pullys.

[mactec54]

87kevin

You should be using a poly-v Belt, this is by far the best for what you want to do, that type of timing pulleys set up are very noisy, the round tooth type timing belts are much quieter, the only time you need a timing belt set up is for rigid tapping

[87kevin]

Thanks guys! That's what I suspected but wanted to confirm before spending the money. No rigid tapping in my future.

-Kevin

[tc429]

Timing belts do get noisy... A couple things, first, they shouldnt run tight like a vee belt- i usually set them just tight enough they dont slap, much quieter. Also there are new tooth profiles with vent grooves down the center of the teeth, and even vent slots thru the belts to quiet them.

Also be certain you have the proper belt- we had some asian machines with a 8YU style belt, looked identical to a RPP panther 8mm profile- but wasnt... Maintenance had replaced one with a RPP Panther belt and it sounded like a siren....the belt tooth form is the same, but the thickness from the tooth notch to the kevlar stranding is thinner on the 8YU style, so when wrapped around the sprockets, the pitch " shrinks" a little, and it wont ride in the sprocket unless insanely tight...just wanted to mention as some asian oems do this in hopes of selling belts. Our 8YU belt price was $700 , the RPP or 8m styles around $60.
We found it best to machine up standard 8m replacement sprockets for more readily available belts. the 8YU style is available stock from europe, but only in narrow widths (ours were like 80mm wide!) nothing in USA, and Taiwan was the $700 option, plus shipping delays...