New to me Rockwell 20" BANDSAW up and running - Need speed control adjustment help?

[Ron VanO]

My dad and I just acquired a late 70s/early 80's Rockwell 28-3x5 20" wood/metal bandsaw with 2 speed gearbox and variable speed pedal. We got it installed, wired up, and running. Motor spins at 1725 rpm - with the motor/gearbox access door off this saw is louder than a freight train? Is this normal? I thought perhaps the wiring was haywire and motor was spinning too fast but double checked all wiring and voltage to the motor. All seems good. The issue we are having is with the pulley system/pedal adjustment for speed. It has a torque converter arrangement similar to a snowmobile or go kart and the pedal operates a moveable cam which moves one of the pulleys in and out. It has a somewhat crude cable arrangement that controls this via the pedal. The belt seems to jump around and the speed control doesn't want to slow it down anywhere near the 50fpm minimum speed? l I'm hoping someone can provide some insight on proper adjustment procedure for this assembly as we cannot seem to make the saw run smooth or speed control work properly. Thanks for any help

[Geoff Crimmins]

I would recommend joining the forum at owwm.org. In the one photo the belt on the Reeves drive is loose on the bottom side, and I don't think it's supposed to be like that. With the belt off you might check that the adjustable pulley moves smoothly when adjusted. The other pulley has a strong spring on it that forces it closed when the front pulley is opened. Both of these pulleys need some oil where they adjust, and could be gummed up if you didn't clean and lubricate them. Just be careful not to get oil on the surfaces that the belt touches. I have have a similar Reeves drive on my drillpress and it works great, so I expect yours will be fine once you get it running correctly.

[Charles Lent]

Yeah, that's a "Reeves Drive" kind of mechanical speed adjustment. Never change the speed adjustment unless the drive is running. Bad things can happen if you do.

It will need periodic lubrication and these can be hard on belts, so keep a spare belt handy. The one that's in it looks too loose and likely needs replacement, or someone has moved the speed adjustment without the drive running. Do a Google search for" Reeves Drive" to learn more about it. The same drive system is also used in Lathes, Snow Mobiles and lawn tractors. They have been use for many years and are a proven way to provide infinitely variable speed/torque. As you move the speed lever, the lower pulley sides should move together, causing the belt to ride higher and higher in this pulley. The upper pulley is held closed by springs, so it will pull apart as the lower pulley closes, so in effect you are gradually changing the pulley diameters, small to large at the motor end and large to small at the saw end. The belt should always remain relatively tight (no slack) during this. The shaft slides in the pulleys need to move freely, but be careful of lubrication, because excess can get on the pulley flanges and belt, causing excess slipping and belt deterioration.

Congratulations on finding a great older band saw. Cleaned and adjusted, it should do everything that you will ever need a band saw for.

Charley

[Ron VanO]

thanks for the info Charles and Geoff. We spent the afternoon tinkering on it yesterday and after replacing the cable that actuates the pedal linkage and making a series of adjustments we got it running fairly well. Was happy to make that ceremonious first cut yesterday. Worked great! Looking forward to having it in the shop. Still welcome any further input on the ins and outs of the Reeves drives and particular adjustment tricks for this saw. From what I can gather we are only getting it down to about 200 fpm (from calculating blade length/wheel rpm). Saw range states 50 fpm minimum ? We are all the way up on the high lobe of the speed adjustment cam - does anyone have an idea what would slow it down further? Thanks!

[Bill Dufour]

The pulley bearings commonly wear and allow the pulley to wallow around causing unstable speeds and loud noises. This was a good technology for the 19th century. Where the line shaft steam engine ran at constant speed. Continued to work well for AC motors. By late 20th century VFDs had replaced them for many applications.
Bil lD