Rockwell Model 15-665 15" Help

[Robert S Farrell]

I recently acquired a Rockwell Model 15-665 15" Variable Speed Drill Press. Serial # 1809601. It has a 3/4 hp, 1725 rpm, 115v motor. The variable speed is supposed to go from 450 rpm to 4700 rpm. The slowest mine goes is 918 rpm to the fastest of 3955 rpm. I cleaned it all up and lubricated it. Anyone know how I can adjust it to get the full range of speed? Any help would be appreciated.

[Mike Hollingsworth]

I've got the same machine.
How are you measuring speed?

[Robert S Farrell]

I used one of these.
http://www.amazon.com/Digital-Photo-Laser-Tachometer-Contact/dp/B0045E0GT2

[Bill Adamsen]

Robert:

I don't have that make/model ... but I have a Clausing of a similar ilk. The manual shows both a slow speed (infinitely variable) and a high speed (infinitely variable). I assumed it was the diameter of the primary Reeves pulley, but it actually appears to be the motor rpm. I've attached a snapshot from the page showing the specs just for illustrative purposes. You might see if you can find the manual for your machine (it doesn't appear on Vintage Machinery under either Rockwell or Delta). What speed is your motor?

I have the same approximate rpm gauge you have, and I find the drill runs fast for the stated rpm on the Reeves drive control handle.

[Robert S Farrell]

Thanks, I ordered the manual. It is a 3/4 hp, 1725 rpm Motor.

[Robert S Farrell]

I got the manual. Speed with the 3/4 hp motor should be 450 to 4700 rpm.

[John McClanahan]

I have a Powermatic with the same kind of speed control. It sounds like the belt may be too tight. That will limit the speed range. Also notice there is options for 1725 RPM and 1140 RPM motors. Mine has the 1140 RPM motor.

John

[Robert S Farrell]

Thanks John. Mine has the 1725 rpm motor. I think you might be right about the belt being too tight.. I see in the manual the distance between the center of the two pullies should be 15 1/8". Mine is 15 9/16". I am going to adjust the motor forward to that dimension and that should loosen the belt.
Bob

[Robert S Farrell]

OK, I adjusted the motor to 15 1/8" from pulley center to pulley center. Lowest speed is now up to 1179 rpm and fastest speed is now 4360. How can I slow down the lowest speed setting? Should be 450 rpm.

[John McClanahan]

Run the drill press and turn the speed down all the way, then shut it off. Now look at where the belt fits in the motor pulley. It needs to be all the way in, almost touching the center where the motor shaft is. The spindle pulley should have the belt riding all the way near the outside/top of the V. When the speed is at maximum, the opposite should be true. The speed dial moves the spindle pulley apart/together. There may be some needed adjustment in that area.


John

[Robert S Farrell]

328853
Thanks, When I turn the speed down to the slowest, the belt does not go all the way to the outside of the spindle pulley. It seems the U shaped bracket that pushes up on the pulley (to make the belt ride to the outside) does not go up enough. The cam on the back of the dial is fully down. I don't see what to adjust to make the bottom spindle pulley push up farther.

When I turn the speed to the fastest it is working fine. The belt rides the outside of the motor pulley giving me 4500 rpm.

[Bill Orbine]

You could have a worn or improper belt.... I'm speaking in terms of width