Speed dial turn by itself

leirbag · Post by **leirbag** » Wed Dec 22, 2010 7:32 pm

When I put my machine on, and I turn my speed dial for sawing, at "saw joint", there is a small vibrations at that speed, and the speed dial turn by itself(slowly) faster and faster, for I would say maybe 1000rpm more, after that it stay there. What could be wrong? My machine is clean and in good shape made in 93. Do somebody experience this before? what can I try to fix this problem. It only turn by itself at that speed "saw joint". Any Idea would be appreciate, thank you.

JPG · Post by **JPG** » Thu Dec 23, 2010 12:15 am

leirbag wrote:When I put my machine on, and I turn my speed dial for sawing, at "saw joint", there is a small vibrations at that speed, and the speed dial turn by itself(slowly) faster and faster, for I would say maybe 1000rpm more, after that it stay there. What could be wrong? My machine is clean and in good shape made in 93. Do somebody experience this before? what can I try to fix this problem. It only turn by itself at that speed "saw joint". Any Idea would be appreciate, thank you.

I would be suspicious of wear to the control sheave bore diameter. That would allow it to wobble in the idler shaft thus allowing the belt to drop further into the pulley.

I am assuming this only happens at that speed setting, and that the floating sheave on the motor shaft is not sticking.

leirbag · Post by **leirbag** » Fri Dec 24, 2010 2:54 pm

Thank you, I'm gonna have a look inside the headstock sometime this week, trying to find out if I can see something wrong in there.

Thank you for your Idea

SDSSmith · Post by **SDSSmith** » Fri Dec 24, 2010 3:17 pm

One other thought is that you do not have part number 73 (spring) in this diagram. This spring rides in the groove on the back of the speed indicator dial should stop the speed dial from turn past the (saw joint) speed. On the greenies this function was performed by a tab that you had to depress to get to the higher speeds.

JPG · Post by **JPG** » Fri Dec 24, 2010 5:29 pm

SDSSmith wrote:One other thought is that you do not have part number 73 (spring) in this diagram. This spring rides in the groove on the back of the speed indicator dial should stop the speed dial from turn past the (saw joint) speed. On the greenies this function was performed by a tab that you had to depress to get to the higher speeds.

Doubt that Rob! Something is causing the control sheave to press against the porkchop hard enough to move it against the worm gear.(he hasn't said if the crank is moving also, I assume it is). He mentioned vibration which would help the quadrant gear nudge the worm gear.

I do not believe the anti-rattle spring would be strong enough to hinder this.

FWIW I have had this same problem, and the control sheave bore was badly worn at the sheave end(the keyway also).

SDSSmith · Post by **SDSSmith** » Sun Dec 26, 2010 4:39 pm

JPG40504 wrote:Doubt that Rob! Something is causing the control sheave to press against the porkchop hard enough to move it against the worm gear.(he hasn't said if the crank is moving also, I assume it is). He mentioned vibration which would help the quadrant gear nudge the worm gear.

I do not believe the anti-rattle spring would be strong enough to hinder this.

FWIW I have had this same problem, and the control sheave bore was badly worn at the sheave end(the keyway also).

As Rocky the squirrel says "Thank you Mr. Know It All!"[ATTACH]11263[/ATTACH]

JPG · Post by **JPG** » Sun Dec 26, 2010 4:43 pm

[quote="SDSSmith"]As Rocky the squirrel says "Thank you Mr. Know It All!"[ATTACH]11263[/ATTACH]
]

"Not it all", just the non-important stuff!;) Had I properly maintained MINE,:( I would have been clueless and left to 'guesstulating'.