Shopsmith Forums

Hello to all.

I am a new user and I am rebuilding a Mark V 500. When turning the speed control to increase speed it turns very easily. However when I decrease the speed the knob is very difficult to turn (much different that increasing speed). I have oiled the sheaths and the worm gear and the quadrant assembly look ok. What am I missing? Thanks!!

Steve

Welcome!

It sounds like you already checked the likely sources of potential problems with the speed changer not moving smoothly.

Just to make sure, however, when you say you oiled the sheaves, did you oil both the upper and lower sets of sheaves? Also, when you say the worm gear and quadrant look ok, did you check for wear, alignment and impacted sawdust and congealed grease?

If those things all check out, I'm not sure where the problem would be.

It should take more force to go from fast to slow, but it's hard to quantify how much more.

Thanks for the quick reply. Yes I oiled both the upper and lower sheaves. No built up grease or saw dust. The quadrant had some slight deformity but filed down easily. Might need to check alignment though. Also put on new belt, perhaps the belt need to break in.

Steve

I dont think it would be the belt, but which belt are you referring to?

ERLover wrote:I dont think it would be the belt, but which belt are you referring to?

Increasing speed, easy peazy(nothing resisting the control sheave movement away from the belt).

Decreasing speed, stiff(you are squeezing the motor belt and the floating sheave must respond by opening the motor pulley to release the tension).

Thus the rate at which the speed control is moved also has an effect. Slower = easier.

A newer(stiffer) belt will resist squeezing more effectively.

An ER SC resists both directions.

I have actually replaced both belts. The squeezing the motor belt and sheath makes sense. It just looked a little stiffer than some of the videos I saw. Perhaps since it is a new motor belt it is a little stiffer. Thanks for all the help. This forum is great and there is a wealth of info. Since I have little experience with SS just did not know the common things and the manual really do not mention the speed control being stiffer when decreasing speed.

Learned something already today about belts.

In order to 'keep it simple', SS ignores the direction and simply says 'Do Not'. Far easier to remember that way.

sadair wrote:Hello to all.
......I have oiled the sheaths and the worm gear and the quadrant assembly look ok. What am I missing? Thanks!!

Steve

Steve - I'll bet what you are missing is a simmple, but thoroughly oiling of the motor shaft and the movable sheave. This is the one lube that is often forgot.

Take off the belt cover and with your hands, pull out the movable sheave, remove the drive belt. Oil the shaft liberally. Now put the machine in drill press position. Put oil on the end of the shaft and allow it to drip/penetrate down.

Now lower the machine to saw position and again using your hands pull out the movable sheave several times. I think you will find it easier to move and your speed control easier to turn slower.

charlese wrote: Take off the belt cover and with your hands, pull out the movable sheave, remove the drive belt.

DO NOT let go of the sheave, return it softly. IF ya let it snap back, you'll have more problems.