Speed control

[jmsabel]

While using my Mark 5 today, there was a loud vibration for a bit. Shortly thereafter the speed would not hold as set - it increases. All the parts seem to be sound, in the right place, and working normally. If I hold the speed control dial lightly, everything works as advertised. The internal spring seems to be making contact with the speed control dial. Any suggestions?

[garys]

Take thei side cover off and run it for a bit. Look at the control sheave area (part #110 on the head breakdown diagram) If you see any vibration there, you possibly have a bad bearing in the end of that sheave.
https://www.shopsmith.com/ownersite/pro ... 0_1_14.pdf

If you don't see vibration at that point, fully inspect the rest of the unit for any vibration.

[jmsabel]

Thanks for the idea garys. my unit part 110 is not like the diagram in that there are no parts 111 or 112, it is a one-piece unit. However, I see that it needs to be replaced. Once that happens we will see if it solves the problem.

[DLB]

Thanks for the idea garys. my unit part 110 is not like the diagram in that there are no parts 111 or 112, it is a one-piece unit. However, I see that it needs to be replaced. Once that happens we will see if it solves the problem.

Your new control sheave will come with button bearing, roll pin, and retaining loop. These parts are essentially unchanged since the 50's. Your old roll pin and retaining loop may be in the bottom of the motor pan. Among the possibilities, your button bearing might have seized which would mangle the retaining loop and there'd be nothing left to hold the roll pin in place.

- David

[chapmanruss]

jmsabel,

If as David suggested

Your old roll pin and retaining loop may be in the bottom of the motor pan. Among the possibilities, your button bearing might have seized which would mangle the retaining loop and there'd be nothing left to hold the roll pin in place.

If this is the case, it would be a good idea to check out the Speed Control Assembly too. The Quadrant (AKA Porkchop) or other parts may have some damage if the button bearing seized and the loop and roll pin "ripped" off the Control Sheave. Since the Headstock is Out-Of-Service it is a good time to check everything out.

[jmsabel]

To David and Russ. It looks like you two are right. My control (dead) sheave looks like a different system in that there is no roll pin this no way to take it apart. I think I bought the machine some time between '81 and '86. The had to replace the quadrant very recently. Now I know why. I think it is still useable. I will know when the new parts arrive. Thank you both for your help.

joe

[jmsabel]

To those that offered suggestions and anyone else interested, the bearing in the end of the control sheave was wiped. It barely turned. After replacing the sheave everything works as advertised.

Thanks to all who offered help. Have a great and safe holiday weekend.

joe

[br549]

Glad your machine is back up and running. For future reference and possibly an option for others with similar problem,the entire button bearing assembly can be replaced and is available from Band Saw Tire Warehouse. Here is a link to one of their many listings on ebay.

https://www.ebay.com/itm/352322562437?h ... xyvSVREl94

Here are two threads full of ideas and advice on replacing the button bearing. My approach with JB Weld is still holding up, and I have been using the advice of keeping the bearing well lubed by generously oiling the control sheave with the machine in the drill press position and letting it remain in the drill press position overnight. If I seen redleg's method before I repaired mine, I would have tried that first.

viewtopic.php?f=10&t=19133

viewtopic.php?f=10&t=19238

[garys]

You can also purchase just the bearing at any local bearing supplier. Just get the number off the old bearing and pick up a new one.

[benmcn]

Here is a video by Jacob Anderson showing one way to replace the control sheave bearing:

https://www.youtube.com/watch?v=lm86LKc4ufg