Repair on power head of Mark V

[turkeyshooter]

I have an older model Mark V. The belts are good, but the handle you turn to adjust the speed is hard to turn & when using it in upright drill press position it makes a rattling noise at certain speeds. I took the covers off the bottom & blew out any dust. Motor turns fine, but the part the belt rides in & comes together to tighten the belt up is hitting part of the inside of the speed handle. Cannot seem to adjust this thing to where the belt will turn now when the motor is on. If I turn the handle as far as it will go in one direction it tightens up but will not let the motor turn. Looks like there should be a way to adjust this. Also how do you get to the side that the speed adjustment is on. I took the shopsmith emblem off the other side of the motor to see what was going on. I really need this Shopsmith going so I can use the drill press. It is the arm coming in on the inside of the motor housing from the speed adjustment that is hitting the back ribbed area of the pulley that is causing the problem. Any ideas would be greatly appreciated. Thanks in advance.

[JPG]

I assume you removed the belt from the motor pulley when you 'took the covers off the bottom'.

Do it again.

With the 'bottom'(motor pan and motor) removed, raise it to vertical(drill press mode). Secure it with the locking screw.

Now that you can 'see' inside from the 'bottom', determine if the motor belt(the one removed from the motor pulley) is caught in between the control sheave and the idler shaft sheave.

Position the belt away from the pulley, and the speed control knob should turn easily and the 'arm' should push the control sheave in and out from the idler sheave.

The idler shaft pulley consists of the movable control sheave and the fixed idler sheave. Turning the speed control crank should easily move the 'arm' thus causing the control sheave to slide on the idler shaft. This opening and closing of the sheaves does NOT provide belt tension.

The control sheave has a small 'button'/bearing and a square clip that connects to the 'arm'(referred to as either the quadrant gear or the 'porkchop').

If the control sheave is hitting the speed control in vertical mode, it may be that the button/bearing has separated from the 'snout' end of the control. sheave.

If you are running 'full speed'(fast) the 'high speed adjustment(limit) may be incorrect.

Getting back to 'how the animal is supposed to work, the motor belt tension is provided by the pulley on the motor shaft. That pulley also consists of two sheaves. The 'fixed' one is the fan sheave and has the fan 'blades' on the backside towards the motor. The floating sheave is movable, but is spring loaded towards the fan sheave.

Both the control sheave and the floating sheave must be kept well lubricated by frequent oiling.

When the control sheave is moved(by the speed control) towards fast, the control sheave opens up and the belt moves towards the shaft. That creates less tension on the motor belt and the spring moves the floating sheave closer to the fan sheave thus restoring belt tension. Since the belt is now at a smaller radius from the idler shaft, and, the belt is now further away from the motor shaft, the speed increases. The reverse happens when adjusting the speed towards slow with a major difference. The control sheave is pushed closer to the idler sheave thus squeezing the belt. This increases the belt tension so the floating sheave will move away from the fan sheave thus relieving that excess tension and the belt will now be further away from the idler shaft, and, closer to the motor shaft thus reducing speed.

A 'cardinal' rule is to NEVER adjust the speed control unless the pulleys are turning. That can be by hand if desired. The reason is the belt squeezing that is done by the control sheave when moving towards slow. If the pulleys are not rotating the squeeze does not get 'relieved' and the stress results in strain to the speed control causing abnormal wear further exacerbating proper operation.

I realize this is a big chuck to absorb, but once swallowed and understood will lead to eliminating going off in inappropriate directions when working on this beast. Truth be known it is very tolerant of misuse and neglect(lubrication lacking), but does have limits.


Please keep us informed as to the progress of yer maintenance journey!

If you run into trouble, we are here and may direct you to some videos that may help.

However posted pix are quickly responded to if you are/have done something incorrectly or have questions re the parts.

[beeg]

A 'cardinal' rule is to NEVER adjust the speed control unless the pulleys are turning. That can be by hand if desired. The reason is the belt squeezing that is done by the control sheave when moving towards slow. If the pulleys are not rotating the squeeze does not get 'relieved' and the stress results in strain to the speed control causing abnormal wear further exacerbating proper operation.

BELIEVE what I highlighted in red.
Here's a PDF on the high speed adjustment procedure.
[ATTACH]15560[/ATTACH]

[turkeyshooter]

Thanks, I decided to try turning the switch on & adjusting speed control like you said and that pulley must have moved over into the correct position and now it is working once again. Can you fellows tell me what are the proper lubrication points you mentioned? Thanks Again for your help. There is still a slight chatter noise. Probably does need some more lubrication.

[fiatben]

We have a permanent "sticky" on this forum for newbies, first-timers and those of us that tend to forget everything we've learned.

https://forum.shopsmith.com/viewtopic.php?t=7092

Start here, learn the cardinal rules, watch the videos, read a few threads (using the search function) and see if you have any questions left. The guys on here are geniune experts on these machines and can answer questions I can't even think to ask!

[JPG]

Thanks, I decided to try turning the switch on & adjusting speed control like you said and that pulley must have moved over into the correct position and now it is working once again. Can you fellows tell me what are the proper lubrication points you mentioned? Thanks Again for your help. There is still a slight chatter noise. Probably does need some more lubrication.

Seen this?:D

http://www.shopsmithacademy.com/SS_Archives/SS111/SS111_Mark_V_Maintenance.htm

[oddie]

Try this site for cleaning and lubricating instructions. [url=http://www.shopsmithacademy.com/SS_Arch ... enance.htm]
If I didn't set this up right for a link, copy this address into your browser and go to it. There are several other Shopsmith Sawdust Sessions that address maintenance. Scan the list of sessions to find them. There are at least 3 of them along with other neat items.

[dusty]

Try this site for cleaning and lubricating instructions. [url=http://www.shopsmithacademy.com/SS_Arch ... enance.htm]
If I didn't set this up right for a link, copy this address into your browser and go to it. There are several other Shopsmith Sawdust Sessions that address maintenance. Scan the list of sessions to find them. There are at least 3 of them along with other neat items.

http://www.shopsmithacademy.com/SS_Arch ... enance.htm