Drive Belt Issues

csanders · Post by **csanders** » Thu Jul 18, 2013 9:49 am

Hello all. I am a new member of this forum. I have recently run into some problems with the headstock of my Mark V. I can not find the exact model number as the unit is 36 years old and the label is no longer legible.

Here is the issue I am having: I turned the unit on one day and the motor was running but the drill press was not turning. I never ran the unit at the highest speed as the instruction video tells you to,but I did move the dial down to give the pulley more room. I disassembled the pan to reveal the motor. The issue was with the Speed Control dial. I simply need a new one as the gears on the dial are bad, not the inner gears themselves. That is fine, no issue I just need a new one.

The trouble I am having is trying to get the Drive Belt back on. I do not remember taking the belt off. I do not think that I did to be honest. I tried stretching the belt by rolling it along the sheave ( what I call a pulley). It simply was not happening. I have put belts on before and realize they need to be stretched a little. As you can see from the pictures I believe they would rip before they would fit over both sheaves (pulleys). I also turned the bushing on the middle pulley to give me more room.

Is anyone able to identify which model number I have? 500, 505, 510, 520?

Here are the pictures:
https://dl-web.dropbox.com/get/ShopSmit ... 2d_H7WFD6g

https://dl-web.dropbox.com/get/ShopSmit ... YNfksOuPkg

https://dl-web.dropbox.com/get/ShopSmit ... uFoOUNmOnQ

https://dl-web.dropbox.com/get/ShopSmit ... tx1O0v4_-Q

https://dl-web.dropbox.com/get/ShopSmit ... E37mhvrCnA

https://dl-web.dropbox.com/get/ShopSmit ... 45IpOr5RaQ

https://dl-web.dropbox.com/get/ShopSmit ... aJVdH9kZDQ

csanders · Post by **csanders** » Thu Jul 18, 2013 10:05 am

I should have mentioned that I took the headstock off the bars in order to give me more room. I was able to get the belt on both pulleys, but the pulleys are overlapping now. That is to say that one is on top of the other. Also, all pictures were taken after it was taken off the bars and the belt is now on both pulleys. There is just no way to get the motor back to where is screws into the panel. You can see the screw holes on the motor and on the panel. It seems as if the motor has no way to be properly seated, which would prevent the belt from pulling the motor back to the other pulley. Hope this makes sense. I really needs some help. If the pictures aren't enough or not working let me know.

JPG · Post by **JPG** » Thu Jul 18, 2013 10:51 am

The pix link keeps us out.

If it is 36 yrs old, it has to be a Mark V and likely a 500 version.

terrydowning · Post by **terrydowning** » Thu Jul 18, 2013 11:15 am

JPG40504 wrote:The pix link keeps us out.

If it is 36 yrs old, it has to be a Mark V and likely a 500 version.

Same Here
[ATTACH]22184[/ATTACH]

csanders · Post by **csanders** » Thu Jul 18, 2013 11:35 am

Here are some of them.

csanders · Post by **csanders** » Thu Jul 18, 2013 11:38 am

and the rest. Sorry about that. I think the belt may have slipped off during operation, which is why the quill only spun during slow speeds when the belt was able to grip the shaft. I simply don't know what's wrong. Thanks for all the help.

JPG · Post by **JPG** » Thu Jul 18, 2013 12:00 pm

Assuming it is a Mark V:

Remove the belt from the motor pulley and reattach the motor to the motor pan and that assembly to the headstock. On the surface that seems a logical course of action, but I cannot see a high success rate doing it that way.

A couple of 'tricks' makes belt installation relatively easy with no 'stretching'.

First some 'terminology'. The Reeves drive in the Mark V consists of two movable sheave pulleys. One is on the motor shaft(fan sheave(fixed) and floating sheave(movable with spring tension). The other pulley on the idler shaft consists of a fixed sheave(the idler sheave) and a movable control sheave. The speed control quadrant gear(porkchop) positions the control sheave along the idler shaft.

In order to install a drive(motor) belt the idler pulley must be opened fully(fast position of the speed control). This allows the belt to 'bottom' out in the idler pulley closer to the motor shaft.

The belt can be started onto the floating sheave. The floating sheave can be pulled away from the fan sheave which allows the belt to drop deeper into the motor pulley as it is rotated. Caution! Do not allow the floating sheave to slip and impact the fan sheave.

Hope you DO have a Mark V and that this helps.

JPG · Post by **JPG** » Thu Jul 18, 2013 12:16 pm

Just now saw de pix.

Tis a Mark V fer sure!

So:

Remove the belt from the motor pulley, and reattach the motor to the motor pan.

Position the control sheave to its fast position on the idler shaft.

FWIW now is a good time to liberally oil the sheaves. There be oil holes in the hubs of the movable sheaves. Both movable sheaves should slide freely, but the floating sheave is under spring tension which must be overcome to move it. Caution! Do not let the floating sheave slip and impact the fan sheave.

Reattach the motor/pan onto the headstock.

You should be able to start the belt onto the motor pulley. Pulling the floating sheave(opening the pulley) should allow the belt to drop into the pulley as it is rotated manually.

When you are remounting the headstock, preposition the lock wedges.

tvidnoviciii · Post by **tvidnoviciii** » Thu Jul 18, 2013 12:32 pm

It also appears to me that the eccentric bushing that controls the tension on the upper belt needs to be adjusted. Check out: http://www.shopsmithacademy.com/SS_Archives/SS123/SS123_Shopsmith_Reborn_Pt3.htm

csanders · Post by **csanders** » Thu Jul 18, 2013 1:24 pm

I watched sawdust sessions on shopsmith.com and they said to move the bushing to allow more belt slack. The motor is back on the pan. The pan and motor are now on the headstock. The Rectangular spring is disconnected from the middle pulley. Is that ok or will turning the control not effect the tension now. I know I need more terminology. Please bare with me.