Shopsmith Forums

I recently added the power pro upgrade to my shopsmith mark 5 model 500. I do like the upgrade. However I did have one problem during routing operations at around 9000 RPM the motor controller gave me a high temp warning after about an hour of operation. Long and short of it I called shopsmith customer service and was told this in normal just shut unit off and allow to cool. Well to me this should not be normal and I made the following fix to prevent this from happening again.

1 The reason this happens is that the whole system just circulates the air inside the head-stock (no exchange of cool air, engineers must have though conduction though the head-stock body was good enough) and the air eventually heats up even in my cool basement of 65F.

2. To fix this, the new motor has a very good fan that moves allot of air when operating, so I glued a 1 inch dense foam ring (7 inch outside dia and 6 inch inside dia) to the bottom of motor (this will fit up and seal to the back of the motor cover.

3. Made 8, 3/4 inch dia hole in the motor cover where the ring above mounts to the cover, this allows fresh air to enter the motor and blow the air inside the head-stock exiting out the idler plate, quill shaft auxiliary tool attachment ,logo plate after modification below and the vent on the bottom of the motor cover.

4. To prevent sawdust from entering the holes in the cover, put air conditioning air filter material over the holes (this can be vacuumed to keep clean)

5. To allow some air up and around the motor controller, place two 3/32 inch thick washers on the two prongs (1/4" dia) on the back of the removable SHOPSMITH logo and replace, the gap between the logo plate and head-stock created allows the air flow but keeps the logo in-place.

Ran the unit for 2 hours at 10,000 RPM with no problems and now even the belt area on the top of the head-stock stays cool.

Cool (pun intended). Now pictures would be great.

I thought you might.

Love your changes. I put your posting info and the pictures into a Word file for my records - I have a PowerPro upgrade waiting for some spare time and I will probably add some ventilation in the upgrade process. Couple of questions:

Q1: do you feel much air moving into the head through the filter and/or out the various points on the head?

Q2: did you think about adding a fan to blow air into the housing?

There was another posting or two on this same subject. I'll have to go back and see what was in those other threads.

As a side comment, there is a rule of thumb that you cut the lifetime of a device in half for each 10 degrees C increase in temperature. So getting the temperature down can have a BIG effect in the long term.

Very interesting concept and I like the idea. One question have you visited with Shopsmith regarding how the changes effect the warranty and to see their level of interest in making a similar revision. Jim

This type of ventilation also works very well for the regular Mark V headstock. Many years ago, I had cut a 4" somewhat round hole in the front of the motor pan (very hard to do, used a grinder) to allow a longer DC motor to be used as a power source. After many failed attempts with the DC motors, I mounted a 4" square louver vent plate (half of a 4" X 8" floor vent with screen), over the hole and used the motor pan for a 1 1/8 HP motor. Not only did the whole headstock stay very cool but a few years later when I checked, there was no accumulated sawdust or crud in the headstock or motor pan after many many hours of use.

It appears the motor draws a vaccum inside the headstock which sucks in sawdust/dirt around all the holes/openings in the headstock. I suggested this fix to Shopsmith several times but was lead to believe that they do not accept most suggestions or changes due to copywrite, liability and ownership issues.

Q1 yes especially at higher speeds which is good because this was where I was experiencing the high temp problem.

Q2 I did at first, but then I ran the unit with the belt cover off and felt so much air flow from the motor itself that I discarded the external fan idea.

Not as of yet, this should not affect the warrant, none of the changes affect the power pro equipment itself, just the SS motor cover. My main cocern was over heating and as any electrical engineer will tell you the more you over heat electronics the shorter their life span. Since SS CS answer was to turn unit off and let it cool that was as far as I went with them.

Quick question, when you said your ran it for an hour, are you saying it was running for a whole hour or was it on and off, some duty cycle?

I've not had that happen but then it has never been on high speed for a whole hour, I'm always cycling it on and off and I've done that for hours. Actual run time would be maybe 20 minutes per hour.

Ed

I hope that this all works out well for you but do be aware that you have altered the air flow through the headstock from what it was designed to be.

I know you believe that this was wise, necessary and appropriate and that you have done nothing but improve the operating conditions by reducing the heat.

But, unless you are an engineer trained in this sort of thing, you could find yourself in an unfavorable circumstance.

Bottom Line: You may have invalidated your performance warranty.