Shopsmith Forums

After using my SS for a while yesterday I noticed the headstock was quite warm. This was especially true after I used it on "Fast" speed to do some minor routing. The SPT coupler was quite warm to the touch too. Not "hot" yet but very very warm. Is this normal?

When working it hard, the top of the headstock, over the drive sleeve assembly, can get warm enough to not be comfortable to touch. The headstock also accumulates a great deal of heat from the sun if operated in direct sunlight. During the summer, I have to shade my Mark V during the morning hours because it is in direct sunlight.

Check poly-v belt tension (I would also assume Gilmer).

I was told by one of the ladies at Shopsmith that the lower aux. coupler hub should/could get really warm while running at high speed! So warm that it's difficult to hold it right after stopping the machine. She also added one of the purposes of that hub is to act as a heat sink.

charlese wrote:I was told by one of the ladies at Shopsmith that the lower aux. coupler hub should/could get really warm while running at high speed! So warm that it's difficult to hold it right after stopping the machine. She also added one of the purposes of that hub is to act as a heat sink.

I would think the air entering through the vent plate would be more effective! The hub does not have much capacity to act as a thermal 'sink'.

Think about what is occurring at high speed. The motor belt is moving very rapidly over the idler pulley near the center of the pulley where there is probably some slippage due to the smaller surface area shared by the belt and pulley. This slippage causes the pulley to heat up. That heat will find an easy path to the shaft.

This is added to the increased heat created by the poly-v(or gilmer) belt driving the main shaft pulley. So the whole headstock gets warmer.

Yes it is 'normal' for it to get quite hot near max speed.

There is not much air flow through the headstock, but some enters through the vent plate(and any other convenient opening) travels across the internal pulleys and into the BACK of the motor, through the motor and slung out the louver in the bottom of the motor pan by the fan sheave. Not a very efficient cooling process, but we do not want a large volume of saw dust laden air traveling through that either!

Since the speed of the motor is constant regardless of the speed setting, the same amount of air flows at all speeds. More heat is generated at higher speeds. Therefore since the cooling is not greater at higher speeds, the temperature rises.

I still want to build a small blower assembly that will blow filtered air into the headstock to not only cool it but also pressurizing the headstock (with clean air) will keep the saw dust from entering through all of the openings.
I'm thinking two of them. One for the one that will normally be a dedicated lathe and another for the 510 which is the one used for things like dado cutting and shaping. Use of the others is not all that heavy.
This shop will not get as hot in the summer since it will be air conditioned in hot weather. That should make everything run cooler, especially me.

A few years ago when playing with DC motors, I had to cut a round 4" hole in the motor pan to allow a DC motor to extend past the end of the motor pan. After storing the DC motors for a later try, I added a 4" square vent plate with screen over this hole and added the motor and motor pan to an existing headstock. I was amazed at how cool the headstock and motor operated with this additional air flow. Also after several years of use, there was still no sawdust trapped inside the headstock.