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How hot is hot?

Posted: Tue Jun 01, 2010 12:17 pm
by ryanbp01
The latest e-mail offer talk about servicing your headstock. In it, it talks about your headstock running "hot". Just exactly how "hot" is hot? Hot to the touch? Hot to move your hand off of the headstock after a short period of time?

BPR

Posted: Tue Jun 01, 2010 12:58 pm
by JPG
ryanbp01 wrote:The latest e-mail offer talk about servicing your headstock. In it, it talks about your headstock running "hot". Just exactly how "hot" is hot? Hot to the touch? Hot to move your hand off of the headstock after a short period of time?

BPR
I believe that depends upon how paranoid you be! If you can feel it, it is at least, warm. If you do not want to touch it again, it be hot.

If you are paranoid, the warm above becomes 'hot'.

How hot is hot?

Posted: Tue Jun 01, 2010 1:56 pm
by dusty
The headstock does get warm. In fact, it gets warm enough to make it uncomfortable to leave your hand on the headstock for very long. It also gets too hot to want to put your hand on the headstock again.

The email that you reference is sent to users of all descriptions. Some probably never lubricate and some never clean out the headstock. I believe these are the folks to whom Shopsmith was directing the email. Excessive heat buildup in the headstock definitely is not good for it and will shorten useful life of the headstock.

The later condition should never occur. If the headstock gets that hot you have a problem (most likely a bearing about to seize up) that needs to be dealt with immediately.

I used to worry about my headstock because it always seemed to be too warm. I then realized, one day when it was almost too hot to touch and I had not yet turned it on, that it heated up considerably from the sun. I have now rearranged my shop so that the sun strikes the headstock only for a short time in the early morning.

Heated bearings is the primary cause of the headstock getting hot. However, there are other root causes. The belts not being properly tensioned is likely the most frequent cause (other than bearings) . The motor being hot is still another as the heat generated by the motor is somewhat captured in the headstock unless you have good air flow to remove it. Don't let the sawdust accumulate in the motor (or in the headstock for that matter).

If not heated by the sun, I find that I normally do not run the Mark V for long enough periods of time to heat the headstock beyond what would be considered warm.

Re: How hot is hot?

Posted: Sat May 28, 2022 9:43 am
by not2shabby
Reviving an old thread here.

I’ve been running primarily in drill press configuration. Yesterday, my machine stopped turning and was humming. I started thinking capacitor, seized bearing, old motor finally breathing its last.

I turned it off immediately. Did some reading, checked my plug breaker. Turned it back on. Fired right up and ran great until it stopped and started humming again after about 20 minutes. I let it cool off and it fired right back up.

I’m starting to think it’s thermal. Is there a thermal switch on the motor? I have the 1-1/8hp. I work in an unconditioned shop in South Texas, so it’s brutally hot.

Re: How hot is hot?

Posted: Sat May 28, 2022 9:54 am
by dusty
not2shabby wrote: Sat May 28, 2022 9:43 am Reviving an old thread here.

I’ve been running primarily in drill press configuration. Yesterday, my machine stopped turning and was humming. I started thinking capacitor, seized bearing, old motor finally breathing its last.

I turned it off immediately. Did some reading, checked my plug breaker. Turned it back on. Fired right up and ran great until it stopped and started humming again after about 20 minutes. I let it cool off and it fired right back up.

I’m starting to think it’s thermal. Is there a thermal switch on the motor? I have the 1-1/8hp. I work in an unconditioned shop in South Texas, so it’s brutally hot.
My first comment is - cease the test runs. Obviously something is wrong.

Yes, it seems to be a thermal problem but there is no thermal cutoff built into the system.

Is the machine, especially the motor, clean and free of saw dust?

Has the machine been properly lubricated?

Does the spindle turn freely?

Does the motor perform the same way if run without the motor belt installed? If yes, it's time to visit a motor shop.

Re: How hot is hot?

Posted: Sat May 28, 2022 10:00 am
by not2shabby
Thank you, Dusty.

I finished a rebuild with new bearings, blew out the motor, and a clean and painted headstock last year.

I will test it with the belt off.

Re: How hot is hot?

Posted: Sat May 28, 2022 10:44 am
by garys
When the motor hums and won't turn, the problem usually is in either the Capacitor or the centrifugal start switch that puts the capacitor on line for starting. If your capacitor is known good, make sure the start switch is clean and has clean contacts.

Re: How hot is hot?

Posted: Sat May 28, 2022 11:05 am
by not2shabby
garys wrote: Sat May 28, 2022 10:44 am When the motor hums and won't turn, the problem usually is in either the Capacitor or the centrifugal start switch that puts the capacitor on line for starting. If your capacitor is known good, make sure the start switch is clean and has clean contacts.
Thank you. I’m okay at mechanical but not great at motors. I’ll check YouTube to see if I can DIY those tests / inspections.

Re: How hot is hot?

Posted: Sat May 28, 2022 4:17 pm
by DLB
A couple of things that are easy to check:

You should have a decent amount of airflow out of the vent at the bottom of the motor pan any time the motor is running.

When running the motor by itself, belt off, you'd normally hear distinct clicks when the start switch (centrifugal) engages or disengages. It is most noticeable when you remove power and the motor is spinning down because there is little background noise. (A bad start capacitor would cause startup problems, not your symptoms as I understand them: motor is running along and quits when it gets hot.) The clicks are not fool-proof, but are fairly reliable as an indicator.

- David

Re: How hot is hot?

Posted: Sat May 28, 2022 4:27 pm
by not2shabby
I got things apart. The motor runs perfectly fine with the gilmer belt and drive removed. I think the drive sleeve is the issue, but the two bearings on the outside are smooth. I don’t fully understand the function, but I think the toothed part of the drive sleeve that the gilmer belt rides on is slipping on the shaft which I imagine is creating a ton of heat and then seizing up the shaft.

Is that possible? Should I take this opportunity to upgrade to the poly v shiv and drive sleeve?