Instructions to shut Shopsmith on high-speed setting during speed control adjustment

[ALarryAaron]

To set the high speed setting, I’ve read several articles (including the one at your linked “http://www.songofthegreatlakes.com/sshighspeed.htm) that instructs to shut off the machine at the high speed setting (make adjustments to the high speed setting via the jam nut and worm shaft), and then turn on the machine again to test.

But I thought one should NEVER turn on the machine when set to high speed and ALWAYS shut the machine when speed setting is on D or lower. I’m not sure if these articles came from this site or from Shopsmith, but either way, I don’t know how to deal with this conflicting information.

Please advise and thank you for being there for us common users.

[dusty]

You can follow the instructions that you have regarding turning on and turning off with the speed control set at high speed.

The issue is (in the minds of some) that the speed control should be at low when you shut down so that when you turn it on (at other than low speed) it does not draw excess current and trip the breaker. That may well be advisable but I do not buy into it. I turn mine on and off all the time at what ever speed I might be. If the power service to your machine is protected by a 15amp circuit breaker you will have no proble.

One possible issue might be turning on the machine with the band saw connected and the speed set too high. It is advisable that before applying power with the bandsaw that the spped be lower to the appropriate level.

[ALarryAaron]

Great insight, Dusty.

Thanks a lot for speaking up.

[edma194]

One possible issue might be turning on the machine with the band saw connected and the speed set too high. It is advisable that before applying power with the bandsaw that the spped be lower to the appropriate level.

This is the reason I'm careful to lower the speed. No accessory or attachment needs to start up at high speed but several of them could be dangerous or just bad for the device if they are.

Also, I was under the impression that there was a chance of the belt getting stuck in the sheaves if the machine was turned off at the high speed settings. Don't know where I got that idea though, is there any substance to that?

[DLB]

The manufacturer's instructions are pretty clear on this, but every individual may have their own approach. I turn mine on and off with the switch up to the top end of saw speed, but never faster. This thread offers some insight into what is going on under the hood at startup: viewtopic.php?f=9&t=16474 (Unfortunately some of the pics are out of sequence to the words, so you need to adjust.) What that means is that the conventional headstock draws maximum current at startup for a period of time, and that time increases as load increases, whether by speed or attachments connected. That power that exceeds nominal startup is mostly being consumed in the windings of the motor as excess heat.

I would not rely on a household circuit breaker to protect the machine. It is designed to protect the household wiring. It may or may not trip before the motor reaches the failure point. Many AC motors have thermal protection, but Shopsmith motors do not.

- David

[JPG]

A bit of history that explains some of this shut down scenario.

Back in the dark ages(1940ish) most residential dwellings had (GASP) fuse panels and most branch circuits were intended to be protected by 15A fuses AND tended to be marginally overloaded as well. As such the dwelling wiring was rarely larger than #14 gauge wire. Also common practice unfortunately was if the fuse blows too often it was replaced with a fuse with a greater current limit(20A/30A/???).

Now the 3/4 HP motor of that vintage tended to be a bit sluggish at startup.

It was into this environment the Mark 5 was created. So it behooved all to NOT attempt to start the motor at other than slow speed setting so as to mimimize the time the large startup current occurred. This reduced the heating of the motor coils and shortened the time the fuses were being heated as well.

Time delay fuses were recommend for these reasons.

Today much of that no longer applies.

[dusty]

The manufacturer's instructions are pretty clear on this, but every individual may have their own approach. I turn mine on and off with the switch up to the top end of saw speed, but never faster. This thread offers some insight into what is going on under the hood at startup: viewtopic.php?f=9&t=16474 (Unfortunately some of the pics are out of sequence to the words, so you need to adjust.) What that means is that the conventional headstock draws maximum current at startup for a period of time, and that time increases as load increases, whether by speed or attachments connected. That power that exceeds nominal startup is mostly being consumed in the windings of the motor as excess heat.

I would not rely on a household circuit breaker to protect the machine. It is designed to protect the household wiring. It may or may not trip before the motor reaches the failure point. Many AC motors have thermal protection, but Shopsmith motors do not.

- David

OKAY .... if one cannot rely on the household circuit breaker to protect the machine what should one rely on?

[garys]

I've had my Shopsmith since 1988 and use it extensively. It is best to shut it off set to lower speeds, but I've never hesitated to turn it on and off set to higher speeds when I don't have any accessories connected to it.
If you need to turn it off at high speed, remove accessories from it before turning it back on. It hasn't hurt mine its first 30+ years and likely won't in the next 30+ years.
It will easily and safely spin up a saw blade when set to high speed. Anything larger than that should be removed including the sanding disc as it is heavier than a blade.

[AEA]

When I service my 510 with the standard head stock, I turn it off on high and do my oiling. Then I have to make sure nothing else is on that circuit when I turn it back on, or else I'll blow a breaker.
So on normal use I turn it down significantly before turning it off otherwise I have to make sure the dust collection is off or anything else.
I think this is a good habit especially like was listed by many others, the attachment of accessories. I know me, and if it wasn't a habit, I would forget it was on too fast when I connected a band or scroll saw and be unpleasantly surprised when I hit the switch.

[JPG]

OKAY .... if one cannot rely on the household circuit breaker to protect the machine what should one rely on?

Common Sense!
If it hums and does not rotate, turn it off.

If it stalls, turn it off(or back out the workpiece).

If it smokes, turn it off.

We ARE supposed to be intelligent beings.