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Need an off/on switch for my PM3520b

Breck Whitworth

Breck Whitworth

Joined
Nov 1, 2013
Messages
325
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Location
Gulfport, MS
Website
www.woodtreasuresbybreck.com
Now that I am able to do hollow forms I really need an off/on switch that can be placed at the opposite end of my lathe for emergencies and for convience. I see a magnetic box with a paddle switch that PM sells for about $110. But I have read quite a few individuals that had to replace their's after purchasing and installing that switch. If you have any experience with one that you made & installed, or bought and installed that you would recommend I would really appreciate any help or advice you can give. I can follow wiring instructions if they are explained well. Thanks in advance.
 
Breck, I picked mine up off eBay, had it installed when the electrician was on the property for other reasons because I don't do electrical myself beyond running wire down the wall. I've not had a moments trouble out of the box beyond accidentally hitting it when I forgot to put it away when I was done. If I don't put it on the inside leg I will surely turn the thing off and stand there wondering why it won't run for minutes on end! But it's way way handy when I'm working off the end of the lathe.
 
I have a friend who finally gave up after replacing the switch several times and even trying a regular light switch. I think that the problem is contact resistance. The switch controls a logic input to the VFD which means that the switch ought to be a type known as a "dry circuit switch" -- meaning that it carries less than 20 mA and has low contact resistance. Dry circuit switches use bifurcated gold or solver contacts to obtain the low resistance. Regular current carrying switches can develop slight oxidation on the contacts which is no problem with when switching power, but prone to logic "maybe" states with noisy contacts in a dry circuit.
 
Don't buy the powermatic switch. Dust gets in it a d causes it to fail. I took mine apart at least 3 times and cleaned it. Finally we t out to my local electronics store and bought an industrial grade switch. Then sealed the box as best I could. No more problems
 
And, despite all this evidence that points to a problem, Powermatic steadfastly maintains that they don't have a problem. My friend got fed up with their tech support person basically telling him that he didn't know what he was doing and that they were not going to send him any replacement switches.

It isn't rocket science. It's just a cheesy switch in a cheap plastic box with a magnet. Anybody can make one that is a lot better than their overpriced and poorly-designed switch.
 
I would think that if you took the switch to any electrical supply place they could get you a replacement for much less than you can get it for from the factory. One thing I like about my Robust is that the speed and on/off switch are in a magnetic box that I can place anywhere. I have it in the headstock almost always from habit developed when I had a 3520A. Don't see why you couldn't just do an extension cord out of the front of your PM and use the box permanently.

robo hippy
 
robo hippy said:
I would think that if you took the switch to any electrical supply place they could get you a replacement for much less than you can get it for from the factory. One thing I like about my Robust is that the speed and on/off switch are in a magnetic box that I can place anywhere. I have it in the headstock almost always from habit developed when I had a 3520A. Don't see why you couldn't just do an extension cord out of the front of your PM and use the box permanently. robo hippy
Click to expand...
I like the ONEWAY pivot arm. The controls are at shoulder level easy to see and reach quickly. The arm pivots the controls through any arc from the the headstock to the tailstock and can be mounted to be on either side of the lathe.
I have a remote on off that I leave mostly by the headstock so I know where it is.

The ONEWAY, Robust, Stubby, and General all come with a moveable switch.
A moveable switch is a great investment for anyone turning bowls or hollow forms.
Both for safety and convenience.

Al
 
I think dust kills most secondary switches. I had replaced two switches until I enclosed mine in a zip lock baggie. Haven't had a problem since. Food for thought.
 
I purchased these items for a switch from Automation Direct and have been happy. I am just a customer. Items: enclosure SA101SL Mushroom GCX1136 and contact block ECX1030-2. Just needed wire and a rain-tight connector from the big box stores.
 
Factory Switch

I ordered my switch with the lathe. I didn't get it put on until last year.

The factory switch or one you make doesn't mess with the VFD. It goes inline with the other switch. Both have to be activated to turn the lathe on. Turning either one off will turn the lathe off. The directions on the Mustard Monster Website give me all the info I needed. I've not had a problem yet.

I think I will blow it out next trip to the shop, and put a baggie on it. Cheap insurance.
 
John Nicholas said:
I ordered my switch with the lathe. I didn't get it put on until last year.

The factory switch or one you make doesn't mess with the VFD. It goes inline with the other switch. Both have to be activated to turn the lathe on. Turning either one off will turn the lathe off. The directions on the Mustard Monster Website give me all the info I needed. I've not had a problem yet.

I think I will blow it out next trip to the shop, and put a baggie on it. Cheap insurance.
Click to expand...

The switch on the headstock and the auxilliary stop switch are wired in series as you state, but they do not switch the AC power. They are strictly a logic input to the inverter. The logic input is used by the inverter to ramp the motor speed either from zero to set speed or vice versa depending on if the logic input is switched ON or OFF.

They probably have used switches from several vendors over the years which may be why some switches have problems and others don't.
 
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