Power Switch problem?

tom_k/mo · Post by **tom_k/mo** » Tue Jul 21, 2009 3:41 pm

Put my 520 through it's paces over the weekend. My son came over and we made a toy box for the twins. Trying to be as safe as possible, whenever doing a switchover I'd remove the safety key from the switch. About 1/2 way through the second day, the key decided it didn't want to go back in all the way, and we couldn't turn the machine on. (insert big frown here)...

Ended up removing the switch from the headstock, disassembling and reassembling it. tested continuity with a DVOM and reinstalled it. Didn't find anything really I could point to as being wrong, but it is still difficult to insert the key in correctly to engage the "innards" on the switch to make it work. Right now I'm leaving the key in, and have another switch ordered.

Anyone else ever experience anything like this, and know what could be causing it?

greitz · Post by **greitz** » Tue Jul 21, 2009 4:57 pm

Tom- my safety key is sort of loose- I often have to hold it in firmly while switching it on. I've always been nervous about losing the key, so I rarely remove it from the switch- I just unplug the SS from the wall instead.

Gary

dusty · Post by **dusty** » Tue Jul 21, 2009 5:19 pm

I have three switches with safety keys like or similar to the one on the Mark V. The plastic safety key is loose in all of mine. On the Mark V I have to apply thumb pressure to the safety key to make it work.

This, however, does not seem to be Tom's problem. If I read correctly, Tom has difficulty inserting the safety key into the switch. I have not experienced that problem.

No one asked for my opinion but that seldom prevents me from giving it. I have never been fond of the safety switch and I do not rely on it to prevent the machine from being accidentally powered.

I turn the machine off and pull the plug to accomplish that. If I need to feel safer that that provides, I will turn off the breaker. I have one that is suppose to be power for nothing other than the Shopsmith.

dcottrill · Post by **dcottrill** » Tue Jul 21, 2009 8:36 pm

I've worked in the commercial industry on complex electronic equipment. When working on electrical equipment we were trained to UNPLUG, LOCK OUT, or in some way remove the POWER Source when working.

This is a practice that carries over into the wood shop. No blade or bit changes with a power tool connected to the source. The On/Off switch with the "safety key" is used for control of the machine when using it to make cuts.

My safety keys stay in the tools (for the most part) and the tools are always unplugged. Safety keys are used when little feet and hands enter the shop area and are "assisting or learning". Then all keys in the shop are in my pocket.

My old SS has a hole for a actual lock that prevents the switch from turning on. I personally, like this option.

You can go to Lowes and pick up an old style switch and install it until the new one arrives. The replacement switches have been on back order at shopsmith last time I checked.

My humble opinion for what it is worth.

dusty · Post by **dusty** » Tue Jul 21, 2009 8:54 pm

And very good advice it is.

a1gutterman · Post by **a1gutterman** » Tue Jul 21, 2009 9:51 pm

tom_k/mo wrote:Put my 520 through it's paces over the weekend. My son came over and we made a toy box for the twins. Trying to be as safe as possible, whenever doing a switchover I'd remove the safety key from the switch. About 1/2 way through the second day, the key decided it didn't want to go back in all the way, and we couldn't turn the machine on. ...

Ended up removing the switch from the headstock, disassembling and reassembling it. tested continuity with a DVOM and reinstalled it. Didn't find anything really I could point to as being wrong, but it is still difficult to insert the key in correctly to engage the "innards" on the switch to make it work. Right now I'm leaving the key in, and have another switch ordered.

Anyone else ever experience anything like this, and know what could be causing it?

Hi Tom!
I have knot experienced your problem, but I will offer this as a possible explanation: Could something foriegn (wood-shavings, sawdust, etc.) have gotten in there? Maybe give it a blast of air from your compressor.

tom_k/mo · Post by **tom_k/mo** » Tue Jul 21, 2009 10:04 pm

Al, I thought of that, and that's why I pulled and disassembled the switch. Nothing I could find in it.

robinson46176 · Post by **robinson46176** » Tue Jul 21, 2009 11:33 pm

I am not making a general recommendation here, just serving my own purposes. I am fond of the old mechanical knife switches in a simple 30 amp disconnect to disconnect power in addition to the main switch. I used to use several in the cobbler shop. I'm simply get very tired of plugging and unplugging cords and that often loosens up receptacles and deteriorates the plug end of the cord as well. I don't trust a silly flip switch of course but those knife switches are quite positive both on and off and it will serve my purposes well as a secondary "off" for simple setup changes. I also like the large easy to grab lever on that type and liked using as light of a fuse as possible right at the machine. For machine repairs etc. of course pulling the plug is the way to go.
As far as leaving things in mid job my shop is always locked especially since it is closer to the county road than the house. If I go out the door the door is locked. "NO ONE except my wife and our grown son has access to my shop. I leave things as they are when I stop.

a1gutterman · Post by **a1gutterman** » Wed Jul 22, 2009 12:07 am

robinson46176 wrote:I am not making a general recommendation here, just serving my own purposes. I am fond of the old mechanical knife switches in a simple 30 amp disconnect to disconnect power in addition to the main switch. I used to use several in the cobbler shop. I'm simply get very tired of plugging and unplugging cords and that often loosens up receptacles and deteriorates the plug end of the cord as well. I don't trust a silly flip switch of course but those knife switches are quite positive both on and off and it will serve my purposes well as a secondary "off" for simple setup changes. I also like the large easy to grab lever on that type and liked using as light of a fuse as possible right at the machine. For machine repairs etc. of course pulling the plug is the way to go.
As far as leaving things in mid job my shop is always locked especially since it is closer to the county road than the house. If I go out the door the door is locked. "NO ONE except my wife and our grown son has access to my shop. I leave things as they are when I stop.

Reminds me of Gene Wilder in Young Frankenstein.

robinson46176 · Post by **robinson46176** » Wed Jul 22, 2009 1:50 am

Some times I get to rambling along about things and forget that not everybody might know what I am talking about. Here is a picture of a common very basic 30 amp disconnect. This one is a double pole (220V). A single pole (110 V) is similar but usually in a smaller box. BTW, one like this is wired with the hot feed at the top for several reasons, not the least of which is that you must reach in past the lower knives to change the fuse. Not where you want a couple of hot copper strips sticking out.

http://farm4.static.flickr.com/3042/2956941020_eb9718ed08.jpg