MG Start Button part number request

Does anyone happen to have the part number for the normally open start push button for an MG machine. I was able to get the apron finished up. Progress is going slow, but here are some pictures. looks pretty good, Nowhere near daryl, daves, or gernoff but I am happy with it. Here are some pics

PLC said:

Does anyone happen to have the part number for the normally open start push button for an MG machine.

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I had the whole plate and both switches for a '42 MG in my hand but days ago as I packed it to ship to another member.

Just now went through my manual for the second time and cannot find either switch in the pictures or associated parts list. No info as to maker or other specifics on the schematic, either.

From the wiring and terminals, there is more going-on than just SPST NO and SPST NC. Interlocks?

Pass. I'm converted to SSD DC Drives. That's why I had it surplus. Hopefully an MG mavin such as Cal Haines can shed more light on that.

It should not be rocket insemination to then find a suitable functional replacement. NRI, Digi-Key, Mouser, several other salvagers or remaindermen.

It will be harder to match the OEM one physically and have the same dual from-the-front mounting screws.

Thanks Bill. Progress is moving a little too slow apparently . maybe the member you sent it to can let me know, or hopefully Cal comes along. I know I can source somewhere else. Probably just momentary push button SPST with plot light rated at least at 240VAC. A couple months ago I picked up era-specific main power contactor in great shape on ebay. I am hoping for a clean install with the original parts if is easy enough.

PLC said:

Thanks Bill. Progress is moving a little too slow apparently . maybe the member you sent it to can let me know, or hopefully Cal comes along. I know I can source somewhere else. Probably just momentary push button SPST with plot light rated at least at 240VAC. A couple months ago I picked up era-specific main power contactor in great shape on ebay. I am hoping for a clean install with the original parts if is easy enough.

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I can assure you with scant risk to either of us, that no member of Monarch Machine Tool's QA department is going to ring your doorbell and wish to 'fail' your 10EE and cart it off to the factory for correction for lack of 1930's design electrical components still in-use into the 1940's and beyond.

"More better" to do as legions of DoD and DoD Contractors did.

Upgrade to modern, safer, 'oil resistant', lighted and otherwise, Allen-Bradley & comparable high-grade industrial switches.

Tons of these categorically BETTER switches are out there in the remaindered/surplus market as NOS and NNB as well as used-but-good.

swatkins is the PM member to whom the 1942 OEM was sent. Steve won't have sight of it until Monday, earliest, a day or two later, probably.

He is working through some wiring issues of his own in another PM thread as we type:

http://www.practicalmachinist.com/vb/monarch-lathes/10ee-electrical-questions-1951-m-g-331942/

I DO have a second MG-era 10EE, as yet unmolested.

Badly worn, mechanically, it is 'here' partly so I can put a 'scope onto it, run it off a 10 HP Phase-Perfect and/or 10 HP RPC, and/or 10 Kay-Dub Diesel with 3-P capability so as to make a record of the relative smoothness under load of 'rotating power' Dee Cee vs Thyristor drives, be they hollow-state, or dirty beach sand state.


I would suggest.. that you duplicate the outline of the brass or 'white metal' mounting plate in a durable insulating plastic[1] or in metal, ASIDE the original plate to safe storage, THEN mount to the NEW plate the appropriate modern A-B switches by the means of mounting THEY expect.

It will look 'enough' like the original to attract scant criticism, and will be a safer, more reliable, and more readily serviced product.

JM2CW

[1] For medium-voltage 'tronics, I tend to grab those thick white or red poly 'cutting boards' at the local Big Lots whenever on sale. Easily cut with sawdust-maker tools, edges filed and sanded to shape. Bamboo laminates work well also.

I do have a Wiad Red Button switch, if it is the same as am
mg unit.

Toms Wheels said:

I do have a Wiad Red Button switch, if it is the same as am
mg unit.

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Mounts with two screws, left and right, from front of panel?

Pretty sure the needed contact forms are 'all there' for adaptation, as it probably switched-in tube filament warm-up, certainly not the not-present Ward-Leonard 3-P drive motor.

OTOH.. part of the contacts utilized are fully exposed at the rear. So, too the mechanical movement of the 'plunger' and a disk it carries.

That may all be safely away from human shock hazard so long as the panel is in-place and no one chooses to reach in that direction from inside, rear.

But... the newer A-B switches are fully enclosed, so also protected against any oils and dirt as might stick to contacts or physical moving parts.

As it has, and will do.

PLC when Bill's switches get here I'll look them over for part numbers and post back.

The switched arrived today, thanks Monarchist!



Bill the start switch has the terminals for the lighting but it does not look like a lighted switch.. Can you explain the difference please?

swatkins said:

The switched arrived today, thanks Monarchist!

View attachment 192976View attachment 192977

Bill the start switch has the terminals for the lighting but it does not look like a lighted switch.. Can you explain the difference please?

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Not really.

Those goods are off EE 17120, shipped September 1942. I wasn't 'shipped' until March of 1945, so was definitely not in the room when Monarch Machine Tool made their 'buy' decision. That could have been as early as the mid 1930's, given R&D lead time, etc. - if the Sundstrand pump drive motors used the same sort of switches.

In another thread, I had advised replacing the switches with (slightly more) modern Allen-Bradley fully enclosed 'oil tight' ones. That whole family has 'provision for' lighting, whether the option is used or not. Have a look at re-purposed 'Modular' era switches on Marks' SSD upgrade, here:

http://www.practicalmachinist.com/v...sd-dc-retrofit-into-1961-10ee-modular-332092/

Now look at all that Medusa-hair snake-wiring on the back of those OLD switches.
Each has four exposed terminals, power-carrying movable disk.

Then recall that one CAN reach that far into the base casting, rear doors off, and get fingers into any of that.

IF.. you really, really worry about "authentic" AKA "period-correct" looks?

Make lookalike mechanical plungers/pushrods to fit the visible faceplate.

Operate MODERN switches mounted on a standoff deck at the rear, activated by those pushrods.

"Lights" you can do anything you care to do with - art-deco to Star Wars.

Not a lot of relay logic added, your 10EE could cue-up "Battle Hymn of the Republic" with real 'fateful lightning'.

B'lieve I'll have mine cue Wille Nelson and "Nothing I can do about it now.."

swatkins said:

... the start switch has the terminals for the lighting but it does not look like a lighted switch.. Can you explain the difference please?

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The original start switch had a light in the start button that illuminated when the main AC contactor was closed. The bulb was about 6 VAC (IIRC) and powered by a small transformer in the contactor compartment on the back of the machine. The transformer needs to be changed when the machine's voltage is changed from 440 to 220 (or vise versa) in order for the light to work. Most folks don't bother.

Cal

I fitted a modern bulb into my start button. I recorded it here, I'll dig out the thread.

Cal Haines said:

The original start switch had a light in the start button that illuminated when the main AC contactor was closed. The bulb was about 6 VAC (IIRC) and powered by a small transformer in the contactor compartment on the back of the machine. The transformer needs to be changed when the machine's voltage is changed from 440 to 220 (or vise versa) in order for the light to work. Most folks don't bother.

Cal

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Not sure when "original" started, or if stopped/restarted due to wartime production strictures.

The ex 17120 SEP '42 I sent Steve 'appeared' to have a smaller, darker, upper or 'Start' button than the JAN '44 one still here. AFAIK, it is opaque. Do look at the plate and see if there is a small hole off to one side of the switch that 'MAY' have had a lamp behind it.

Second opinion...

Just now went and checked, and the button on the JAN '44 MG round-dial seems larger, shows signs of 'greenishness' in the otherwise black when a strong LED flashlight is placed tight to one side of it.

If a 'museum grade' restoration is what Steve is up to, he is welcome to this switch as well.

I personally have no more patience for high-voltage control switching directly under sometimes sweaty-salty-wet human hands than OSHA has, so it has long-since carried its last electron under this roof.

How I did mine.

++

Nice job, no distractions.

"Authentic" enough, and wot I've been sayin'..

1950's or later tech switches vs 1930's tech will be safer, more resistant to dirt and oils, even if they are still switching 115 VDC Field+Control circuitry 'stead of 24 VAC back of the panel.

FWIW, that arrow sez the red one is a proper E-Stop type as well. Have to reset with a partial twist. That, too, is more righteous than not, 'specially at as little as five bucks, each, brand-new, bought pack of ten as I did.

Zahnrad Kopf said:

How I did mine.

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Here is a picture of the one Bill so kindly sent me...

It looks like someone installed another push button at one time, then inserted small screws to repair the holes left behind. What surprises me is this switch does not look to be lighted in any way yet it has terminals for the wires coming from the small transformer.

swatkins said:

Here is a picture of the one Bill so kindly sent me... View attachment 193013

It looks like someone installed another push button at one time, then inserted small screws to repair the holes left behind. What surprises me is this switch does not look to be lighted in any way yet it has terminals for the wires coming from the small transformer.

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It ain't exactly as if we have to figure out if King Tut was murdered - or just run-over in a Chariot mishap and died young of internal injuries.

Follow one or more good examples, get the rest of the 10EE back in working order lest you be worrying this switch scandal to a 9th death when even *I* get paint and bed re-grind done...

and that.....is slooooooow.

swatkins said:

Here is a picture of the one Bill so kindly sent me... View attachment 193013

It looks like someone installed another push button at one time, then inserted small screws to repair the holes left behind. What surprises me is this switch does not look to be lighted in any way yet it has terminals for the wires coming from the small transformer.

Click to expand...

Nope, that's what the original start/stop station looks like, complete with the screw in the stop button. The stop button unscrews to allow you to change the bulb. It's translucent green plastic. The oldest MG schematics that I have all show a light for the start button and the transformer which powers it.

Cal

Cal Haines said:

Nope, that's what the original start/stop station looks like, complete with the screw in the stop button. The stop button unscrews to allow you to change the bulb. It's translucent green plastic. The oldest MG schematics that I have all show a light for the start button and the transformer which powers it.

Cal

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'Start' button - the upper one that looks black - may unscrew on its own threads, then?
Probably can be buffed, with enough extra care.

Lower 'Stop' button is totally absent on the '44 here.

The one I sent Steve (photo) has a solid metal disk for the 'STOP' function.

I've no idea if that is original - or if there is lighting behind it that would show around the edges if it is such.

swatkins said:

It looks like someone installed another push button at one time, then inserted small screws to repair the holes left behind. What surprises me is this switch does not look to be lighted in any way yet it has terminals for the wires coming from the small transformer.

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That looks a lot like my original switch. Mine can be unscrewed to expose/replace the 6V bulb.

rke[pler said:

That looks a lot like my original switch. Mine can be unscrewed to expose/replace the 6V bulb.

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Just tried that here. Got about a tenth of a turn, then resistance.

Tried to wiggle it out as if there was a bayonet cam track. No Joy, either way. Didn't want to break it if some new owner would rather try soaking it free of crud.

Perhaps we now know why these so often have teeth marks from ignorant pliers on their ribs?

I STILL say Zahnrad's approach make far the better sense, so.. off to meddle with other procrastination kits now... Certainly no shortage of 'em here....