Need to replace electrical switch on my 818P Jet metal bench lathe with milling head

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Jul 4, 2012
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The original switch has six buttons. These are for

forward phase one
reverse phase one
forward phase two (twice the speed of phase one)
reverse phase two (twice the speed of phase one)
mill on and off

This is a 1980 model lathe that I acquired in 2010. When I got it the phase two switches did not work which was not the end of the world, but now the mill switch has ceased to work. The phase two switches do nothing when pushed, but the mill switch will run the mill if the switch is held down, but will not stay on otherwise.

I would replace the switch in a heart beat, but I don't believe a direct replacement is available. I would also replace the switch with another with similar functions, but I don't know electrical switches well enough to know what to get and how to wire it. I would also consider modifying the existing switch just so the mill switch would hold in the on position, but I would love to have the phase two on the lathe if the motor is still capable of doing it.

Also, wondering if there is some sort of forum with discussions on older Jet metal lathes.

Thanks for any thoughts on this. Jim
The motor plate reads as follows (plate was difficult to read as the letter/numbers were very fine:

Stanley Electric Motor Company

Induction Motor

Type - TTC
HP - 1 3/4 (on the plate as 1/3/4)
Pole - 2/4
Rotor - 0
Rating - Cont.
IN2.CL - E (this is the one I'm the least sure of)
Volt - 112
Cycles - 60
Amps - 56/6A
RPM - 3450/1710
Gave bearing numbers
Mfg number - 85618
Year of mfg - 1980

Some thoughts occur:

Is there anything between the switch and the motor? I am wondering if there is a circuit board or one or more relays involved here.

Can you find any other information on the motor regarding connections, with small type saying something like "line on terminals 1,2,3", or some-such. There may be a pictorial or schematic diagram inside the terminal box on the motor.

There may be information like a wiring diagram or an original instruciton manual online that could help you.

You may also find a source for parts online, which may have a diagram that could help you decide what parts to get. You will need the actual model number of your machine, your serial number, possibly a date of manufacturer or a "type" or "series" designation in addition to the model number. What I do (and what service techs that come to my house do) nowadays, is take a photo of the tags and etc. before searching for parts. I have had more than one friendly service tech show me that he checks generic online information first before using a proprietary system to attempt an order through "official" channels.

For older machines and appliances, an original part may be indicated as needing a generic substitute part, or even a part ordered from another brand source.

Where are you located? If in the USA, we can recommend vendors that may be able to help.

Thanks. I'm in California. I located a reproduced manual and I have it coming. It has an electrical schematic.

Here is what it looks like from the outside.

That switch looks pretty bad, in appearance at least. It may still be OK, depending on what's inside the machine. I'll be watching to see what that manual you ordered has to show.

We will probably need some pictures of the back of things or what you may end up removing from the machine.

Here are two photos of the inside of the electrical box.

There are 7 wires coming from the lathe motor:

And, from the mill motor there are 3 wires:

The electrical box also contains two capacitors; one large one for the lathe and one small one for the mill (I believe).
001 (2).JPG
002 (2).JPG
001 (2).JPG
002 (2).JPG
The extra photos are me not that good at attaching photos. I live in Northern California.
You photos show capacitors - so this is a single phase motor ? I presume it is a 4 pole motor which can be hooked up as a 2 pole.
The double caps are start / run.
2 pole will run at 3600rpm @ 60Hz (less ±5% slip = 3420)
as 4 pole 1800rpm (1710)
I am guessing there will be 8 wires coming out of the motor to the switch. Possibly 10 if there is a centrifugal cut off switch - but this may be wired up internally - there are going to be a lot of permutations and a wiring diagram will be a big help.
Refer to the diagrams I posted in this thread - post #41
Zx45 wiring question
And that's for a single speed - its going to get a lot more complicated for a dual speed.

Regards, Ken
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It looks like an original wiring diagram may be needed. Your picture of the wiring side of the switch sure looks like someone did some things to make it work, but that the final result wasn't that great.

What jumps out to me:

1. Wire-end terminals look like some or all have been replaced and they are not insulated. I'm not sure about the way that they are bent over.

2. Soldering looks rough, even if we are used to rough-looking solder jobs from some factories. It looks like there are places where insulation on adjacent wires is partially melted, possibly from a too-large soldering tool.

3. Green jumpers soldered in from terminal-to-terminal accross the switch. Green is supposed to be ground, and unless this is really a ground wire someone has improvised connections with whatever was available. (And pretty much everyone in the world respects the "Green, Bare, or Green-and-Yellow" for the indication of ground [earth].)

4. The use of plastic electrical tape on the capacitors, and no other means of securing them that I can see.

5. Capacitors look like they are aftermarket, maybe even recycled. (Just a guess)

IMHO, I think that it might be possible to create a replacement for this switch, if it can be determined how it was originally connected and how it was originally supposed to function. Possibly that replacement may not fit into the machine as a direct replacement for this switch.

I think it is do-able, and if it was my machine I would repair it.

How many terminals are there on the motor terminal block - what labels ?
A photo of the motor's terminal block would help.
If it was mine I would replace the complex switch with three switches driving relays - a green start button and a red stop button (Duhh..) a toggle switch for high/low range and a toggle switch for forward and reverse.
Still need to know the motor layout before I can suggest a circuit.
Once you have a circuit you could also build a rotary cam switch for all those functions - the sales guys for such are usually quite helpful in specifying all the components - but only for a coherent diagram.
Or - just maybe you might be able to dope out and repair the existing switch - but from appearances it looks like it is quite broken and been simply bodged to get some semblance of operation out of it.

Regards, Ken
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Stanley Electric Motor Company

Induction Motor

Type - TTC
HP - 1 3/4 (on the plate as 1/3/4)
Pole - 2/4
Rotor - C
Rating - Cont.
INS.CL - E (this is the one I'm the least sure of)
Volt - 112
Cycles - 60
Amps - 5.6/6A
RPM - 3450/1710
Gave bearing numbers
Mfg number - 85618
Year of mfg - 1980

Here is the motor plate as shown in my post above with a few corrections. The tape on the capacitors is merely to keep them from touching the metal case.
Does anyone know what the type of switch I have is called (such as contact, magnetic, etc.)? I'm not sure what to call it so I can seek a similar replacement.
I think your motor has 2 HP ratings
1HP for 2 pole operation
and 3/4 HP for 4 pole operation
so it is 1 or 3/4 not 1 and 3/4

That is the way the other numbers are called out. RPM, Amps and poles

Can you take a photo of the motors's terminal block like this :-

The terminals will (or should be) marked with U1, U2, V1, V2, W1, W2, X1, X2, Z1, Z2 or similar

Also look inside the cover, there is sometimes a printed diagram sticker or moulded-in diagram of the motor circuit.

As regards the switch - it looks like a custom unit - probably only available from the manufacturers (if you're lucky).

Regards, Ken
What Ken says is what I was thinking.

Series of buttons or combination of buttons and switches that drive relays to duplicate the function of the original switch.

It would be important to incorporate safety features into the design so that machine doesn't start when line (mains) power is applied and to allow "stop" switch to stop everything.

All of this goes back to trying to determine how the original circuit and the original switch were designed to operate when the machine left the factory.

As far as the original switch goes, it was most likely custom-built for the machine (or for a range of machines made by that manufacturer). I don't think that there is a description of it that could find you a generic substitute. You might find one out there somewhere, but you also might spend a long time looking and pay an exorbitant price. Over time, I have seen a lot of OEM custom parts for all kinds of devices show up on the surplus market. Most of the time, you would find something with a "guesstimate" description like "Panel Switch, 8-position, 8 colored buttons, originally made for a machine tool." You would have to guess whether that item could be used. This takes us back to designing a new control panel for your machine using currently available industrial components.


Here is what I think today:

1. Look for a diagram of the motor connections and take a picture of the terminal board inside the motor where all the motor wires attach to the inside parts of the motor. Post those. Do that for both motors.

2. When you get the manual you ordered, Post the schematic and any relevant pictures for us.

3. Photograph or copy all of the machine tags and post those.

4. If there is information in the manual you receive that tells how the controls were designed to operate, post those descriptions.

5. Post the infomation you can read on the capacitors and anything else connected to the wiring.

6. If there are any additional switches, such as safety interlocks, note where they are and what they were supposed to do.

Note that I heavily used "were designed to" above. How it operated with the present switch as you bought it may not be the same thing. You may also find that other things are lurking, such as removed or bypassed safety switches. It is also conceivable that original color coding is no longer true.

This switch looks similar to the one on my Emco Maier V10P (70’s vintage too). That switch offers forward/reverse with low/ hi speeds and an on button for the mill motor. There is one “off” button that cuts power to the lathe or mil motor. If you join the Groups.IO
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there are several write ups in the files on how to replace this fiddly switch block with more readily available components. Hope this helps.
Well, as I've developed an academic interset in this electrical problem and possible solutions, I just went tripping through the link posted by karlw144 above.

It certainly looks like the problems with the original switches on the V10P are like the Original Poster's problems. By most of the talk on the V10 forum, it looks like cooking up a new set of controls is possibly the best approach to solving what the OP is dealing with.

But..., the chatter on that forum also gets into the reality that there are multiple solutions and a request for a "cookbook" solution is hard to address.

I guess at this point if it were my machine, I would start planning new controls. I have some electrical and electronic experience and I would not hesitate to do the work myself for my own machine. I don't know if yellow_cad wants to take that approach.

I have pretty much resigned myself to the fact that I would do best with an entirely new switch. I will check the forum and the varied solution. Thanks.

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