Mini Lathe Switch Roulette

I have a well developed hatred of electronics.

My usual approach goes along the lines of, "if it's not broken, don't fix it". This has held me in good stead for many years.

However, and there's always one of those, now it's failed me. I have just replaced the spindle bearings on my Sieg C3 mini lathe. So the electronics box on the front had to be removed. Imagine my surprise when I realised that virtually ALL of the connections to the Forward/Off/Reverse switch, were not only loose, but in removing the box, had become disconnected. The F/O/R switch has something like 12 connections. I have had a good scratch around trying to find a wiring diagram that shows which wire goes to what numbered terminal. Some of the wiring diagrams show the non switch end of the wire, but no diagrams indicate which terminals they are supposed to connect to. Does anybody know of a wiring diagram which shows this level of detail??

Back when I was a lad, something like this would have a thing called a "Wire List" which showed every wire, and what terminal each end was connected to. Those days seem to be long gone!!

At the moment I have been playing fuse roulette trying to determine the correct connections, to no avail. By the way the lathe was working perfectly (despite the loose connections) when I started the overhaul.

Hope that somebody can help.

cheers

Bill

ps Did I mention that I hate electronics??

Bill,

The only way I can help is to bump this back up to the top of the page!

Bill, if you go to the Little Machine Shop website, they have an instruction manual for the Sieg C3 with a wiring diagram included.

I do not know if it shows enough detail for you to sort out where the wires should go.

HTH

Hi Bill,

I am presuming that you are in Australia, and I am presuming that you actually have a SIEG C3 - brushed motor mini-lathe.

Provided at least my presumption about the machine is correct, then here are some pictures below. I too am surprised that the wires just fell out. They are screw on terminals. There must have been a serious amount of vibration over time for this to happen. You better also check the other screw-on terminals too while you are at it.

Ketan at ARC.

Before dismantling any switch gear take a photograph and if necessary make notes.

Hi Bill

first stop the random tests !!

I have the sieg C2 that I had to reverse engineer the speed control board - no one would supply any service information

see - **LINK**

yes, I found the push on connector used on Chinese machines have a habit of dropping off - too thin and not springy enough

who supplied the lathe webco . chester , warco , axminster ?

machines from different suppliers will have variations in the wiring

can you post photos of the loose wires , switch terminals and the control board

once the control board is identified and the type of forward / reverse switch

it will be easier to give you the help you need

(my lathe has a 4 pole toggle switch to select the motor direction others have a rotary switch

the control board used will determine the interlock circuit used )

John

one version of the C3 lathe manual --

**LINK**

PS

the wires K1 and K2 in Ketans photos are the interlock wires shown in the C3 manual

the problem with the motor an speed control board connections to the switch is not all connections are obvious

like the jumper between terminals 3 and 7

with some versions  rotary cam switches they have internal links so the two switches in each section are connected to form a SPDT switch

two of the SPDT elements will only need  two links as in the photo to control the motor direction

Edited By john swift 1 on 15/10/2015 15:55:51

Do a google image search for 'mini lathe wiring diagram'

Unfortunately there are many variants and you will need to be sure you have the right one.

On my machine all the wires have numbered tags that match up to the circuit board, and the power leads all use spade connectors that vary in size and gender so you can't connect them the wrong way round.

Neil

Thanks for the responses chaps. I'm in Australia. The machine is a Sieg C3, (180mm x 350mm, or 7" x 14" as the 'Mercans say). I've had it for about 10 years.

I had done several searches on the net, using things such as "Sieg C3 lathe wiring diagram". I found a fairly close one on the LMS site. In fact it's pictorially identical to the one in the manual I have, but most of the component and termination idents are different, both diagram to diagram, and either diagram to physical item!! Nowhere are the switch terminations identified!!

Thank you Ketan, that switch looks to be identical to the one that is on my machine. I will print this page and do some more re-assembly work. I usually do make a sketch, prior to disassembly, sadly in this case the disassembly work seems to have been semi automatic!! I'm not sure how it happened, the F/O/R switch is about the only part of the machine that has caused a problem. The original one failed after about two weeks (i.e.about 518 weeks ago), was promptly replaced by the supplier, and fitted by me. So the auto disassembly looks as if it's down to me!! I think I must have prepared a sketch to show the connections way back then. Sadly lost now.

I will report back after todays efforts.

Thanks again

cheers

Bill

Hi Bill

based on Ketan's photos of the switch

I've made a sketch of how I expect the switch contacts to interconnected

John

Edited By john swift 1 on 16/10/2015 01:03:19

Well there's good news and bad news. The good news is that I connected up the F/O/R switch i.a.w. Ketans photos, and it worked!!

Triffic

The bad news is that there is now an intermittent fault. Sometimes, well most times, it will not run "forward". After I've had a cup of coffee I shall go and recheck everything.

Thanks again guys

cheers

Bill

Now it all seems to be good. The intermittent fault seems to have been one of the spade connectors, that had to be "just so" to work. So it's up and running, at least it will be when the change gear bits have been reassembled.

So once again, thanks everyone, it shows the power of the internet!!

Cheers

Bill