opinion; old German milling machine

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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John Hasler
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Re: opinion; old German milling machine

Post by John Hasler »

Are you going to grind down the broken gear?
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liveaboard
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Re: opinion; old German milling machine

Post by liveaboard »

John Hasler wrote: Sat Dec 05, 2020 7:38 pm Are you going to grind down the broken gear?
Yes, I cut it down already so it will clear completely.
I'm going to leave the change box as designed, so if put into one of the broken ratios it will just spin.
I was going to change it so they couldn't be engaged, but it's actually really complicated.


The center gear on the shaft opposing the broken one was slightly loose. It's held from sliding by a tiny gruff screw.
If it had at some point slid along the shaft, it could have been in 2 gears at once, on a 4:1 reduction and a 2 HP 3-phase motor.
Even then, I'm surprised. the motor drives the gearbox through a single V-belt.

All in all, I'm feeling pretty clever that I was able to figure out how all those pins and levers are supposed to work.
I never did get a user's manual.

So far I've only been into the spindle drive. Supposedly the rest works fine, but we'll find out soon.
The feed system is more complex that the spindle drive, with automatic fast reverse.
Then there's the mad scientist electric system.
And so much more!
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NP317
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Re: opinion; old German milling machine

Post by NP317 »

Well done, so far. Well earned feeling of Clever.
I look forward to reading more of your adventures with this mill.
RussN
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liveaboard
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Re: opinion; old German milling machine

Post by liveaboard »

I was about to assemble the gearbox when I stumbled across another problem; the high/low motor speed switch was smashed by whoever was there before me.

I decided to energize the machine and see the motor spin without belt, to check the switch wiring before replacing it.

Wouldn't you know it, nothing works.
Nothing at all.

Tomorrow I'll figure it out.
Hopefully.
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GlennW
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Re: opinion; old German milling machine

Post by GlennW »

Look for safety switches. The first time I tried to run my Moore Jig Borer it was totally dead. I spent a couple of hours going over wiring diagrams and wiring until I discovered that if the spindle is disengaged, it kills everything. Engaged the spindle and guess what? Everything worked perfectly!

The good thing was that I learned a whole lot about the machine, as you are with yours.

Your "figuring out" skills are impressive!
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
pete
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Re: opinion; old German milling machine

Post by pete »

Genn's got a very valid point. And not impossible there's inter locks on that mill that might prevent the machine being started with any of the power feeds engaged.
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liveaboard
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Re: opinion; old German milling machine

Post by liveaboard »

Thanks for your thoughts;

I got the spindle motor to turn, it was a a rotary selection switch, knob slightly out of whack.

But the speed selection switch doesn't seem to change speed.
The feed motor turns but the clutches don't engage.
The spindle brake works if I press the relay by hand, but the button on the control panel doesn't activate the relay.
Brake and clutches work on 28 or so volts DC, the relay coils are all 220ac.
instead of taking 220v from between neutral and one phase, it has a 380-220 transformer.
The transformer is very large; like 500 watts at least. While the relay coils are just a few watts each.
The coolant motor still doesn't talk at all.
Somewhere, the control power is interrupted.

There's a company in Germany that will send me a file of the wiring for $50.
That price really angers me; they didn't write it and don't own it.

I found a museum for the company, mainly for their watch manufacture. I wrote to them but they're 'temporarily closed', the virus I assume.

So I'll continue to bumble about the thing and try to "stumble across the problem" as my boss used to describe my diagnostic technique when I was a car mechanic in the 70's.
It usually worked too.
John Hasler
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Re: opinion; old German milling machine

Post by John Hasler »

>instead of taking 220v from between neutral and one phase, it has a 380-220 transformer.

Use of a control transformer is standard. Neutral might not be available and in any case it's better to have the control circuitry isolated from the line. That transformer probably has taps so that it can easily be rewired for different voltages. It will also be fused. The transformer limits the available fault current.
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liveaboard
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Re: opinion; old German milling machine

Post by liveaboard »

I reinstalled the gear change box, and put it's switches back in, just to feel better about something.

Some buttons cause relays to click and / or motors to turn, but not as they should, and the relays don't stay on when the button is released.

I'm not making a lot of progress; I suspect that either a relay is bad, or miswired.
A few have been changed.

I think I'm going to have to pay for a wiring diagram.
Russ Hanscom
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Re: opinion; old German milling machine

Post by Russ Hanscom »

Good luck. I have a west german drill press imported by Wilton. Had issues with the control panel for power feed and cycling; the wiring diagram was only close, all of the wires were red, not all marked, I was not the first one in it, and the panel was installed in the column. I ended up having to replicate part of it in a separate box.

I made copies of the wiring diagram and marked it up with colored pens as I figured out each wire, so there was some type of working record.
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liveaboard
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Re: opinion; old German milling machine

Post by liveaboard »

This machine has different colors; 3 of them. But most are numbered at least.
The relay bank is the crazy thing. Normally open circuits, normally closed ones, and they trigger each other.
Each motor has 3 power relays [fast, slow, reverse], which is fine; but then there's a dozen more that switch each other and the motors on, off, or reverse.
The relay wires are hidden behind the relay mount plate so I can't tell where they go.
Then there are 2 servo mercury switches, I have no idea what they're for.
They look rather evil.

I'll keep poking around, maybe the problem[s] will make themselves known.
Russ Hanscom
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Re: opinion; old German milling machine

Post by Russ Hanscom »

Normally power relays, or contactors, have several sets of built-in auxiliary contacts, which are wired so that only one power relay at a time can be activated. If enough auxiliary contacts are not available in the power relay, sometimes supplemental relays are required.

What size is the wiring to the mercury relays, that might give a clue as to control or power function.

One way to test most of the relays might be to make up a set of leads or probes, connected to the appropriate voltage, and carefully apply to the coil terminals of each relay. If you can hear a click of it activating, there is a decent chance that it is good.
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