Gallery, Projects and General > Oooops!

Myford M type safety warning (Dewhurst switch)

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Eugene:
My Myford  M type lathe has the original Dewhurst reversing switch fitted onto the front of the cast iron stand.

Yesterday leaning across the machine to change the primary drive belt my hip brushed the operating lever with enough force to move it from the "off" position into "FWD" and start the motor. Thus I had my fingers holding a moving drive belt, and my chest on the rotating chuck, a very dodgy proposition.

No harm done (other than to underwear) but I'm going to modify the switch asap to a shrouded NVR type. I don't see the need for reversing anyway, so nothing will be lost. In the meantime I'll turn off at the main before playing with the drive belts. On reflection that's probably normal shop practice, but I didn't know it. Not a qualified Safety Manager's finest moment.



If any other beginner has a switch like this I can only advise them to think on.

Eug

awemawson:
Surely all you need is an isolator switch in the incoming feed, and use it when belt changing ?

These things can rapidly develop into panicky situations: the other week I was using the Bridgeport under power feed, and the table handle got caught in my workshop coat pocket. Got quite entangled before I got to the big red off button  :bugeye: Reminds me - I need to replace that coat - torn to bits now  :(

RussellT:
Could you change the lever to a round knob.

Reverse is quite useful for cutting metric threads on an inperial machine.

Russell

John Stevenson:
I cannot see the fascination to use these drum switches. Is it just because they were fitted as OEM equipment ?
Whatever the answer technically they are illegal in that they are a not a no-volt switch.

Power cut for any reason and the lathe stops, power is restored and the lathe starts unattended.

Even Myford were forced by H&S to be dragged screaming into the 19th century on later models due to the inherent danger of these switches.

steampunkpete:
"Not a qualified Safety Manager's finest moment".

But cancelled out by the finest hour of acknowledging the problem and doing something about it.

Don't worry, we've all been there, done that, got the blood-stained T-shirt (or nearly so).

In my newly graduated days we had a workshop with a Super 7 and a pillar-drill. One had a red button to start, the other a red button to stop (they were wired correctly as the stop buttons were proud of the box, and the start buttons recessed. The Guvnor had the idea that one was on the principle that starting the machine was a dangerous thing to do, so it was red for start, and the other was on the principle was that the big red stop button was because red represented danger when something unintended happened. It seemed daft to me even then because they were different and it caused confusion.

Your Myford looks very well cared for, I wish I had the space for one.

Regards

Pete

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