e-stop addition to old equipment

[kwb]

So I just got a benchtop lathe that is about 30yrs old. From the bit I do remember from my machining class ~30yrs ago on a machine that was probably from the 50's they had a mechanical stop (foot brake). The lathe is nothing special, price was right and being able to make a bushing or spacer will be handy. As I started getting familar with it one thought came to mind - WTF doesn't this thing have an e-stop on it?

The F-S-R knob is kind of clunky and if somehow I was to get tangled up in the thing - I think that might be a bit hard to shut off. Has anybody added an e-stop to one of these or any recommendations on a switch that might be as simple as inline with the cord?

 

[RTM]

Put a foot switch on it? Set it F S R, then step on the foot pedal to make it go.

 

[Firebrick43]

So I just got a benchtop lathe that is about 30yrs old. From the bit I do remember from my machining class ~30yrs ago on a machine that was probably from the 50's they had a mechanical stop (foot brake). The lathe is nothing special, price was right and being able to make a bushing or spacer will be handy. As I started getting familar with it one thought came to mind - WTF doesn't this thing have an e-stop on it?

The F-S-R knob is kind of clunky and if somehow I was to get tangled up in the thing - I think that might be a bit hard to shut off. Has anybody added an e-stop to one of these or any recommendations on a switch that might be as simple as inline with the cord?

Most E stop switches are wired to hold in a contactor. If the estop is hit the circuit is broken and the contactor is disengaged and therefore no power to the motor. Many machines have braking circuits as well and even dual chain circuit which is a whole nother ball of wax.

Is it a three phase machine by chance? Estop switches are easy to wire to VFD's (varible frequency drives) which can offer programable Acel and Decel rates, even can be varied on some depending if off or E stop button is used. Be careful if its a screw on chuck. Heavy braking can unscrew the chuck and you end up wearing a heavy piece of spinning cast iron.

 

[kwb]

Not 3 phase - just a small 120V belt driven table top model. I think the HP rating on the motor is .75 if I recall.

Not that I want to test it but if a serious accident was to happen it probably slips the belt but would keep the pressure on and leave you scrambling.

I don't want to go with a deadman foot switch, just something I could either hit with a knee if mounted on the front of machine or the non-captured appendage if I put it on top of it.

 

[rharman]

I have one of these mounted on my table saw (Shopsmith) where I can reach it with my hand, foot, or knee if needed.

 

[HoosierBuddy]

My SouthBend Heavy 10 (1960's) had no e-stop of any kind when I bought it. However, as it was a 3 phase motor it was easy to include an e-stop button on the control box I built for the VFD.

In the many years I've owned it, it hasn't bit me yet, but it might the next time I use it...so glad I have the e-stop and I think what rharman posted would be the simplest way to accomplish it.

Phil

 

[tool_scrounge]

One word of caution on cheap e-stop switches off on Amazon. I bought a bunch for work once and found most had high contact resistance. If I had used them they would have melted or melted and caught on fire. For personal use I usually get NOS industrial ones off of EBay.