Will I ever need a reversing switch?

I made some spare contacts once ,because all of my Dewhurst switches came from kit that had been used for many years. Most Chinese switches that I have seen, would not have lasted that long anyway! So I don't see making a few spares as proof that the switches are no good. Most trouble comes with idiots switching from forward to reverse instantly. I don't cater for idiots.

I have no problems with including a NVR switches, a good thing in my opinion. I brought my Dewhurst switches over a period of time and never paid more than £30, sometimes a lot less. The type of switch illustrated in one of the responses above, are excellent too, but considerably more expensive than my Dewhursts, even when purchased second hand.

Andrew.

P.S. My workshop is not approved of by Health and Safety and I really don't care.

Hi Andrew

the reversing DOL starters like the one in my 19/11/17 post at 20:15 use a double contactor assembly like this

it could be incorporated with overload protection inside the machines electrical cabinet instead of the external box

on 3 phase machines the mechanical interlock makes it safer when you put the motor into reverse to stop the motor quicker !! - both the contactor & motor will have to be rated for this use

( I have known the brief application of reverse without stopping as "plugging" )

with single phase motors you will have to stop the motor before reversing

John

Yes I need to get one of those "round tuit's".

Probably will happen when my need for reverse is greater than my reluctance to crawl under the lathe's bench to access the underslung motor and try to figure out the wiring on my Australian-made motor that does not match the terminal lettering/numbering protocol described in all the UK-based literature on how to wire up a lathe reversing switch for a non-capacitor type motor. Probably the next time I need to turn a long metric thread.

Meanwhile, I do my milling much the same way as Geoff W shows in his pics, but start the cut with the job behind the slitting saw and bring it forward to make the cut.

The one on my Mini Lathe is huge and was wired so it tripped the NVR as you went through stop. It's a failing of the Dewhurst that it doesn't do this.

The SC4-510 has low voltage 'tactile' forward and reverse switches. I pressed when running as an experiment - a bit more demanding with 1kW of motor... The lathe came gently to a halted, waited a fraction of a second, then accelerated up to speed in the opposite direction. A lot to be said for electronic control, although i obviously can't make any statements about longevity yet.

The SX2.7 is the same you can switch direction while running and it just slows to a halt and then ramps up to speed in the other direction though the sympathetic user in me means that I will stop it first.

Infact the tapping feature is simply a fwd/rev switch on the end of the quill handles that changes direction at the speed selected (will only do this below 500rpm)