PM 1340GT with Simgle Phase Power

I've always threaded barrel tenons to a shoulder around 60 rpm. I've got a 1340 nearly ready to run and I don't know how comfortable I'm going to be at that speed. I've got Mark's VFD upgrades with a proximity stop on it's way but I'd like to somehow be comfortable without using the proximity stop.
 
Parshal please tell me more about a “proximity stop” ..... how one works and where one can be purchased.
 
There's quite a bit of info on this forum. Mark Jacobs makes one but it'll cost you about $1100 in addition to the cost of the VFD, braking resistor, enclosure and a couple other odds and ends.

Here's his YouTube video showing it in action.
 
I installed a Mark Jacobs Control Board with proximity stop on a three phase PM 1440 GT and eliminated the anxiety of the thread dial engaging and disengaging. Well worth the effort and joy of threading all materials against a shoulder without the fear of stopping in time. Check out Mark's video on the Proximity Stop at MKSJ on this site.
 
Parshal please tell me more about a “proximity stop” ..... how one works and where one can be purchased.
I made a swing up toolholder http://www.hemingwaykits.com/acatalog/Swing_Tool_Post.html.
You can come very close to the shoulder -even when traversing quickly when cutting threads. Doesn't cost that much and works well for me.
theoretically stopping a 3 phase motor in milliseconds can cause damage .:guilty:
 
I like my VFD system as it allows me to change the rpm on the fly. At times chatter makes it appearance and a twist of the knob can help reduce or eliminate it. Threading is also nicer as I can rapid back to my start position and restart the cut at a slower speed. This when I am cutting metric, as I am not sold on the idea of disengagement of the halfnuts like others claim to do.
 
I'll gladly trade my single phase motor for your 3phase.

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I have seen some example of finish issues with single phase motors on some of the Chinese lathes. Can't imagine it would affect threading at all. I have never heard of a single phase PM-1340GT having finish or threading issues.

I have a VFD / 3PH setup on my PM-1440GT. It is hard to beat the soft start, variable speed control and having both forward and reverse jog that can be tuned to your liking. I find the fwd/rev jog feature invaluable for power taping. I also have the proximity sensor setup but didn't find it very useful. After a few times of steel swarf tripping the sensor in the middle of a cut I took it off.

I do all my threading away from the shoulder at 200 rpms or more.
 
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