# Pm935ts Or Pm935tv



## taildraggerpilot (Jan 26, 2016)

Hi All:

I've read about every thread on the PM935 mill and every time I think I've nailed down a decision, something changes my mind.  What I'm really trying to decide is whether to go with the PM935TS with 3ph and VFD, or the PM935TV single phase.  I've read the pros/cons of both.  

I was getting quite serious about the single phase TV model, but then keep worrying about things wearing out and the difficulty of replacing bushing and such.

A number of folks on other forums with Bridgeports recommend the step pulley with a VFD.  My only issue with the VFD is dealing with more wires, boxes, etc.  I have a small shop 16'x24' and need to keep the clutter down.

Do you have any recommendations?  
Thanks.


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## tomh (Jan 26, 2016)

On my Bridgeport changing the belt from pulley to pulley  gets old quick and having used VS mills makes it even worse, so I say go VS. The  VFD's are the way to go and don't worry about the wires or wiring. I vote for the pm935tv plug & play.
The ease  to change the speed with the turn of a knob / button is great and in my opinion is the way to go


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## JimDawson (Jan 26, 2016)

Here is where I mounted my VFD, no extra wiring.  I just use the front panel buttons for all the functions.  I like the VFD along with the variable speed.


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## wrmiller (Jan 26, 2016)

Just went through this (for the nth time) and ended up deciding on a 935s. There are no extra wires, as you need one cable to the motor and one to the fwd/stop/rev switch anyway, and the VFD can be mounted in the column per Matt at PM. With a similar setup on my 12z I can honestly say I prefer the near whisper quiet operation and simplicity of my current mill, and am not interested in the complexity and future wear issues of a reeves drive. And once the VFD is installed, I will seldom be changing the belt settings anyway. YMMV.


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## mksj (Jan 26, 2016)

Either way, I would probably stay with 3 phase, no capacitors to burn up and more even motor power delivery. Start capacitor can go if you are cycling the machine on/off sequentially which one often does with a mill. A VFD for this setting is very small, you could mount it in a 12x12x8 box in the back of the machine, so it should not be a limiting factor from a space perspective.  Even with the TV, I would go three phase and use low voltage momentary buttons using a 3 wire configuration to control the mill. These are all direct connect to the VFD, so no real need for relays or control logic in this setting. If you want to get creative you can use an induction or proximity sensor for things like threading to reverse the motor direction at a particular quill position (I have this on my BF-30 mill). 

Parts replacement would be one of my concerns long term, so if going with a TV, I would get some spare parts for the drive system. I would like to upgrade from a bench top to a knee mill at some point, probably would go with either a 3 phase PM935TV or a Sharp LMV. Would use a VFD with either machine, would be very simple set-up. Would do power drives for the X and Z axis.


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## wrmiller (Jan 26, 2016)

Jim, I like your setup. Simple. I'll have to consider this.


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## ch2co (Jan 26, 2016)

VFD rules.

CHuck the grumpy old guy


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## Smudgemo (Feb 9, 2016)

I have the step pulley/VFD and don't wish I got the variable speed model.  I think the bottom line is that you'll be happy with either model.


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## taildraggerpilot (Feb 9, 2016)

Thanks for all the replies.  I really like both machines as well as Tormach PCNC1100.  Been flopping back and forth, but now leaning toward the Tormach after seeing one in operation.  The only reason for the switch is due to the ability to machine more complex parts.  On the flip side, I like the compact nature of the PM935 and quality.


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