PM 25 or 30 ?

alfaspider

alfaspider

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Comparison of 25 vs 30 for initial mill drill purchase. $400 difference, and wonder if the extra HP, Speed Range, and Table size are the main issues to compare? Usually told to buy the largest, heaviest unit and not be sorry .. Are there any other real comparison issues between these two? Website says 25 w/DRO not available, and 30 w/DRO on backorder..
 
No comparison, PM-30MV. There is a very big difference between 1 and 2 Hp, in particular running the latter on 230V. Since they are both 2 speed belt drives, the PM-25MV will be limited with low speed work. Weight is also rigidity, the PM-30MV is almost twice the weight. The Z and Y axis you want to maximize in particular if you add a DRO scale, you loose Y travel. Also the maximum distance from the spindle to the head, as this gets eaten up quickly when you add a vise and a chuck. If you have only 120V then the PM-727V would be the way to go over the PM-25MV, if you have 230V and a bit more budget room, then the PM-30MV would be my recommendation.
 
I was in the same boat a while back...at first I was hell bent on getting a 25 but just ordered a 30 the other day. I really wanted the belt drive so spent a ton of time comparing the two and in the end I believe the extra few dollars was buying a lot more machine, more table, more power and a lot more weight...but I'm fortunate to have 220 available. Also, not that it means anything but after looking around and plotting the sizes I started to think that the 25 would "feel" like a mini hobby mill just on its size to me

I had planned to add DRO as a DIY to save the money (like half) but thanks to this site and all of the good info available I believe I will be CNC'ing it.
If you want a 30 soon, better order quickly, they have a shipment on the way from the mfg but most are already accounted for and only a few remain...as of the other day is was about 6-7 week lead time till they get it and start shipping out.
 
mksj said:
No comparison, PM-30MV. There is a very big difference between 1 and 2 Hp, in particular running the latter on 230V. Since they are both 2 speed belt drives, the PM-25MV will be limited with low speed work. Weight is also rigidity, the PM-30MV is almost twice the weight. The Z and Y axis you want to maximize in particular if you add a DRO scale, you loose Y travel. Also the maximum distance from the spindle to the head, as this gets eaten up quickly when you add a vise and a chuck. If you have only 120V then the PM-727V would be the way to go over the PM-25MV, if you have 230V and a bit more budget room, then the PM-30MV would be my recommendation.
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The question I have is PM-30MV vs PM-932M as I was looking at the Z positioning motor as a plus, any input you have on this would be appreciated as I'm stepping up from a Sherline.
 
I went with the PM-30MV over the 932 for 2 reasons. DC belt drive and spindle speed. I'd read a lot recently on single phase motors and the harmonics of them with lathes, due to issues with an under powered non-run capacitor type motor on my own lathe. I'd read some people having surface finish issues with gear head single phase lathes. I also read someone having issues with a fly cutter on a gear head mill. All that led me to the belt drive DC combo over the gear drive single phase. In reality it may not have been that big of a deal, especially since the 932 is heavier. I was also moving the machine into my basement, so saving a couple hundred lbs actually helped me there. I was able to hand carry all the pieces down after a disassembly.
 
I am researching the same two models for my first purchase. The one thing I noticed is that the max end mill for the pm27 is 1” with 1.2 hp. Yet with the 2 hp pm30 it is the same as the pm 25 at 3/4”. Why might this be?
 
I believe the PM-27 has a gear head which allows speed reduction and torque increase from the motor. That’s the probable explanation. In reality you will not get more work done faster with less HP regardless and these Mills shine with 3/8” or 1/2” cutters running full speed.
 
The PM27 PM25 & PM30 mills are not gear head mills. They are electronically controlled variable speed belt drive driven by a DC motor. The motor RPM can be changed on the fly with a turn of a knob but also the belt position can be changed on the pulleys to change speed range.

On a gear head, like the PM932, the motor (usually AC) will always turn at the same RPM (w/ no vfd) & the gear changes will change the speed (need to stop the motor to make speed changes).
 
darkzero said:
The PM27 & PM30 mills are not gear head mills. They are electronically controlled variable speed belt drive driven by a DC motor. The motor RPM can be changed on the fly with a turn of a knob but also the belt position can be changed on the pulleys to change speed range.

On a gear head, like the PM932, the motor (usually AC) will always turn at the same RPM (w/ no vfd) & the gear changes will change the speed (need to stop the motor to make speed changes).
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darkzero you’re confusing the PM-25 and PM-27. There is now a variable speed version of the 27 but the original and VS both have the same gear selection available. The 25 and 30 are both pure belt drive.
 
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