I would like you to compare the actual dimensions to the print just to understand more about the expected precsion of the cnc conversion mill PM-25mv? if you could advise me on that even after 4 years of the video :)
The main reason I went with my own post was to get all the things I'm used to seeing. For instance, I have my post setup to create an optional stop on the approach move. That helps me prove out new programs more quickly. At this point, the standard Fusion360 post for Centroid will probably work ok. But, I like to use mine because I have confidence that it will do what I want it to do.
Hi Franco, did the RPM doubler workout or not? Looks like this video is more recent than the RPM doubler one but the PM25 doesn't have the attachment on it-
Hello. I'm using what is called an R8 End Mill Holder. FYI: never use a drill Chuck to hold an endmill. Drill Chuck's are designed to bite into the soft shank of a drill. Endmills don't have soft shanks and the drill Chuck can make the end mill fracture unexpectedly.
Great video! Followed all your vids for the PM25. I have your F360 download (awesome job btw), and my question is did you eventually go with one home microswitch on each axis? My Clearpaths are ready to go and this is my last mechanical setup.
Did you end up using the DMM servo and DYN4 for your spindle? I purchased the entire DMM system to include the spindle setup. Almost ready to bench test the whole thing. Quick question, did you use a braking (regenerative resistor) and if so what size? I think 200 watt but not sure about the ohm rating.
In manual mode, it all depends on the operator. If you are a skilled machinist and you know how to deal with backlash and the "flex" in these little machines, you can hold ±.001" tolerances with machines like this when it comes to positioning. Maybe eve better in some cases. In CNC mode, things can get better (or worse) depending on what you do with the machine. If you try to program it like a "real" CNC machine, you will get in trouble because these little machines have a lot more "flex" in the X-axis direction than they do in Y or Z axis. You always have to be thinking about the limitations of the equipment.
@@FrancoCNC Thanks for the reply. So am I better with a different bench mill converted to a CNC to prevent backlash/flex? Possibly a PM-728vt? I know some uses something like an anti-backlash nut of some kind to prevent backlash. So if the Pm-25 is converted into a CNC and accounted for all of the flexes and backlash in the gcode, I guess the tolerance would be 0.003”?
@@sto2779 Hi. When it comes to machines, the bigger/heavier machine will almost always be better, in my opinion. That said, no matter what benchtop mill you buy, you will always see they are their "weakest" when you are milling in the X axis direction - that is where the column will flex the most. If you convert to CNC, you will be best if you use ball screws (minimize the mechanical backlash). You will also snug up the gibs as much as reasonably possible. But, when you write your programs, you need to consider the fact that under a given cutting load, the machine will deflect a little more in the X axis direction than it does in the Y or Z axis. Not a big deal. Take a few spring passes and don't try to push the little machine beyond it's limits. You can hold ±.001" tolerances with these little machines if you are careful and keep their limitations in mind while programming.
@@FrancoCNC Thanks for the reply. I plan on using your guide to convert the PM-25 into a CNC. Have any recommendations for anything such as where to source and choose the correct rails and balls screws?
Loving the videos man. I really want to do one of these mill conversions. Was thinking of doing a larger one but now im thinking it would be good to do the small pm25 to start with. Seems like quite a capable little mill:) Thanks for the videos!
Awesome! I'm glad you like them. The PM25MV is the smallest mill I would bother converting. Anything smaller than that will cost about the same money as the PM25MV but have less capability. Also, the smaller the machine, the more difficult it can be to fit ball screws and ball nuts. That's why I like the PM25MV - it has more room under the table than the Grizzly G0704.
I have two acorn boards: one for my lathe and another for my mill. But, I suppose it is possible to share an acorn board if you make all the connections via the DB25 interface. You will be updating the acorn firmware every time you switch between machines. It is possible, but it sounds messy.
The Grizzly was ok. I believe the PM to be a better machine. It was easier to convert to CNC. The castings are bigger/heavier and seem to be a harder metal. I'd go with the PM over the Grizzly.
@@FrancoCNC I've been eyeing the PM 25 for awhile. I need to transition to a more robust mill than the extrusion gantry type routers I'm used to running and I think Tormachs are over priced
Nice job Franco. I see you don't have a spindle encoder on there yet, if you need an idea for one I have one I installed on my PM25. Mines up and running but waiting for spindle control with the isolation board that you suggested in an earlier video. Looking forward to rigid tapping and as always more of your videos.
@@Roadstercycle Thanks for send that email - very clever! I have more questions for you: I see you added a gas prop to help lift the Z-axis. Can you share any details for that?
@@FrancoCNC can you show the tool change process next time? how are you indexing the tool height? do you have a point of reference/ touch off tool or are you just inserting the tool and teaching acorn the new height? also im not sure if its me but it sounded like your spindle motor was bogging down on some of those more aggressive cuts.
@@FrancoCNC yep lol. lots of acorn videos building things now its time to make some setting up the software and start to finish work flow. if you want to that is :-)
