Pm-25mv Vs Pm-727m

[wildo]

I'm new to machining and looking forward to purchasing a PM mill soon. I found this forum and PM mills while doing research on the Grizzly G0759 mill. While I don't have the experience to know better, I see plenty of threads discussing the upgrade to the belt drive system in the PM-25MV vs the plastic gears in the G0759.

Ok. Sold.

But then I discovered the PM-727M. I don't think that I'll actually need the heavier duty mill for the things I want to make (precision spinning tops, small air/steam engines, maybe a few clocks) but on the other hand- purchasing the heavier duty mill now could reasonably cover my needs for a very long time into the future. However, I notice that the PM-727M is a gear driven system.

So again, not having any actual experience in this area, I'm reaching out for some advice on these two mills. I'm pretty sure that the smaller PM-25MV will perfectly suit my needs and apparently the belt drive is smooth and enjoyable to work with. On the other hand the heavier duty PM-727M being just about the exact same capacity, yet heavier duty, could be a future-proof investment as I grow into machining. But it's not belt driven...

Can you guys shed some light on this for me? Is the belt drive the way to go? Is there good reason to buy the heavier mill even when the lighter mill will probably fit my needs perfectly? Ultimately, the $300 difference seems like a no brainer to me to go bigger, yet I lose the belt drive- and I don't know if that's a big loss or not. Thanks for any insight!

[EDIT]- Also, considering that I'm new to machining, perhaps the belt drive in the 25MV would save me some stripped gears in the 727M since I'm a newbie and will likely at some point do something dumb out of ignorance. Is that a reasonable thought?

 

[burtonbr]

I'm no expert by far. I bought a G0704 when they first came out and have since sold it to buy something a little larger to fit my needs. though I haven't pulled the trigger yet.
The one thing that was a problem with the smaller mill for me was shorter distance between the spindle and table, at 13" max many times with a vice, and a drill chuck and the bit or tool, it didn't leave much room for work, especially using boring head. The 2" quill travel was many times a problem when making larger parts too. Your considering the G0759 that has the DRO and that is a big help for a beginner well it was for me I added one within the first 2 months of using mine. My G0704 had plastic gears and I ready many having problems with stripping the gears and I had an extra set but I never stripped a gear, though I was probably just lucky. the PM727 has steel gears and I believe a beefier headstock than the grizzly mills. Belt drive would be nice but I there are alot of the PM mills used with the geared heads that I've read good reviews about, I liked having variable speed and will miss it if I buy a PM727 but I think the other features will be much better.

you'll have to decide which mill is best for you, this hobby gets expensive fast, or it did for me with all the tooling that goes with having a mill but I sure did enjoy making parts. My experience was that it didn't take me long before I felt the need for a larger machine, probably most just being impatient wanting to do larger parts and heavier cuts as the G0704 is a capable mill. my advice would be to buy the largest heaviest machine you can afford or have space for.
Good luck.

 

[wildo]

That's a really good point about the vertical distance spindle to table! I read the 13" for the 25MV and thought that seemed like a lot. But you raise a good point about a vice, jacobs chuck, and drill bit not leaving much room for the work. The PM727 has a bit over 18" in this dimension. That might be worth the cost itself! Thanks for pointing that out.

 

[T Bredehoft]

In addition to the Z distance you will want to check out the length of Quill Travel. the PM25 has about 1 3/4", that's not really enough. If you're center drilling and drilling a 5/16 hole, you have to move the head up/down to accommodate the two tools. That is a BIG thing to consider.

I've been running the PM25 about 6 months, and planning sequence of operations is a major consideration because of that shortcoming. I am just about to power the head so I don't have to crank it up and down, but it still will be a hassle.

If cost is no object go with the 727. Opt for X and Y DRO, too. I did, in 10 inches the dial is .003 different than the DRO. I'd trust the DRO. The quill has a DRO and the head doesn't need one, save $300 by not getting a Z DRO.

 

[wildo]

It's not exactly that money isn't an object (this little hobby machine shop is costing me a FORTUNE!) but perhaps more so that I'm building this shop in a small bedroom (10.5' x 12') over a crawl space. Considering I want to mount the machine over a 27" wide Harbor Freight tool chest that would hold all the milling related tooling- weight is a consideration. I might have to get in the crawl space and brace this section of the floor joists if I decide on the heavier mill. It sounds like the Z axis limitation on the PM25 is kind of a nuisance that I didn't foresee.

 

[tweinke]

I like the shop layout plan! Only problem I see is the metal chips in the bed they are bad enough when I track them in the house. Just pulling your leg a little there. It is amazing how non traditional shops are put into use. I will also assume a Bridgeport is out of the question.

 

[wildo]

I like the shop layout plan! Only problem I see is the metal chips in the bed they are bad enough when I track them in the house. Just pulling your leg a little there. It is amazing how non traditional shops are put into use. I will also assume a Bridgeport is out of the question.

Thanks! I'll start a new thread on it!

 

[figgman7]

I'm new to machining and looking forward to purchasing a PM mill soon. I found this forum and PM mills while doing research on the Grizzly G0759 mill. While I don't have the experience to know better, I see plenty of threads discussing the upgrade to the belt drive system in the PM-25MV vs the plastic gears in the G0759.

Ok. Sold.
I was told...ypu can do small world on a large machine, but you can't do large work on a small machine.
But then I discovered the PM-727M. I don't think that I'll actually need the heavier duty mill for the things I want to make (precision spinning tops, small air/steam engines, maybe a few clocks) but on the other hand- purchasing the heavier duty mill now could reasonably cover my needs for a very long time into the future. However, I notice that the PM-727M is a gear driven system.

So again, not having any actual experience in this area, I'm reaching out for some advice on these two mills. I'm pretty sure that the smaller PM-25MV will perfectly suit my needs and apparently the belt drive is smooth and enjoyable to work with. On the other hand the heavier duty PM-727M being just about the exact same capacity, yet heavier duty, could be a future-proof investment as I grow into machining. But it's not belt driven...

Can you guys shed some light on this for me? Is the belt drive the way to go? Is there good reason to buy the heavier mill even when the lighter mill will probably fit my needs perfectly? Ultimately, the $300 difference seems like a no brainer to me to go bigger, yet I lose the belt drive- and I don't know if that's a big loss or not. Thanks for any insight!

[EDIT]- Also, considering that I'm new to machining, perhaps the belt drive in the 25MV would save me some stripped gears in the 727M since I'm a newbie and will likely at some point do something dumb out of ignorance. Is that a reasonable thought?