The Infamous what Mill should I get

[lSherlockl]

Hello,

I know this is probably one of the more frequent topics "what machine to get" but I tend to get myself into research holes as I like to call it and end up looking like a conspiracy theorist with a stack of spreadsheets and red yarn going everywhere. So If anyone cares to read through and or give any suggestions of feedback on important features or considerations it would be much appreciated.

The shop is a basement shop with access from the garage but with wooden stairs, but the fools that built the house only used a 32 in entry door on it. Shop is decent size but given the above and the thought of ever having to remove it makes me lean to go "bench top" style of mills (and or lathes for that matter). garage technically a option but in WI even the garage gets quite cold and adding heating and wiring out there would also increase the budget sooo.

I had considered used machines but they seem far and few between in central WI and are usually much larger machines. That and unfamiliarity on what is "good or not" and or how to tell wear etc, I was less inclined to start out with a machine that requires me to rebuild it.

I'm a individual hobbyist not a business or anyone looking to do production runs, or be using the machine non stop. Predominately will likely be working in aluminum, pot metals, some plastic (delrin), with some steel work mixed in (no huge plans with steel but making the occasional replacement part and or want to maintain that capability). I'm not purchasing for automotive, cycling, or gunsmithing just enough times in my other hobbies I find myself really wanting to fix a part or make a tool that well requires a machinist or a mill to make or would be better if milled vs Dremel and right angle Grindered into shape. IE some tools on the list of things i would like to make and or improve is a decent belt grinder, die filer, various jigs and other tools for other work i do. Its a bit hard to bin the specific use cases as I only know some of them, and i know others certainly will come up as one uses and recognizes the uses of the tool.

I should add while I think CNC is neat I don't have the right temperament for it so at least conversion to CNC is not a major consideration in this decision (also famous last words).

That in mind I pretty much settled on PM, seeing their well regarded Customer service, or at least the fact that it has customer service and had ability to get parts if needed really seemed the place to go with, and their prices were close enough or even better to other resellers that it just made that part of the decision easy.


Budget $3000 on the upper limit on the machine itself (yeah i know tooling is a expensive slippery slope hence the budget).
Power: I can run a 220v outlet wherever I need to in the shop but no 3phase etc as I'm residential.

Based on my initial research reading and findings I thought the PM 932M (not the basic) fit the bill quite well its on the heavier side of bench type mills (heavy = more rigidity = good) still wrangle-able into the basement. At its price point ~2700 has nice features Powered Z axis and x axis power feed, and a good sized table with a decent work envelope that should be bigger than anything I need (famous last words).

However the PM 932M is out of stock and supply chains not being stellar with a sort of unknown restock time (seeing the other 932 family take several months to get in) I'm a bit less inclined to wait till I would guess near fall for them to restock the 932M. That leave me a few options I could step up to the PM 932M-PDF ($3k right at my limit) though I really don't think I would need or use the PDF feature, or I could side step to the less advertised PM-932V which is no power feeds but belt drive and VFD at $2600 (i would probably add on a x axis power feed if I went that route).

Here is where I have some questions

Geared vs Belt? I know belt will be a bit quieter, and in theory isn't belt more stupid proof as in if you do something really dumb the belt will slip vs mess up the gears or in this size of machine is it just hard to mess up the gears. Also would assume belt is lower maintenance.

VFD i roughly understand the science but question is, is it better low RPM torque than say brushless or than say geared. Is there concerns about the Chinese made electrics longevity vs the longevity of well Chinese made gears.

X power feed: desirable as it saves your arms, but also because you can get a constant x feed rate, better cuts and in theory better life on endmills if you feed them proper correct?

Z axis power "lift": i know not to call it feed as its not really designed to feed the Z that would be the job of the PDF, but really how useful is this or how often do you need to move the head up and down if working on say similar sized stuff. I guess it would depend if you do drilling operations etc that use a chuck as that would add a lot of height. Basically is it something I would regret not having


I had also considered like the PM 30MV as i liked brushless motors on other tools but really that and the other smaller mills really compared to the $2700 932M just didn't seem to come close in I guess "value". and really just the quill travel was a huge seller for me when looking at the 932 family or size bracket (which is based of the Rong Fu Rf45 at some point in its history if research tells me anything) .

Oh last notes in this book of a post. DRO is planned but I think I have the skills to mount one myself. Stand being 6'2" plan was to make my own as to my calcs all the sold ones would put everything short. Probably build around a tool chest cabinet get some useful space, as well as some sort of leveling, and or caster option to let me move it should I ever need to without needing a crane in the basement.

any comments, opinions, suggestions, or feedback are appreciated.

 

[wrmiller]

Heavier is not always more rigid. My PM935 outweighs my old CO 9x40 bench mill by hundreds of pounds. But the bench mill was more rigid. Different designs, different webbing in castings, etc..

You didn't mention quality or accuracy. You did mention light(?) gunsmithing. I do mostly pistolsmithing, but I do occasionally work on long guns. IMO accuracy and repeatability are the topmost requirements for this. But that's just my opinion.

You also bring up the age old gears vs. belts subject. Given your description of what you're going to be working with as far as material, how much torque do you think you need? Are you going to drill 1" holes in something? Just asking to get a better idea of what you intend.

 

[fursphere]

I just purchased and received a PM-30MV about a month or so ago. So far it seems to be a good solid machine. Keep in mind you're going to add $200-$250 for shipping and lift gate services (if you need it), and possibly another $200 for the stand, and then possibly sales tax (damn you California!). That's a a big chunk of that $3,000 budget. (add a vise and some tooling.....and well, its a rabbit hole).

When I started looking I figured out what I wanted to do and came up with the PM-25MV would be the smallest I'd want (when compared to other vendors). Then went one bigger out of principle.

I also may want to convert it to CNC in the future, so having conversion kits avalable for the PM-30MV (and the PM-25MV) was factored in as well.

 

[lSherlockl]

Heavier is not always more rigid. My PM935 outweighs my old CO 9x40 bench mill by hundreds of pounds. But the bench mill was more rigid. Different designs, different webbing in castings, etc..

You didn't mention quality or accuracy. You did mention light(?) gunsmithing. I do mostly pistolsmithing, but I do occasionally work on long guns. IMO accuracy and repeatability are the topmost requirements for this. But that's just my opinion.

You also bring up the age old gears vs. belts subject. Given your description of what you're going to be working with as far as material, how much torque do you think you need? Are you going to drill 1" holes in something? Just asking to get a better idea of what you intend.

That is a fair point, i guess i was going the generic rule of thumb. Though in the land of PM bench top mills i do think it may be the case for the mills of Chinese manufacture. fitment and how the column attaches can certainly have a large bearing on flex/rigity observed in practice. As a person who hasn't physically interacted with any of them all i can do is best guess based on provided info and hope for helpful insights from others.

Sorry I should re-phrase my use cases as looking back at it now it certainly could be misleading, by light gunsmithing i was more so going for the action and types of activities and work envelopes in both in aluminum or steel would be probably at most similar to basic gun smithing for the sake of a simple reference point of a capability set I would like to have. That being said I don't have any actual plans to say mill slides make competition guns or RMR cutouts. I'll try and go back and add a better use case.

In terms of drilling I don't think I would often go over a half or even 3/4 in. HP and torque are something I don't practically understand how to relate as to what's needed, or Ideal for milling various materials or what limits that they can impose i understand yeah that generically more torque is better, cutting steel likes lower speeds and being harder either means slower and smaller passes or with the right tooling yeah you want some more low end torque to cut deeper.

I also do know of the adage or advise to get more of a tool than you need, as generally you don't come to regret it later.

 

[wrmiller]

FYI, I milled 1911 slides and frames on a belt driven PM25 using 1/4" and 3/8" end mills. It worked fine, except that I needed to get a bit creative when I ran out of Z-axis travel for some frame cuts.

Which is how I ended up with a CO 9x40. Monster machine, and I spent almost a year getting it where I wanted it. After that, I swore off Chinese machines. At that time, Matt (PM) didn't have the 833 mill, nor the PM30. So my 'upgrade' options were limited. Had those offerings existed, I might have just gone with the 833 and dealt with the shortcomings of a non-articulating head using other means.

I don't need machines as big as I have now, but I'm an outlier in this regard. I bought the machines with the features I wanted, and ended up with machines a bit larger than I had intended.

I don't know that you could go wrong with any of Matt's offerings. I think it just comes down to what you really want to do with the machines and choose accordingly.

 

[Pcmaker]

I would save more and buy a Taiwanese made machine like the 833T

 

[kb58]

I have to speak up in defense of the PM-935 with the following disclaimer: every machine flexes, the issue becomes "is it too much." Said another way, it all depends on what you're doing with the machine. I work both aluminum and steel, including machining a large block of steel for a custom alternator mount. Did it flex? I'm sure it did, some amount. Did it matter for my application? No.

All depends what you're doing.

 

[lSherlockl]

I just purchased and received a PM-30MV about a month or so ago. So far it seems to be a good solid machine. Keep in mind you're going to add $200-$250 for shipping and lift gate services (if you need it), and possibly another $200 for the stand, and then possibly sales tax (damn you California!). That's a a big chunk of that $3,000 budget. (add a vise and some tooling.....and well, its a rabbit hole).

When I started looking I figured out what I wanted to do and came up with the PM-25MV would be the smallest I'd want (when compared to other vendors). Then went one bigger out of principle.

I also may want to convert it to CNC in the future, so having conversion kits avalable for the PM-30MV (and the PM-25MV) was factored in as well.

Yeah my price limit was before shipping etc as well those stayed constant across pretty much any option as well as the basic tooling so that all to me is a fixed cost part of the tooling budget and the variable part left for me is the choice on the machine. but yes very much a rabbit hole

I would say a similar point I started looking at like a PM25 mv or that size/type of mill technically should cover the work area that i would need. then I sat back and went hrmm should go up a size like the pm30Mv, and then i looked at the PM932 which seemed to offer a bit more at the same ish price bracket.

I don't have direct plans to CNC, but I guess I shouldn't rule it out entirely as conceptually the complex cuts and curves you can do is pretty wild

 

[mksj]

You also need to break it down and get it down the stairs. I would recommend a belt drive in this category, much quieter and higher top end speeds. Weight is often proportional to the size mill. Taiwanese manufacturer tends to be a bit lighter, but may have better iron and webbing which can add rigidity. I have not seen any complaints of rigidity for the bench top mills working within a reasonable milling envelope for the size mill. VFD at this level, probably not as practical, just because these often come in a variable speed model with controller and tach.

The PM-30MV is within the budget and is small enough to break down and will give a very decent work envelope. If you are looking at higher quality mills then the PM-728VT and if stretching the budget the PM-833TV. You then start to talk about X and Z drives and some basic tooling and you add another 1K. You can get by w/o the drives, but hand cranking does get tedious and you will get better finish with a X axis drives. I wouldn't worry about how long an end mill will last, they can be picked up inexpensively and last a long time unless you drop it or are doing exotic alloys. A PDF, most people rarely use them. Many individuals overthink their needs on some of the numbers, but I will say that you want to maximize the Y and Z travel within your budget. DRO are an easy install and a 2 axis can be purchased starting at around $200. You only need X and Y, the quill has a battery operated DRO, never needed a column DRO.

CNC, all the models above have conversion kits, but you are looking at $$$, you will need some form of coolant system and enclosure if you do not want a big mess.

 

[fursphere]

CNC, all the models above have conversion kits, but you are looking at $$$, you will need some form of coolant system and enclosure if you do not want a big mess.

Very good point. I estimated around $2k to convert my PM-30MV to CNC (hardware and electronics), using an extra PC I already have. That project is on my "maybe someday" list.