What Mill (mill/drill) Should I Buy?

[catsh16]

something smaller than a standard bridgeport- I was looking at a Clausing 8520, but missed the sale.
what brand/model can you guys recommend in the bench top/ mill-drill category? anything new & USA made still out there? I'd like to own something that isn't a piece of junk.

features I'd appreciate:
travel 15x6x12 (X Y Z), DRO included or available, 1-2hp motor - preferably variable speed motor.

mostly we're just doing prototyping in aluminum, or performing small modifications/corrections to parts coming into our shop from a bigger production shop.
is something like the Bolton Tool ZX45PD actually a worthwhile machine?

 

[TomS]

Take a look at the Quality Machine Tool website. Then read thru the Precision Mathews section of this forum. I've got a PM-932M bench top mill drill that I converted to CNC. Quality wise it is very good. I also have a round column Enco mill drill that is also very good quality. Don't know much about the Bolton product so I have no opinion. I don't know of any USA made mill drills that you can buy new. Obviously you can buy used USA equipment but you are limited to used equipment if you want to stay in the same price range as an Asian mill. I may be off base here but I can't think of any USA machinery that meets your criteria, e.g. USA mill drill. There are other distributors of Asian machinery such as Grizzly, Wholesale Tool, Travers Tool, and many others.

Good luck with your search.

Tom S

 

[GLCarlson]

something smaller than a standard bridgeport- I was looking at a Clausing 8520, but missed the sale.
what brand/model can you guys recommend in the bench top/ mill-drill category? anything new & USA made still out there? I'd like to own something that isn't a piece of junk.

features I'd appreciate:
travel 15x6x12 (X Y Z), DRO included or available, 1-2hp motor - preferably variable speed motor.

mostly we're just doing prototyping in aluminum, or performing small modifications/corrections to parts coming into our shop from a bigger production shop.
is something like the Bolton Tool ZX45PD actually a worthwhile machine?

You're looking for a square column RF45 equivalent (that's what the Bolton is, too). They're OK. No, you won't find a US made equivalent- they're all Chinese made to start. These are all pretty much equivalent; not very rigid, fairly limited, hobby machines, adequate within limits as mill-drills-differing largely in how well the finish work has been done, which determines the price. Jet, Grizzly, etc carry the same thing. An 8520 is a better choice, if you can find one (sorry you missed the sale!)

If you shop a bit, you can have a used Bridgie (or good equivalent) for the same price. It'll weigh 4x as much, be a stinker to move, and has its own problems (try cranking that knee up and down all day...). It'll be hard to sell, too. Today, I wouldn't buy one unless the price was a screaming deal.

I suggest a different approach. Go used low-end (RF30) first, and wait to afford a good prototype/R&D CNC mill (Tormach). A round column, used mill-drill can be found for about 600 bucks, maybe a grand with DRO, and for a while (in my shop) did everything needed- every bit as good as the RF45 once set up (that square column doesn't buy much extra performance). When you are ready, spend the money you've saved (and, yes, more) on a machine that will greatly increase your capabilities. I took this approach, and have been happy with that path.

The one thing I'd advise against is buying a compromise machine for the long term. The name says it all- "mill-drill". A drill press, attempting to be a milling machine.

 

[Dan_S]

You're looking for a square column RF45 equivalent (that's what the Bolton is, too). They're OK. No, you won't find a US made equivalent- they're all Chinese made to start. These are all pretty much equivalent; not very rigid, fairly limited, hobby machines, adequate within limits as mill-drills-differing largely in how well the finish work has been done, which determines the price.

and wait to afford a good prototype/R&D CNC mill (Tormach).

This is kind of contradictory, considering a Tormach is just a square column mill drill that's been converted/tweaked to be a cnc machine.

catsh16

Pretty much any of the square column rf 45 clones are going to meet the requirements you gave above.

 

[brav65]

You're looking for a square column RF45 equivalent (that's what the Bolton is, too). They're OK. No, you won't find a US made equivalent- they're all Chinese made to start. These are all pretty much equivalent; not very rigid, fairly limited, hobby machines, adequate within limits as mill-drills-differing largely in how well the finish work has been done, which determines the price. Jet, Grizzly, etc carry the same thing. An 8520 is a better choice, if you can find one (sorry you missed the sale!)

If you shop a bit, you can have a used Bridgie (or good equivalent) for the same price. It'll weigh 4x as much, be a stinker to move, and has its own problems (try cranking that knee up and down all day...). It'll be hard to sell, too. Today, I wouldn't buy one unless the price was a screaming deal.

I suggest a different approach. Go used low-end (RF30) first, and wait to afford a good prototype/R&D CNC mill (Tormach). A round column, used mill-drill can be found for about 600 bucks, maybe a grand with DRO, and for a while (in my shop) did everything needed- every bit as good as the RF45 once set up (that square column doesn't buy much extra performance). When you are ready, spend the money you've saved (and, yes, more) on a machine that will greatly increase your capabilities. I took this approach, and have been happy with that path.

The one thing I'd advise against is buying a compromise machine for the long term. The name says it all- "mill-drill". A drill press, attempting to be a milling machine.

I would not be too harsh to the mill/drill machines. Not everyone needs, wants, or can afford a large Bridgeport. If you want to be a tool snob do it on the "other" forum!

 

[GLCarlson]

a Tormach is just a square column mill drill that's been converted/tweaked to be a cnc machine

No. Designed from the ground up as a CNC machine. See the Tormach white papers on the subject for details and perspective on the design decisions and trade-offs. The specific (I think key) design difference is that the spindle is fixed in the Z axis head, not a movable quill as in the RF45 style designs...thus, by definition not a mill-drill. There are other differences as well (only operable via the controller-no handwheels, spindle options, VFD drive, etc). Certainly does use a square column, but that's a characteristic of any modern CNC VMC.

The Tormach isn't a Fadal, a Haas, or a Mori-Seiko. It's not as fast, not as rigid, has a smaller envelope, limited hp, and is generally restricted to less than 7 ( 3-4 optimally) cu in of metal removal/minute. It does seem to hit the prototype/R&D/small manufacturing CNC niche pretty well. It's somewhere around a $15-25K machine depending on options.

Qualitatively and quantitatively different from the RF45 style mill-drill chassis.

 

[Dan_S]

No. Designed from the ground up as a CNC machine. See the Tormach white papers on the subject for details and perspective on the design decisions and trade-offs.

Pull a Tormach apart and set its parts next to that of any other rf45 clone, and you will find it hard to tell them apart.

The specific (I think key) design difference is that the spindle is fixed in the Z axis head, not a movable quill as in the RF45 style designs...thus, by definition not a mill-drill. There are other differences as well (only operable via the controller-no handwheels, spindle options, VFD drive, etc).

These are changes most people make when they convert an rf-45 clone to cnc. well, if they do a good conversion. The Tormach spindle cartridge for example is 3 3/8" in diameter, rf-45 clones have quills exactly the same diameter.


The biggest difference between a rf-45 clone and a Tormach besides the obvious cnc, is that the tormach has Turcite on the ways. Even that's not that significant as it's only ~1/32" thick, and basically requires thicker castings, and a little more machining.

This is kind of like a mid 60's mustang, it's cool, groundbreaking, and looks different, but it still had a lot in common with the falcon it was based on.

 

[catsh16]

thanks for the commentary!
any thoughts on a belt drive vs. gear drive? (PM25MV vs. 932?). lately, I see people putting VFDs on their machines. I used to work with a machine that had an adjustable speed dial such that you could adjust speed while running it... I don't like having to move belts frequently. (it also had an automatic air driven collet/spindle which was awesome! - no blind overhead wrenching)

Bridgeport - I can't find anything for less than $6000 delivered (rural location). and planning to expand to a new location soon... wouldn't want to have to move it twice! they pop up every few years <$1000... so I'll keep waiting on that front.

 

[Dan_S]

thanks for the commentary!
any thoughts on a belt drive vs. gear drive? (PM25MV vs. 932?). lately, I see people putting VFDs on their machines. I used to work with a machine that had an adjustable speed dial such that you could adjust speed while running it... I don't like having to move belts frequently. (it also had an automatic air driven collet/spindle which was awesome! - no blind overhead wrenching)

Belt drive is usually quieter, and provides a greater rpm range, but gear is "usually" better at transmitting torque. Keep in mind the PM-25MV & PM-932, are completely different classes of machine. You could almost make a pm-25 with a pm-932.

Vfd's require a 3 phase motor, and if you want a wide speed range, you need a 3 phase motor that is specifically designed to be run with a vfd ($$$).

Bridgeport - I can't find anything for less than $6000 delivered (rural location). and planning to expand to a new location soon... wouldn't want to have to move it twice! they pop up every few years <$1000... so I'll keep waiting on that front.

Bridgeport's are nice (I've used a few), but they where designed for maintenance shops and the like. Not to mention people almost always want more for them used then they are worth. Southbend lathes are the same way. If you are going to get a used full sized knee mill, id recommend something like a Kearney & Trecker, or Cincinnati. They where production machines with power everything.


If you want something new & bigger than an rf-45 clone, but smaller than a Bridgeport, take a look at the 2/3 or 3/4 sized machines.

Pm makes the 935 & 836, and i think grizzly has some as well.
http://www.machinetoolonline.com/PM-935HighPrecisionMills.html
http://www.machinetoolonline.com/Jet836MIll.html

Mike Gausha has a 935, and has several videos online showing him using it.
https://www.youtube.com/channel/UCjycmBWYzwtovLvW3Cd6Ksg