Mini Mill vs Round Column Mills

[Mitch Alsup]

as a noob I’m curious. So you don’t use the quill on Bridgeport if you‘re milling?

Mostly no. Setting depth by raising the knee is (generally) more accurate, and results in a better surface finish.

For work in aluminum that does not need extreme accuracy:: sure I use the quill for milling.

 

[ChandlerJPerry]

I don’t see how you would be happy with either the mini or drill/mill coming from a Bridgeport. The Rf45 square column mill requires less strategic planning because you don’t lose register if you have to change Z like the round column. There is a nice work work around/add on that one of the members here came up with that I plan on adding to my RF30/round column to rid me of the problem when I get a chance. But I’ve gotten so used to thinking strategically I’m not sure I’ll benefit. There are quite a few of us here who admit to having a drill/mill and do good work with it. I like mine. I bought it super cheap and it fits my budget, space and pocket book. And at 3x’s the mass of the mini mill can actually get something done.

Of course nothing will compare to a real knee mill, but compromises have to be made in my single phase, 110 only garage. I've heard pros and cons for the round column units and have been trying to weigh whether they are worthy of the increased cost compared to a square column mini mill, the general consensus seems to be yes. I'll have to keep an eye on local classifieds, mills are few and far between near me.

 

[DavidR8]

Per chance a round column mill just went up for sale near me today.
Fully loaded; vise, collets, end mills, power feed and coolant spray for 1200.
Too far from you but it’s a good deal for here.


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[ChandlerJPerry]

There is another option- a small horizontal mill with a vertical head added. Small footprint and very versatile. I have one.

View attachment 335393

I've been curious about these kinds of setups. Are there more or less universal milling heads available? I sometimes see horizontal mills for sale for quite cheap but I've never seen a milling head on its own locally. I would imagine it would be cost prohibitive to ship such a thing.

 

[ChandlerJPerry]

Per chance a round column mill just went up for sale near me today.
Fully loaded; vise, collets, end mills, power feed and coolant spray for 1200.
Too far from you but it’s a good deal for here.


Sent from my iPhone using Tapatalk

That would be a good deal around here as well! Milling machines of any type aren't particularly common, the few round column ones that I've seen for sale hover around $1,000 without tooling in my area. There's actually a Rutland mill/drill in my area for that price right now. Not to say that price is unreasonable, especially considering the price of new. They just always seem to have a way of coming up for sale when I'm not in a position to buy . There's also a Microlux true inch version of the mini mill listed near me for $500, but I do have some hangups about such a small machine that I will likely quickly outpace/grow tired of, especially considering the spoiling I've experienced from the gear head Bridgeport I had access to at my former employer.

 

[ChandlerJPerry]

I have both a mini-mill (Harbor Freight 44991, bought new) and a round column (Grizzly G1007, RF-30 clone, bought used). Used both extensively for a number of years. Being a lightweight, the mini is indeed limited in capacity. I usually use it for aluminum, but have done some light cutting on steel. It does nice work. The Grizzly is for heavier duty work on steel or on for larger workpieces. The biggest headache on the round column is that you lose XY when you have to change the head height. This is especially troublesome if you have to go from an end mill (collet) to the drill chuck. The chuck eats up a lot of the ~5" available spindle travel. There's lots of schemes out there on the interweb for holding the head true when moving it, but I don't think any of them are really worth the effort. I just get out the edge finder.

That said, my Grizzly is starting to show its age. So I've just ordered a Precision Matthews PM-835S "mini Bridgeport" knee mill. Too bad you're so far away. I'll be selling the Grizzly fter I have the PM up and running. You might want to give PM a look. https://www.precisionmatthews.com/shop/pm-835smill/

Back to your original topic - if you have any specific questions about either of my mills, either post them or send me a PM (personal message, not Precision Matthews

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What sort of depth of cut can the mini mill manage on steel, let's say with a 1/2" endmill? Also, realistically how large of a work piece do you feel you can fit on it with a milling vise mounted? I'm trying to get a better idea of the limitations as I have never had the opportunity to be hands on with one.

 

[Aaron_W]

Not sure what you consider a mini-mill but an RF-31 or clone which is the usual round column mill is not remotely in the same class as something like a Sherline, Taig or Seig X2 which is what I picture when someone says mini mill.

Have you ever seen a round column mill in person? They are actually fairly large mills with an 8x28" table with pretty good X-Y travel (roughly 20" and 8") and they weigh around 650lbs, so they are bigger / heavier than many of the popular small bench mills like the PM-25 / Grizzly G0704. They are a little bigger than my Clausing knee mill.

Personally dealing with the head on these sounds like a pain but if you find one really cheap or that comes with a decent amount of tooling they can provide a lot of machine for a relatively small amount of money. As always actual use matters, for small precision work a mini-mill will probably make you happier, but the round column mills are a pretty good value if you can deal with their issues.

 

[ChandlerJPerry]

Not sure what you consider a mini-mill but an RF-31 or clone which is the usual round column mill is not remotely in the same class as something like a Sherline, Taig or Seig X2 which is what I picture when someone says mini mill.

Have you ever seen a round column mill in person? They are actually fairly large mills with an 8x28" table with pretty good X-Y travel (roughly 20" and 8") and they weigh around 650lbs, so they are bigger / heavier than many of the popular small bench mills like the PM-25 / Grizzly G0704. They are a little bigger than my Clausing knee mill.

Personally dealing with the head on these sounds like a pain but if you find one really cheap or that comes with a decent amount of tooling they can provide a lot of machine for a relatively small amount of money. As always actual use matters, for small precision work a mini-mill will probably make you happier, but the round column mills are a pretty good value if you can deal with their issues.

When I say mini mill I mean the Sherline/Harbor Freight/Seig class of machine. I've never gotten to use a round column either but am aware of the substantial size difference between the two machines. I would definitely prefer a knee mill, but I've yet to see a small knee mill come up for sale locally. Same goes for square column machines, mini mills crop up from time to time but their bigger siblings are quite rare. I think a bird in the hand might be worth two in the bush here... a round column definitely has some inherent compromises but it's likely my best option for now.

 

[Aaron_W]

When I say mini mill I mean the Sherline/Harbor Freight/Seig class of machine. I've never gotten to use a round column either but am aware of the substantial size difference between the two machines. I would definitely prefer a knee mill, but I've yet to see a small knee mill come up for sale locally. Same goes for square column machines, mini mills crop up from time to time but their bigger siblings are quite rare. I think a bird in the hand might be worth two in the bush here... a round column definitely has some inherent compromises but it's likely my best option for now.

You might look at something like the Grizzly G0704 or PM-25. They are quite a bit bigger than the common mini-mills but new they are not a whole lot more expensive than the typical asking price of a round column mill. That is probably what I would have bought if I hadn't found my Clausing mill.

 

[markba633csi]

The small horizontal mills are much more rare unfortunately. With an added vertical head even more so. I got lucky and found mine locally for 1K$
Plus, I happened to live in the state where they were made (Diamond tool, Los Angeles. Rotex, San Leandro)
But most were made back East
-Mark