My first mill

I've started looking at buying my first mill. I've been looking at the Harbor Frieght Micro mill. I've looked at it in a store and it looks like it'll be fine for what I want to do. My main concern though is the size of the motor. It is rated somewhere between 1/3rd and 1/5th of a horsepower depending on where you look (the label on the actual machine says 1/5th).

One of the specific things I want to do is cut slots through 304 stainless plates up to .075" thick. Anyone know how this machine would handle this (how many passes required, what diameter mills would I be able to use, etc..)?


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I'll leave the capacity questions to the experts. Some simple things to consider:

You have seen the machine, which is great. Is the travel adequate for your needs? Will have have room for clamping?

Unless someone here disagrees, get an R8 spindle. You can do a lot with just a couple of R8 collets (imports cost about $5 each), but they are a little bit of a pain to change; see mention of ER below. It is common to want a good chuck for drilling (I have never regretted buying a Jacobs chuck). If you are going to be changing tooling often, you might want to get an ER collet chuck. It's expensive, but very helpful, especially on smaller machines. It will cost you some table/spindle distance, but no more than a drill chuck, and allows not only faster changes than messing with the draw bar, but it also allows you to change tools in limited vertical space. Also, the fact that it consumes space similar to a drill chuck is useful on a mill-drill, as it increases your chances of doing a job in one setup; the business ends of drill bits and endmills are more likely to line up than they would be when using a drill chuck and R8 collets to hold endmills.

IMPORTANT: NEVER (really) put endmills or anything that exerts transverse forces in a drill chuck; they must be held in a collet either directly in the spindle (such as an R8 collet) or in a suitable chuck/holder (such as ER).

Some mill-drill buyers have reported funny scaling on the vertical feed, suggesting that it is labeled British but in fact has metric threading. You can easily check it with a dial indicator. Some machines have table screws that move 0.125/rev; my preference is 0.1/rev, though I am assured that one adapts very quickly.

A mini mill might be perfect for you; had I known about them several years ago, I would have bought one almost on sight. Still, you should at least consider the options. There are square and round column mill-drills, and benchtop knee mills, all with pros and cons. I have a rebranded RF 31, which is working very well for me. Some people hate the design because any head movement loses dial settings; in my case, I'm happy to have the extra travel it offers relative to similarly sized machines. Without my ER collets, I would not be so happy.

If you have the money and space and weight are not a concern, you might pop for a knee mill. Buying your first mill does not necessarily make you a beginner, but if you are new to machining, you might seriously consider buying an R8 mill drill to beat up and then get something better later, assuming you ever feel the need to change. There is a lot to be said for a compact machine that does what you want.

There is no doubt other info I should pass along, but that's what pops into my head for now. You have already done the important thing, which is found this group before your purchase. Ask questions and you will get good answers. Also, use

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to search this group; there is a lot of good info to be found with keywords such as mill-drill, knee mill, ER32, square column, round column, benchtop knee mill, etc. Reading about the options is a good idea, even if you know what you want.

Good luck!


Reply to
Bill Schwab

If you have any interest in a knee mill, take a look at the one I'm selling. Here is some discussion:

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and the original post:
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Watch the line wrap.


Bill Schwab wrote:

Reply to
Steve Smith

There is a formula to get the ballpark of power required for a cut:

P = a * f * v * N / 20

P: power in [kW] a: depth of cut in [mm] f: feed rate in [mm] v: cutting speed in [m/s] N: number of teeth cutting (for a 3 flute cutter, it would be 1.5)

That formula is for "general steel". For SS, you have to multiply by about 1.2


Reply to
Nick Müller

Bill Schwab wrote: ...

I'll second that. Much more accessories available than for MT3 (say).

Happened to me: I had ordered the metric model. It came with scales

0-150, and what surely must be 1.5mm leadscrews (on all axes). But why could I never get my work to come out right? Took me a while to find the screws were 16TPI. Aargh!
Reply to
David R Brooks

I believe you're talking about the mini mill. The OP asked about the Micro mill.

And to the OP, if you can afford it I HIGHLY recommend you spring for the mini mill instead of the micro mill. There's a world of difference in what you can do with them and the available accessories. Then Bill's suggestions apply except that the table feeds are 0.0625/rev instead of the 0.125/rev he mentioned.

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Best Regards, Keith Marshall

"I'm not grown up enough to be so old!"

Reply to
Keith Marshall

First and foremost, as everyone has said check and double check the screws, and get 5 or 10 TPI, the 6 and 12 TPI screws are.... screwed.... it's a REAL pain in the ass to keep track of things if the dial isn't calibrated in either .1 or .2 per turn.. unless of course you stick a DRO on it..

Also as has been said, R8 taper tooling quite available so you can't go wrong there.

With ALL machine tools buy the BIGGEST thing your budget and space can afford, even if you don't think you need the capacity... in general bigger machines are more ridged but still allow 'fine' work.. I have a 9x42 Bridgeport mill and a 12x36 clausing lathe and the both work just fine doing small little .250x.250 things and 4-40 threads... and when I need to work something big I don't even think twice.. i just clamp it or chuck it and go at it..

And on a Mill, ya really should get a knee, the first time you can't do what you need in one pass on a 'bench top' and realize you are going to loose the calibration when you raise/lower the head you'll understand... Believe me, I speak from experiance...

--.- Dave

Reply to
Dave August

Unless you are totally space challenged..this is the minimum mill Id consider

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Look for Hales

R8, 1hp motor, 5x 26" table, power feed, rigid, solid, movable easily on casters or a pallet jack.

This particular mill has both horizontal and vertical spindles..but vertical only are more common. Ive seen them badged as Yamazan, Jet, Birmingham etc etc.

About 1/2-2/3 the size of a Bridgport. Screws are 5tpi---.200 per rev. Decent enough Taiwanese machines.

No..this one is NOT for sale. Its for when Im retired and wind up living in a refridgerator box somewhere


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