[tungstenfish]

I'm trying to get an idea of relative speed of the Asian mills before choosing one. Can anybody estimate roughly how long it takes to cut a 3 inch diameter disk out of 1/2 inch aluminum plate? and 1/2 inch steel plate? What CNC equipment are you using?

Thanks,
Jonathan Miller
Washington DC.

[psychomill]

I'm trying to get an idea of relative speed of the Asian mills before choosing one.

What mill isn't 'Asian'? Very few left are 'American'. The cycle you're asking can be anywhere from seconds to minutes. Depends on the machine. Some are alot faster than others. Even within the same builder, some models are much faster than others. I think the decision and research for "what machine to buy" should be based on much more than how fast to cut a 3" diameter though.

[tungstenfish]

Yup, there's a lot to think about in choosing a mill, and the number of choices is bewildering. I've spent hours reasearching (mostly reading posts here), and I've kind of matched up my requirements (noise, space, money, materials, size of parts, etc.) with either the Sieg X1 or X2 with CNC kit & Xylotex controls... maybe. I'm trying to get a handle on what to expect for cutting times. - Whether certain equipment is particularly fast or slow etc.

Jonathan Miller
Washington DC.

[psychomill]

So you're looking at benchtop mills..... stick around..... there are plenty of people who have/use them here for all types of work.

[mjarus]

I have an asian mill. A Sieg X2 to be precise. I bought it to CNC, but still have it manual as I think that it is important to learn how it works before placing it under machine control. That way if something goes wrong, at least maybe I'll know something is wrong before something catastrophic happens...

Anywho, the Sieg X2 (sold by HF,Grizzly,Micromark,etc...) seems to be pretty good for MY needs. Yours may be more, dunno. It took me awhile to determine that the X2 was a good jumping off point. At one point I was almost sold on the Sherline or Taig. You need to get a list of your requirements, then see what will fit into your budget.

I wanted a machine that had a 4X8X4 minimum envelope, would do aluminum with relative ease, but could handle steel if required. I wanted it cheap, but "decent" tolerance.

The last point was the tough one. What is decent? That is for you to decide. I figured my skills, being a noob, would be well within the X2 envelope of "decent" for awhile. Even if the machine can get to .001 or .0005 accuracy repeatably, can I? Probably not right now.

Eventually I may move up to something larger, but that will be a while.

mjarus.

[Zumba]

Can anybody estimate roughly how long it takes to cut a 3 inch diameter disk out of 1/2 inch aluminum plate?

I would never cut a disk out of a plate on a milling machine. I would use a horizontal bandsaw to chop off a 5/8" thick piece from 3.25" bar stock and use a lathe to take it down to specification.

I come from a woodworking background where there were many ways to accomplish a given task. Took me awhile to figure out that when it comes to metal machining, there are one or two "right ways" and a whole lot of "wrong ways".

IMO, using a milling machine to cut round stuff is the wrong way. Not saying that you can't do it... in fact, with the proper fixture, a boring bar mounted backwards in a boring head, and the spindle spinning in reverse, you could probably get a pretty decent part out of it (though you would have a few holes in the middle of the part from mounting it to your fixture).

In any case, the best way to proceed would be to tell us your budget, what kind of stuff you want to make, and go from there. A Sieg X2 with a CNC conversion can bore a 3" hole in a piece of aluminum fairly quickly using a 1/2" end mill. But since I always like to clean up holes with a boring bar, I'd be hesitant to use a 3" boring bar on such a small machine.

[tungstenfish]

Thanks for the comments. Here's what I'm aiming to do with the Mill: I want to make parts for kinetic sculptures. These sculptures are kind of unusual - they have a central assembly of 4 to 6 bevel gears, and then other parts of the sculpture are attached to the gears & move according to them.

The axles on which the gears spin are sometimes made from stainless ground rod, and they're press-fit into a central block of stainless. Sometimes they're made of brass tubing, with bundles of steel wire inside & injected with epoxy. Other parts of the sculptures are irregularly shaped, but they all must be accurately cut to avoid collisions during motion.

I buy the gears & bearings from various sources, but the central hub which joins the axles must be custom made. For years I've contracted machine shops to do the work based on drawings but in the long run it'll be less expensive & give me more freedom if I have a mill. Also, I bet the mill would let me branch out & try all sorts of ideas.

So. That's my motivation.

The parts are generally small - maybe 6 inches max dimension, but they're all irregularly shaped: crescents, pie-shapes, cubes w/ corners removed. Most are aluminum or brass. Sometimes wood or (rarely) plastic.

My budget: not more than $3k. Hopefully less.

I'm interested in making batches of these sculptures - start making alot more of them. That's why I asked about cutting speeds.

Jonathan.