The lowest speed on my mill is 180 RPM, which is about right for High Speed Steel at a 50mm (2") cutting diameter and hasn't dulled a well- lubed 100mm slitting saw cutting steel, yet. Slower by half would be better for that.
jsw
Agreed that a drill chuks should NOT be used to hold milling cutters. Most milling cutters have hardened shanks that a chuck will NOT grip adequately. The cutters will slip and pul out under load. This can make a real mess of the work, and is potentially quite dangerous to the operator. It's a BAD idea, even if the chuck is secured with a drawbar.
Collets, in good condition, properly seated, are usually acceptable for holding milling cutters. This is especially true for small low powered machines. An "End-Mill Holder" is certainly more secure, but can induce small (usually not serious) runout problems.
For light precision work, use collets ... for heavy work use end-mill holders.
Dan Mitchell ============
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There is an exception to this -- with chucks made by Albrecht with diamond grit faced jaws which *can* grip a milling cutter shank without slipping.
However -- these particular ones also don't come with Morse Taper shanks, nor with Jacobs taper sockets. The come with integral R8 or 30, 40, or perhaps even 50 taper holders. I think that they are for gripping solid carbide drill bits -- where even the shank is carbide. I don't think that they advise using it for holding end mills anyway.
Generally -- the runout is minimal with a Weldon shank end mill in a quality end mill holder. The fit is so tight that you can create a "pop" as it is drawn out if there is no through connection to the drawbar for airflow.
And some of them are designed to be heated, and the shank put in there at which point they shrink fit -- very strong grip, and essentially no addition of runout.
Also -- for those in the UK and Australia -- look into Clarkson collets. they are designed so the end mill *can't* be drawn out. The end mill has a cylindrical shank with a threaded end and the holder has a keyed nut which presses the center hole in the back of the end mill against a center pip in the body of the holder. There is a collet which tightens on the shank to maximize concentricity.
I've got some Clarkson holders -- but not any reasonable number of matching end mills.
Yes -- because R8 collets (at least -- perhaps others) will let the helical flute mills be drawn down under heavy cuts, resulting in a cut which gets deeper as you go along -- and sometimes even continues through the workpiece and into the mill's table. :-)
Enjoy, DoN.
That just changed! :)
My thanks to all of you who offered helpful advice: your warnings caused me to wait, think more carefully, and search more diligently for alternatives. In the end, I came across a person who imports Taig machines in his spare time, and, because he has no employees, and pays no rent, is able to offer them for sale at very reasonable prices.
I'll be buying a Taig X2 mini-mill from him next week.
-tih
That just changed! :)
My thanks to all of you who offered helpful advice: your warnings caused me to wait, think more carefully, and search more diligently for alternatives. In the end, I came across a person who imports Taig machines in his spare time, and, because he has no employees, and pays no rent, is able to offer them for sale at very reasonable prices.
I'll be buying a Taig Super X2 mini-mill from him next week.
-tih
With metric dials and lead screws, I hope.
jsw
Are you sure? I did not know that Taig came out with a X2 version. They do have a micro-mill, but that is considerably smaller than an X2:
snipped-for-privacy@athene.hamartun.priv.no... ...
...
Congratulations, you've progressed from asking to answering.
jsw
Oops! No, of course, that's wrong. I've been looking at too many products, and I'm mixing up names. :) I meant Sieg Super X2, which is their upgraded X2, with the 500W brushless motor.
-tih
Thanks - I should check that. It'd be somewhat confusing to have this be different between my lathe and mill, I think. :)
-tih
I can work comfortably in either system as long as the graduations on the machine are the same as the dimensions on the drawing. There are too many things that demand close attention when machining to rely on mental math.
Do you see any products made to inch dimensions in Norge?
jsw
None at all. Not for a long time, now. We still speak of lumber in inch dimensions, even though it's no longer actually cut like that (a two-by-four is thinner here than in the US, but we still call it a two-by-four in everyday parlance) -- but that's the only use I can think of. Oh, one more: yardsticks are called "inch sticks" here, even though they're now marked in metric units. :)
The mini-lathe I bought has a nice solution on the handwheel scales on the cross- and topslide: since it's built for the European market, it has metric lead screws throughout, and the slides advance 1 mm per revolution of the handwheels. However, the scales are marked with 40 divisions. So, four units is a tenth of a millimeter, and each mark is "a quarter of a tenth", or 0.025. Not too difficult, but why not 50 divisions? Because 1/40 mm is very close to 1/1000", and that's the unit you see all over the literature, on the net, and so on. Smart!
-tih
A "two-by-four" here is within carpenter's tolerance of 40 x 90mm, and "inch" planks are 19 - 20mm thick.
jsw
OK, that's what we do, too. Whatever happened to the good old inch? :)
-tih
When I was a kid in the 1950's I 'helped' my father renovate old houses. Some were built with rough-sawn framing a full 2" by 4", more recent ones had planed framing timbers for easier handling that averaged 1-1/2" to 1/5/8" by 3-1/2" to 3-3/4". At that time we could have the millyard plane the rough wood to custom thickness to match the house we were working on.
I saw my oak to a target thickness of 5/4".
Looks cool! What is that thing? - and why?
-tih
It is a bandsaw mill made from a wrecked motorcycle and the engine from my log splitter. I have a large library and use the planks for bookshelves, and to rebuild my doors and windows. The trees on my property are much too nice to waste as firewood when they die or blow down, look behind the saw:
On Fri, 26 Mar 2010 15:09:05 -0700 (PDT), the infamous Jim Wilkins scrawled the following:
Jim, the shadow of the tin roof on the side of the log is downright eerie. I was trying to figure out why the bark looked wavy like that. Har!
-- "Not always right, but never uncertain." --Heinlein -=-=-
This shows that roof from the opposite direction after I put a shed over the log pile:
jsw
On Sat, 27 Mar 2010 05:00:49 -0700 (PDT), the infamous Jim Wilkins scrawled the following:
Hey, looks like a logging trailer made from an old boat trailer. ;)
It was the corrugated shadow that I was talking about. You can't see the crossection of that in the pic you just showed me.
Cool.
-- "Not always right, but never uncertain." --Heinlein -=-=-
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