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Cheap Mini Mill

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brino

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#31
ex_isp,

I guess we are getting a little further away from the "Cheap Mini Mill" title, but it is your thread.......

Thanks for those links, that is very interesting.
I had looked for plans several years back and found many examples, but not much detail.

I wish the Rusty/Dusty/Super Rusty plans were available in PDF......I would have bought them already!

-brino
 

ex_isp

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#32
If I had a creek next to my house, I'd build a concrete funnel and channel the water to run a water wheel for this:
 

ex_isp

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#33
Here's another interesting design that one could build for not too much time or cash

 

Charles Spencer

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#34
Today, I did a test cut in the brass with a 1/8" dremmel bit in the collet as I don't have real cutters yet. Was able to chew through over 50% of the 1/4" thickness of stock
in a single pass with no strain at all. I'm impressed and must agree, the Chinese ebay machine would not have done that. Again, THANKS for pushing me towards the
larger machine!!!
By the way there is a ton of information available online for your machine. Just look up Sieg X2 mini mill. For example, here's one:

http://www.hossmachine.info/
 

ex_isp

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#35
Thanks Charles! Truly a lot of info there!
 

ex_isp

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#36
ex_isp,

I guess we are getting a little further away from the "Cheap Mini Mill" title, but it is your thread.......

Thanks for those links, that is very interesting.
I had looked for plans several years back and found many examples, but not much detail.

I wish the Rusty/Dusty/Super Rusty plans were available in PDF......I would have bought them already!

-brino
Ah, what's a wee tad o thread drift amongst friends? ;) Especially if there is still good info coming from it!
 

ex_isp

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#37
Meanwhile, back at the ranch...

I would guess the two fluted "bits" to require much higher rpm than a bur, to keep it cutting with less tendency to hop or chatter... yes?
The burrs cut fine all the way down to 700-800 rpm (~). I'm guessing the I'd want to run a two fluted at 2000 rpm or so.
 

mikey

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#38
See this discussion: http://hobby-machinist.com/threads/need-new-end-mills-for-my-g0704.50192/

I would download and print out those pdf files I planted there. They give you the cutting speeds for end mills in different materials based on whether the end mill is a finishing or a roughing end mill and how much of the cutter is buried in the cut. Once you know the cutting speed in surface feet/minute (SFM), you plug it into a formula:

RPM = (SFM X 3.82) / Diameter
, where SFM is the cutting speed from the table in surface feet per minute and Diameter is the diameter of the end mill you're using expressed in decimals, such as 0.375 for a 3/8" diameter end mill. The 3.82 is often rounded to 4 by many folks. The result will be your mills rpm for cutting that material with that depth of cut. Note that cutting speed varies slightly by the type of cut you're making - profiling or slot cutting. This gives you a starting point for your rpm. For many non-ferrous metals the calculated rpm will be higher than your mill can achieve; in that case run at top speed and adjust your feed accordingly.

You will learn how an end mill feels and sounds when it is cutting well and when it isn't. A clean cutting end mill will offer a slight resistance to feed when your feed rate is right and will have a steady hiss or drone. If it vibrates or chatters then alter your feed - slow it or speed up and see what it does. The same is done with speed - slow it or speed it up and see how the cut progresses. I know this sounds rather primitive but learning how metal likes to be cut is more a feel/sound thing than you might think. I mention this here because you don't have a way to calculate or set your feed based on inch/minute or by chip load so use your other senses instead.

There is more to milling than this but it should get you started. The thread referenced above also has other information that will be useful to you.
 

ex_isp

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#39
I just had this feeling I was going to really enjoy this forum! Very good info Mikey! I have always had a very good feel for feed rates in things from tooling to heavy equip. I'm glad it applies here as well!
Have experienced same with the burrs I've been using to cut, but understand that a real end mill bit will cut faster and perhaps smooth with correct feed pressure and rpm.
 

mikey

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#40
Anybody who can forge a knife from raw steel has to be mechanically inclined so you'll take to the mill with no problem. As everyone has said here, the mill will be very, very useful to you in ways you cannot imagine right now. Glad you stepped up to something that has a chance of doing some real work.

As you go along you will have questions - don't be afraid to ask them. There are some really knowledgeable folks here who will step up. Welcome to the HM forum - best site of its kind on the net!
 

ex_isp

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#42
Received a 10 pk of 2 flute end mill bits and tried them on the brass I use...
I suppose it goes without saying, but WOW. 3 or 4 or times the cutting speed vs
the burrs I'd been using. Many thanks again guys!!!

BTW, I got the 10 pk for 8.95 shipped off fleabay. They are plenty tough for the brass.
Don't know hoe they'd run on steel, but I really don't have a need to mill steel at this point.
May pick up some stainless to use as finger guards, but not yet.
 

ex_isp

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#43
Finished the Kukri a couple days ago. Not for sale so it won't be on my sale site, but I thought I'd stick it in here for laughs. Pretty crude considering I
started with 1/8" X 1.5" flat 1095 which left me no room to grind hammer marks out. Putting that longitudinal bend in it was definitely an experience!
Simple oak handle, and a brass guard (not traditional on a Kukri).
And a photo of the mill bit holder I
IMG_0481.jpg
felt compelled to make from a drop piece of maple burl.
IMG_0477.jpg
 

kwoodhands

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#44
Make sure you have a collet for the size end mill you buy.Either that or use an endmill holder ,#3 Morse taper or R-8 depends on your spindle. I would use a 4 flute HSS 1/4" x 3/4" long cutter with a 3/8" shank.You should be able to cut the slot in 2 or 3 passes without lubricant.

mike
 

ex_isp

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#45
Thanks Mike! The machine did come with a pretty full set of collets for it ranging from 1/8th" through 3/4".
See here
http%3A%2F%2Fi1138.photobucket.com%2Falbums%2Fn532%2Fexisp%2FStuff%2FLastWords%2Fshop%2FIMG_0471.jpg


And, since really all I'm using it for right now is to cut slots in brass, I ordered a bunch of 1/8th" bits.
See up just a couple of posts to the assortment in the maple block. Appreciate the input, always!!! ;)
Can add other sizes of bits as I need them. Should order some up to 3/16ths" as I will be needing them
to use on thicker blades.
 
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