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  1. #1
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    Scratch build small mill

    Hello I'm scratch building a small mill with X2 spindle hopefully this is a little more rigid than standard X2 here are a couple pics

  2. #2
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    That looks pretty cool. What kind of travel are you going for and what are you going to be cutting with it?

  3. #3
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    14x7x9 aluminum and mild steel

  4. #4
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    Nice effort !
    Some opinions ..
    Get the spindle much closer the the z-axis.

    The z-axis is almost a flat beam.
    Make it a box, using the same thickness of metal as the vertical z axis base plate.
    Seems to be about 25 mm (Good!).

    Milling force (with a 0.5 Hp spindle, using approx 10 mm end mill) is about 50-60 kg (almost a bodyweight).
    Put a di in the spindle, indicate against table in x and y, ie horizontally.

    Lean on top of the spindle, horizontally, about 60 kg or 150 lbs.
    Towards the z.

    Does the needle move ? (Ill guess about 1 mm).
    The needle movement needs (should) to be less than endmill deflection about 0.04 mm or 2 thousandths or 0.001".

    This is for milling metal.
    For routers, it looks good.

    The section sizes should be proportinal of the third power of free length.
    Ie a free length of spindle from z-axis of 100 mm equates to x/100x100x100.

    So for 200 mm, its x(200x200x200) ==> 8 times more flexible.
    So for every doubling of free length, its 8 time less flexible.

    A good result is same free length as is the distance between spindle bearings (ie about 80-100 mm).

    Let us know how it works !

  5. #5
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    I plan on putting plates on the z-axis and the base is 1 1/2 inch thick this is a hobby mill basically I am trying to do a little better than the standard X2 which the z-axis is a total weak point but I'm trying to get a little more in the Y if I get too much deflection I'll move it in basically the plates are not on on the Z yet because I want to try use the machine to drill them and make parts for mill it will be close to the table and totally engaged on the right angle plate supports the Z the right angle plate that supports the Z is a heavy machining plate 8 x 8 x 18 x 1 inch thick cast-iron I have seen massive amounts of force applied to these right angle plates like mine during machining with stock fastened to them I asked a friend of mine the had any right angle plates and I got this one for free from him the ballscrews are cheap Chinese junk but maybe in the future I will upgrade

  6. #6
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    That looks pretty good. Almost the same travel I have on my 80/20 mill. It uses the X2 spindle as well.

    Mine is a little beefier if you can call it that. Still aluminum, but extrusions for the base and column. I also used the first iteration of the mill to make parts to better itself.
    What I wound up with was a little workhorse that ran almost all the time. I just bought a Novakon Torus to take some of that load off and to do rigid tapping for me.
    I still run the 80/20 a couple days a week. It does special and odd jobs that it was already setup to do with tooling plates, etc.

    I think you have a very good start on yours. Take a look at my build log. There is info in there about spindles and motor stuff that may be useful.
    Good luck with it and keep updating with the upgrades you make.
    Lee

  7. #7
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    Well, I may be late since you've already done most of it but I must say that while I admire your effort, you're aiming pretty low when it comes about design and materials used.

    Aluminium is not good material here. It neither has the strength and elasticity of steel nor the vibration dampening qualities of cast iron. Unless you aim to build just an engraver, in which pretty much anything works, for any real work that stresses the machine aluminium will give in and begin to warp. Tapped holes will begin to distort and bolts will get loose. Keep in mind that at room temperature aluminium is very near the melting point, that's why it is ductile.

    In general, If I were to put the effort to make a mill from scratch I would use nothing but cast iron for the structure and steel for parts subject to friction and impact, such as the spindle. Did you know that you can get cast iron in bars, plate, pipe, etc? Search for Dura bar, Versa Bar, etc. Also, casting is not as expensive as people thinks and offers a good opportunity to design the parts very neatly. A quick suggestion would be to make the structure hollow from cast iron plate and use dry sand to fill it. Sand absorbs vibration a little and adds mass to the machine cheaply. This way you drive the resonant frequencies up and it is less prone to chatter.

    In a machine tool only two things matter: stiffness and accuracy. Stiffness begins with keeping overhang low in all places. Say, in your design, you have several places in which there is nothing but a plate keeping stuff from flexing. One is the plate that connects the table with the column and the other is the plate you use as a column. Why you decided to keep that plate in the middle of the cast iron angle block and not simply touch the bottom plate and bolt from below is beyond me.

    As hanermo said, get used to the idea of analyzing your designs with extreme force applied. Where would it break from if you applied extreme force to it? Reinforce there. Until you get the entire structure to break under force, you can always improve it.

  8. #8
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    Quote Originally Posted by zhagoox View Post
    "Keep in mind that at room temperature aluminium is very near the melting point....
    Only if you consider about 1100 degrees below the melting point to be "near"....

    Regards,
    Ray L.

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    Quote Originally Posted by SCzEngrgGroup View Post
    Only if you consider about 1100 degrees below the melting point to be "near"....

    Regards,
    Ray L.
    1100 what? See, room temperature is about 300K. Aluminium melts at about 900K and iron at 1800K. 600K vs 1500K seems much closer to the melting point to me.

  10. #10
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    I gotta say I do not have any resonance issues in my aluminum based mill. Now to be fair, the entire Z axis is cast iron bolted to a 1" thick aluminum plate. That plate is bolted to the 80/20. It also has a cast iron angle plate backing it up. Then the table ways are also bolted to steel, then aluminum. I have been running it in a semi production mode for several years. I could not do that with a machine close to the melting point.
    Granted everything else you say may be true right up to the point that aluminum will not work. It certainly can. Not quite optimal, but surely a valid material to use. My lathe is built using the very same material and technique. It turns fine too.
    Lee

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    Leeway nice build log I like your machine if I can come close to your results in machining I will be happy I think the other people that commented are very knowledgeable engineers but I think they think this is going to be some high-end high rate of stock removal machine I am dealing with fairly low horsepower and RPM basically I'm just after a hobby machine that's a little stiffer than most and yes I left plenty of ways to strengthen it up whether it be flat stock or 8020 bolted to the sides of the bed and column if they ever looked at a standard x2 base and column I think they would have a heart attack or if the standard X2 was engineered correctly then there's something wrong with the figures the cast-iron that the the Chinese machines are made of is very malleable it actually bends I bought a twisted 7 x 10 lathe bed off eBay real cheap and actually over bent it straight without cracking it

  12. #12
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    Nice machine. I wouldn't worry about the melting point being real close.

  13. #13
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    Quote Originally Posted by dick cnc View Post
    Leeway nice build log I like your machine if I can come close to your results in machining I will be happy I think the other people that commented are very knowledgeable engineers but I think they think this is going to be some high-end high rate of stock removal machine I am dealing with fairly low horsepower and RPM basically I'm just after a hobby machine that's a little stiffer than most and yes I left plenty of ways to strengthen it up whether it be flat stock or 8020 bolted to the sides of the bed and column if they ever looked at a standard x2 base and column I think they would have a heart attack or if the standard X2 was engineered correctly then there's something wrong with the figures the cast-iron that the the Chinese machines are made of is very malleable it actually bends I bought a twisted 7 x 10 lathe bed off eBay real cheap and actually over bent it straight without cracking it
    I really don't want to be negative, if I'm giving advice is because I really admire your effort. But you know the saying "Whatever is worth doing at all is worth doing well".

    Right?

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    Quote Originally Posted by wizard View Post
    Nice machine. I wouldn't worry about the melting point being real close.
    I've been building the electrical enclosure/combination operator station I decided to do it this way seemed to be pretty easy and seems nice and you sit down on a high stool so you can use it standing up or setting down is a couple of pictures

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    Did you use MIC-6 plate or just rolled stock aluminum on the mill? If rolled stock was there much warpping/distortion when you milled it to shape? Like when you cut the channel for lead screw clearance.

    Nice looking job!!!

  16. #16
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    Quote Originally Posted by zhagoox View Post
    1100 what? See, room temperature is about 300K. Aluminium melts at about 900K and iron at 1800K. 600K vs 1500K seems much closer to the melting point to me.
    This makes absolutely no sense to me. For starters, very obviously Ray was talking Fahrenheit, I'm in OZ and use metric but I still got that. Now if your talking Kelvin (which is what the K signifies so far as I'm aware), your statement that Aluminium melts at 900K means when you convert to Celsius, 900K is equal to 3.3 degrees Celcius. And if we're talking kelvin, the difference between 600K and 1500K is infinitesimal when comparing to metals.

    As Ray pointed out, if the acknowledged standard for room temperature is ambient 25 degrees Celsius, aluminium melts at 660 degrees Celsius. Significantly above the 3.3 degrees Celsius equivalent of your 900K?

    I'm not aware of any iron, or aluminium that melts at that range of temp? And I can't see any way to creatively inflate that figure an additional 656 degrees Celcius before the aluminium will start to melt?

    Can you explain this statement of yours please to help us understand?

    cheers, Ian
    It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!

  17. #17
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    900K is not 3.3C, since 273K is 0C. So, 900K is actually 627C, so pretty hot.
    Michael Anton
    http://manton.wikidot.com - http://laserlight.wikidot.com

  18. #18
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    Quote Originally Posted by manton View Post
    900K is not 3.3C, since 273K is 0C. So, 900K is actually 627C, so pretty hot.
    Okay, my mistake, that's what you get for using the first converter link that comes up!

    1800 Kelvin to Celsius Conversion - Convert 1800 Kelvin to Celsius (K to °C) - Temperature Conversion

    Using another online one 1800K converts to 1530 Celsius. That makes sense now thanks. I couldn't work out how in the hell are you melting alu at barely above room temp!

    cheers, Ian
    It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!

  19. #19
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    Okay now I'm a little worried I'm going to have to do a temporary electrical hookup and actually cut something I can't believe that what I'm building is less rigid than the taig or sieg x2 and actually isn't the haas mini mill made of aluminum granted it's not a production machine and I don't even think I'll be close to that obviously I have a small horsepower spindle you people are saying it's as stiff as a piece of overdone pasta this is a hobby mill look at the X2 or the taig which I think is as rigid as an overdone piece of pasta and the reason I started this build was to be stiffer than them if it is prone to flexing like you say I will quit trying this is all new to me I built plenty of things in my life and machined a lot of things never been accused of building anything light-duty granted this is more or less what I have what I can do with the equipment I have usually i have people give me a hard time about building things to strong

  20. #20
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    Dick, for the sake of clarity, not trying to upset or be a smart@ss, but can you please use punctuation! Your multi-line, single continuous sentence paragraphs make it really hard to read. I can't speak for others, but it kinda makes my head want to explode, when trying to understand your intent mate!

    cheers, Ian
    It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!

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