X3 mill issues..

Discussion in 'General Engine Discussion' started by Drei, Feb 14, 2012.

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  1. Feb 14, 2012 #1

    Drei

    Drei

    Drei

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    Hi,

    I have recently bought the super X3 mill from axminister and overall I am very pleased with its performance. the only problem that I saw is that the coulum vibrates and "moves" especially in boring process. I also can confirm this because when I measure the holes they tend to be slightly oval. between 0.05 and 0.02 which is a value to big when building these small engines. I also tried to give the tool very small cuts but still comes out slightly oval ( less than bigger cuts). Tough the boring head is eccentric, I run the spindle t about 350rpm thus vibration doesnt effect (I think).
    I was thinking in building some sort of re-enforcement to the head any ideas....

    Thanks
    Andrei
     
  2. Feb 14, 2012 #2

    Jasonb

    Jasonb

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    Are you sure its not the spindle that has play in it on my X3 the bearing adjustment nuts were completely loose when it arrived and gave 0.030" play. Tightened them up and its been fine for aboyt 5 years now.

    J
     
  3. Feb 14, 2012 #3

    lensman57

    lensman57

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    Hi,
    Check all the gibs first to make sure they are as tight as could be then worry about other things.

    A.G
     
  4. Feb 14, 2012 #4

    Mosey

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    When you tighten them up, make sure it is the rightamount, as too tight, and they can get hot and burn up. Don't ask me what the right amount is. On mine, I experimented until I got the right tightness and not too much to get hot.
     
  5. Feb 14, 2012 #5

    Drei

    Drei

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    Yes i already have tighten them which i think is the right ammount. I have to recheck the gibs... But when you bore you can see the head moving....does anyone own one and has the same problem??

    andrei
     
  6. Feb 14, 2012 #6

    firebird

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  7. Feb 15, 2012 #7

    Drei

    Drei

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    What part exactly i need to refer.. I saw the part which he adjusts the gibs of the column... today I tried to tighten the bolt but it seems to be tight enough. it also seems that the whole structure moves column and head.. i will know make some boring trials in a scrap and take readings in different parts with the dti..

    andrei
     
  8. Feb 15, 2012 #8

    Jasonb

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    Are you slackening off the lock nuts when you try to adjust the gib screws, they won't turn otherwise.

    Check the column is bolted tightly to the base casting as thats all I can think of that would cause flexing, they are quite solid machines unless you try to take silly cuts

    Have you got enough back clearance on your boring tool, if its rubbing that will tend to put a lot of side pressure onto the spindle,/head/column.

    Post a couple of pictures of your boring set up.

    J
     
  9. Feb 15, 2012 #9

    lensman57

    lensman57

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    Hi,
    Is the mill trammed in X,Y and Z planes and if so can you do a straight cut in any one direction or drill perpendicular to the base?
    If the mill is still under guarantee I would get in touch with Axminster tech dept asap and see what they suggest as I have found them to be helpful. You have mentioned a couple of times that the head moves and in any mill this is a no-no scenario it just should not happen.

    Regards,

    A.G
     
  10. Feb 15, 2012 #10

    tombstone

    tombstone

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    Had a similar problem with a KX3 which looks similar machine I was getting about .025” movement with the head at top of column moving it with light hand pressure. The column is held down with 4 M10 bolts with star washers which I thought was causing the problem replaced with 4 hitensile cap scews and decent flat steel washers and had .003” play which improved finish 100%. Ray
     
  11. Feb 15, 2012 #11

    tomrux

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    Hey lensman

    "Is the mill trammed in X,Y and Z planes"

    I got tramming in x and y but how do you tram in z?

    surely if it is straight in x and y it will cut flat in z no.

    Tom R

     
  12. Feb 15, 2012 #12

    lensman57

    lensman57

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    Hi Tom,
    The mill could be in tram in X and Y but not necessarily in Z as the point of reference during measurement ie: the spindle is static in relation to both X and Y but the Z could be in tilt in any direction and this would only show up once the spindle starts rotating. Sherline knew about this that is why their 2000 mill can be tramed in 8 different directions. If the mill column and susequently the spindle are in absolute tram with the base in both X and Y then the X and Y traming would suffice, given that most of machines that are available to home machinists and hobbyist are usualy the import variety, I doubt very much if The Z could be in absolute tram but then again I myself am happy with 0.03mm over a swing of 50mm for both my SIEG X1 ( after a lot of shimming and messing about) and the Taig mill, some insist on 0.05mm over 200 mm of swing.

    Regards,

    A.G
     
  13. Feb 16, 2012 #13

    tomrux

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    no. if it is in tram in the x and y planes then the spindle is at right angles to the table. that is it, end of story, good night Irene, that is all she wrote, the fat lady has sung, Elvis has left the building.

    Right angle fore and aft. right angle left and right is right angle every where else. or every thing I have ever buit in 40 years of engineering is based on incorrect thinking.

    Tom R
     
  14. Feb 16, 2012 #14

    Jasonb

    Jasonb

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    If you are only checking your tram by holding a test bar in the spindle and offering up a tri square then your tram could be out once the spindle is rotated.

    BUT most people rotate the spindle by hand as they check the X & Y tram so Tomrux is correct if the x & y tram while the spindle is rotated then it can't be out elsewhere.

    J
     
  15. Feb 16, 2012 #15

    Harold Lee

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    Tom your thinking is not incorrect, your understanding of the construction of the minimill is. The head is made up of two parts that are bolted together and while the column can be in tram the head that is mounted on the carrier can be canted and cause this problem.
    There is a yahoo group that is dedicated to this mill and in the files section there is a document written by John Pitkin who is a retire 737 airline pilot that addresses this issue. A person would probably need to join to see this but the group also has a lot of collective experience with this mill. Here is a link to the forum - http://groups.yahoo.com/group/GrizHFMinimill

    Regards,

    Harold
     
  16. Feb 16, 2012 #16

    hobby

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    I had pretty much the same problem with my HF-micromill/drill
    The quill is loose enough to be able to use as a drill press, but to loose to use for milling operations.
    As I was cutting I noticed the whole spindle assembly moving about in an arc, so to remedy that, I made a adjustable wedge

    [​IMG]

    that i could tighten enough to make the quill and the headstock act as one unit for milling, depth adjustment is made by lowereing the whole headstock unit, I also back tighten the microfeed of the quill until it no longer moves, as well as set the depth guage on the quill feed handle in a locked position so the handle can't move, and it works very good for precise milling even at heavy cutting depths.

    When I need to use the drill press feature, I quickly unlock the quill microfeed and the handle, and just loosen and remove the adjustable wedge, so the quill is free to travel again.

    Your machine appears to be completely enclosed so doing any kind of wedging the quill may not be possible, however for milling purposes try locking all the quill travel adjustments, microfeed and the quill handle so these could not move, any quill locking would be primarily with the microfeed adjustments on the quill. If it is made the same way as its smaller cousins.
     
  17. Feb 16, 2012 #17

    Drei

    Drei

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    Well infect today I did took some reading with the dti and I noticed that when the head is fully raised and push slightly the head from the front edge the dti gives a reading of 0.20mm more or less. I understand that by performing a force on the front most of the head, places a large moment on the head fixture to the column. But this is also performed in every cutting process and as you one can see the values are pretty large.

    Then I also placed the dti at different part of the column and repeated the push but this time the dti almost didnt move....

    I also tightened the head to column fixture bolts one by one. I know was going to replace the bots that connect the column to the base and add some large washers but I dont think it would make any difference since the dti gave no readings from the column.

    Andrei
     
  18. Feb 17, 2012 #18

    lensman57

    lensman57

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    Hi Andrei,
    Please make sure that your mill is trammed properly first, you can google how to do this if you don't know already.
    Can you drill straight and true, about 2" lets say.
    If all this is OK then check the gibs and if these are OK then lock the table during boring or drilling in all the none moving directions and see if it makes any difference.
    Check your boring head and its gib.
    Please remember that even an X3 super is not classed as a shop floor industrial mill, if you can get within 1 Thou of accuracy then be happy and get on with your life.
    I am still intrigued as to how the head appear to move during boring.#

    Regards,

    A.G
     

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