9x20 Lathe CNC conversion

jumps4

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I took my old 9x20 apart today to start cleaning and converting it to cnc
I took a few pics before i took it apart and noticed the camera said something " no memory card" duuuhhh!!!
So i included the pic from Harbor Freight. this build is going to be bare bones as cheap as possible with parts scavenged off of the mill and what ever else i have around. the motors for this were here on ebay( http://www.ebay.com/itm/3-Axis-Nema...674?pt=LH_DefaultDomain_0&hash=item2575668faa) and the cost for the lathes parts are $484.00 less 1/3 the motor driver and power supply i used for my zx45's 4th axis comes to $319.44. most everything else will be from leftovers from the mill build.
this poor lathe has had an abused life with an owner who had no idea how to even turn it on when he got it " me "
it has been crashed several times and still turns out nice work, but it is starting a new life and probably all new crashes:lmao:
I dont care for the way most 9x20 lathe conversions come out looking with everything cobbled on the front so i'm going to see it i cant find a nice way of doing this without it looking like a box of rocks gobbered to the front of it.
steve

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jumps4

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i have decided on a rear mount on the x axis with a solid coupling and no thrust bearing since the other end of the screw will not be fastened. I dont believe the solid coupling will have an effect on the finish because of the high micro stepping i use there is no vibration. i will see, i may be just making premachined parts for future projects here and have to redo it adding a flex coupling and thrust bearing. here is a pic of a acme screw stepper motor no coupling and they make them ballscrew output shaft also. a mock up of my idea is the other pic but the coupling shown wont be used
steve

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jumps4

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I started on the x axis today , the motor mount was made from scrap so there are a few cuts in it that wont matter ( i said i was going to be cheap ) and i face milled the back of the saddle inline with the dovetails. started cutting out a spacer and thats about it for today my back is at it again. the video is a bit long ( like watching paint dry ) but it shows my redneck riggin to mill the end. the sound in the video is terrible my mill does not sound like that it just humms??
steve
[video=youtube;sZH7xBOZWpQ]http://www.youtube.com/watch?v=sZH7xBOZWpQ[/video]

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B

Bill Gruby

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Steve;

How long did you make that apron extension? This is scaring me. I can understand it all and I know squat about CNC.


"Billy G" :thinking:
 

jumps4

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bill
i'll measure it to see exactly for you, i didnt want to alter any of the original parts too much so i can return to lathe to manual if i wanted, so it's longer than needed to keep from cutting the end off the screw. all i'm going to change about the screw is mill a small flat on it for a set screw.
a better way would be to make a new screw and run it to the front and put a thrust bearing and even the handle back on for your purpose.
for mine i have to have it cnc to run the z axis so the handle would serve no purpose except something spinning around to hit my knuckles lol
steve
 

jumps4

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I made the coupling but i still have to add the set screws and i stripped a lot of the excess weight off the motor bracket.
[video=youtube;tatV60OwONs]http://www.youtube.com/watch?v=tatV60OwONs[/video]

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jumps4

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i spent all my time in the shop today making a shaft to fit every part perfectly, centered for alignment between the stepper motor and leadscrew.
when it was done it did not look like much but keeping everything perfectly centered, sized and concentric was a measuring and double check project that really took some care to produce. with the 5" long shaft is on the stepper shaft and the lead screw inserted there is less than .0002 wobble. i bored the holes with a boring bar and lapped them to size. the larger part aligns the motor mount to the center of the shaft. I will need this tool to align everything any time i take it apart and also to locate the bolt holes for mounting.
i did notice the mount is about .005 to tall for the table to clear right now so i will get everything built and installed and remeasure to mill the top down. i'd like the table to ride on the mount for a little extra stability if i can align it all properly.
the more this alignment is off the faster the acme screw and nut will wear so i'm really taking my time here. i think a ballscrew would take misalignment better than an acme screw due to not having internal friction like a thread has.
steve

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jumps4

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i got the x axis mechanical parts done and assembled they work good, the motor in the vid is from the mill i just hooked it up for testing. i havent done any wiring for the lathe yet. if you watch the very end you can see i didnt get the set screw tight and the coupling is pulling off the motor lol[video=youtube;zwBa5CGJ1O4]http://www.youtube.com/watch?v=zwBa5CGJ1O4[/video]
steve
 
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