8 Position Lathe Turret CNC Controlled pneumatic lock/unlock
Click on thumbnails to get large picture
MPEG VIDEO #1 MPEG VIDEO #2 MPEG VIDEO #4 You can also see a couple of streaming video's at www.youtube.com I have found that uploading vid's to youtube is easier and faster to view. Click on the links to go right to them. Enjoy!
http://www.youtube.com/watch?v=hdngeM662PE
http://www.youtube.com/watch?v=XcEBfJLgZXE
http://www.youtube.com/watch?v=BnKmLGP6lIg&feature=related
Here is a testimonial from a recent buyer of my plans:
Dear Ron,
Just received the plans, got them converted and copied off. I would like to
thank you for these plans as they were the last piece of a puzzle
that I have been working on for quite a while. I have been collecting quite a
few materials/machines to make a cnc lathe while trying to figure out what
software package to jump into.
I never had this project at the top of my to do list mainly because of not
having cnc turret tooling. I figured why should
I stand there and feed in tool when I would just as easily do it myself. Well
you just changed all that.
The quality of your plans are wonderful. I have bought some plans off the
internet that their sellers could take lessons from you. Especially the hand
drawn variety.
The only thing that I am fuzzy on is that the location of the air line holes.
But after reviewing your movie clips its fairly obvious that the they just need
to go on either side if the part 4.
Again I would like to thank you for these plans. The only thing that ticks me
off is that I found them by just chance. I know that there are allot of other
people out there who would be interested.
You really should try to advertise in the "The Home Shop Machinist" or the new
magazine that they just started "Digital Machinist". You have an excellent set
of plans here but you need to get the word out.
Brief overview:
Here is how it works: the indexing lock mechanism is a simple 8
pin design, the main body has 8 hardened dowel pins installed and the front
turret has 8 holes. the pins are chamfered as well as the holes to help
with lining things up when locking. the drilling of the 8 holes on each
piece was done at a local cnc shop because of the critical accuracy
demanded. cost me 100.00 for this which was cheap to me. the pins only
stick out about 3/16 " this is good enough considering there are 8 of them
and the 4" piston at just 40 psi exerts a locking force of 500 lbs!
so much for all of that, now comes the internal workings. the inside bore
is machined (out of a monster chunk of steel) to accept the piston and
indexer drive and receiving plate to stroke out just about 1/4"-5/16" so
the movement is just enough for the 8 pins to move out of the 8 holes, the
turret now spins freely because the piston "floats" on the shaft so there is
little turning resistance at 40 psi.
the end cap is machined to accept a stepper motor and since there is air
pressure in the unlock stage of 40 psi the end cap has an o-ring groove
machined in it. so for a stepper motor with a 3/8" shaft i machined a
groove to accept a #110 o-ring. very simple. dwg's will show all of this.
end cap is sealed with oring.
now for the drive mechanism. i used a 4" round aluminum plate 1" thick and
turned 3/4" of it down to 1" diameter bored it to .375 and installed set
screw. this is now mounted to the stepper. the coupling setup was simple
yet very accurate, i drilled a 1/8" hole in 2 spots 180 degree from each
other and pressed in 1/8" hardened dowell pins 3/4" in length. the
receiving plate which is bolted to the turret shaft has 2 identical holes
that line up with the drive plate dowells, these are slightly slotted to
allow for slight misalignment.
i drilled and tapped 2 holes on the outside of the body for the air fittings
1/8" npt. a mac or versa 4 way solenoid control valve 110volt ac does the
job of unlocking the turret. the front port closest to the turret is
always pressurized keeping it in the locked position, when you energize the
coil this port will exhaust and the other port will pressurize moving the
turret ahead 1/4"-5/16" and unlock it. totally cool.
mounting the entire thing to your lathe is critical here. since the body of
the assembly is big you may have to machine a flat on the bottom to lower it
to the chuck centerline (i had to do this) it is best to carefully bolt
everything together not weld. i welded everything together and i warped my
bottom plate which when bolted to the crosslide JAMMED IT! what a mess to
fix.
in mach3 lathe i have set up the turret stepper motor as "B" axis and set
steps per unit to make the stepper rotate 1 full turn for 1 unit of measure.
so in the unlock position b0.00 is tool bit 1 b.125 is tool bit 2 b.250 is
tool bit 3 and so on. the neat thing is you can go in either direction! go
to tool 8 then to tool 2 then to tool 6 it doesn't matter! just a gas to
watch!
turret head. (important here!) ok, now that it is mounted to the carriage
and everything moves freely it is time to machine the slots that hold your
tool bits. this is done on the lathe that you are installing it on! i use
1/2" tool bits so i chuck a 1" milling cutter for a 1" slot 1/2" deep i
used multiple small cuts of .050 to get to a depth of .500 make sure to
purchase a high end milling cutter to do this. i did this in position 1,3,5
and 7 to mount 4 different tool bits. you may wonder how to lock the tool
bits into place. i used 3 grade 8 bolts (1/4" nc x 3/8 long) and just
slightly machined a point on each head, a cold roll steel flat bar (1/4" x
1/2") 3 inches long has 3 holes drilled and tapped. this little assembly
slides in nice above the tool bit and a 7/16" wrench locks the tool bit into
place! it aint going anywhere. since my main tool #1 has removable inserts
i was even thinking of drilling a 1/8" hole through the side of the tool bit
into the turret face and loctiteing in a 1/8" dowel pin but after using it
for a bit i don't feel this is needed.
position 2,4,6,8 is for center drills and boring bars when needed.
that's the brief outline of the entire turret. hope this all helps!
Email me here if you have any questions or call me at 1-778-892-0150 I am located just outside of Vancouver, B.C.
BUILD IT YOURSELF FOR $49.95 usd Use www.paypal.com account is nytrus54@shaw.ca All plans including detailed cad drawings, instructions and macro's to control it will be emailed to you. And yes you can email me with questions if you have a problem. PLEASE, these plans are copywrited, if you want to make more or go into production please do the right thing and pay me a modest royalty. I will leave this up to you.
ok, so how do you control it? i can't get the hang of vb scripting yet so i made macro's for each tool. M11 is tool #1, M12 is tool#2 and so on up to M18 tool#8