Taig Headstock 4th Axis Conversion
Question: I am attempting the oft-mentioned but apparently seldom-documented Taig headstock to 4th axis conversion. I have chosen to use an anti-backlash worm gear at 64 pitch, with 140 teeth, for a 140:1 reduction and 56000 steps/rev at half-step with a 200 steps/rev stepper, with 0 backlash! My question is, will a 64 pitch brass gear stand up to the task? Is 140:1 too ambitious? I've never built anything that takes significant torque before. I have never seen anyone use anti-backlash worm gears save for these people at 72:1, do they work well? http://www.kdntool.com/_sgt/m3m1s1_1.htm
And of course, anyone with links or information - any little bit helps!
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So, I've got a converted Taig (XYZ). Up until a little while ago, I thought I was happy, and then I saw this and thought of how completely insufficient my machine was for all the things I've never used it on before. All I can think of now are parts that require a 4th axis...:
http://members.shaw.ca/mryankey/4th%20axis.htm
I've always put away the idea of having a 4th axis since I don't have the budget for it, but I have seen 3 examples of the headstock to axis conversion (only 1 documented that I could find), and I think I can do it.
I'm ready to fire on the following parts:
$71.40 4-jaw self-centering chuck (Taig part #1060)
$60.25 Headstock & standard spindle (Taig part #100-00 or 200-60)
$6.00 Headstock mounting plate (Taig part #200-48)
$52.53 64-pitch 140-tooth Anti-backlash worm gear (SDP/SI part S1B86A-P064B140S)
$17.50 Worm (SDP/SI part S1D96Z-P064SS)
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$197.68 Total (w/o motor, versus $270 for the Sherline 3700CNC w/o motor)
I already have some pieces, but I priced them out for the benefit of those who don't. Buying your gears from Nordex instead of SDP/SI will save you ~$10, but you have to register (free) to see their prices. If you don't use anti-backlash gears you can save another ~$20, and about another ~$10 if you go down to about 72:1 ratio.
So I just have to make the NEMA 23 stepper mount (I'll post the 3d model later, nearly done) and fabricate an adapter to fit the anti-backlash worm gear (.25" bore) on the 5/8"? spindle. I can't just bore it out like a normal gear since the anti-backlash gear is composed of two halves. The worm itself is pre-bored to .25" in which is standard size for the motor so it will slip right on.
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3 Attachment(s)
Made the mount, works great!
Hello all,
I got my order from SDP/SI. I am glad I went with the 48 pitch, as it is just at the limit of what I think would be appropriate in CNC duty.
I will now post my files in 3DM and DXF format, but read the description first:
I made my mounting plate out of 0.25" aluminum today, but the thickness is not absolutely critical. There is room for adjustment (sliding side to side to allow for different thicknesses of worm wheels) where it mounts to the headstock. There is also room for up and down adjustment where the NEMA23 motor mounts to allow for different diameter worm wheels. So this mount can be used for pretty much any combination of worm and wheel.
Notes:
- I used a .125" end mill to cut the bolt slots (They are .200" wide) and a .25" to do everything else.
-That cut out area on the bottom slot is to allow access to the clamping screw.
-Whatever thickness you make your plate, remember that the NEMA23 motor needs a 1.5" diameter recessed area around the shaft to fit into. On the model I made mine .08" deep and 1.6" dia, but I think the standard says .06". You could just cut all the way through, but I think that would reduce the strength of the mount the way I have constructed it.
-The mounting plate extends about half an inch / ~15mm below the headstock's bottom. The headstock must be elevated at least this high above the table when it is mounted. Just stick something underneath the dovetail mount when it is put on.
-I found that the ridges on the headstock make the lower t-slot area stick out just a bit farther than the top t-slot protrusion. You may want to account for this on your plate by pocketing away a little on the backside, or adding a shim under the top area. I don't really think it matters that much.
Re: Taig Headstock 4th Axis Conversion