X2 CNC Conversion

Mike, I have been using that same pendent control on my BP for 6 months or so with good results.
 
I'm an electrician and the guys at one of our wholesalers are really good about giving me the lowest price if it's for my personal use. The box cost me about $13 including tax. I never have to ask for a discount. I found the same box on their web site for $35.
 
I think I'm okay as far as a lathe is concerned. But then, that's what I thought about CNC in general. :thinking:

I've gotten this far without pictures, but I think the mods are getting ready to revoke my parking pass. I got the control box done today. The setup has been running the adjusting lever for about an hour and the fan on the power supply hasn't come on yet. The big fan I put in the control box is doing it's job.


A 12 x 12 junction box is just the right size for the power supply and control board, with a bit of room for small extras. The white terminal strip at the bottom will handle the connections for the homing switches.
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Nicely done Mike!


M
 
Catch-up time. I decided to extend the Y-axis as part of the conversion instead of a later upgrade. Since I didn't have any steel in a suitable size (I wanted a piece 2 1/2 x 2 1/2 x 6), I picked up that piece of mystery-cast I had used to make the base for the surface gauge (http://www.hobby-machinist.com/showthread.php/5435-Surface-Gauge). It had eaten a 10' bandsaw blade when I cut off the first piece, so I have been hesitant to use it for anything.

I figured one of the previous problems could have been grit and such in the surface from the mold. I used my radial arm angle grinder to cut about 1/4" into the piece all the way around.
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Then, out to the big bandsaw, running at its slowest speed. And yes, I did use a bit of coolant. No problems.
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Some careful facing with an indexable end mill ...
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And on to cutting the dovetails. The portable bandsaw would hardly touch this metal, but drills and shaper work fine. It even dulls centre punches. I drilled rows of holes and broke out the waste outside of the dovetails, then smoothed it off with the indexable. I took out all the waste I could below the slopes with a 1/8" woodruff cutter.
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I spent most of the day today using a brand new 3/4" dovetail cutter to very carefully cut the dovetails, 0.010" at a time.
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I carefully measured the original dovetail with a pair of 1/4" carbide shafts and I was quite proud of myself when I finally finished the extension to the same measurement. I took it out of the vise and held it up to the base of the mill. For all my life, I never expected that the mill would have a different angle than 60[SUP]o[/SUP]! And it's not 45[SUP]o[/SUP] either. It's only a few degrees off, but it totally screws up all the work I did today.
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I think what I'll have to do is mount the block on the base, then mill them both to 60[SUP]o[/SUP]. But first, I'll make an indexable dovetail cutter. With the change in angles, I'll need a new gib anyway, so I'll make it thick enough to counter the loss of metal from the correction.

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Time for another update. I finished shaping the y-axis way extension and mounted it on the base. Then I cut out enough of the front wall on the original ways to allow the ballnut to pass.
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I got the dovetail cutter made and reworked the y-axis ways. The metal the extension is made from is a lot harder than the original. I'm pretty sure it's white cast iron - made by cooling cast iron quickly. Really tough stuff.
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I wanted to make sure the X and Y axes were at 90[SUP]o[/SUP] to each other, so I mounted them together and dialed them in, then milled the saddle dovetail that mates with the base dovetails.
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The ballnuts are a lot bigger than the originals, so a bit of cleaning up is required to let them fit. A 1" ball end mill comes in really handy.
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Next came the ballscrews. I turned the end down to 12 mm and threaded part for the bearing nut. A 3/8" shaft finished off the end, with two flats milled at right angles to take the coupling setscrews.
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The couplings are made from aluminum and are one-piece. One end fits the 14 mm motor shaft and the other takes the 3/8" ballscrew end. I made a mandrel to hold the couplings while I cut the spring slots on the big bandsaw.
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The couplings will flex slightly to handle any slight misalignment in the motor mounts, while having no slip in the rotational movement.
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I see what you mean by "projects within a project". Very nice work so far. I caught the bug a while back and set a ridiculously low limit for my expenditures, thinking this would save me from myself. Ha! Fat chance. I'm in the process of converting my tiny Sherline. So, I'm following your progress anxiously. I love the couplers you made. Is there a specific number/size or rotation of the spring cuts? Also, I saw a warning at the beginning of Mach3 demo that said you must reboot before running the program. That may have caused the issues you experienced at first.
As a comparison, I went with the cheapest hardware I could find. We'll see how it fairs. So far, the seller has been very responsive and supportive on questions I have had.
Good luck and Happy New Year!
 
The cuts on the couplings are arranged in pairs cut from opposite sides. One pair is at 90[SUP]o[/SUP] to the other pair. The cuts stop about 1/4"short of coming out the other side.

My couplers are a fair bit larger than the commercially available ones, due to the 14 mm shafts on the oversized steppers I'm using. They are 1 1/2" long by about 1 1/4" diameter.
 
I've been locked out of the site for a week due to a technical glitch - mostly fixed now, thanks to Nelson and Tony. Time to add to the build record.

I got the ballscrews done. Each one required a different mount for the ballnut. An interesting exercise if you don't want to buy the pre-made kit.
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The X and Y motor mounts are finished. I decided to buid them up out of steel because I didn't have large enough blocks of aluminum and didn't want to risk casting in the winter weather.
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I cut and spliced the two way covers to make one long enough to do the back section. I'll have to make up something for the front part later. The light spring works to pull the cover up as the table moves to the back of the ways. Without it, the cover becomes pinched behind the table and blocks full movement.
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I added a pair of microswitches to use as homing limits so the computer can set the table to a consistent 0,0 position. Sorry about the poor focus.
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Since I extended the Y-axis about 2", I wanted to have the centre of travel close to the centre of the table. This required extending the spindle about 13/16" out from the column. I milled some aluminum to thickness on the Victoria and drilled it to take some 3/8" bolts in place of the original 8mm ones. I retrospect, I should have just milled the counterbores deeper and used the original bolts. It would have saved at least a day of shop time.
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While the head was off, I used the old plastic gear to mount the magnets for the MachTach tachometer sensor and mounted the Hall Effect sensor inside the head.
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Today, I finished the bracket to mount the Z-axis ballnut. It is mounted where the quill handle used to be, using a custom-fitted expanding shaft to take the majority of the force and a couple of screws into existing holes to hold position. The ballnut will bolt into the large hole in the end of the bracket back beside the column.
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So now you're up to date. More to come as it happens.

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Re: X2 CNC Conversion - It's Alive!

I got the Z-axis installation done today, as well as replacing the old spring support with a gas strut I've had for some time. I've run the three axes using the pendant. Smooth and quiet. I still need to build a tray for the keyboard and mouse, and move the 3-ton arbor press somewhere else.
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The MachTach is ready to go as soon as I get an enclosure built. I really should cut the display window on a CNC machine ... hmmm.

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I managed to get the homing function working last night. This morning I drew up a simple shape and ran it without any tooling, just to see how the mill moves. I had to retune the motors to get them to run smoothly, now that there's some resistance on the motors. I took a couple of videos, but this software doesn't support AVI files, that I can see.

I'm having a problem that will keep me from using the mill to cut anything. Rapid returns don't work. The table moves through all it's paces (I haven't measured yet to see if it's accurate.), but when it comes time to move to the start point, or to retract the bit on the Z-axis, it gives a quick twitch, but doesn't move very far. Then it goes on to the next operation. In this morning's test, the head ended up a few inches lower at the end than at the start. Guaranteed table crash.

Any ideas on what to tweak? I noticed this when the motors were sitting on the floor in my living room, but figured it could wait until the machine was finished. I guess I could try editing the G-code for normal (slower) feed rates on returns, but I'd rather have full functions.
 
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