By gholbrook on 4/7/2010 8:46 PM

I had today to myself in the ye olde shoppe, so I decided to work on some CNC projects.  One of the projects that has been stalled for quite a while is the creation of a tool plate for my X3 mill.  For this project I purchased a 3/4” thick piece of aluminum.  The idea behind the thickness was that I could anchor the edges with short screws so that no part of the fasteners holding the plate to the table would poke out above the top of the plate.  Interesting idea, but probably not work the effort.  First, it’s really really annoying to try cutting that size chunk of material.

While trimming the material, I broke one bandsaw blade and two 1/8” endmills.  First I tried the bandsaw, but I got too eager and broke the blade.  It seemed like a good plan to try my mill instead.  That worked fine until the endmill made it to a depth of about 1/3”, at which time the cutter was unable to evacuate chips.  After two broken cutters, and a failed attempt with a jigsaw, I put a new blade on the bandsaw and took my time...

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By gholbrook on 3/26/2010 4:04 PM

In the fall of 2009 I had this brilliant idea.  I wanted to be able to CNC cut aluminum without damaging my machine.  Since my machine at the time was a MaxNC, making cuts in aluminum or mild steel was simply out of the question.  It could be done, but it couldn’t be done well.  That’s when I got the bright idea to buy an X3 and a conversion kit from CNC Fusion.

When I bought the kit, I had no idea how ballscrews work.  I didn’t even know what a ball nut was, and I certainly had no idea how to repack one of them.  Seven months later I have learned all of these things and a good deal more.

After taking my mill apart and putting it together about a dozen times, everything finally seems to be in good working order.  The machine is completely reassembled, and my workshop is slowly getting organized again.  In the picture below you can see my X3, and a small MaxNC on the other side of it.  The CNC controller for the X3 is wall mounted behind it.

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By gholbrook on 3/14/2010 10:18 PM

Recently our office formed a soccer team.  I’ve never played soccer but I joined anyway.  So far it’s been a lot of fun, but it started reminding me of the hockey team I played on last summer.  We had fun, but scored very few goals.  In our first soccer game we didn’t score at all.  In our second game we still lost, but we scored twice.  To be precise, one of us scored twice.  She was the hero of the day, all the more because she isn’t a regular player.  I decided that Mo deserved to gloat a bit, but in order to gloat…you need a good conversation starter.  Like, a trophy!  It would be really great if...

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By gholbrook on 2/14/2010 7:01 PM

I’m waiting for the parts to break in (I may need to polish the ends of the screws where they meet the helical couplers), but the preliminary results are in. After fashioning some parts and putting the X axis on my retrofitted mill back together, the results are quite a bit better than they were initially. I’ve now got double ballnuts on the X axis, along with zero backlash helical couplers.

1/1000 of backlash on the X axis. I don’t actually have the helical coupler screwed in because the initial fit was so tight, so it is possible that it’s causing a wee bit of slip (I doubt it though). 1/1000 is way better than the initial 7.5/1000 that I was getting before though. Later this week I will write a CNC program to run the axis back and forth a couple hundred times…then I’ll recheck the thrust bearings and measure backlash again.

By gholbrook on 1/6/2010 10:22 PM

After a couple month hiatus, I’ve finally returned to working on my mill.  About two months ago I tested the backlash and was sorely disappointed.  Both X and Y axes were in relatively poor shape.  I got back in touch with the company that I ordered the original parts from and ordered extra ball nuts for the X and Z axes and oversized balls for the Y axis.  Along with the balls and nuts, I also ordered HeliCal couplers (zero backlash) and new, higher quality thrust bearings.

So, I got started the other night.  Yet again, I found myself carefully repacking ball bearings one at a time.  There were actually extra balls in the kit, which is good, since I have a demonstrated ability at losing balls.  When I started packing the balls I actually said to myself “I should do this sitting at a table, with my magnetic bowl.”  Of course, that isn’t what I did.  And I lost a ball as a result.



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By gholbrook on 9/25/2009 11:23 PM

First, fun stuff.  I cut this on my smaller mill.  In the end, the top was pink with black lettering.  The best way that I found to paint it was by machining it first, then priming it liberally.  After the primer dried, I liberally dabbed black ink into the lettering (at .1” depth) and sponged the excess paint from the top.  After the paint dried, I used a roller to roll a couple coats of pink over the top.  I wasn’t smart enough to take a picture of the final plaque, but it turned out really well.  It’s about 6” wide, and I cut it with a 1/16 endmill.  The material is oak, although pine seemed to work just as well.



The big excitement for me...

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By gholbrook on 9/22/2009 5:59 AM

Ok, I’ve been anxious not to stall on this project.  Momentum is key!  Over the weekend I got all three axis wired up, and I put the electronics in this neat enclosure.  Notice the monster heat sink, and the cooling fan.



Last night I finally finished rudimentary software tuning.  When I told the Z axis to move 1”, it did so.  Since X and Y are configured the same, I could hardly just stop there.  All three motors seemed pretty happy, so I decided to try cutting something really simple.







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By gholbrook on 9/15/2009 9:08 PM

This evening I had only a few spare moments, so I raced downstairs and plugged in my soldering iron.  Within a minute or so the tip was hot enough to melt solder, and I tinned the ends of the stepper wire that I soldered to the Y axis motor last night.  With the motor attached to the table, and the table back on the mill, I was eager to see how it would do!







So, the motor did just fine.  I should be able to run it at 3 amps, but the driver started getting uncomfortably hot.  No big deal.  I dialed down the power a bit and ran through the paces.  In and out fast, then slow.  I ran the table all the way to the column, then all the...

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By gholbrook on 9/13/2009 10:07 PM

In an earlier post, I briefly discussed building the Hobby CNC driver board.  In the following photo, you can see the board on my bench while I test it with the power supply and tune in the vref for current control.



By some fluke, the entire kit ‘n kaboodle worked on the very first try!  Now, Monstro The Stepper is NOT a fast motor.  My initial attempt to run it at a reasonable speed failed quite conclusively.  At very low speeds, it does just peachy.  While testing, I noted that the stepper driver got very warm.  When I came back and did some testing later I used a clothesline clip to fasten a piece of aluminum to the driver.  You can see it in the...

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By gholbrook on 9/12/2009 10:25 PM

This evening while Aimee was making fidgets this evening, I took the time to assemble my Hobby CNC Pro 4 Axis control board.  This board comes as an olde tyme electronic kit.  It’s a circuit board and a bag with about 80 parts in it.  The rest is up to the person doing the assembly.



You might be thinking something to the effect of “Let me get this straight, you have dumped an absurd amount of money into this project, but then you skimp on the driver board?”  Well, yes, and no.  Some of the other drivers\controllers are very nice.  Gecko comes to mind.  Gecko is also very expensive.  Instead of paying $80, I would have paid $700...

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