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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By gholbrook on 9/11/2009 7:51 PM

This afternoon I finished piecing the Z axis together.  It still needs screws and  tightening, but I wanted to get the motor test fitted first.  You can see the motor mount at the bottom of the above picture.  There was just one itty bitty problem with Bertha, my Z axis motor.

Bertha is the largest NEMA 34 ever captured in the wild.  She was brought down as she savagely plundered the African plains.  At 650 in. oz. of holding torque…the motor is quite large.

 



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By gholbrook on 9/11/2009 10:05 AM

I was really sick yesterday and only got out of bed for an appointment.  Thank goodness my wife is very understanding!  This morning, I felt much better and decided to make some progress and write an update.

At first I was going to try working on the Z axis without removing the head of the machine, but the more I thought about it, the more I realized that I wasn’t being practical.  The head is really heavy, and trying to get the machine put back together with the head on would be a headache.  With the head removed, I removed the four screws holding the lead screw in the back of the machine and the eight...

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By gholbrook on 9/9/2009 11:19 PM

When last we heard from our hero, I, er, he was bellyaching about his lousy day…

First thing this morning, I awoke to find an email from CNC Fusion (where I bought the kit) explaining how to repack the errant bearings for the ballscrew.  That’s a good thing, because the other advice I found was quite involved.  Despite their lack of formal documentation, CNC fusion has done a good job responding to my questions.

Whilst actually following their advice, I ran into the inescapable truth.  My workshop was a mess.  From the time that the new mill arrived until today (it’s been about three weeks), I have never gotten things organized.  One of the ball bearings bounced off the bench and into oblivion.  I could no longer call my workshop anything other than a “sty”…so most of today was spent finishing my newest bench, taking out the trash, and getting things back in order.  It isn’t finished, but it’s definitely much, much closer.  The...

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By gholbrook on 9/8/2009 7:55 PM

We planned on taking all of last week for a family vacation, but we didn’t end up leaving town until Wednesday night.  Since work has been particularly draining lately, I decided to take this week off and spend some time in the Secret Laboratory (TM).  There are a number of projects that I want to work on, but the first one is getting my new mill converted to CNC.

The kit that I purchased (from CNC Fusion) comes with ball screws as well as the applicable motor mounts.  The kit does not come with instructions.  Since I can only work on the mill at odd intervals, I found it in this state this morning.  The X and Y...

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