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We can rebuild it...

Posted by qwindelzorf on March 12, 2012

A while back I bought a house. Obviously, that entails moving.  Specifically, moving this beast of a machine. 

That was an adventure in its own right. But all the parts made the move and have been sitting on the floor in my shop (I have a shop!) for the last several months.  I've finally gotten around to the reassembly process.

Previously this whole thing was built atop a wooden table.  At the time of construction, that seemed like a great idea.  In retrospect, not so much.  I was confident that I could overbuild the wooden table to such an extent that it would withstand the ravages of an 80lb gantry slamming back and forth.  Over time, the table top began to warp and bend, and eventually started to slide down the legs.  Which was intriguing, given the number of screws and the amount of glue that were used to join the two.  Needless to say, all these failings drastically reduced the system's accuracy, in turn necessitating constant recalibration.  It was far from an ideal configuration.

So, when I moved, I elected to ditch the wooden table, and instead build up a steel "table" to replace it.  As designed, it was not really a "table" as such, since it was without a top, which is really kind of a defining characteristic of all tables.  The plan was to build something along these lines:

table_render.png

So, just after Thanksgiving I went to my local supplier and bought $700 worth of steel.  A few weeks later, I got a call telling me that my order had arrived, and I needed to come get it.  I arrive at their facility, and discover that they had ordered the steel in the full 25-foot lengths that it comes to them from the factory, rather than the 8-foot lengths I had been expecting.  So, after some creative engineering and entirely too many ratchet-straps, I had all the steel affixed to my truck and precariously rolling down the road to my house.  

I was unable to return to the project for several weeks, but in January, I and a friend got serious about completing this project.  So, we spent a saturday cutting all the steel in preparation for assembly.

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After mutch cutting, and lots of sparks, and surprisingly few fires, this was the result.  All the parts (theoretically) required to build my table.

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Then began the task of welding it all together.  Sounds simple enough...

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... Except for one critical flaw.  This was all welded up with my little MIG welder.  The emphasis there should be on the word little. It runs off a normal 110v 15A circuit.  The steel here is 3/16 thick.  It just doesn't have the juice to put down a durable weld.  Immediately after that picture was taken, I flipped the frame to weld the other side, at which point the whole thing promptly fell apart.  I would be needing a bigger welder to make this work right.

Enter my father, who is a professional gas pipeline welder.  He has several welders just setting around.  And he was conveniently scheduled to come out for a visit at the end of January.  So, I called him up and he agreed to bring out a more powerful unit.

I don't have pictures of the rest of the welding.  We got wrapped up in the process and got the whole table structure built in a Saturday.  At that point, we patted ourselves on the back, my father went back home, and I took a couple weeks off this project.  

I came back around to this in late February, with intentions to paint the structure before reassembly.  So, I got a couple friends together one Saturday morning and we all went at it with brushes and some red Rustoleum.  We then left it to dry for a week.

This weekend, I and my compatriots began reassembling the gantry on th enew base.  Here are the results:

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As it stands now, all three axes move and the system is operable.  The limit switches need to be reconnected, and the router needs to be installed, but it is almost ready to go.  Hopefully, next weekend, I can build a new, slightly less disreputable box to house the control electronics.  I also intend to put a swivel arm on one of the corners to hold the keyboard and monitor.  We'll see how those plans pan out.