When maintenance becomes a rebuild

I’ve recently been toying with my cnc and some regular maintenance turned into some calibration checks that turned into some simple repairs that turned into rebuilding most of the gantry.

Three hours of messing around and I am here:

I’m starting to get a little obsessed with how good i can get this machine.

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Guess this isn’t a done project then :wink:

This project is my Jeep.

I like how it has become like any flat surface in a shop. Full of tools and other projects.

Those are active tools for the job at hand!

Most of the gantry is back together.

Next is finishing up rebuilding the z-axis.

Ive been systematically adding loctite to each bolt.

As it stands, I am measuring around 0.0008" of backlash in the x dimension which I don’t think I’m going to get much better.

The cnc’s x axis is entirely rebuilt now. I built some simple jigs to ensure that the rails go on straight and i paid a lot of attention to bolt patterns this time around. Hopefully this results in a better tram angle across the whole gantry this time around.

I just finished retesting the tram across the gantry. I measured an angle of 0.026 degrees on the left side and 0.078 degrees on the right.

This would be an error of about 0.001" on the left and 0.003" on a 2 inch deep cut.

By rebuilding the gantry I was able to cut my error in about half so I’m going to say it was worth it. I feel like I am at the point of rapidly diminishing returns and basically at the limit of what my measurement tools will allow for.

Im not even sure what this machine does with temperature fluctuations so I could be running into that as well.

I also ended up finding extra backlash in my z and y axis as well which I was able to correct.

Everything was rebuilt with loctite so it should be robust against vibration.

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For a tram test I flattened a slab of walnut shown in the picture next to another raw slab. It was super warped so I had to skim off a lot to get it flat. All said and done it came out awesome. It almost feels sanded.

The one circle spot is from a toolpath where the bit sat in the spot and rubbed a little. You cannot even feel it. A small amount of sanding will take care of that.

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