I found in the drawings/XAxis folder all sorts of drawings and photos I had done a few years ago. Working with ordering parts from AliExpress for the Robot Arm I realized I should get after getting ball screws. The thing that put that project #42 on hold was not knowing whether to use a 16mm, 20mm or replacement 2505 sized ball screw to replace the 1" ACME 0.2" pitch screw.
I had a photo of the screw nut and where it went when I had the table off a few years ago.
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But I really couldn't tell from those pictures whether the much larger ball nut and holder would fit. So first step is remove the RH side plate, wind the lead screw all the way over so the edge of the table lined up with the frame section in the photo above. Dangled a square over to measure to the screw center line.
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Well lots of measurements. Sketches, then CAD drawings and finally taking the original ACME screw and nut assembly drawing I did in 2017 and adding it to the two parts I drew today.
Here's a perspective view.
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So similar end view with the ACME screw centered on the X axis.
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Looks like there will be plenty of room for a larger ball nut holder. Why not just go with a 16mm screw? Well the pulleys and bearings and spacers etc are all sized for the current 1" ACME screw. The cost of a 25mm over a16mm isn't that high and the rounded ends then match all my bearings and the pulley.
All I need to do is cast new end plates with the hub in line with the new ball screw center line. Easy to do since it was a two part pattern. Just move the hole up and use some wax to plug the old one.
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All for now. Time to download the 1" double ball nut step file and model it with the parts done here.