Another slight difficulty in my plan for attaching the ball-nut to the saddle is the fact that the saddle casting has no machined surface to bolt to on the side! There was just no way I could machine this surface myself with the temporary el-cheapo X-Y table. So this calls for some slightly louche behavior.
First I have to get the screw exactly parallel to the table before attaching the ball-nut mounting plate. This image shows the setup for truing against the front edge. I also do the same from the top surface.
Here is where the mounting plate has to go. The bolt holes are the same that held the Y gib locks; preferable to making new ones. I've cleaned off the paint with a steel brush and filed down the worst of the casting mess leaving the rough surface that is more or less square to everything else. Then the louche sauce: West System 105/207 epoxy with 403 microfiber filler. There are better alternatives to the filler, such as stone dust or steel filings, but all I'm trying to do is provide a flat and perfectly perpendicular skim coat exactly level with the peaks of the casting. The bolts that hold the mounting plate in place should ensure that the epoxy is under permanent compression, so I suspect that flex will not be an issue.
Tape on the screw to catch any spills.
A clamp is used to push the ball nut up against the saddle with the epoxy in place.
First I have to get the screw exactly parallel to the table before attaching the ball-nut mounting plate. This image shows the setup for truing against the front edge. I also do the same from the top surface.
Here is where the mounting plate has to go. The bolt holes are the same that held the Y gib locks; preferable to making new ones. I've cleaned off the paint with a steel brush and filed down the worst of the casting mess leaving the rough surface that is more or less square to everything else. Then the louche sauce: West System 105/207 epoxy with 403 microfiber filler. There are better alternatives to the filler, such as stone dust or steel filings, but all I'm trying to do is provide a flat and perfectly perpendicular skim coat exactly level with the peaks of the casting. The bolts that hold the mounting plate in place should ensure that the epoxy is under permanent compression, so I suspect that flex will not be an issue.
Tape on the screw to catch any spills.
A clamp is used to push the ball nut up against the saddle with the epoxy in place.
The bolts, also covered with tape are just hand tightened.
24 hours later. Not bad, but I think I need to have another go to fill in the middle section. The little light blue spots are remnants of blue-tack - the stuff used to hold up posters - that I used to fill the threaded holes in the mounting plate.
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