DIY Double Tilt Base Experiment
Posted: Sun Dec 11, 2022 1:04 pm
Part 1: Not all castings are alike
While swapping parts between 2 PowerPro headstocks to isolate a problem, and moving the conventional headstock from my 510 machine to the sanding shorty at the same time, I ran out of machines ready to use. An extra shorty just for working on headstocks seemed like something useful to have around in general and something that would help immediately under the those circumstances. One of the PowerPro headstocks was mounted on a double tilt base that made it much easier to assemble and reassemble because the headstock could be oriented either way vertically in addition to horizontal mode. So I thought I could easily assemble a shorty just for working on headstocks, and it would be an added bonus if it had double tilt also. So I dredged up an old idea to make a shorty with 2 right side base castings that could tilt either way.
The plan was simple, assemble a machine using 2 right side hinged base castings facing each other. Nothing fancy in the process, to tilt the way tubes in either direction required knock the hinge pins out of one of the castings so I removed the roll pins holding those hinge pins in.
I dragged out 2 right side hinged bases, a set of legs with half decent casters, 1 bench tube and 1 way tube. To make it a shorty I was going to cut both of those tubes in half. I knew the cut way tubes would be too short to fit all the way into the castings. The way tubes come out short on the official product also so I planned to adjust the length later on so they would fit tight, although that wasn't absolutely necessary.
This looked like a half day of work to do, so I thought I might get it done if I worked a whole weekend on it.
First step, cut the tubes. Got done without a problem.
Next step was remove the roll pins holding in the hinge pins in the two bases. Immediately nervous because the roll pin in my drill press base is jammed in the hinge pin. But this time I remembered to get some penetrating oil on the roll pins first and they came right out.
Seems like I was cruising toward success until I put it all together. Turns out not all base castings are equal. I fit all the pieces together to see what I had. What I had were base castings that didn't line up with each other. I could barely assemble the way tubes into the castings once the bench tubes were in place. Full length tubes have a little flexibility that allow them to account for a very minor misalignment, which is still not a good thing, but I don't know how those castings could have worked on a full length machine either, everything was off by too much. I don't know what beat up machines the castings came from but either or both may have come from machines that were in parts when I got hold of them. I checked the tubes for straightness also. I would expect most used Shopsmith way tubes have a slight bend in the middle from the weight of the headstock and/or table bearing down over time. There was such a slight bend, but not enough to matter, certainly not enough to cure by rotating the tubes.
Loosening the bench and way tubes to allow some flexibility I managed to close it all up and mount a headstock on the way tubes, but the headstock wouldn't slide because the tubes were so misaligned. After checking for bent way tubes and all other issues I determined one of the base castings just didn't hold the way tubes in the right position, they just weren't parallel with the bench tubes mounted in that casting. It looks like the front way tube socket was not bored straight, and the other side wasn't perfect either. Photos below show the hole bored off-center and one bored straight. The shiny circle where the bore has bottomed out is clearly non-circular in the problem casting. The part must have been mounted off center when the casting way tube holes were bored.
So back to the pile of parts, carefully organized in totally random order, and found another right side base casting. Putting it all together again with a good casting was a breeze, but I had already spent the weekend with repeated assembly and disassembly to find what was wrong.
While swapping parts between 2 PowerPro headstocks to isolate a problem, and moving the conventional headstock from my 510 machine to the sanding shorty at the same time, I ran out of machines ready to use. An extra shorty just for working on headstocks seemed like something useful to have around in general and something that would help immediately under the those circumstances. One of the PowerPro headstocks was mounted on a double tilt base that made it much easier to assemble and reassemble because the headstock could be oriented either way vertically in addition to horizontal mode. So I thought I could easily assemble a shorty just for working on headstocks, and it would be an added bonus if it had double tilt also. So I dredged up an old idea to make a shorty with 2 right side base castings that could tilt either way.
The plan was simple, assemble a machine using 2 right side hinged base castings facing each other. Nothing fancy in the process, to tilt the way tubes in either direction required knock the hinge pins out of one of the castings so I removed the roll pins holding those hinge pins in.
I dragged out 2 right side hinged bases, a set of legs with half decent casters, 1 bench tube and 1 way tube. To make it a shorty I was going to cut both of those tubes in half. I knew the cut way tubes would be too short to fit all the way into the castings. The way tubes come out short on the official product also so I planned to adjust the length later on so they would fit tight, although that wasn't absolutely necessary.
This looked like a half day of work to do, so I thought I might get it done if I worked a whole weekend on it.
First step, cut the tubes. Got done without a problem.
Next step was remove the roll pins holding in the hinge pins in the two bases. Immediately nervous because the roll pin in my drill press base is jammed in the hinge pin. But this time I remembered to get some penetrating oil on the roll pins first and they came right out.
Seems like I was cruising toward success until I put it all together. Turns out not all base castings are equal. I fit all the pieces together to see what I had. What I had were base castings that didn't line up with each other. I could barely assemble the way tubes into the castings once the bench tubes were in place. Full length tubes have a little flexibility that allow them to account for a very minor misalignment, which is still not a good thing, but I don't know how those castings could have worked on a full length machine either, everything was off by too much. I don't know what beat up machines the castings came from but either or both may have come from machines that were in parts when I got hold of them. I checked the tubes for straightness also. I would expect most used Shopsmith way tubes have a slight bend in the middle from the weight of the headstock and/or table bearing down over time. There was such a slight bend, but not enough to matter, certainly not enough to cure by rotating the tubes.
Loosening the bench and way tubes to allow some flexibility I managed to close it all up and mount a headstock on the way tubes, but the headstock wouldn't slide because the tubes were so misaligned. After checking for bent way tubes and all other issues I determined one of the base castings just didn't hold the way tubes in the right position, they just weren't parallel with the bench tubes mounted in that casting. It looks like the front way tube socket was not bored straight, and the other side wasn't perfect either. Photos below show the hole bored off-center and one bored straight. The shiny circle where the bore has bottomed out is clearly non-circular in the problem casting. The part must have been mounted off center when the casting way tube holes were bored.
So back to the pile of parts, carefully organized in totally random order, and found another right side base casting. Putting it all together again with a good casting was a breeze, but I had already spent the weekend with repeated assembly and disassembly to find what was wrong.