dusty wrote:Contrary to my longtime assumptions, the bench tubes are not parallel to the way tubes. I don't know if this is by design or if my two machines are screwed up.
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I don't know if you ever got to the bottom of this Dusty, but mine aren't either. And I have a hunch I know why in my case.
After disassembling and reassembling the base tonight I noticed something that I had not noticed before: my bench tubes do not sit perfectly centered vertically within the holes in the base arm casting but do sit centered vertically within the holes in the headrest casting.
After examining the situation, the only thing I can surmise is that the internal ribbing in the base arm and headrest against which the bench tubes are pushed by the tube clamps are of different heights relative to the holes that bench tubes pass through, with the base arm ribbing less tall than the ribbing in the headrest. Thus, when the bench tubes are fully inserted in the base arm and the clamp tightened, the bench tubes are forced by the clamp upward against these ribs almost to the top of the holes in the base arm casting. The result is the bench tubes will never be centered vertically within the holes in my base arm casting (absent shimming between the tubes and the ribs in the base arm).
In contrast, the internal ribbing of the headrest appears to be somewhat taller than the ribs in the base arm. In the case of the headrest, when the bench tubes are inserted and the clamp tightened, the bench tubes are also forced upward but due to the height of the ribs, the bench tubes are left centered vertically in the hole of the headrest casting.
If am right, and assuming the bottoms of both casting sit on the same plane, the bench tubes will always be on a slight slope (higher at the base arm end) and thus closer to the way tubes (at the base arm end) assuming that the bench tubes are level.
I suspect the double tilt upgrade, by using two identical castings, eliminates this issue.
