I took my main- and layshafts and stuck them in the lathe at work. I used the cone shaped fixtures in either end moved into the shafts tightly, and turned the shaft by hand, measuring run out with a 0.001 resolution dial indicator thru several revolutions to assure repeatability in magnitude and location (to prove to myself that the shaft wasn't wobbling.) The layshaft had < about 0.4 mils runout under 3rd gear. The mainshaft however, (under 2nd gear ) had 2 mils runout in the area toward the center of the shaft, and less as one moved to toward the end. Any thoughts on this data? This normal, or no good? I am no machinist, and I can go back and do this again tomorrow if this doesn't make sense. Or are there threads that already address this? I tried to search but did not find anything. One other thing, the rod that the selectors ride on was bent fairly badly, I could hardly get the selectors to slide over the whole length, so I got a new one (rod.) That is what made me put the shafts on the lathe, and the fact some one (Ludwig?) suggested a guy do that when rebuilding gearboxes just to be sure the items were ok.
Mainshaft runout
- Thread starter rwalker28
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- Oct 19, 2005
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The trans shafts I've bent were not bent like striking with a hammer or over a knee to leave one area off centered but more like a twisted candy cane to unwind trying to straighten again. Ken Canaga told me .002" crank run out is good enough to race on, if that applies to tranny shafts.
A few years back when I installed my primary belt I had noticed how the clutch wobbled somewhat when mainshaft was rotated. After pulling the shaft and checking with a dial indicator it was obviously a little curved (I do not remember how many thousandths). Using some hardwood blocks, a hydraulic press, and some patience I was able to get zero deflection on my dial indicator while rotating the shaft supported on "V" blocks, consequently the clutch spins nice and true now.
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