Nothing is as simple as it would first appear. Even a spline has issues, the one you mention presumably assures a good radial fit. however, i was intending to tig the gear to the shaft (just a small tack) to stop it moving along. If the spline isnt a tight rotational fit it's likely the weld...
No i'm sure the original maker of the gearbox wouldnt recommend using 2nd gear where 1st used to be.
I'm warming to the idea of splining the shaft, it was my first choice way back, however the diameter of the gear that has to be removed is near a damnit the same as the bearing surface next to it...
Yes, the secondary shaft gear is from a lower ratio box, its splined and just slips off, the synchro teeth line up, the baulk ring fits. The mainshaft gear (primary shaft if you want) is the one i'll be cutting off the mainshaft of that same gearbox. So i'm pinching a pair of lower ratio gears...
i looked into a new mainshaft, but the gears would have to be helically cut to match the secondary shaft, which makes it difficult, and more specialised.
I have considered building up the shaft with weld and getting a spline cut into it, with a matching spline in the gear. Maybe the best option...
Thank you both for answering, to answer both your replies in turn, and explain some of my assumptions:-
The original gears were machined from the shaft for cost reasons, and 1st couldnt be anything else sice it is barely bigger than the shaft at its root.
I don't believe there to be an issue...
I've copied this from my original post in the metallurgy forum, since it overlaaps both, with a little luck someone with some experience will have an idea. I'm not after a 50,000 mile fix, if it coveres 500 in the rest of its lifetime it will be a miracle...
My question relates to removing...
My question relates to removing (through grinding) 1st gear on a mainshaft, removing a 2nd gear with a lower ration from another gearbox, and welding it onto the original shaft.
I had originally hoped I could do this by tig welding, cooling, repeat. This would have avoided annealing shaft and...