Pressing the gear onto the input shaft

[GregT]

When the gearbox input shaft is rebuilt on many GS chain drive engines, a gear must be pressed onto the shaft.
The manual specifies a correct overall length for the gear train on this shaft - within .1 of a mm.
So how do you get it correct.

The gear takes a pretty good press to get on - several tons pressure - and does not bottom out against a shoulder.
So the press has to go just so far and no further.

So you either measure the exposed length of plain shaft before removing the gear - or if you missed this, you measure the parts and calculate how much plain shaft will be left exposed.

You then make up a limit stop piece, ID the same as the plain shaft OD and length the amount of plain shaft you want exposed. Made up in steel of a reasonable OD as you will then use this to push the gear on. With this in place you press until the shaft end is flush with the end of your limit stop piece - it can't go any further as the end of the press will be bigger than the shaft.

In my latest job, an 1150 gearbox - the exposed end of plain shaft needed was 17mm exactly. I found on old ballrace that was 17.0mm wide and slipped onto the plain shaft nicely. Used this to push the gear on until the shaft bottomed against the press end. Done.

[Guest]

Nice tip Greg! Had a mate of a mate press the Kat's second gear on and none of us thought of doing that, it was press, measure, press, measure, press, measure until it was right.

[TeamDar]

Actually, you press 2nd gear onto the input shaft. Dar

[GregT]

Actually, you press 2nd gear onto the input shaft. Dar

Correct. My error. I need a mod to change the title. thanks for pointing it out. Thanks Don for the change too.
I plead advancing senility.

Pete - The press I have access to is a large power operated one - with no sensitivity. Without a limit stop I'd never have got it right.

[Guest]

Ah ok yeah that's awkward Greg! This was a hand operated hydraulic press, so definitely a little easier to work with in this instance. The smartest decision we made was for me not to operate it myself

[GregT]

Ah ok yeah that's awkward Greg! This was a hand operated hydraulic press, so definitely a little easier to work with in this instance. The smartest decision we made was for me not to operate it myself

Local engineering co lets me use theirs - in violation of OSH rules. The deal is that if I hurt myself, they found me on the road outside....I can live with that, LOL.

[Guest]

Sounds like a fair deal to me