Mainshaft gear separate from main shaft A10

[Sluggo]

Trevor, reread what I wrote,,, you quoted 2 very important dimensions first at the 4 decimal point which I can change by holding in my hand or breathing hard on it,,, and then the 3rd decimal point which requires a bit more heat.

Secondly then you talk about alloys, Are you talking alloy castings or gears and shafts made out of steel?    The method I describe was a method for gears and shafts I was shown in Aviation school with FAA approved tech materials and using a Cessna service center tool, I can assure you thats a time proven method with extensive scrutiny.  I summarized the technique as applied to a motorcycle part, and generally a hydraulic press would be sufficient, but I was trying to illustrate what heating and cooling techniques can do.

I *THOUGHT* I was competent with a Micrometer and worked in Aerospace as well as vehicle fleet maintenance for over a decade when I went back and took some more classes to get my federal Aviation license.  In one of the classes one of our instructors *RETAUGHT* us proper use of a caliper and micrometer.  Despite working for some of the biggest names in aerospace I learned I was using Micrometers wrong.  In which case there is a LOT of people reading them wrong.  But ol' Harold taught us a valuable lesson.  One of which is how even a little bit of heat can change dimensions.   The lesson was Mic'ing a crankshaft journal and a rod bolt.  Then we had to hold the parts in our hands during part of the lecture.  After 5 minutes we had to remeasure.  I would suggest you or anyone else try it with a Micrometer (with up to 3 decimal point measurements  IE:   0.000) you will find a surprising difference in measurements.

Now the same lesson with a caliper going to 4 decimal point.  Most modern digitals are 0-5-0 for the 4th point but some can actually read 1-9.   I can breathe heavily on a part and change that 4th point.

Now, do the same measurements with gears, bearings or shafts with one part in the freezer for 10 min and the other in a oven at 250 deg F/121.11 C and again check dimensional changes ID & OD.  I am certain you will find the measurable differences remarkable.  Its worked very well for me over the years.

[peter]

Hi,
before I forgot to mention, I dismantled all parts without warming, in the assembly I warmed the Layshaft gear, but only little, about 120° Celsius, the Layshaft I cooled in the refrigerator about 4° Celsius then under my press all slippt in without problems.

regards Peter


 

[Sluggo]

Peter, that should do it,  You just forgot to mention one thing (Assuming there is a spouse here) Is unless your workshop is very well appointed is do this when the MRs is not at home and always clean up the evidence.
I often will open some potporri, light some incense or put some vanilla extract on some tin foil in the oven afterwards.

Installing bearings in engine cases is often quite fragrant.  I used patchouli oil and my wife came home and accused me of killing some hippy chicks.  Wanted to know why the house smelled so strong.

[Greybeard]

I had an old Land Rover that had its parking brake drum just behind the gearbox. Gear oil would leak onto the shoes. I would wash the shoes in petrol, dry them off and finish by baking the shoes in the oven. A bit smelly!