Keying the Mainshaft

My motor has an output shaft of 1 1/8″ with a 1/4″ keyway. How do I mate that to the mainshaft with an OD of .920″ and no keyway? Well, I machined a collar to slip over the mainshaft with an OD of 1 1/8″. Then, I milled out a deep keyway, to make sure the key bites into the mainshaft and not just the collar.  Of course, this means I had to make an extra deep key to fit.  But, that’s not too hard.

I was impressed with how well everything fit together. It really looks like a professional job. *Pats self on back*  Thank goodness that I have access to a machine shop at work.  And while I’m baby-sitting the battery tests at 3am I can take my time and do my best work.  With this high speed rotational stuff, accuracy is very important.  A poorly aligned mainshaft can vibrate the car violently, even to the point of breaking something expensive.

While working on the shaft, I accidentally cracked a nylon gear that feeds the speedometer cable.  That part wasn’t available anymore from the usual Spitfire parts sources.  So, I bought a gear from a later model, and lathed it out so it will fit on my larger shaft.

The shaft coupler was over an inch too long, as well as being just a touch too wide at the end that is inside of the rear extension.  I lathed it down to fit, and the results were great.  I was really on a roll in the machine shop.

I tested everything on the motor, and it fit extremely well.  I hooked up the motor to a 12V battery and spun it up.  Everything was nice and true.  I was very pleased with the result to say the least.  Next I need to fit the bearing into the rear extension, and drill out the mounting holes in the adaptor plate.  I’m hoping to have the motor mounted in the car in a week or so!