[fox46]

If you don't have a shop press, you can make your own using a hydraulic bottle jack like this one: http://www.princessauto.com/pal/prod...on-Bottle-Jack. (Maybe a mentor has one at home or will let you use one from a spare tire kit in a car. - Toyota trucks have awesome little bottle jacks although they are mechanical and not hydraulic, they will work as well).

Simply make a frame out of some beefy steel and place the bottle jack inside. When you actuate the jack you can press things together between the jack and the frame of your home-made press. A 6-10 Ton bottle jack can be found at places like Harbour Freight (USA)/Princess Auto (CAN) for about $20-$30, (I bought a couple 20 Ton ones on sale for $19.99) and some heavy scrap steel can be used to make an excellent frame

If a bottle jack isn't for you however, you can try the following. I don't like using hammers because they can often mushroom and distort metal shafts and gears. If you have a good-size vice it will work well but getting everything aligned can be trickky. Place the motor and pinion in the vice with the pinion aligned with the shaft. Make sure you are pressing between the pinion gear and the motor's shaft that pokes out the back of the case, not the back of the motor or the contacts. Make sure the vice is a good quality unit with square jaws and will not start to skew once you begin to apply force. use the jaws of the vice to press the pinion onto the shaft while carefully observing the alignment of everything. Make sure things don't start to bend or skew and realign if needed. be observant of how far the pinion has been pushed onto the shaft as when the pinion has made it all the way onto the shaft you will be essentially be squeezing just the shaft of the motor and it will certainly bend if you keep applying force. If you have to press the pinion further onto the shaft, use an object like a washer or nut as a spacer to apply force to the pinion while letting the shaft poke out the end. I personally don't like using heat to install things like this because the heat makes the metal more malleable and easier to bend/distort. With a press-fit, heating the item too much can cause it to deform permanently while pressing it on thus reducing the effectiveness of your interferance fit. The retaining compound is good because it will help act as a lubricant while the parts are being pressed together and will lock up when you stop. Make sure you buy several motors and pinions as replacements and install the pinions and any backing plates on your spares before the competition. You don't want to have to muck around with limited tools and time, pressing pinions onto motors when you are rushing to get your machine back on the playing field.

Good Luck