1. You can heat the balaner up in a oven to about 200+ degrees.
2. Have the proper tool ready to press on.YOU CAN RENT FROM AUTO ZONE.
or buy one for $25.00 from most parts stores.
Put anti-seaze on the crank shaft.before installation.
Then press on.
To help even more you can freeze the crank by turning a propane tank upsidedown with a hose on the tank.And spray the crankshaft to freeze.
It will just take maybe 30 seconds to freeze crank.
The balancer will press right on with the proper tool.
Like David N said you must keep a interference fit.I don't know if the machine shop would loan you a caliper or a micrometer either will work just fine for you to measure your cranks OD.If you do not know how to read either tool.They both have thumb locking screws to lock the measurement you made down.Then take the tool back to the machine shop,and they will read it for you.They may not loan you a mic or caliper, good ones are not cheap.
Hope this helps RANDY
RANDY