-My background is electronics - I am pretty green when it comes to mechanical work.

I just bought two ENCO 1/2" ball bearing pillow blocks and plan to run a 1/2" ACME threaded rod supported by them. A quick look shows the bearings to be cocked in the block - I assume this is because they are self aligning, but they are tight. The rod will not fit in the inner race without pressing..

Do I heat the race to get the 1/2" rod inside it and do I force the bearings to align? Sorry for the dumb questions - but I gotta learn.

check the size of the screw compared to the bearing , if you are within a couple tenths then it should be fine to fit , rather than press fit , if you have an old deep fryer , throw the bearing in there to heat it up , and the bearing should slide on nicely
, you don t want too tight of a fit or the bearing won t turn

Pack the shaft in ice.

Heat the pillow block with a heat lamp or bright spotlight.

If the interference is REASONABLE (measure to see how much press you have), they might slip together.

If the interference at room temp is more than 0.0005" you might want to sand the shaft down.

You REALLY should take the time to do some research into fitting shafts to bearings.

This link will help:

http://www.jp.nsk.com/app01/en/catalog/index.cgi?ec=bearings

Get the NSK E1102 catalog for starters

Deep frying a bearing can screw up sealed bearings or melt out the grease. Freeze and heat from spot lite should work fine.