Compass Oil

The compass has a very small fill hole, so I decided to use a syringe to insert the oil. The compass holds 66 oz., so this turned out to be a tedious procedure. It took me about an hour last night to fill it up.

A friend told me that I could use any type of odorless mineral oil for this purpose, and not to bother buying expensive "compass" oil. I went to the grocery store and found some in the first aid section. "For intestinal use" it said on the bottle. (Someday I'll have to investigate what the medical condition is that requires such a use.) One thing that I noticed right away is that the new oil is more viscous than the oil that came out of the compass. I didn't think that would matter too much.

After filling, I noticed that the compass is almost unresponsive to rotation. It takes forever for the card to respond to a 90 degree turn. So long in fact that I got tired of watching it and came back this morning to see if it had found north. It had. Anyway, my conclusion is that viscosity matters a lot. I'll have to see if I can find some thinner oil at the drug store or hardware store. If not, I'll be buying some of that "special" compass oil from the compass manufacturer.