Trees - I know the tool you're talking about and I do have a source ... thanks. I was thinking of another tool that has prongs situated on a wheel (kinda like a pizza cutter) ... these are used for marking out holes to be punched but, for some reason, they never make them with less than 5 holes per inch.
DanTwoLakes - Thanks for the clarification. I guess there's no such thing a thicker thread, eh? They are all the same thickness ... it's just that some are heavier in weight ... correct?
Also, correct me if I'm wrong: Nylon is stronger than poly ... but poly has a better UV protection and I should use polyester thread rather than nylon?
You also said "They also make a topstitching thread that looks heavier." -- what do I ask for if I want to buy this one? And I gather this one should only be used for top-stitching or french-stitching, not for sewing seams - right?
I found what appears to be an elaborate sewing center in Princeton ... I'm going to go check it out Friday morning to pick up that Roller Foot and whatever else I can get my hands on.