So spring is around the corner and the plan is to build an air compressor any one with experience or knowledge please share

What have is a rolair wheel barrel style compressor motor a 1.5 hp 1725 rpm 115v 15amps

what im planing on getting is the harbor freight air 3hp pump rated 1050 rpm 10.5 cfm at 90 psi
aslo a 30 gallon tank of craiglist

If I did the cacluation correct with a 7 and 1/4 inch pulley on the motor i can spin the pump at 1042 rpm
The question is did i do the math right ?

What do you plan to use this compressor for?

I Want to use this strictly for painting my gun is an lvlp gun 5-6 psi at 30 psi also iwata air gunsa 10 cfm at 30 psi

Last summer I painted with a gas style compressor and that was just to loud I try to paint during night or early morning when the neighborhood isn't really gonna notice.

It might work but the motor may be too small to get the CFM out of the pump as rated.

Who would know more I thinking about calling grainger or what's that placed called

You may be better off trying to find a used compressor that will handle the job. You could spend a lot of money trying to build something only to have it be a disappointment when you try to use it.

Yeah I understand where your coming with that.
Another option is I have a dryer that runs off 220v in my basement the problem is the house is above the garage so I don't wanna stink up the house