guess its a 4 pole motor as they like to spin at 18000 rpm on 60hz

Is a standard 60Hz 120V AC outlet a "4 pole" motor? If so, then yes, it's 4-pole. I will not give the impression I understand AC motors, so I'd rather provide the information on the power supplied to it.

Well, let's start with how to properly calculate three pulleys as I believe this hasn't been answered. I do understand gears for the most part (or a pulley in this case) where a small drive pulley connected to a larger pulley slows down the speed whereas a large drive pulley turning a smaller one will move faster.

I've always dealt with two pulley systems like the gears on a bike. It was answered early on in this thread how to find the total number of speeds, but believe my thought on how to calculate the chuck speed on a three pulley system is still confusing me.

As mentioned, my thought process was: I need the speed of the idler to know the speed of the chuck. Therefore, if the motor is spinning at (rounding up) 1800RPMs, the idler is 3" in circumference, and the motor is 1" in circumference, it's simply 1800*(1/3) = 600RPMs.

Now if the chuck pulley is 4" in circumference, I divide the idler pulley size (now this belt would be on a different location since it can't share the same pulley) by the chuck pulley size. Let's say the idler is 2" in circumference, and the chuck pulley is 5" in circumference, then it's: 600*(2/5) = 240RPMs

Am I doing the math correctly or am I miscalculating (let's ignore belt pitch diameter for now until I grasp the concept of properly calculating speeds)?

If I'm doing the math correctly or not, does an easier method exist to run these calculations because each time I want to figure out one speed, I need to work through all the math again.

As for why I used an elastic band, this wasn't my initial method of measuring the speed. I used the normal setup, however, when I began questioning pitch diameter and stuff, I thought the best way to catch the surface of the pulleys without the thickness of the belt messing up things was to use elastics.

For the most part it seems the pulley was turning correctly and not slipping as the drill press is lubricated and spins quite freely, but I will not disagree, it's a crazy and not accurate way of performing a speed measurement.

The theory of the speed chart on the side of the drill press being wrong is a very good possibility. What I"d like to do is first learn the correct (and simplified) method of calculating the speeds, fix my Excel spreadsheet, and then be able to tinker with the "fudge" number factor along with maybe figuring out whether I can buy another off-the-shelf pulley that will give me middle speeds.