Do Canadian Tire or Princess Auto even sell 6-48, 8-40 taps and corresponding numbered drills?
Think this is from Brownells Gunsmiths Kinks. Sooner or later, you are going to break a tap in a hole. Seems to be usually in a blind hole, but not necessarily. If it comes to it, a high carbon steel tap can be broken with a punch, to get the pieces out. High speed steel on the other hand, is very tough, and won't shatter. Harder to remove. Broken tap extractors might or might to work, and there are two three and four flute taps, and you would need one for each type. Sharp, high quality taps are a sound investment. There are shops that use a new tap for every customer's job. A tap is cheap, compared with the time and effort of removing a broken tap.
Also, use a good cutting fluid.
Crappy Tire most certainly does NOT sell those sizes.
CanadianBacon', I'm afraid for you that this is one of those "in for a penny, in for a pound" sort of deals. You simply cannot do the work you want to do without the drill press and good taps and drills. And that means a number set. And you WILL want to buy the taps from Brownells.
The pilot holes for these extra fine thread sizes is so important that the wiggle you can get with a hand drill is often enough to be the difference between a good thread and hardly any thread and the screw simply stripping even with slight torque. The only way to get a good size hole is with the barrel mounted in a proper vise and sitting on a drill press. Also how in hell would you guarantee that you can drill the depth to the proper sort of accuracy? You'll soon learn all about that sinking feeling when the drill bit jumps through into the rifled bore and digs into the other side if you insist on using a hand drill. So it's a positive thing that you've gone for a drill press.
Holding the barrels is another issue. Forget about just sitting them on the drill table. That's a recipe for skittering around and making a bad job. If you want to avoid buying a GOOD drill press vise for now then at least do some wood working to make a supportive saddle for each job and clamp it securely so the holes stay in the right spots. You'll also want to set up a ruler and indicator needle or some other setup to measure the drilling depth accurately for the times you want to do blind holes. It's not stretching things to suggest a dial indicator mounted point up on a magnetic stand and zeroed for when the drill bit just touches. When you need to drill .094 depth and NOT .101 such a trick really comes in handy.
But WAIT! If you buy NOW you also get the joy of having to buy THREE taps for each size ! ! ! ! You WILL need a taper tap for through hole tapping where you can. But for tapping the really shallow blind holes you need a plug (middle) tap and a bottoming tap to start then finish the threading as deep as you can in the really shallow holes. In fact you'll want to buy TWO drill bit sets so you can grind one with a very shallow end angle or even grid them for a flat bottom end so as to get that last turn of thread in the really shallow holes.
You will also want to figure out some pretty good ways of setting the depth to avoid punching through into the rifled bore. That's pretty much a newbie mistake that we all want to avoid. See my idea of the dial gauge and magnetic stand mentioned above. For this sort of thing "close enough" seldom is good enough.
Sorry for all this but even if you want to just get started at this sort of work there's no wading into the shallow end to test the waters. It's pretty much tie the bricks to your ankles then it's off the high diving board if you want to have a hope of doing it right.
The good news is that for all this the work itself is pretty easy to do right when you have the right tools. The only thing I'll add to this is that after drilling the pilot hole use the same setup without moving anything other than swapping the drill bit for the tap and BY HAND turn the chuck with the tap in a couple of turns to start the thread. This ensures that it starts dead on axial to the hole and produces the least load on the tap. For the really small taps, which is pretty much all you will be doing, unhook the drive belt so you have more feel for how much pressure is on the tap. Go easy and back out frequently. I generally use 1/2 a turn in then a full turn out to break the chips then back to feel the contact then a 1/2 turn in can back out. This is a slow way to do it but I've only broken a small number of taps over my 63 years. And removing a broken tap takes a LOT longer than doing it this way in the first place.
A really good cutting fluid like Tapzall or Tap Magic works a LOT better than the often recommended black cutting oil. I can really feel the difference on how it works with these smaller sizes. Both of those products come in versions for steel and aluminium.
The good taps from Brownells also are ground more accurately and sharply so again this reduces the torque needed to cut the threads and the likelyhood of snapping a tap off in the hole.
For these small sizes you also want to use a smaller size "T" handle tap wrench. The short arms on the smaller size wrench again makes it easier to feel the cutting load and to feel for and reduce any side loads. Be cautious of sideways bending when turning the wrench in. The torque combined with any bending is a good way to hear that dreaded "CRACK!". Practice first on some scrap metal and cheap common size taps like 8-32 and 6-32 from the local hardware stores to develop this feel before you dive into working with your more expensive Brownell's taps and actual guns.
If I haven't scared you off yet I wish you the best with collecting the goodies and learning to develop "The Touch" for the lighter taps.
BC Rider's advice is dead on. 
