Yep, 8-32's. You can google a drill/ tap index and it'll show you all the bit/ hole sizes you need- BUT, don't nec just trust it at face value. It will likely tell you to use a 7/64" bit, which is good if you're tapping through a relatively thin walled area, but IMO if the wall you're tapping has any thickness to it at all you're better off going with a 1/8" hole. That's plenty of substance to the resulting threads still, and they'll likely turn out WAY cleaner/ better than they do with the smaller starting hole. The intial threads will turn out a lot better- the tap really has to fight through that smaller hole, and has a tendency to chew up the first threads as it grips/ bites and pulls itslef deeper into the hilt wall, and believe me patience and a gentle touch is the name of the game when it comes to tapping. DONT FORCE THE TAP, EVER. It will start to bind/ stick with every little smidge of a turn you manage to get on it at one point- but that's ok! That's totally normal. When it binds, just let it- let it stick and just stop moving/ turning altogether, then gently reverse the direction of your turning and unscrew/ back the tap out a bit. This will allow the debris that the tap cuts from the aluminum to fall out of the hole, unclogging those threads you're working on cutting in, freeing up a little more wiggle room for you to turn the tap in a pinch further this next time. And you just keep repeating that. Back the tap out just a tiny fraction of a turn when it sticks, and then go back in again- getting a micropscoic bit further each time. Takes patience, but you'll get through the whole thing eventually
. Other than that you just wanna make sure that you keep the tap level, aligned as you turn it in- especially for the beginning- once it gets started it will kinda guide itself in and you don't have to watch that so much.
The guides/ indexes will also tell you to use crazy nonsense like kerosene and mineral oil as lube, but you really don't need to bother lol. First of all, a bottle of cutting oil is cheap/ available at any hardware store and works just as well (especially for aluminum its soft)- and I'm honestly not even convinced lubrication really helps with something as soft as aluminum. I've tapped a ton of screws using oil, a ton without, and I haven't noticed any difference in how easy they were to cut in or how well the turned out really. Doesn't seem to do much- if anything, ironically, the lube just turns to a paste with all the ground aluminum coming off the tap that's turning in the hole, and holds that debris in there, so the tap will want to bind more- in a dry tap the debris is dust, which will remove from hole easier when you back the tap out a pinch, allowing you to make progress faster.
It's way easier than it sounds- just DONT FORCE IT, and you'll be golden
. Also, from experience, 6-32 screws work just as well and have a noticeably smaller visual impact, they're more subtle in a hilt. Shoot, even 4-40 screws will hold stuff nice and secure (maybe not best for blade tho)- but the smaller the tap, the more important it is to go gentle. Give the shaft of the tap a death stare as you turn it and watch for the second it starts to bog down, don't even blink as you turn it, you don't want to be turning the tap if the shaft of it is slowing/ stopped moving- it won't take much torque/ flex that way, carbide is super dense/ strong, but not flexible- brittle when bent.
Hope that helps
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