The not taking part is likely 10mm chuck, even though the twist drill for hole saw tend to be 8mm. One the pictures has a 10mm plastic chuck.
Lots of hole saw have even 6.3mm (the 1/4) hex drive for impact drivers.
Other than that it's quite baffling the guy had rather poor tools, and likely kept buying low quality tools too. Yet, he was very determined.
These tools cost here ~1200€ and are not expensive at all. Nobody in a trade job wants to mess with a torch, gas cans, dirty paste and soldering chemicals all day anymore. It takes seconds instead of minutes for one pressed connection. Ok, pressed connections are thicker than soldered, but doesn’t matter for most cases. Obviously as a hobby builder I can toy half day with torch and solder paste for 40 connections in my house.
copper pipes are not popular in this part of the pond (not any longer at least, outside gas). The most common domestic pipes are "pex/aluminum/pex" type which are designed for crimping and bending (by hand).
Other than that it makes a lot sense to go w/ crimping if possible - quite surprised it's rated up to 2".
I have steel pipes for my central heating flow (UK) because my house was built during a copper shortage in the late 1960s. Every plumber has said they're a nightmare to work with compared to soft copper.
The story I know is that US gas (used to) cause corrosion of the Cu pipes. I don't have a gas line (in the house), so no recent installation - and of course I won't be installing a gas line on my silly-own (while I can go by and do some plumbing for the water). Yet, if i see a tiny (8mm) copper tube I'm quite confident, it's for the gas.
Perhaps a relic of the days of manufactured coal-based gas that they kept because there was already so much infrastructure. Out of curiosity I’ve been trying to see if the local steam utility offers new supply connections but I don’t see anything.
The not taking part is likely 10mm chuck, even though the twist drill for hole saw tend to be 8mm. One the pictures has a 10mm plastic chuck. Lots of hole saw have even 6.3mm (the 1/4) hex drive for impact drivers.
Other than that it's quite baffling the guy had rather poor tools, and likely kept buying low quality tools too. Yet, he was very determined.