[mjb]

The haters will hate, but tap guides are great (e.g. https://biggatortools.com/v-tapguide-faqs, but even a block of hard wood with a clearance hole drilled in it works fine).

Unless you're tapping something super tough (306?), Amazon taps are fine for hand tapping. Go in straight, use a good lubricant.

[analog31]

I've got two of those tap guides, one for US and one for metric. They're great. Also for drilling since I don't have a drill press at home.

I've examined cheap taps under a microscope. Maybe they are of varying quality, but the ones I got had burrs all along the cutting edges. A tap that I borrowed from a machine shop was flawless in comparison. So maybe the middle ground is caveat emptor.

Another trick for tapping is to use something pointy in the drill chuck to center the tap after drilling, assuming you've clamped down your workpiece in a drill press or mill. This works for really big taps when you don't have a guide for them. Likewise the tailstock of a lathe can be used for this purpose.

[aj7]

All good advice above. I’ve tapped 1000’s of holes and haven’t broken a tap in 50 years, and I have nothing to add to the above. Berkeley Physics Dept. student machine shop training.