if you are hand tapping, it is definitely a "touch" operation, the tap will usually tell you before it breaks. drill and tap a bunch of holes in different sizes just to get the "feel".
A BIG Amen to that Scott!!!
When I read that I was having "flashbacks" to my hand tapping days!
I have a tapping head attached to a 10" drill press, so my tooling needs are a bit different then if I were doin it by hand. Prior to the tapping head, when I was doing it all by hand, it was very common for me to break a couple of taps with each folder I built. I think in this case your issue(s) are two fold..... poor quality tooling, and the fact that its just plain difficult to hand tap with these small size taps and not break them.
That being said, the drill bits I use for folders are all made in USA cobalt and carbide bits. Its actually a bit of a challenge to find "made in USA" taps anymore, but when I can, I use that variety. Something else that came to mind when I read your post and saw the pic....is the 0-1 your using fully annealed stock, or is it "spherodized annealed"? The reason I ask, is because if your using it as it comes (without annealing it yourself), its very likely spherodized..... to put it bluntly, "spherodized" means it just "half way" annealed. What tipped me off is the photo you posted....that bulging around the outside of the hole, only comes from two reasons....the hole you drilled is not large enough for the tap your using, or the steel isn't fully annealed.
When working with the types of materials we do in knifemaking, you can't always follow the standard "guidelines" when drilling/tapping. For example, a 2-56 thread calls for a #50 drill bit on most charts....that info is intended for use "mild" steels. With harder/tougher materials, you need to slightly enlarge the hole to facilitate tapping. For example, in "knfe steels" for a cutting type tap, I use a #48 or #49 drill bit, depending on material thickness. For the same thread size in titanium, I use #48, 5/64", or a #47, depending on material thickness and the type of tap (I generally use thread forming taps in titanium)... Some folks might balk at that, thinking "I want to make sure I get "full" thread depth!" As with most anything in knifemaking its a trade-off......you can dig yoru heels in and insist on "full thread depth", and wreck a lot of tooling and parts.....or you can have SLIGHTLY less thread depth, that provides plenty of strength for the job, but bypass the broken tooling and wrecked parts.
