Hydroracer
Plastic
- Joined
- Apr 21, 2020
So, getting ready to build a little machine (a 2x72 grinder) in 3/8" steel. Of course, I'll need to tap a few holes here and there. Like usual, I don't just go buy a generic whatever tool and and go at it, I want to "understand" more about the process, etc, etc. So...I did a lot of reading on taps and dies and the entire process which leads me to some questions, perhaps more for my own education than any real need for consideration in this project.
So, first question, when buying a tap (I am looking on industrial supply houses in order to buy a good quality HSS American made tap, I don't want no chinesium junk), I am looking at the H and L designators. Am I correct to understand that, say an H5 tap will provide a "looser" fit for any given bolt, whereas an H3 will be a little tighter? L speced taps are just going to make the threads undersized and even tighter to the point of not fitting. Also, 2B vs 3B, I'm guessing the majority of the grade 8 bolts available are probably not going to be toleranced to 3B specs.
Anyway, I guess my real question is, if you were buying a tap to make threads for generic grade 8 3/8" and 1/2" bolts, would you choose an H3 or an H5 tap?
Any particular brand of tap to recommend? I was planning on a taper tap since all holes on this machine are through holes, but I see they have spiral and spiral tip. Are these worth the extra cost for hand tapping operations? I plan to use my drill press to do the tapping (manually, not under power) just to keep things lined up. What about forming taps? Is a 3/8" form tap too difficult to do by hand power in A36 mild steel?
So, first question, when buying a tap (I am looking on industrial supply houses in order to buy a good quality HSS American made tap, I don't want no chinesium junk), I am looking at the H and L designators. Am I correct to understand that, say an H5 tap will provide a "looser" fit for any given bolt, whereas an H3 will be a little tighter? L speced taps are just going to make the threads undersized and even tighter to the point of not fitting. Also, 2B vs 3B, I'm guessing the majority of the grade 8 bolts available are probably not going to be toleranced to 3B specs.
Anyway, I guess my real question is, if you were buying a tap to make threads for generic grade 8 3/8" and 1/2" bolts, would you choose an H3 or an H5 tap?
Any particular brand of tap to recommend? I was planning on a taper tap since all holes on this machine are through holes, but I see they have spiral and spiral tip. Are these worth the extra cost for hand tapping operations? I plan to use my drill press to do the tapping (manually, not under power) just to keep things lined up. What about forming taps? Is a 3/8" form tap too difficult to do by hand power in A36 mild steel?