natewi
Plastic
- Joined
- May 2, 2019
- Location
- Durango CO
Hello all,
I am a blacksmith that makes cabinet hardware. I use a pneumatic tapping arm and tap blind holes 3/4" Deep with an 8-32 thread. Material is Mild Steel.
I currently use OSG, B2 H3, 3 spiral flute, bottoming, HSS or cobalt taps. I drill the hole on a drill press with a wire #26 bit prior to tapping. I use lots of quality cutting fluid, blow out the holes after drilling, and have a clutch drive on the tapping arm.
I have 2 main issues I run in to currently:
1. Screw does not want to go in all the way to bottom of hole. I often run in to this issue and am not sure why. Should I use a higher H factor? Would that mean
more room for the screw or less? I've read a lot on H values and pitch etc but I can't seem to wrap my head around whether or not a higher number means a tighter or looser fit. These are cabinet handles so I don't need a super tight fit, I'd rather have more room for error.
2. Taps break too often. Is HSS better for this than cobalt or another material? What do you sacfrifice with each option? What type of coating is best?
At the end of the day I'm looking for suggestions on the best type of tap for my application and why.
I respect you machinists greatly. What a science! I'm a humble blacksmith that prefers to bang on it till it fits lol.
Thanks in advance,
Nate
I am a blacksmith that makes cabinet hardware. I use a pneumatic tapping arm and tap blind holes 3/4" Deep with an 8-32 thread. Material is Mild Steel.
I currently use OSG, B2 H3, 3 spiral flute, bottoming, HSS or cobalt taps. I drill the hole on a drill press with a wire #26 bit prior to tapping. I use lots of quality cutting fluid, blow out the holes after drilling, and have a clutch drive on the tapping arm.
I have 2 main issues I run in to currently:
1. Screw does not want to go in all the way to bottom of hole. I often run in to this issue and am not sure why. Should I use a higher H factor? Would that mean
more room for the screw or less? I've read a lot on H values and pitch etc but I can't seem to wrap my head around whether or not a higher number means a tighter or looser fit. These are cabinet handles so I don't need a super tight fit, I'd rather have more room for error.
2. Taps break too often. Is HSS better for this than cobalt or another material? What do you sacfrifice with each option? What type of coating is best?
At the end of the day I'm looking for suggestions on the best type of tap for my application and why.
I respect you machinists greatly. What a science! I'm a humble blacksmith that prefers to bang on it till it fits lol.
Thanks in advance,
Nate