Neil
Hot Rolled
- Joined
- Jan 1, 2005
- Location
- Lockport, NY
Dear Forum,
It's been a long time. I am a design engineer and I was asked to use GH3 threads for an automotive bracket. I am only used to class 1,2 and 3 threads and 99.99% of the time simply designate them 2A and 2B and leave it at that.
I went to google school and learned that GH3 are ground threads with a larger pitch diameter. I read Machinery's handbook section on classes of threads but only classes 1,2 and were there.
I searched this forum and General forum and found nothing about GH3.
My question is this: are GH3 class thread and 2B class thread-mutually exclusive?? In my drawing can I specify a 2b class thread that is further refined by being a GH3 thread? The quoted text below from a CNC forum says I can and that GH is merely a type of tap (I thought GH3= ground threads!). What say you roomful of wise men and women?
"2b simply indicates an internal thread class, or size range. 3b is a tighter tolerance.
A gh3 is a size specification of the tap's pitch diameter...where a 1 is the smallest and a 5 is the highest, in increments of .0001", depending on the size of the tap.
If you need sloppy threads, you might specify a 2b, and you'd use a gh5 tap. You might also use a gh5 if you're going to plate the part and the effective pitch dia will get reduced."
It's been a long time. I am a design engineer and I was asked to use GH3 threads for an automotive bracket. I am only used to class 1,2 and 3 threads and 99.99% of the time simply designate them 2A and 2B and leave it at that.
I went to google school and learned that GH3 are ground threads with a larger pitch diameter. I read Machinery's handbook section on classes of threads but only classes 1,2 and were there.
I searched this forum and General forum and found nothing about GH3.
My question is this: are GH3 class thread and 2B class thread-mutually exclusive?? In my drawing can I specify a 2b class thread that is further refined by being a GH3 thread? The quoted text below from a CNC forum says I can and that GH is merely a type of tap (I thought GH3= ground threads!). What say you roomful of wise men and women?
"2b simply indicates an internal thread class, or size range. 3b is a tighter tolerance.
A gh3 is a size specification of the tap's pitch diameter...where a 1 is the smallest and a 5 is the highest, in increments of .0001", depending on the size of the tap.
If you need sloppy threads, you might specify a 2b, and you'd use a gh5 tap. You might also use a gh5 if you're going to plate the part and the effective pitch dia will get reduced."