Pete F
Titanium
- Joined
- Jul 30, 2008
- Location
- Sydney, Australia
I wrote a post in the metrology section to Gordon, who many here consider the resident thread expert, to check some thread calculations as we were getting different results. However for reasons best known to himself, the "moderator" in the metrology is deleting posts of mine. I frankly don't have time for such childish BS, and it's easiest to just abandon that forum and repost the question here.
Can you (Gordon) or others please check my figures for a 40 x 1.5 mm 4h as they seem to be different and I can't figure out why. Furthermore, the figures provided didn't make sense to me, and I want to become more confident with using metric thread tolerances.
Actually I was referring to 4h and my understanding is the maximum major diameter on an h thread will be the nominal thread diameter, so in this case is 40.00 mm (I'm not keen enough to work to 3 decimal places on a thread, as that's better than I can cut! ). So the figures would be:
OD max 40.00 min 39.85
PD max 39.03 min 38.93
Minor max 38.38
However what's more concerning to me is that I'm not getting the same figures as Gordon on a 4g thread as I'm getting:
OD max 39.97 min 39.82
PD max 38.99 min 38.90
Minor max 38.34
I'd be grateful if Gordon or others could steer me straight on where I'm going wrong with my figures, as some of mine are quite different to Gordon's. I've stopped the job until I can figure out what's going wrong here.
Thanks in advance.
Pete
Can you (Gordon) or others please check my figures for a 40 x 1.5 mm 4h as they seem to be different and I can't figure out why. Furthermore, the figures provided didn't make sense to me, and I want to become more confident with using metric thread tolerances.
Assuming you are referring to tolerance 4g both for major (OD) and pitch diameter (PD) then:
OD max 39.974 and min 39.862
PD max 39.324 and max 39.244
Actually I was referring to 4h and my understanding is the maximum major diameter on an h thread will be the nominal thread diameter, so in this case is 40.00 mm (I'm not keen enough to work to 3 decimal places on a thread, as that's better than I can cut! ). So the figures would be:
OD max 40.00 min 39.85
PD max 39.03 min 38.93
Minor max 38.38
However what's more concerning to me is that I'm not getting the same figures as Gordon on a 4g thread as I'm getting:
OD max 39.97 min 39.82
PD max 38.99 min 38.90
Minor max 38.34
I'd be grateful if Gordon or others could steer me straight on where I'm going wrong with my figures, as some of mine are quite different to Gordon's. I've stopped the job until I can figure out what's going wrong here.
Thanks in advance.
Pete