• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

Metric thread web calculator variances

PeterT

Ultra Member
Premium Member
I thought I made a prior typo error, but now that I input the exact same (custom) metric thread into 3 different web calculators I've bookmarked, I see they are giving me slightly different answers.
Has anyone had this same issue? For example M30 x 1 6g (external) just comparing major diameter & pitch diameter to spot check. If the calculator provides a min/max I averaged the two just for spot check

1738694289893.png




 
Ok, here goes: using the M Profile Screw Thread limits from the MH 29th edition, pages 1878 to 1900, and comparing with tabulated values for the standard M30x1.5-6g thread size, we get the following values for:

M30X1.0-6g

MAX MAJOR DIA.: 29.974
MIN MAJOR DIA.: 29.794
MAX PITCH DIA.: 29.324
MIN PITCH DIA.: 29.199


1738717403516.png
 
Thanks.... I think! :/
I made a typo on the Ames PD, now corrected, so this how they compare. I would never expected any discrepancy, but obviously there are subtleties to the standards or sources?
Close enough for what I need but I'll have to pay attention to this. Might explain when I was doing my CAD generate threads from formulas, they were a bit off.
1738720859059.png

1738720793558.png
 

Attachments

  • 1738720662520.png
    1738720662520.png
    13 KB · Views: 3
Ok, here goes: using the M Profile Screw Thread limits from the MH 29th edition, pages 1878 to 1900, and comparing with tabulated values for the standard M30x1.5-6g thread size, we get the following values for:
Thanks for this. Are you saying you used the formulas to validate what they show in the tables for M30x1.5 & then applied to M30x1.0 because they don't include x1.0 in the tables?
I have MH 29th too. When I didn't see M30x1.0 in tables & was too lazy to do the math opting for online calculator.

I bet the devil in the details of 'es' & 'Td' factors. I'm sure I wrote an Excel app to do this once upon a time & subsequently lost it.


1738773338107.png

1738773535932.png
 
Major Dia=nominal dia - 2*(.125*(pitch*.86603)) for metric and UN threads. TR Fastener table is out right wrong. Bible ISO is closest.
Yes, that confused me too. Unless they mean 'nominal diameter' but they say Major Diameter. The insert sketch shows d4=major diameter (inferring some class reduced OD) so ???? I guess avoid this source.
1738774150797.png

1738774204252.png
 
Thanks for this. Are you saying you used the formulas to validate what they show in the tables for M30x1.5 & then applied to M30x1.0 because they don't include x1.0 in the tables?
I have MH 29th too. When I didn't see M30x1.0 in tables & was too lazy to do the math opting for online calculator.

I bet the devil in the details of 'es' & 'Td' factors. I'm sure I wrote an Excel app to do this once upon a time & subsequently lost it.


View attachment 59235
View attachment 59236
That's exactly what I did - took the tabulated values for M30x1.5-6g, dug out the formulas and factor's like es and Td, then applied same logic to the 1.0 pitch that was not in the table. My years of teaching might be a bad habit but I like to sort out this type of detail.
 
Back
Top