EN24 Rockwell Hardness
EN24 Rockwell Hardness
(OP)
Hi, I am soon going to be rolling some threads from EN24 bar before having them heat treated. Looking at page 10 of this pdf http://www .landisthr eadingsyst ems.com/Th readRollin g/Library/ TechnicalS upport.pdf how should I know what column I should be referring to? They refer to material hardness, which I am unsure of. EN24 is equivalent of SAE 4340. The threads will be 7/16 unf and unc.
I am also getting myself confused between the difference in class 2 and class 3 shown on the same page.
I am also getting myself confused between the difference in class 2 and class 3 shown on the same page.





RE: EN24 Rockwell Hardness
Thread Class refers to the tolerances and allowances (i.e. slop). Class 1 thru 3 get progressively tighter. Its all defined in American National Standard Institute (ANSI) B1.1, titled 'Unified Screw Threads'. There are probably online calculators, but here's an example.
.4375-14UNC-[what the class is]A ('A' means external.)
EXTERNAL Class 2 Class 3
Major Dia 0.4360 +.0000 - 0.0103 0.4375 +.0000 - 0.0103
Pitch Dia 0.3896 +.0000 - 0.0050 0.3911 +.0000 - 0.0050
Minor Dia 0.3587 Max, Ref 0.3602 Max, Ref
.4375-20UNF-[class]A
EXTERNAL Class 2 Class 3
Major Dia 0.4361 +.0000 - 0.0081 0.4375 +.0000 - 0.0081
Pitch Dia 0.4036 +.0000 - 0.0047 0.4050 +.0000 - 0.0047
Minor Dia 0.3820 Max, Ref 0.3834 Max, Ref
RE: EN24 Rockwell Hardness
RE: EN24 Rockwell Hardness
Depending on ruling section and heat treatment it can achieve 100 T/in2, "condition Z".
We use condition T for shafts.
RE: EN24 Rockwell Hardness
Can I assume that some of the information I will been and have been using is slightly complicated by the fact that the EN24 info is UK based whereas most of the thread rolling etc info is US based?
RE: EN24 Rockwell Hardness
I don't understand your last question, but if you want information on thread rolling that is from a European company, LMT Fette will have standard sizes, etc. for metric threads:
http://w
RE: EN24 Rockwell Hardness
RE: EN24 Rockwell Hardness
RE: EN24 Rockwell Hardness
RE: EN24 Rockwell Hardness
There is a BS for unified threads, I was going to say 1936 but I think that's undercuts for unified threads.
www.boltplanet.com has a calculator for unified threads which can be useful to check your own calcs.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: EN24 Rockwell Hardness
However in the late 1960's the UK started looking East to Europe and metricated.
RE: EN24 Rockwell Hardness
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?