I am working on a small project. Kind of a backwards design for some small steel brackets that are in the process of being detailed. The drawings the steel detailer call for Grade 8 1/4x20 bolts. I have found some information on the internet. What I think should be called out should be ASTM A354 Grade BD (it appears that it is in the same category as SAE J429 Grade 8). It has a yield strength of 130 ksi and a tensile strength of 150 ksi. Am I correct?
In addition, the shop drawings that are in production, call for a ¼”-20 FH MSCR in another application on the project. I can see that it will be a ¼” flat head screw (the drawings show a countersunk part for the application and I believe the receiving part will be drilled and tapped. But what does the “MSCR” stand for? Sorry for the confusion here. And, what would the correct ASTM designation be? Same as above for the bolts as the table I found from American Fastener shows ASTM A#%$ Grade BD being for Bolts, Screws, and Studs.
Thanks for the help
Joe Grill