If you see a note on a drawing like , check the context.
Provides a safe exit zone for threading tools during manufacturing. Understanding Thread Undercuts: Form A vs. Form B
I understand you're looking for information on (often mistakenly typed as "DIN 76-A" – the "A" likely refers to an older edition or a specific section on thread run-outs and undercuts). din 76-a pdf
The standard categorizes undercuts into four primary forms based on whether they are for external or internal use and their required length: Application Description External Threads The normal (standard) case for shafts and bolts. Form B External Threads
Generally, the undercut width is approximately three times the thread pitch ( If you see a note on a drawing like , check the context
Without a DIN 76-A undercut, you encounter two major problems:
The dimensions of a DIN 76-A undercut are directly tied to the pitch ( Form B I understand you're looking for information
If you need the actual , you must buy it from a standards distributor. For a quick reference table, search for "DIN 76-1 summary chart" in reputable engineering forums or tooling catalogs.