A machined tension specimen is turned down so that it breaks in a reduced section, which proves the steel but never loads the head, the fillet under it or the threads as they were made. The wedge test pulls the finished bolt with its head bent a few degrees, so it also shows whether heading or forging has left the junction of head and shank sound and ductile.
For ASTM A193 and A320 bolting the two tests work together: headed bolts 1-1/2 in. and under, three diameters long or more, made by upsetting or forging, get the wedge test as well as the machined tension test. They must break in the body or the threads, with no failure and no crack where the head meets the shank.
Read the full wedge tension testing page →
model dataWedge drawn to ASTM F606 Fig. 3 with its Table 3 angle (10° for bolts 1/4 to 1 in.) and Table 5 hole clearance and edge radius for 7/8 to 1 in. bolts; 45 HRC minimum and half a diameter thick at the thin side (F606 §3.5.1, A370 Annex A3). Six exposed threads and the 1 in./min speed limit from F606 §3.4. Acceptance from F606 §3.5.1 and ASTM A193 §12.1.3. Minimum load: 125 ksi (A193 Table 2) × 0.606 in² stress area (A962 Table 1). Bolt drawn to ASME B18.2.1 heavy hex proportions. The load curve and readings are an example only; the machine, yoke, grip and fixture are generic.
© 2026 Innovation Fasteners. This interactive drawing, its 3D models and its code may not be copied, hosted elsewhere, scraped or used to train AI models. Terms of use.