04-02-2015, 05:59 AM
(04-01-2015, 08:14 PM)Dr Stan Wrote: Shapiro has some A36 in 1/2" thick and 1" thick bars. 3 1/2" wide on the 1/2" thick and 4" wide on the 1" thick both under $19.00. While it is primarily a structural steel it should work well in this application.
http://www.shapirosupply.com/index.php?m...ts_id=9650
A36 is NOT a good material for that application. It's got a tensile strength of 36,000 psi, and is soft as puppy crap. Even the original part on a Chinese import arbor press would be stronger. Using 1018 CRS would be a better choice at nearly twice that strength.
The structural steels are good in compression or when mass can make up for lower strength. The ratchet part is stressed in shear by the pawl. You want tensile strength. 4140 is 95Ksi.