May 10, 20188 yr I was just looking for any technical info on rubber for casting springs for a Bradley type hammer , and I have to admit , I am more baffled than before. It almost looks like industry gave up on elastomer springs. I was curious if anyone knows the original durometer of Bradley cushions? If I had a gage I would run out to the shop and check. Perhaps a tire shop could gage them for me???
May 11, 20188 yr I had mine tested at a tire shop and I think they were in the low 60A range, I could double check my notes. There have been threads on this topic before with no real consensus. I made new rubbers from 70A urethane and it seems a bit to hard. Others have mentioned higher hardness values.
May 11, 20188 yr Author The new ones I have are noticeably harder as well. It has been quite a long time since I had them made so I don't recall the specifics. It looks like 50-60 is the standard in industry, but all my references are somewhat lacking in details. Machineries Handbook has even failed me.
May 11, 20188 yr Author Urethane. They are apparently the same material as " super balls" were made from. A guy in Michigan made them for me in the 90s. They work well, I was just curious as I may track down another Bradley some day.
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