The place to come to share your technical expertise, or just find out what the little springy thing is that's just pinged out of sight under the work-bench.
I think they are the same as the standard nipples. I've just measured the pitch of one of my old nipples and they are 1.25 thread. I replaced mine with stainless steel ones.
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.