Engineering Properties of Roller Chain Pins
Engineering Properties of Roller Chain Pins
(OP)
We use a machined element in a #80 roller chain to move a heavy load. We simply remove one link and insert the "dog" in the chain and use two 5/16" grade 8 bolts to complete the assembly. Grade 8 bolts aren't holding up too well. Does anyone know the engineering properties of the roller chain pins that I'm trying to replace? Tensile strength, hardness, material grade, etc.....
Thanks in advance
Thanks in advance





RE: Engineering Properties of Roller Chain Pins
I saw hits from Timken and U.S. Tsubaki.
RE: Engineering Properties of Roller Chain Pins
RE: Engineering Properties of Roller Chain Pins
RE: Engineering Properties of Roller Chain Pins
RE: Engineering Properties of Roller Chain Pins
Until I get that far CoryPad made me wonder; what would happen if I tried to case harden a grade 8 bolt? Would it lose its native hardness? I'm guessing it would. Could I substitute a dowel pin?
RE: Engineering Properties of Roller Chain Pins
But, I think you will also find that even with precise fit between link pins and the mating bearing holes, that the dog link pins still wear quickly. This is because of the extra loads carried by the links due to bending moments from the loads on whatever the dog is pushing/lifting, and the extra flexing those pins see. You'll probably also begin to see some excessive wear on the female links. So, have plenty of spare female links as well as the pins on hand and replace both.
RE: Engineering Properties of Roller Chain Pins
Bending, breaking, wearing?
I'd think about making a "lug" that engags the chain roller full width and with some curvature, like a sprocket tooth does, and use larger bolts to secure the "lug" to the load.
RE: Engineering Properties of Roller Chain Pins
Tmoose, the bolts are breaking near the edge of the chain. I think it's all about the offset load. The load is off to the side of the chain; not on top of it. That puts a hard bending moment on the bolts. I'm going to try to fit a double strand master link through the dog and see if that helps. If I'm interpreting the dimensions I found on-line correctly, the inside dimensions of a double strand master link should be 2.250" and the dog is 2.125" wide. The link plates are 0.125" thick, so that works out perfectly! I'm going to try that before I try a dowel pin b/c I'd have a sloppy fit on the dowel and no good way to hold it in place.
I really appreciate all the input; you guys are great!
RE: Engineering Properties of Roller Chain Pins
Do not use a large preload on a carburized fastener, that can result in delayed fracture due to hydrogen assisted cracking.
RE: Engineering Properties of Roller Chain Pins
-handleman, CSWP (The new, easy test)
RE: Engineering Properties of Roller Chain Pins
I appreciate the help everyone. I'm going to try the double strand master link. If that doesn't work out, I may make some custom fasteners with Corypad's 8620 suggestion.
RE: Engineering Properties of Roller Chain Pins
Timelord
RE: Engineering Properties of Roller Chain Pins
RE: Engineering Properties of Roller Chain Pins
RE: Engineering Properties of Roller Chain Pins
I'm not following you here - are you saying your drive dog plates are thick enough to take up all the slack between the ~1-1/8 wide single strand side plates and the width of a double-strand master link?