Chain Strength Formula

[Molten]

I have a chain and need to know how strong it is. I just don't know how to check without loading 100+pounds onto it. For those with a machinary handbook the W is .735 in., the L is .668 in., The P is1.322 in.
I do not know wwhere to begin with this problem. I tried several handbooks and none of them had the right size. Anyone that knows anything of help please let me know. I can use the formula myself if you just don't have time to solve it. I am hoping that the FIRST community can help me as this is a big project for me.

[sanddrag]

Is it ANSI roller chain, like, #35 or something like that? If so, you can use the specs on the McMaster catalog page for that chain for a rough estimate of maximum working load and breaking strength.

[Molten]

How would I know if it was ANSI or what Number it is?

[John Gutmann]

You can measure the pitch of the chain then look on McMaster, or any other chain provider.

-John

[dlavery]

Originally Posted by Temper Metal

I have a chain and need to know how strong it is. I just don't know how to check without loading 100+pounds onto it. For those with a machinary handbook the W is .735 in., the L is .668 in., The P is1.322 in.
I do not know wwhere to begin with this problem. I tried several handbooks and none of them had the right size. Anyone that knows anything of help please let me know. I can use the formula myself if you just don't have time to solve it. I am hoping that the FIRST community can help me as this is a big project for me.

You are going to have to provide a little more information. Just the size of the chain is insufficient - what material is it made from (plastic? aluminum? steel? and what alloy?) and what is the condition of the chain (pristine fresh-from-the-manufacturer, or covered with corrosion after being buried under a tractor for 10 years)? Is it single- or double-course (or triple-course)? Are the side plates on each link pressed into place, or welded? Has the chain been significantly stressed before? Etc.

All of these factors, and many others, will contribute to the overall strength rating of the chain. If this is just a length of chain that you had on hand, and you don't know the history of it's use (or abuse), then it may be impossible to accurately predict the actual strength of the chain. The only reliable way to determine it will be to use a short length of the chain and conduct a destructive loading test to see when the chain actually fails.

-dave

[kramarczyk]

Originally Posted by Temper Metal

I have a chain and need to know how strong it is. I just don't know how to check without loading 100+pounds onto it. For those with a machinary handbook the W is .735 in., the L is .668 in., The P is1.322 in.
I do not know wwhere to begin with this problem. I tried several handbooks and none of them had the right size. Anyone that knows anything of help please let me know. I can use the formula myself if you just don't have time to solve it. I am hoping that the FIRST community can help me as this is a big project for me.

Based upon your description, assuming it is actually a standard ANSI roller chain, it sounds like a #100 (1.25" pitch, .75" wide, link plates thickness of .156"). That's a bit beefy for a bot. If this assumption is true then the following exerpt from the Machinery Handbook (26th Ed, p2424) applies:

Minimum Ultimate Tensile Strength: For single-strand chain, equal to or greater than 12,500 × (pitch in inches)2 pounds. The minimum tensile strength or breaking strength of a multiple-strand chain is equal to that of a single-strand chain multiplied by the number of strands. Minimum ultimate tensile strength is indicative only of the tensile strength quality of the chain, not the maximum load that can be applied.

Soooooo..... 19.5 kip per strand
yowza

'course Dave's test is the only way to know for sure.

Mark