welding 1144

Date 06-07-2005 07:21

If the loading direction changes, like going from accelerating to decelerating in a go-kart keys and pins can both beat out unless fitted perfectly. Tapering the shaft and hub (like a lawnmower flywheel) increases reliability. Machining is difficult though. The two piece hubs which tighten on a non tapered shaft like the collet chuck in a die grinder work very well, you get both key and clamping. Relatively expensive though. If you heat the sprocket and chill the shaft you can assemble interferance fits with little trouble. I believe up to .001 inch per inch of shaft diameter if the temperature split is large enough. When the temperature evens out the assembly is very reliable. Disadvantage is that careful machining is required.

Want to say what you're building just to satisfy the curious?

Bill

By ttveter Date 06-07-2005 12:51

I am replacing a failed shaft on a welding cell material handler. The original design used a 1018 Cold Finished shaft with set screws for the two sprockets. Over time the maintenance department decided to weld the sprockets to the shaft, which I believe caused the "hot crack" and therefore the shaft failed. They have now replace the 1018 CF with 1144 CF and welded the sprockets on. My questions is: Is this the proper fix (will it continue to fail due to "hot cracking") or should I redesign the shaft with key ways or thru holes for the sprockets. Thanks.

By billvanderhoof (****)

Date 06-08-2005 06:44

http://www.emerson-ept.com/eptroot/public/prod/main.asp
There's a place to start for sprockets and hubs. Your local bearing guy can describe this stuff better than I can.

The material seems simple enough that welding should be possible but I have no experience with it.
Bill