What Stock would you use to make a new back gear shaft?

Stefen

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Hey guys first an foremost, thank you for all your help answering my questions about my old 101/618 the last few days. Instead of buying a $64 back gear shaft ( it's pretty worn ) I figured I'd just turn one for a 1/8th of the cost. I have all the measurements I need, It's pretty much a 3/8 stock to start before I get it down just a hair. I wanted to see what you all thought about the material that should be used? I was thinking of 4340, 1018, 1215, 4140 PH. Something along these lines since my local dealer has 3/ 8 in stock. Let me know what steel you would use.
Thanks
 
4140 first then 1144. Think of 1144 somewhere between c12l14 and 4140. Machines great! Quite durable without being brittle and way cheaper than 4140. 4140 no doubt would be my first choice other than exotics. You could always make two or another down the rd.
 
I'd use whatever is on the shelf that's the closest in size. It's not going to see alot of load or wear, especially if you keep it oiled. Do you have a good way to measure the bores of the bushings in the backgear? I'd go by that measurement, maybe even think about reaming them out to the next sensible size up, instead of the old shaft.
 
4140 first then 1144. Think of 1144 somewhere between c12l14 and 4140. Machines great! Quite durable without being brittle and way cheaper than 4140. 4140 no doubt would be my first choice other than exotics. You could always make two or another down the rd.
That's true. I can all ways have an extra!
 
I'd use whatever is on the shelf that's the closest in size. It's not going to see a lot of load or wear, especially if you keep it oiled. Do you have a good way to measure the bores of the bushings in the backgear? I'd go by that measurement, maybe even think about reaming them out to the next sensible size up, instead of the old shaft.
Yes, I went ahead a measured them The only thing I need to make other than the shaft is the left eccentric. I'll use the same material for that as well.
 
If you are going to be machining the shaft with your 618 then I would suggest staying away from hard and tough materials, and ones that work harden instantly if they rub instead of cut. You will find them a major frustration if you cannot take a deep enough cut to get and stay below the work hardening. I would stick with basic mild steels for the job. It will also be less expensive, besides more forgiving. Keep the grit out and the oil in and it will outlast you. A36 or 1018 would be fine.
 
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If you are going to be machining the shaft with your 618 then I would suggest staying away from hard and tough materials, and ones that work harden instantly if they rub instead of cut. You will find them a major frustration if you cannot take a deep enough cut to get and stay below the work hardening. I would stick with basic mild steels for the job. It will also be less expensive, besides more forgiving. Keep the grit out and the oil in and it will outlast you. A36 or 1018 would be fine.
I will be using my south bend. It's a beast.
 
Agree with Bob, just use garden variety steel and keep it well lubricated, it'll outlast the zamak gears
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