Banebot 56mm gearbox - double D - RELOADED

[cbpetrovic]

Originally Posted by ZZII 527

By some twist of luck, my steel came early this morning AND I was able to get 20 minutes on the waterjet. So I now have four A2 tool steel 56mm carriers, which are about the same hardness as the originals but can be treated to pretty much anything from C20 to C40. I will probably shoot for C23 for now to match the current shaft.

My dimensions were as the drawings say, except:
a) I went tighter on the double-D: 0.470in (11.94mm) radius and 0.350in (8.89mm) flats. With the taper from the jet, this seems to be a good press fit, but may require some filing.

b) The pins will be press fit in the other direction, against the taper of the jet, so I just made their holes extra small, 0.150in (3.81mm), and I'll drill them out later.

The stock I used is McMaster part #9019K147, 18"x2"x5/16" A2 tool steel.

In the attached picture, the two carriers at the left are the originals (1CIM, 12:1) with almost no visible damage after "mild" usage. The four at the right are the new A2 tool steel ones that I will try to harden to C23 for testing.

The 4140 prehardened stock has arrived for us as well, and should be in the hands of our model shop along with the drawing package.

Our plan is to remanufacture the 3:1 DoubleD plates and we should have some test results this weekend. We're running a 4 transmission/motor chassis.

C. B. Petrovic - Team 166