Trying to make a gear pump

[Futterama]

Yeah, maybe press fit is the only way, I just like that the cylinder pin is surface hardened and probably more smooth and straight than I can make with my lathe.

The gear on the picture is 11SMnPb30 / C45 steel and the pin is some surface hardened steel (so hard you cannot machine is with HSS).

Brazing could be an option if a suitable filler for steel could be found, I've never tried it or seen it done.

[JAMMER]

The easy way to press fit it is to have a shaft that is just larger than the hole in the gear then heat the shaft and put the gear in the freezer for a while and they should go together and you should not need a keyway this is called sweat fit and works great. Ed

[Trackerman]

Ed,
" just larger than the hole in the gear then heat the shaft and put the gear in the freezer for a while and they should go together " you mean the other way around don't you? freeze the shaft to shrink and heat the gear to expand, gear slips on shaft and the shaft heats and expands locking the gear in place.

cheers

Paul