Making a recessed rack?

[Tinkering_Guy]

I can't find any pictures online, so I'll have to try to describe it..

It seems to me that I've encountered an odd sort of rack gear -- namely, a cylindrical rod with the rack recessed into it.  I don't mean the teeth are cut across the surface; I mean they're in a slot.  Possibly I encountered this somewhere in my box of old printer parts, or maybe I just dreamed it.

I can't think of a way this might be made from a single piece without a lot of odd steps (like milling the teeth and then using specialised broaches to square the ends of each tooth face/bottom land at the slot shoulder).  Perhaps the slot is milled or cut as a keyway, and the rack is made separately and dropped/fastened into the slot?  Or the whole thing is drop-forged?

Am I making any sense?  (It is the wee hours here.)  Any clews as to how this might be done simply?

Not that I want to do it; I'm just curious.

Thanks!

[Ned Ludd]

Might it have been made using an EDM ?
Ned

[cidrontmg]

If I had to do one, IŽd do it in two pieces, like you suggested. Mill a deep slot in the bar, and attach a separate rack into it.

[Lew_Merrick_PE]

The parts may well have been made using the "PM" (Powder Metallurgy -- aka "sintering") process.  Basically, you make a ceramic mold, fill it with a specially processed powder mix of the alloy constituents you want, heat it up until it is almost molten, and then kick the pressure up to "forge" the part.  The retainer clip in a commercial airbag inflator that retains the initiator (the thing that ignites the propellants) is a PM part.  I have only been involved with PM production parts half-a-dozen or so time, but it is an amazing process that allows you to do things that leave others scratching their heads.