I have a couple sets of specialized bits from Rawkrafted. The sets contain one for mortise, one for tenon. They’re not fool proof. I know @DocAitch has a way to do the tenon with his metal lathe, and I believe he’s made his own bit for drilling the mortise.
ETA, lathe is not COMPLETELY necessary to use the sets from Rawkrafted.
Essentially any setup for this is a variation of something to cut an angled tenon (a flat tool with a 1 degree rake would work on a lathe) and some matching tool to cut the mortise with a slight (and matching) angle - whether it's a drill or just a reamer with the angle on it. But in truth it's much easier to do this kind of thing on a lathe. Set up a cutter and slide it where you want, inside or out.
The bottom set here is a tapered reamer with a Delrin guide from the J Alan Design military mount bit https://vermontfreehand.com/product/j-alan-tool-design-military-mount-kits/. You drill a pilot mortise the same diameter as the distal end of the tapered reamer, ream out the mortise to the tapered profile, then cut a ring trench with the toothed piece of tubing using the Delrin quide. The other sets I made myself with different diameter mortises and different diameter tubing.
I use a drill press.
The photo with the drill press shows how thin and delicate the little briar lining is, so my subsequent iterations used a smaller mortise with a home turned reamer and Delrin guide. The finished pipe has a thicker briar llining.
I cut the stem tenons with the compound on my lathe and have a couple of specially ground cutting bits to avoid getting a step at the junction of the flare and the tapered mortise.
You don’t have to put a reinforcing ring around the mortise but I almost always do. Once this is set up in the drill press clamp, its only a matter of changing out bits and pieces of tube.
You cut your own teeth on the tubing and the key to using the toothed tube to cut that groove is to be slow and gentle with frequent clearing of the swarf to prevent heat and binding.