Does this mean one size mandrel will work for every kit? It was looking like every supplier had their own mandrel and bushings.The B mandrel was introduced many years ago by Berea. For a while they made kits that used that "beefier" mandrel, the Churchill and Cambridge among others. The mandrel never caught on, so now you can get "A" size bushings for those kits. So, presently there is no real reason for a B mandrel and I have never heard of a C mandrel.
Yes and no - most kits are designed to use the so-called 'A' mandrel (which is 1/4" in diameter). But as Ed noted, one kit vendor (Berea Hardwoods) introduced a line of kits that used a larger mandrel (the so-called 'B' mandrel). However, that was unique to kits sold by Berea, and no other kit suppliers jumped on board with the idea and it never gained much popularity. So as a practical matter, most kits today can be done using the ubiquitous 'A' mandrel. Must pen turners prefer the simplicity of using only one mandrel (and actually, many pen turners have shifted away from mandrels altogether in favor of turning between centers.Does this mean one size mandrel will work for every kit? It was looking like every supplier had their own mandrel and bushings.
(I've been interested in pen making for a few years but the lathe I've been using is a 1940's vintage entry level model that doesn't accept a lot of newer accessories. I just bought a 1960s Craftsman that will take MT1 accessories so I can start gearing up for pens now.)