Will a straight flute be much harder to use than a spiral flute due to the "biting/chatter" ?
By the way, those drawings are great!
I don't have a lathe, but I might be able to rig something on my mill. Put the reamer in a collet and a rotary tool on the table. I'll have to look at that as an option since it would be far more accurate than a bench grinder. Height is my biggest issue here, only have a little desktop micro mill, but I've never let it stop me from doing projects bigger than it can handle.
Here is a photo of one of my custom chamber reamers.... and no, I do not make them for sale.... The pilot portion is a thou or two smaller than the land diameter and the tapered cutting flutes start smaller than the lands and taper up to the chamber diameter.... Behind that point the diameter is constant.... Here is a drawing of a .22 cal version....The step down behind the pilot is about 0.010" to where the flutes start.... Here is a generic drawing with the dimensions of the flutes in calibers....The dotted blue lines are for a single flute, the solid blue lines for a three flute.... The depth that you plunge the mill past the centerline provides an angle to the cutting edge.... The deeper it is, the faster the reamer cuts, while the closer it is to the centerline the finer the cut and the smoother the finish.... I use 5% of the caliber, as shown in the drawing....I have not used a modified pin reamer, but others have, and very successfully.... I understand that the flutes are simply ground away where the taper reaches the desired chamber diameter, and do not touch the barrel at all behind the tapered part.... As such, that could be done with a hand grinder....Bob
Did you rotate the tool under power or slowly by hand? Sometimes hand rotation prevents a cutting edge from biting or chatter .
I run my lathe at about 50 RPM and feed VERY slowly....