Maintain the angle you want for the bevel and always work in a circular motion to get an even surface; the larger the working surface of the hone, the easier it is to maintain the geometry of the work. The harder the flint, the more resistant it is to cutting in a single direction and thus is why natural flints don't take kindly to sawing as do the common agates. Biggest thing to avoid is producing a knife-edge on the flint; it's okay to get a knife-edge while working the angle but then use the hone/file to take the knife edge off before firing as the too-sharp edge will tend to break and/or chop a crater into the frizzen.
There's no wrong answer in which style of tool you use, whatever works best for you is the best for you to use but there are differences between CBN/diamond coated tooling and common abrasives like aluminum oxide. Don't use too-much pressure as it will reduce the cutting action and increase wear on the cutting surface. The cutting surface on this tooling is sharp from the start and does not require a certain amount of contact pressure to break the grains in order to expose new sharp cutting points as is the case with Zirconia and A/O (Aluminum Oxide).
Never use oil on any of this tooling as it will only load-up the cutting surface causing uneven cutting. If a liquid is desired to keep dust down or flush away the cut material, plain water with a few drops of a liquid detergent is best but be sure to fully flush the surface of the hone/file. When working them dry, do not bounce them or run a card/brush over them as is commonly done with a steel file but rather blow them off with compressed air (of course the warning about airborne particulates, eye & skin protection and bla, bla, bla all apply)
If you work a flint while it's in the gun, hold the gun so that the dust falls away from the lock as the dust is highly abrasive.
CBN & S/C (Silicon Carbide) are somewhat similar in application but S/C is softer and does not work in a coating form on solid substrates like CBN does. CBN will readily cut carbides and ceramics, pretty much anything except real diamond while S/C has considerable limitations beyond hardened steel and certain carbides. CBN is normally a thin coating on top of tool steel while S/C is best when formed into a shaped mass to be used as a stand-alone or glued to a mounting plate or shank as is the case with face-cut wheels and abrasive grinder points. Both CBN & S/C are very useful on hardened steel such as frizzens and lock parts because they do not require annealing the part in order to work it. S/C hones and stones are available in a variety of sizes and shapes but like CBN tooling, S/C is best used with water rather than an oil. The biggest killer of both CBN & S/C tooling is using too much contact pressure - let the abrasive do it's job because if you force it, you're defeating the purpose of the abrasive. CBN maintains several advantages over S/C in its ability to cut harder materials and also in that it won't load-up when cutting soft materials like brass & copper. CBN also works on dry hardwood but oils & sappy wood will cause clogging the cutting surface.
Just a word on grit sizes too. 180grit CBN will "feel" much rougher than 180grit A/O sand paper because the A/O is not fully sharp as is the CBN - normally only about 65% of the surface of A/O, be it paper backed or solid formed as in a stone, is actually sharp enough to cut. With use and the necessary amount of applied pressure between the work and cutting surface, the A/O breaks down exposing new sharp cutting edges but still the surface maintains only about 65% sharpness on cutting surface. CBN has 90%+ surface area sharpness while formed S/C runs around 85-90% on average.
Cost for both CBN & S/C is simply a matter of how much the retailers can sucker out of the customer. The thickness of the coating on CBN tooling varies greatly but it all wears the same and cannot be re-surfaced with anything other than real diamond so once it's done cutting, it's done cutting and it doesn't matter how much coating remains on the tool. Same deal with S/C hones and finishing sticks, S/C is S/C and the color is added to the binding agent for nothing other than brand/grit identification purposes. If you abuse S/C, it's wrecked just the same as anything else and paying $4-$12 each for S/C finishing sticks doesn't make them any better cutting or more durable than paying $2 each buying a set of six.
The majority of my experience with abrasives is as the end-user, I didn't start selling until my body crapped out in '05 putting an end to my industrial business. BTDT (Been There, Done That) on most of this stuff like getting suckered by the "salesman" into paying high prices for Zirconia coated sanding belts only to find out that they ain't worth a hoot for use on anything softer than alloy steel because you need an excessive amount of contact pressure to break the grains and expose new cutting edges. Got suckered into paying around $240 for thick-coated grinding wheels to sharpen tungsten GMAW electrodes only to find out that they don't work any better or last any longer than the thin coated ones costing half as much. It's the same with PSA sanding discs, where the sales hype will get you to pay more for "white" by telling you it's "special for use on wood" despite the fact that the only difference between the "white" A/O coating and the "yellow" A/O coating is the color - then too, there is one mfg that makes a number of different "brand names" so you can buy the same discs in the plain generic white box for $29/roll or wait until they get stamped with a brand name and put in a fancy box so you can pay $49 for the same roll.
I'll submit a read-only ad to Dennis if anyone is interested in this stuff.
