I've made hundreds, if not thousands of Perfect Fit. It is one of my very favorites. It sells well ,uses a Monteverdi or Parker Ballpoint, and can use a 7mm pencil insert without modification.
THE ONLY THING HARD ABOUT PERFECT FIT IS THAT BEREA DOESN'T KNOW HOW TO MAKE THEM. I'm surprised that anyone can make a perfect fit using the instructions and tooling recommended in the instructions.
STEP ONE: THROW AWAY THE INSTRUCTIONS, they are useless.
Measure and square a top blank EXACTLY 1 7/8 inches long. FORGET ALL THE "tenon cutting" BS! It'll just screw up the centerband fit. I like to use my miter saw to make an exactly square top 1 7/8 inch blank.
STEP TWO: DISREGARD the recommended drilling bits. OVER-SIZED holes are your worst enemy on the Perfect. Take a caliper reading of the outside diameter of the top tube. Select a drill bit exactly that size. Even with the most precise lathe drilling set-up, there is probably enough "slop" to allow for a perfect tube fit. IF not, use a rat-tail file to obtain perfection. This only takes SECONDS and OVER-SIZED holes will make PF fail. Make the exact measurement for the bottom tube, too. Size is EVEN MORE critical on the bottom blank.
Next, Prepare you tube (if you MUST sand the tube, go ahead. Say a little prayer if you like, too- neither will help if you've "overdrilled" the hole) Glue the tube EXACTLY FLUSH with the clip end of the blank. This will leave the EXACT AMOUNT of a perfectly round, exact diametered tube EXPOSED to press a centerband over. THERE IS ABSOLUTELY NO REASON to turn a tenon down to a brass tube! this is a recipe for disaster, and just creates more work.
STEP THREE: If you MUST use bushings and a mandrel, go ahead. JUST BE SURE to insert the "filler" bushing over exposed tube at the centerband bushing. NOT inserting this "filler" bushing is essential for those of you who over tighten the tail stock, as you could crip the exposed tube.
I find the Berea "B" adjustable mandrel perfectly USELESS for making a perfect. If you must use a mandrel, for about 1/4 the cost of the mandrel, you can buy a piece of drill rod (Size D, I think, but look it up), tap it to a size you like so the bottom barrel bushing does not have to fit half over the mandrel and half over the threads, but instead your "custom" threads transition perfectly to the mandrel, then mount the drill rod into a Beall collet chuck.
Personally, I think TBC is the way to go on the bottom half of the perfect fit.
STEP FOUR: Throw you pen mill away! On the bottom barrel, length is critical. A sanding jib shouldn't shorten your blank OR ream out the hole so that the nib is a loose fit.
STEP FIVE: assemble the center band in the proper order (unless you make your own custom band). That order is: large decorative ring over the center band coupler and small ring on top of the decorative ring. THEN, drop one drop of Loctite thread sealant over the exposed tube where the center band presses. The Loctite acts as a lubricant while pressing, and works like a "removeable" glue when it dries.
STEP SIX: Charge at least $65 for this pen as it will be much better made and more exact than any instruction kit pen.
