what are the sorts of things that a master builder will do that lesser ones don't? What are these 'unseen' things? What are those extra touches? I'm not experienced enough to know.
Well, this is what draws my eye when I see a Potts frame.
The first item that demands my attention are the classic lines; the frame/fork/stem seem to flow together proportionally and with grace. Technically, all tubes are bowed slightly...did the builder take the time to roll out the tube on a surface plate to find the anomoly and place it in the vertical plane or is the tube just haphazardly mitered and placed. You'd be surprised how many frames, production or custom, have not had this simple quality control. The Potts frames I've seen do have this important but small detail attended to.
The Potts frame is purpose built, meaning that the tube diameters, profiles and placement tell the story of the intended ride characteristics. By looking at the design, one can tell how the builder inteded the frame to feel. The Potts reveals much...a stable, predictable front end, vertically compliant stays that fend off trail chatter, and a lower half that is supple yet will be laterally responsive for those out of the saddle climbs. The bike speaks to comfort for longer trail rides without giving up performance.
The fillets are fabulous...even though they are filed and smoothed, you can see an even transition from tube to fillet to tube. Uniformity in the transition line tells that the fillet was layed consistantly around the joint and that sufficient brass is in place to create the strength required for longevity. The shape of the tubing at the fillets is straight and consistant, proving that the joint was not overheated during the process...sometimes a fine line between amateur and pro.
Functional artistic touches like the custom seat tube cluster and through-stay pinch bolt are intensive pieces. People do not seem to understand just how long it takes to create such a small part of the entire process. The seat cluster is many hours of work; in machining, brazing and filing. This one piece tells alot of his ability and patience for the work.
Alot can be told by how the builder connects the dropouts to the stays. Are they quickly attached by slotting and welding or has the builder sculpted the area, filled with silver, created a custom touch, etc... Take a look around, you'd be amazed how many stays are just crimped and tacked in place on "high end" production bikes, or stays slotted and welded with the ends left open...ughh! It's the attention to detail that sets it apart.
How's the paint. With the investment of time in the construction, what does the builder spec for his minimum acceptable paint work? The Pott's I've seen have high quality materials used with multiple layers of sanded clear. It's not uncommon for some paint to take as long as the frame construction.
So, enough rambling. Just some diatribe in my opinion on what sets a quality frame apart from others.
In the end, I'd love to have a Potts, but alas, will never be able to aford one.