irvin00 said:
My point is very simple, actually: let's assume you get your pencil to the exact thickness because you value/need that level of precision. That's fine and there is absolutely nothing wrong with that. However, most guys, in my experience, do not own a shop where every tool is calibrated or can deliver the same level of precision. So, the original ultra-precise measurement is wasted as soon as you hit the 'lesser tools'. For example: aligning your line to the Festool rails by eye, cutting your wood on a Ridgid/DeWalt, Jet or any generic table saw, working with a hand plane, using some types of wood or even suffering the ultimate betrayal: your skill level is not the one that can extract the most from your tools!
Most woodworking does not need (or even exhibit) that type of precision. Look around you and you will see that even the most expensive furniture has the little flaws that we, hobbyists, worry so much about.
But, I, like most, lust after a high-end, shiny new tool I find. The lesson, for me at least, is that sometimes too much can be just that: too much. Even when it comes to precision.
Irvin,
I understand where you're coming from and no arguing those points, however, and this is just the way I prefer to do things and my opinion which is not laid out to force upon anyone reading this:
I feel that guys that make furniture using hand tools or a mix of power and hand tools that don't use some form of precision, usually have to fidget with their joints to get them tight or loose or lining up, etc. doing a lot of tweaking that could have been reduced or avoided all together. Also, cabinetry might be a little bit off to the eye, holes might not line up and things frustrate the person doing the final assembly because of that.
I look at most things I'm making in regards to multiplicity error and how to keep it as low as possible. Your final result is only as good as your weakest link or measurement. When I start with as high a precision as possible throughout the project, there will be something that doesn't achieve that level and the more things that don't, the increase in error. By starting high, my low is usually very acceptable.
I understand that most people aren't making cabinetry on CNC equipment and therefore the error is greater, especially including the human factor like you mentioned with lining up a guide rail to pencil marks or having your table saw adjusted flawlessly.
I've seen many times where on a framing job, guys won't put a lot of care into things like stud placement on layout marks. They say things like, "So what if it's off by an 1/8 here or 1/4 there" or more. When you do that enough down a wall those sheets of drywall ain't gonna land on a stud at some point like they were meant to and somehow that door or window opening doesn't line up or a roof truss doesn't land over a stud for proper load transfer that the architect spec'd or later down the line the trim guy is cursing at the framer who's long gone --- just extreme examples I'm throwing out.