Chris, bad example with the car engine. Yes, when we're machining the block at the factory we have blueprints to work from. With blueprints you have tolerances. Take the deck height of the block (we called it a "case"). It's measured from the crank centerline to the head deck. If I remember right, we had .020" tolerance on this dimension, with the 4 corners having to be within .005 of each other. Most of us Toolmakers have enough pride in our work to set the fixture to cut flat within .002". As the machine wore the dimensions would creep to the outer limits. To "blueprint" the engine as we call it, the machine shop will mill this surface to within .001" of being flat, to the low end of the height, and equal on both banks. The idea is to bring everything to zero tolerance/right on the basic dimension. If you have a 85 thru 96 350/305 V8, built at Flint Engine, odds are that it's got my fingerprints somewhere on it [img]images/icons/grin.gif[/img]
In engine building and machining, there are acceptable tolerances and clearances. Blueprinting for an engine or whatever, the way I understand it, technically, is done before or after the work is performed, either to establish the specifications and or to define them.
So, is this term used loosely? In my understanding it certainly is. That word does not guarentee what you want done will be done, probably someones interpretation of it maybe done, but unless you specify the actual machine work you want done, I wouldn't count on it.
In reality, your rifle is blueprinted from the factory to an extent, just not what you and I equate to blueprinting, same with a factry engine, sorry AJ, but I'm sure you'll agree. If you want minimum spec ring end gap, get oversize and start filing. If you want every oz. of oil pumped from the pan filtered, you better tap and plug the bypass valve then. Port match the intake and exhaust for best flow and scavenging to increase VE. And there is so very much more to blueprinting a race engine I won't even go into it. Makes the rifle look all too simplistic though!
Yes, there are tolerances, but the is now blueprint for true-ing an action. Rem has BP that they build to, but custom smith's this does not exist. My point is the term is used loosely if not incorrectly.
Well, hell I'm sending my rifles back to Chris.. I asked for blueprinted actions and all I got was trued ones!!
If I had only known what the hell I was talking about...
Thanks Chris for clearing that up!
Now I am wondering how many guys ask for a blueprinted action and actually supply you with the blueprints???
The way the term "Blue Printing" any action was explained to me is: The smith has a set of blue prints, or a drawing of the action and all the specs. The action is then machined to those "specs" and tolerances. Either the smith makes the drawing, or it is supplied to him. The point is he has exact "directions" to follow.
I guess it would be similar to building a house off of prints. If the print calls for using 2x6 construction on all walls, it better have 2x6 on the walls.
Brent, I used to have a paper that described what Hendrick does to their motors, more like a book! GM tightened so many of our tolerances that the quality of the factory motor was unbelieveable. They had full expectation for a smallblock, with proper maintenance to last for 300,000 miles. I can give you a clue though, its called "Mobil 1" As sais "blueprinting" is used in the wrong context, for a gun it has more to do with removing everything thats out of square, or in a M700 case, putting the dang scope mount screws back in alignment with the bolt axis
Chris, might I ask, Do you have specific dimensions you try to hold, say as an example, when your squaring up the action face, other than eliminating the runout? I understand that if your rebarreling you measure the boltnose and make the barrel counterbore to a specific size, you might create your own blueprint.
Ya gotto do something with that guy from Wyoming, his slobber is making my keyboard messy [img]images/icons/grin.gif[/img]