Blue printing

Discussion in 'The Basics, Starting Out' started by marketello, Nov 9, 2004.

  1. marketello

    marketello Well-Known Member

    Oct 6, 2004
    OK, yet another newbie question.

    What does it mean to blue print an action? How is this done, how expensive is it. Does a gunsmith have to be good at it, or can any gunsmith handle the job?

    People blueprint handguns also, right?
  2. Fiftydriver

    Fiftydriver Official LRH Sponsor

    Jun 12, 2004
    Well let me tell you how I do it,

    Step one:

    I install the action in my blue-printing fixture which is a round aluminum cylinder with four bolts around the front and rear of the cylinder. These bolts allow me adjust the action inside the fixture to dial it in to perfect concentricity with the axis of the botl way.

    When the action is relatively close to true I place the entire fixture in my 4 jaw lathe chuck and take out all the run out inteh fixture as it spins.

    I then use specially sized bushing to match up with the internal bore of the bolt way, one in front and one in the rear of the action. A precision ground mandrel is then slide in these bushings which has a nose that projects 6" out in front of the action.

    This mandrel is perfectly centered to the axis of the bolt way of the receiver.

    I then take two 0.001" dial indicators and place one at 12:00 onthe mandrel right at the face of the receiver and the other again at 12:00 out on the end of the mandrel, 6" out from the receiver face.

    I then adjust the front and rear bolts until the dial indicators are reading under 0.001" run out.

    The 0.001" indicators are then replaced with 0.0001" indicators and the dialing in process is carried out until the action is running as perfectly true as my eyes can read the dials. Well less then 0.0001". This takes some time for sure but the results are worth it.

    Once the receiver is running true in the lathe I remove the mandrel and set up the single poitn thread cutter to go in and true up the thread so that they are in perfect concentricity to the bolt way axis.

    To clean up the thread, they generally need to be opened up anywhere from 0.005" to 0.015" larger in diameter.

    Once the receiver threads are trued, I then square up the bolt locking lug recesses in the receiver by taking light facing cuts until the recesses are perfectly trued up.

    Step three is to true up the receiver face by taking light facing cuts until the surface is perfectly square and free of defects.

    Now the receivers critical surfaces are all true in relationship to each other.

    It is now time to true the bolt itself.

    I switch to my 6 jaw chuck and insert a precision ground threaded stub into the chuck and dial indicate it to 0.0001" or less.

    I then thread on the stripped bolt body onto this stub and bring the tail stock with the live center into ride off the firing pin hole.

    Now the bolt is centered on the firing pin hole and the axis of the rear of the bolt.

    Light cuts are taken to true up the forward surface of the bolt nose (on push feed style bolts), the diameter of the bolt nose is trued (again on Rem 700 style actions), the front surface of the locking lugs and the rear baring surface or th ebolt locking lugs are recut perfectly square to the action.

    A collar is then fitted to the bold body and dial indicated to remove as much run out as possible. The collar is then turned down concentric to the firing pin hole.

    The Steady rest is then brought in and with the bolt still supported by the live center of thetail stock, the three fingers of the steady rest are adjusted to support this trued collar and the live center is then pulled away from the botl face.

    Light facing cuts are then made onthe bolt face to assure it is perfectly square.

    The bolt is then untreaded off the stub and cleaned as is the receiver.

    The bolt is inserted into the receiver and measurements are taken fron the face of the bolt to the face of the receiver.

    This measurement will tell you how perfectly square the four critical surfaces of the action are. These are the receiver face, the receiver bolt lug locking recesses, the bolt locking lugs and the bolt face.

    I generally take a measurement at 12:00, 3:00, 6:00 and 9:00.

    These measurements should all be within 0.0001" to 0.00015" before lapping the lugs or the action does not pass inspection and the out of square dimension is found and corrected.

    Once I am confident the action is perfectly trued, I will lap the bolt lug surfaces to an 800 grit finish which generally only take a few minutes after printing in this manor.

    The only other step I will do when printing an action is to recut the bolt way and sleeve the bolt for a tighter quality fit.

    if your interested in prices please e-mail me and I will get you that information.

    [email protected]

    Yes I believe a smith should really know what they are doing to get a quality printing job for your money.

    Good Shooting!!

    Kirby Allen(50)
  3. Guest

    Guest Guest

    YOU DA MAN KIRBY! Hope to send you one of mine in the near future. It's really nice to know that there are quality Craftsmen out there; who still take pride in their work! As for me, when there are tolerances, my questions is, "What's that zero for?" but I'm a bit of a perfectionist, and I can tell that you are as well. Great explanation!!!
  4. Mysticplayer

    Mysticplayer Well-Known Member

    Jul 27, 2001
    Greenhorn, Kirby has given you a wonderful description of what I call Truing/accurizing an action. Some smiths can do this, others can't. Some do it well, and so on.

    Where you may run into problems is that blueprinting in the machining world simply means that the object is returned to within the orig factory BLUEPRINT dimensions. That is not what Kirby is doing. In fact, he is taking the action outside the factory dimensions and tolerances. That's a good thing.

    When asking your smith about 'blueprinting', see what answer he gives you. If the Kirby answer, then that costs bucks. If the machining blueprint, then not really worth the time because any commercial action is already within factory specs if it not damaged.

    Is Truing/accurizing necessary? I guess that depends on what you are using the rifle for. If I were to build a full out BR rifle, then you bet. Every little thing matters.

    I were building a varminter or hunting rifle and all I needed was 1/4 to 1/2 MOA, I would spend the money on a good quality barrel and have the install done properly leaving the action as is. Focus on proper bedding, trigger work and good loads. Actions within factory specs will offer that level of performance.