Marking/layout techniques

[Jerry V Lape]

I understand the importance of maintaining center lines while building and have also found it useful to have a way of marking lines other lines which need to appear on both sides of the stock as well.  Question is what are some of the ways experienced builders are setting these various lines and maintaining them through the build.  I seem to lose lines and need to remark as building progresses. 

[Acer Saccharum]

I work off the barrel. Looking down on the barrel, I use a 1/8" spacer to draw a line along both sides of the barrel. In the lock area, I can have 5/16 to 3/8 or more, depending on the lock and type of gun, on either side of the barrel.

I use a centerline for wrist to buttplate, and from trigger to buttplate toe. If there is cast off, I account for that when I first make my lines. A vertical line on the butt end will help me remark if I lose my top or bottom line.

[Mark Elliott]

I use the same center lines as Tom.   I use a 48" drywall rule to layout the barrel center line on both the horizontal and vertical.  To some extent, the center line is eyeballed for "looking right".   Everything has to "look right".    Once I have the barrel in,   I use a divider (antique) to scribe a 1/8" or 3/32" line along the barrel for the sides of the forearms.   I layout the lock panels relative to the barrel using a six inch flexible rule to mark the width of the lock bolster.    I use a flexible rule to extend the lines of the barrel back in order to get the back portion of the lock panels.  Again, it all has to "look right"    I do have templates to start the layout for each stock profile.    Basically,  it is all magic.       

[okieboy]

" I use a 1/8" spacer to draw a line along both sides of the barrel. In the lock area, I can have 5/16 to 3/8 or more, depending on the lock and type of gun, on either side of the barrel."

 Some of the handiest layout tools for this sort of spacing are pieces of square keystock, which you can buy at the hardware store in various sizes from 1/8" to 1/2".     

[Hank*in*WV]

I've been using drill bits for spacers.

[WKevinD]

I layout the same lines, butt to tang, heel to trigger, trigger to entry thimble, lock panel/ sideplate panel.
I use flexible stainless steel rulers and I have a set of horseshoe shims 1/16", 1/8", 3/16", 1/4" that are used in window and architectural glazing installations. The horseshoe shims are inexpensive, plastic easy to use and stack for different combinations or replace, the ones I use now hang over a nail above the bench for easy reach. The only thing I use more for consistent dimension and layout is the "Lucky Bag" depth gauge...best layout tool ever!  
http://americanlongrifles.org/forum/index.php?topic=26975.0