needing a new set of calipers

[Pete G.]

Pete, I used to think like that. Buying quality tools was a good investment, but after having thousands of dollars worth of quality tools stolen I now buy junk. I got tired of fueling peoples drug habits with my tools.

I must admit that factor has never crossed my mind.
Perhaps some pawn shop junk that is easily accessible to act as a decoy.
.....that and label the Aqua Fortis as "Liquid Meth".

[bob in the woods]

Going through the Colonial Williamsburg site,  I was astonished that the gun shop is able to keep tolerances extremely close with the old tools of the time. Worth a look.

[P.W.Berkuta]

Bob, the "secrete" is knowing how to use those tools  .

[bob in the woods]

Yes, indeed !    But, we are talking within .0005 of an inch       That is pretty darn good by any standard.

[Mark Elliott]

There is no way the gunshop at CW is measuring anything to .0005" and I think it is very misleading to give numbers like that.   I am sure they are fitting parts by feel to within .0005" but it has all got to be a matter of fitting things together and not making them to an exact measurement.   That is the nature of making anything by hand.  I don't use my modern measuring tools to make something a particular finished size.  I am just using them to get me in the ballpark and establish limits.   I just need the measuring instruments to get me to within 1/32"- 1/64" for inletting or .002" for lock assembly work.  The final critical fits are by feel and trial and error.    I am pretty certain the CW gunshop is doing the same thing and some marketing person is trying to mix apples and oranges to impress potential visitors. 

[bob in the woods]

I agree with you, Mark.  It is not the measurement process , but rather, the end result that I find so interesting.
The context for this was 2 barrels being reamed [ a double barrel gun ] and the bores when measured were within .0005 of each other.  Sorry to complicate this thread.  When building long rifles , the tools I use for measurement allow me to better duplicate a given part rather than actually give a numbered measurement.

[DutchGramps]

.... and have magnetized for some reason.  This is a problem.  I cannot set them down on the bench when I'm working with them because they'll pick up steel dust, such as steel wool fragments, that ends up in the track and causes them to skip.  I confirm that they are zeroed each and every time I pick them up.  I wish I knew how to de-magnetize them!!

I had the same problem with other tools that became magnetized: screwdrivers, chisels. An old trick is as follows: make a coil of stiff copper wire, some 50 will do. Wrap tape around to keep the coil together. Then connect to an AC welding trafo, lowest output. It starts to humm, (if it smoking, there is something wrong, disconnect quickly...)
Now move the parts to de-magnetize slowly through the coil, several times, and then it should be ok.
Hope this helps!
Hans