BoomJ asked about the Frankford 1859 star gauge set-pix

[cannonmn]

There were many dozens of parts in this set, it looked complete.  I really hated to have to pass it up but my company can only afford to carry so much slow-selling specialized merchandise.  Personally, I already have a full set for measuring 16-inch naval guns, about 1000 lbs worth of stainless steel in four huge mahogony boxes, so I think that's enough star gauge for me, even if this one is far prettier and infinitely more historic:













Direct links for bigger pix:

http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9467.jpg
http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9468.jpg
http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9469.jpg
http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9470.jpg
http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9471.jpg
http://i17.photobucket.com/albums/b62/cannonmn/miscforumsetc/forums42/IMG_9472-1.jpg

[Cannoneer]

Thanks for posting these pics, Cannonmn. I paused on the photo in the slide show, and looked, and looked, and looked, and for the life of me, I couldn't figure out what was inside the wooden case. It's interesting to note how a utilitarian tool of this era was given such care, and extra time in crafting it, as to make it seem almost like a work of art.

If you've got the time, would you give a brief description of how it was put together, and used?

You mentioned 16-inch, and stainless for the star gauge that Springfield A has, so I'm guessing that it's meant for checking the barrels of the big guns of WWII.

[cannonmn]

Machinists call a star gauge a bore gauge.  Each caliber of gun is represented by a set of three points that fit into the head (thing at end with rectangular sockets in it.)  The long shafts screw together.  At "out of bore" end is a micrometer.  The thing is put together with appropriate set of feet for that caliber, then calibrated with one of the steel ring gauges provided.  Come to think, there should really be one for each caliber, and there were only two or so?

Anyway, once put together and calibrated with ring gauge, it is put down the bore at say three-inch intervals of length, and a reading of minimum bore diameter taken at each position, and recorded.  The shiny bar with half-loop in middle is where the intrusion is read, or stopped, as that fits across muzzle face.

I made up all the foregoing, but I based it on how these type instruments always work so shouldn't be too far off, if more precision desired, one of the old Ordnance manuals on googe should have more complete insts.

You mentioned 16-inch, and stainless for the star gauge that Springfield A has, so I'm guessing that it's meant for checking the barrels of the big guns of WWII.

correct.