Official Luthiers Forum!

This tool is for sale for $60. It appears from the photo that had other tools in it to have about a 6" throat. I am thinking of getting it because it would be 1) useful for plate and side thickness, and 2) it's as cool as all get out

Ed M

That's definitely cool. I use a similar tool that has a dial indicator in place of the protractor-looking gauge. Same trigger and jaws though. I use it all the time.

Dave

Hi Ed,
What units does it measure in? Are there others available or is it a one off?
I know you have an interest in old tools, as do I, so at the risk of derailing the thread I will show you something I picked up a number of years ago at a flea market. It measures in Truchet points, which are 1/12th of a ligne, which is 1/12 of a pouce, which is 1/72nd of a toise.
To small to be much use for measuring plates, but someday I may find a use for it.

There are a bunch of similar designs that have been around for a long time--here's a quick Google search I did that has lots of interesting pictures:

https://www.google.com/search?q=antique+thickness+caliper&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiG6NnP1snuAhXnY98KHVrECXIQ_AUoAnoECBUQBA&biw=1581&bih=1249

I really love cool old tools too...

Dave

Thanks for the link Dave,
I found a picture of the same one I have. Apparently it was used by watchmakers:
https://www.gilai.com/product_436/Propo ... asurements.

The truchet point, ligne, pouce, toise, are divisible by 12, something common in horology.

There's a similar device that was apparently used by opticians for measuring lens thickness.

Back in my British car days, keeping up with SAE, Metric and Whitworth was tough enough! Truchet point, ligne....

Dave

On the other side of measuring thickness--this is one of my favorite old tools. It's a cello maker's thickness device to punch holes on the inside of tops and backs to leave marks at a certain thickness. Sort of like people do with a drill press any more. You can adjust the distance between the punch and the fixed platen to set the desired thickness. Cool old hand made tool though:

Clay Quoi?

Dave

Dave,
Those old French measurements have that "je ne sais quoi" , that I find attractive.

Having spent a good part of my professional life making measurements and converting measurements in everything from links, rods, chains, and perches, to Russian Mils, to dump truck loads, I have developed an interest in archaic measuring systems and tools and how they relate to the fields of endeavor they were developed for.

Very cool look on things. I've spent my professional life living in hexadecimal and earlier on octal, not to mention binary. But measurements and conversions are definitely fascinating! At least to me.

I still speak hexadecimal on occasion but I don't speak French...guess it's not too late to learn.

Dave

Hi Dave,
I don't speak French either. I have faint remembrances from 3 years of high school French. I do find the way languages are put together, interesting. That some languages are SOV (Japanese, Korean) and others SVO (English, Chinese, and most Romance languages). And then there is Welsh ...

OP, That looks like some sort of torture implement!
I use an old "dial indicator" mounted on a wood base and arm to increase the reach a bit. It is fairly accurate, enough to know that my tops are .130" when I stop thickness sanding.

_________________
https://www.facebook.com/profile.php?id=100008907949110

That looks like a well thought out design. How do you adjust it for the initial 0.10 inch?

For anyone interested, a friend gave me a thick little book entitled 'Measure for Measure', by Young and Glover, Sequoia Publishing, several years ago. It's got every conversion factor you'll ever need. It gives several different ones for 'pouce', depending on whether you're in Belgium, France, Haiti, Paraguay or Switzerland. Fun to just browse through, if you're into that sort of thing.

Hah, I made both of those things. The punch on the thickness punch is a bolt with a 1.mm pitch, and I ground five sides on the top, so I can start at 5mm, and move it in .5 mm or whatever I want. The gauge was a tenth mm gauge that was on sale in a catalog. It only has 10 mm travel. Both work good for violins up to arch tops and cellos.

The dial is especially nice on backs where I might go from 5mm in the middle to 2.5 at the edge. You can watch the dial spin around, and if it slows down, or goes backwards it is too thick there, Makes it very easy to fine tune. The punch I basically only use only for roughing, and for marking rib stock when it is thinned down to maybe less than 2 mm. Set it at 1.5 mm or so, and slide the ribs under it, scratching it up. Plane, scrape, file until the scratches are gone. Then you can bend with your fingers to find any stiff spots.

_________________
Why be normal?

I bought this at a flea market in Pennsylvania for $10 years ago and have been using it ever since. I had been using a home made one that sat on the bench top, but for me anyway, having the hand held caliper works better.

Dave

Dave

OP here - your link to the google search showed one like I posted, and said it measured in 64th's. It also showed that the throat was more like 4". Would this be accurate enough for plates and sides based on your experience with yours with a dial indicator?

Who would have thought that a tool like this would garner so much ihterest?

Ed M

Clay, most dial indicators allow you to spin the dial & lock it to "0" it, then slide the wood into the gap for a direct reading of the thickness.

_________________
https://www.facebook.com/profile.php?id=100008907949110

For me anyway, it would be plenty accurate enough--that's measuring in increments of close to .01 inches. I think that 4 inches deep is a bit shallow, but it would get the the middle of any top/back wood that I ever use.

Cool old tools are always interesting!

Dave

There is a school of thought which says that since Strad et al used 'Cremona inches' in their work, you can't make a great violin using any other measure. You can get rules and such graduated in Cremona inches, calibrated from the old pillar in the market place.

A fellow student in my violin making class had a home made gauge based on a dial indicator marked in thousandths of an inch. When the teacher came over to check his work she'd do a double take at the numbers. He just took all the measurements she gave in millimeters and multiplied by forty; close enough.

When I moved into an old house a long time back I found a boxwood ruler with brass tips in the cellar. It was marked: 24" in 24-1/4". Sure enough it's exactly 24 -1/4" long, and is divided into 24 over sized 'inches', demarcated accurately, so far as I can tell, in both fractional and decimal divisions. It's a 'shrink ruler', used by pattern makers for making the the wood patterns used for producing brass or bronze castings. The metal shrinks as it cools, so the pattern needs to be made over size from what's called out for the part on the blueprint. Having a shrink rule like this saves the guy making the pattern having to do a lot of math. I still have it, but I have not yet slipped it in on a student...

I love old rules, especially wood with brass ends. I have a 48" rule,(marked in whole inches only) 2" wide x 1/4" thk. with a brass hook at one end. It is supposed to be a cloth seller's rule. I use it from time to time, but not for guitar stuff.
I have a collection of Starrett machinist rules, 6", 12" & 18" that I constantly use, and one of those goofy Stewmac 0-centered rules, pretty handy though.
I also have a wood rule that I made myself, a saddle compensation rule marked for short and long scale, used for setting the bridge on my guitars.

You know what would be a fun challenge? Build a guitar without any rules or measures, and see how it turns out. Actually, I get quite a few repairs in the shop that seem to have been built that way.

_________________
https://www.facebook.com/profile.php?id=100008907949110