A capodastro or capo tasto is a device that allows the "open" notes on a guitar (played without fretting) to be raised in pitch. They are commonly used in place of tuning an instrument higher because a capo is safer and runs a smaller chance of breaking a string or the instrument such that a guitar tuned to E standard can be capo'd on the 5th fret and be in A standard without any increase in tension.
Guitar capos have a wide history of designs and uses but one that is often overlooked is the built-in capo. Pictured below is a 1920s Lyon and Healy built guitar with a capo that was installed into the guitar at the factory. It slides down a channel in the fretboard and is tightened with a thumb screw to set the instrument's pitch. I am unable to find any catalog scans or L&H patents for this design but it is the first one I've seen.
|1928 Lyon and Healy Washburn|
Image Credit: Reverb - DFW Guitars
1894 was the year that F. R. & R. Whelan patented their "Capo Tasto" for the guitar. It was a bulky device that slid along a short track spanning a single fret. It was secured to the headstock via an elastic band which would pull it back out of the way when not in use.
Inventor Czar Prince patented his capo in 1897 which also could only modify the pitch from a single fret. It was inlaid into the guitar behind a specific fret and activated by a lever which pushed a secondary fret upwards just behind the primary fret. It likely would've been praised for its ease of use and fluid movement in changing the tuning despite the intrusiveness of the device.
E. H. Winchell applied for a patent in 1901 for a capo that used threaded inserts in the guitar's fretboard to attach and remove the device. If you wanted it on the 3rd fret then you simply unscrewed it from the headstock, lined it up on the 3rd fret, and tightened the thumb screw to mount the capo. This allowed for infinite placements as long as you had the inserts installed in the board but would've taken more effort to change tuning.
Integrated capos have disappeared from modern guitars entirely and are incredibly rare to find in antique guitars. The standalone capo was patented in 1850 by James Ashborn and improved upon alongside the integrated capo through the late 19th and early 20th centuries. The Hamilton Capo is a common piece with old guitars along with the elastic fabric capos that are even more common with budget instruments.
|Vintage Hamilton Capo|
Modern capo units are removable which allows them to be attached to any number of guitars and they benefit from being cheap and reliable. The spring capo is probably the most common design out there right now. There just isn't a demand for a capo that is limited to a single guitar much less one that involves so much drilling and modification. Unfortunately they are a relic of a gone time but I believe they are worth remembering.
|Modern, Inexpensive Spring Capo|
There is a great site called TheGuitarCapo.com which features a brief timeline of the capo's design as well as other tips. It currently appears to be online but the Internet Archive Wayback Machine has a copy of it which can be viewed here: