First steel string build - Martin 5 style small guitar

[Bob_H]

I am making some progress with my current project, a Martin 5-style small steel string acoustic guitar (LMII plans). Big leaf maple back and sides, western red cedar top, Queensland maple neck, gidgee fretboard. Will be making a gidgee bridge, and applying some Blackwood bindings.

Pretty happy with things so far, although with much to learn. Box is closed, and after some adjustment, neck fits nicely. Should have left the final finishing of the fingerboard till later - next time!

I have a question about bridge design - I was reading a review of the Martin 5-18 on the Vintage Guitar magazine site, where they featured photographs of a 1932 originalhttps://www.vintageguitar.com/19313/martin-5-18/. The saddle does not feature any compensation. Was this common at the time? How much effect would it have on the ability to get the guitar into a decent state of tune? The LMII plan does include some compensation in the bridge design, in line with larger steel strings, but I wonder how important it is for a smaller guitar?

[56nortondomy]

Hi Bob. I'd compensate the saddle, I do on all my guitars now matter what the size. I'd re think a gidgee bridge it's a heavy timber, it's ideal to have the lightest bridge possible, I use EIRW but walnut is good also, there's plenty of other choices as well.
Wayne

[TallDad71]

Compensate the saddle. The guitar has taken a lot of effort and looks great by the way, the least you should do now is make the notes sound close to perfect.

Stew Mac make the Intonator which is brilliant for getting your saddle spot on. You can easily make one yourself.

https://www.stewmac.com/luthier-tools-a ... nator.html

The only hassle is that ideally you cut the saddle slot after it is glued to the guitar, it’s easy enough but you have to make another jig.
https://www.stewmac.com/luthier-tools-a ... g-jig.html

[johnparchem]

Nicely done. good looking guitar. I love small guitars.

[Bob_H]

Thanks all - will go with compensation in the bridge. Might also have a look at bridge materials - although I have a gidgee blank - perhaps a practice piece - I have made ukulele tie bridges, but they are pretty simple compared to an acoustic bridge.

[Mark McLean]

Hi Bob. That terz looks great. I also vote for compensating the bridge but I prefer to cut the saddle slot in the bridge blank before gluing it on. I calculate the amount of compensation I am likely to need for a given instrument, and this calculator by Liutaio Mottola is really useful - especially for a short scale instrument like yours. I use the straight saddle method ( explained in the notes at the site).
https://www.liutaiomottola.com/formulae ... sation.htm

As an example, for my builds of a 25.4 inch steel string I add 2mm compensation for the 1st string and 5mm for the 6th string. Therefore there is 3mm slope between the two. This is the important number to know (lets call it X) as you cut the slot, and it will work out to be a bit different for your shorter scale length. I take a bridge blank and mark the centre line, and then the lines that will correspond to the paths of the 1st and 6th strings. Then draw a line perpendicular to the centre line about 4-5mm from the front edge of the bridge blank (lets call this line A). Draw another which is parallel to it, Xmm behind the first line (line B). Your saddle slot will connect the point where line A crosses the first string, with the point where line B crosses the 6th string (and will extend a bit further in each direction). I cut that slot with a router while the bridge is still a rectangular blank. Then shape it to whatever design you want and drill pin holes. When it comes time to glue it onto the guitar I measure the distance from the nut (or zero fret for that one you are building) to where the leading edge of the saddle should be for string 1 and 6 and stick it down