Designing a peghead

[seangil]

I'm working on a new build using the Scott Antes OM 25.4" scale. The plans use a fairly square paddle head that starts narrow and widens. I prefer to do a peghead that narrows towards the top. My question is how to decide on the location of the tuner heads and whether or not there are any principles that I need to follow. For example, I have often seen advice to install the tuners 1/2" in from the side. Are there any guidelines about:

1) How far apart to keep the left and right tuner heads from each other horizontally?
2) Are there any principles to follow in deciding the line of travel from the nut to the tuner head?
3) What distance can I place the tuner heads from the side?

Thanks!

[Rudy4]

Originally Posted by seangil

I'm working on a new build using the Scott Antes OM 25.4" scale. The plans use a fairly square paddle head that starts narrow and widens. I prefer to do a peghead that narrows towards the top. My question is how to decide on the location of the tuner heads and whether or not there are any principles that I need to follow. For example, I have often seen advice to install the tuners 1/2" in from the side. Are there any guidelines about:

1) How far apart to keep the left and right tuner heads from each other horizontally?
2) Are there any principles to follow in deciding the line of travel from the nut to the tuner head?
3) What distance can I place the tuner heads from the side?

Thanks!

If you are doing your own headstock design (peghead is really the nomenclature for instruments using actual straight mechanical or geared pegs such as you will find on common banjo designs) it is best to draw out your design full size, preferably after you have your chosen hardware in hand.

A few minutes of drawing time will quickly reveal any problems you might run into like tuning machine bases that overhang the headstock edges, string post locations that aren't oriented to provide string paths that don't hit the string posts, or enough back angle to provide sufficient down force in the nut slots.

This fits into the "measure twice / cut once" theorem. It's WAY easier to correct improper layout at the design stage than living with poor choices after you start to do final assembly.

I'm personally not a fan of headstocks that taper inward because the string often spools off the string post at a weird angle, in the example of slot head headstock designs. The outward splay of conventional headstocks are designed so the string meets the string post closer to the ideal 90 degree pull. If your thought is to have the string more in line with the nut slot locations then I would again suggest drawing it out. The snakehead design trades one solution for another problem. If you simply like the look then there's nothing wrong with that. Other than practicality I'm sure there might be more flying V acoustic guitars built!

[Howard Klepper]

If you are not too far along to change, I recommend that you find another plan. The Antes plan is not taken from an actual OM, and it is overbuilt.

[redir]

Grellier's OM plan is a good one.

https://www.grellier.fr/en/downloads

It's just an 8/11 PDF and he changed the original Martin peg head and bridge design but it has all the measurements of a 1930's OM on it.

[phavriluk]

Seagull guitars use the headstock shape OP asked about. Go shopping with a camera?

[Fathand]

Originally Posted by redir

Grellier's OM plan is a good one.

https://www.grellier.fr/en/downloads

It's just an 8/11 PDF and he changed the original Martin peg head and bridge design but it has all the measurements of a 1930's OM on it.

I agree, I built a 000 by modifying the Grelliers scale length and it sounds great. Best thing is it's a free download and it prints out accurately. I paid about $10 Canadian at Staples for a print out and sometimes print out small details at home.

[seangil]

Originally Posted by Rudy4

I'm personally not a fan of headstocks that taper inward because the string often spools off the string post at a weird angle, in the example of slot head headstock designs. The outward splay of conventional headstocks are designed so the string meets the string post closer to the ideal 90 degree pull.

Thanks for your detailed thoughts Rudy. Could you explain this point a little further? I am not sure that I understand. What angles would I want to target for strings exiting nut and (separately) in relation to the post?

[seangil]

Originally Posted by Howard Klepper

If you are not too far along to change, I recommend that you find another plan. The Antes plan is not taken from an actual OM, and it is overbuilt.

Thanks - I have used the Antes Plan already on a couple instruments, but am not attached to it. Do you have an OM plan that you would recommend as better? I saw the PDF from Grellier, which I will download.

[Rudy4]

Originally Posted by seangil

Thanks for your detailed thoughts Rudy. Could you explain this point a little further? I am not sure that I understand. What angles would I want to target for strings exiting nut and (separately) in relation to the post?

Exact angles and measurements are dependent upon the specifics of what design you come up with. I cannot emphasize enough the importance of drawing it out full size to check this.

If you are working off a tried and true construction drawing then this has been done for you.

[seangil]

I have drawn out the peghead on graph paper. The strings are clear of each other. I'm not sure what I should be looking for in considering in terms of the angles that you are trying to describe here.

[phavriluk]

I had to remember to consider the diameters of the string posts and the strings themselves when I drew up a peghead.

[Rudy4]

Originally Posted by seangil

I have drawn out the peghead on graph paper. The strings are clear of each other. I'm not sure what I should be looking for in considering in terms of the angles that you are trying to describe here.

You're half-way there. Check the side profile, too. You need to factor in the string post height of the tuners you are using and also how far back the tuners are from the nut. Those two relationships will show you if you have factored in enough headstock angle to ensure proper down force in the string slots.

The fact that you're looking for specific numbers for "measurements and angles" shows that you need to give more consideration into understanding the ramifications of those numbers. Drawing your design out is the very best way of verifying your particular design will work.

I've seen newbie builders end up with guitars that had headstock angles that were insufficient to the point that the strings would pop out of the nut slots.

There are a number of things that can, and do, go wrong with designs that are not sufficiently thought out. That's why the usual recommendation for new builders is to work with a good construction drawing.

When we get into building initially there's normally the excitement in designing something for ourselves, but the old saying that "There's no need to re-invent the wheel" is a wise consideration.

Simple top / side profiles will verify your relationships:

[phavriluk]

Headstock angle is all but universally 15 degrees. Every luthier I know (both of them) uses the same headstock-alignment jig to assemble headstocks to neck shafts, no calculating, just saw and clamp and glue - - - at 15 degrees.

[Rudy4]

Originally Posted by phavriluk

Headstock angle is all but universally 15 degrees. Every luthier I know (both of them) uses the same headstock-alignment jig to assemble headstocks to neck shafts, no calculating, just saw and clamp and glue - - - at 15 degrees.

Slotheads oftern are set with less back angle because the break angle over the nut is increased due to the string post position.

Little details like this are why I suggest that a new design is checked. I've learned that someone new to building sometimes fails to mention design details like that when asking questions, so I never give simple statements for construction details.

[seangil]

Originally Posted by Rudy4

You're half-way there. Check the side profile, too. You need to factor in the string post height of the tuners you are using and also how far back the tuners are from the nut. Those two relationships will show you if you have factored in enough headstock angle to ensure proper down force in the string slots.

The fact that you're looking for specific numbers for "measurements and angles" shows that you need to give more consideration into understanding the ramifications of those numbers. Drawing your design out is the very best way of verifying your particular design will work.

Can you point towards any resources (or share any guidelines) about the parameters to target in the two relationships that you mention? I have built in a 15 degree angle to the headstock. I understand something of the issues to consider, but can't find materials that help define the numerical parameters to target or the mathematical relationships to consider. The books that I have consulted simply point to a scarf joint angle as the main factor to manage.