Martin 000 / OM-45 Build (Questions)

[rccosta]

Hi all -

I'm taking on a Martin OM-45 Deluxe-style build and have a few questions I'm hopeful you all can help out with:

1. Body Template: Anyone have a template / body outline to scale they wouldn't mind sharing? I've effectively traced mine on a laptop screen after normalizing the image to a known dimension - brute force but it has worked in past builds.

2. Top Radius: Is the top radiused? I am under the impression OMs are flat tops, but have seen some threads that suggest a 48'-56' radius (which would be virtually imperceptible, so what's the point?)

2b. This is a stupid question but I just want to confirm: to accomplish the "top radius", the soundboard is never actually radiused - correct? The mechanism is, instead, radiusing the braces, and then upon glueing the braces to the soundboard it causes the soundboard to contort to the desired radius?

3. Side Lamination: There seem to be two camps in this regard, I think I'm in the solid wood camp as opposed to the 3-piece lamination for sides, but curious if anyone knows what vintage 1930 Martin OMs used?

4. Back Radius and Thickness: I'm aiming for a target back radius of 15" and thickness of 0.9", but wondering if anyone has seen the 1930 Martin OM-45 specs?

Any other dos/don'ts of OM building that you would advise me to be wary of?

[Skarsaune]

1) No, sorry I don't.

2) It's radiused. The point of radius is, it is stronger (look at bridges, low boy trailers, etc) and less affected when humidity changes inevitably occur.

2b) Correct. Radius is applied via the braces and matched by sanding the assembled sides/blocks/kerfing in a dish, or by other methods.

3) I'm not an expert, but '30s Martins would have been solid wood.

4) Target back radius is more like 15 feet, thickness of .09", hopefully that was a typo.

[JonWint]

You could buy a plan:

https://www.stewmac.com/luthier-tool...itar-plan.html

[Rudy4]

Originally Posted by rccosta

Hi all -

I'm taking on a Martin OM-45 Deluxe-style build and have a few questions I'm hopeful you all can help out with:

1. Body Template: Anyone have a template / body outline to scale they wouldn't mind sharing? I've effectively traced mine on a laptop screen after normalizing the image to a known dimension - brute force but it has worked in past builds.

2. Top Radius: Is the top radiused? I am under the impression OMs are flat tops, but have seen some threads that suggest a 48'-56' radius (which would be virtually imperceptible, so what's the point?)

2b. This is a stupid question but I just want to confirm: to accomplish the "top radius", the soundboard is never actually radiused - correct? The mechanism is, instead, radiusing the braces, and then upon glueing the braces to the soundboard it causes the soundboard to contort to the desired radius?

3. Side Lamination: There seem to be two camps in this regard, I think I'm in the solid wood camp as opposed to the 3-piece lamination for sides, but curious if anyone knows what vintage 1930 Martin OMs used?

4. Back Radius and Thickness: I'm aiming for a target back radius of 15" and thickness of 0.9", but wondering if anyone has seen the 1930 Martin OM-45 specs?

Any other dos/don'ts of OM building that you would advise me to be wary of?

Even if top radius isn't easily discernible you'll find even large top radius prevents the illusion of concavity that results from building with a perfectly flat surface. The same holds true for fret boards. If you build with a flat fret board the tops of the frets can appear to be dipped even though that might not be the case.

A slight top radius can add other attributes such as strength and even effect tone and/or volume, but don't discount small details that contribute to producing a superior instrument.

If you don't want to work from an established plan you might consider working with a simple 2D CAD program to import and scale any image you might want to work with. Once you draw what you want then you can use your drawings for producing full size form templates, etc.

[ClaptonWannabe2]

At the "45" level a Martin would be all solid. Gotta be...

When would Martin have first started laminating the sides on any of their guitars? Honestly asking not trying to be snippy toward the OP.

[Neil K Walk]

Originally Posted by ClaptonWannabe2

At the "45" level a Martin would be all solid. Gotta be...

When would Martin have first started laminating the sides on any of their guitars? Honestly asking not trying to be snippy toward the OP.

Yup. Martin doesn't do laminated sides on higher level guitars. Even though they have done laminates (such as with their old Road series guitars) that was typical with a lower quality wood like poplar in the center ply.

[H165]

When would Martin have first started laminating the sides on any of their guitars?

Probably the Sigma line. 1970.