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Author:	mountain whimsy [ Mon Jan 23, 2017 10:58 am ]
Post subject:	Octave Mandolin Top Thickness
Good morning. I've been a long time reader at OLF, though this is my first post. Looking forward to getting some input from the experts here! I've built 7 acoustic guitars and a couple of electric so far, and am just starting into my first Octave mandolin. I'm building off of Don Kawalek's OM plans, so pretty basic flat top (slightly radiused). He calls for top thickness of 0.120 to 0.125". That is thicker than what I shoot for on my guitars and surprising given the typical thinking that smaller body instruments should have thinner tops. I'm using Western Red Cedar on the top with Engelmann spruce bracing. Walnut back and sides. Here's a quick taste of the back. Any input is appreciated. Thanks! -Tony

Author:	Steve Marcq [ Fri Feb 03, 2017 1:30 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Hi Tony - I am building an octave mandolin as well, also from Don Kawalek's plan, although I am going off-course a bit. I've built 4 acoustics and 3 electrics so far. My top is spruce, and will be about 2.4mm when I'm done IIRC. I made a 000 from curly walnut with a WRC top last year, and while I can't recall the final thickness, WRC definitely needs to be a bit thicker generally speaking. I'll post a few pics as I go, looking forward to seeing yours as well - I don't know if it's me, but I don't see your pic in your post, I'll check later from my home computer.

Author:	Cush [ Thu Feb 09, 2017 10:01 am ]
Post subject:	Re: Octave Mandolin Top Thickness
String tension can be fairly high on an OM depending on the scale length and the string gauge. Having 8 strings rather than 6 adds some extra tension. I am not surprised that the top is slightly thicker than a guitar. I don't have any experience with building an OM and I am not sure of the total string tension on one. I do know that a mandolin has much more string tension than a guitar. Matt

Author:	mountain whimsy [ Thu Feb 09, 2017 6:49 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Thanks, Mahogany and Coco. Seems like I need a wood name around here! I went with 0.120, with a little thinning on the edges. The bracing is installed, and I'll probably taper it out a little to open up the tap tones, as they are a little bright. Linings are installed and I'm getting ready to close up the box. I'll just keep posting in this thread. As it turns out, I'm doing a flattop at the same time, so here's a few shots of that build.

Author:	Cush [ Fri Feb 10, 2017 8:55 am ]
Post subject:	Re: Octave Mandolin Top Thickness
Nice looking work Tony! Sticking to the plan is always a good bet. It seems when you have a sound hole in the string path as this plan calls for, a thicker top plate is needed to hold up to string tension. Mandolin top plates are usually carved a bit thicker on models that use the oval hole design than those that use the F- hole design. Matt

Author:	mountain whimsy [ Fri Feb 10, 2017 10:26 am ]
Post subject:	Re: Octave Mandolin Top Thickness
Cush wrote: Nice looking work Tony! Sticking to the plan is always a good bet. It seems when you have a sound hole in the string path as this plan calls for, a thicker top plate is needed to hold up to string tension. Mandolin top plates are usually carved a bit thicker on models that use the oval hole design than those that use the F- hole design. Matt Good info, Cush! Thanks much.

Author:	mountain whimsy [ Fri Feb 17, 2017 4:38 pm ]
Post subject:	A Pair of Mandos - Octave and Army/Navy
A quick update. Tops and sides are attached. This afternoon I'll get the necks started by scarfing the headstocks and perhaps starting in on the fingerboards. Hopefully a change in the Subject/Title to this thread. Thought I'd rename to make it more into a build thread. Some of you probably are seeing duplicate on another forum.

Author:	Cush [ Sat Feb 18, 2017 9:13 am ]
Post subject:	Re: Octave Mandolin Top Thickness
It looks like you are progressing nicely. I'm am anxious to see a photo of the walnut back/sides. Matt

Author:	Steve Marcq [ Wed Mar 08, 2017 8:48 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Tony, that looks awesome, you are ahead of me for sure. Here's my top with the rosette planed flush. I'm doing the bracing and blocks now.

Author:	mountain whimsy [ Wed Apr 12, 2017 3:07 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Thanks for the bump on this. I've been meaning to do an update to bring the thread up to date. I was out of the country for a couple of weeks, then playing catch up with work, but I'm back in the shop lately. I did put some radius into the top and back as indicated in the Crytal Forest plans. With such a small instrument, it hardly adds any doming, but I like the concept of adding radius to guitars, so I did so with the mando, too. I haven't measured, but the neck angle only came out to probably less than one degree. Both necks are from a couple pieces of torrified/baked/roasted/etc. flame maple. Standard scarf headstock joint and stacked heels. No truss rod on the Army/Navy, but I did put in a graphite reinforcement rod. Standard double action truss rod in the Octave. Both fingerboards are ebony with ebony binding that came from the waste edge of the fretboard. The Army/Navy neck joint is a hand cut dovetail. I used my band saw to do the rough cut, then followed up with chisels and a good flossing session. It's hard to tell from the photos, but there is a little taper to the dovetail. For the Octave, I cut a strait dovetail in the neck block with a jig and router. I put the neck in my neck jig and set the angle to match the fretboard plane on the body. It turned out to be spot on with the plans, so that was a nice double check on how things were lining up. The neck cut was about 1/16" oversized on each side of the dovetail so I could do final fitting with chisels. On piece that I should have spent a little extra thought on before doing the neck joint on the Octave is the width of the fingerboard at the neck/body joint. My fb was a little wide, but I was able to plane down the binding enough to get them to match. It required redoing the side dots, but that was an easy recovery. In the future I will hold off on the fb until the body and neck are ready to go. And here they are. The backs have since been secured, so now I'm working on the binding. I have a couple of hand-stitched rasps coming directly from Liogier in France. So I'm looking forward to a couple of good neck shaping sessions in the near future! Cheers!

Author:	mountain whimsy [ Wed Apr 12, 2017 3:09 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Steve Marcq wrote: Tony, that looks awesome, you are ahead of me for sure. Here's my top with the rosette planed flush. I'm doing the bracing and blocks now. Steve, that's looking great! Lovely rosette. I keep telling myself to do a custom wood inlay of some sort, but for these I kept them as simple as possible. -Tony

Author:	mountain whimsy [ Wed May 17, 2017 3:15 pm ]
Post subject:	Re: Octave Mandolin Top Thickness
Other than some detail sanding here and there, these two are ready for finish. I'll hopefully get that started this weekend, as long as it stops snowing and raining here in Montana! I wasn't planning on any purfling on the Army/Navy mando, but I had a little tear out on the back when routing the binding channel, so I covered it up with some purfling. Turns out that I love the way it looks better than if I didn't have the herringbone purfling. -Tony

Author:	mountain whimsy [ Wed May 31, 2017 10:37 am ]
Post subject:	Re: Octave Mandolin Top Thickness
It was a productive Memorial Day weekend in the shop. Final flow coats of lacquer on the mandolins and a guitar that has been waiting for me to break out the spray gun. I'll let them hang for another couple of weeks before doing final sanding and buffing. In the mean time, I have some nuts and bridges to make.

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