OM 'popsicle' brace?

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Andy Mitchell
Posts: 58
Joined: Mon Dec 28, 2020 8:54 am

Re: OM 'popsicle' brace?

Post by Andy Mitchell »

tippie53 wrote: Mon Mar 22, 2021 5:05 pm the facts
this had nothing to do with the string gauge.

The neck block changed in 1939 the original neck block was 1 9/16 thick this was changed to 1 3/8 in 1939.

they also changed the transverse brace from 5/16 and 3/4 hi to 1/2 wide 5/8 high

then the fretboard was also changed from 1 3/4 2 1/4 to 1 11/16 and 2 1/8

the warranty work went through the roof . There was a false assumption that the string tension was causing this failure and tops were cracking along the fretboard . What was happening with the thinner neck block the extension was cracking the top because of the expansion differential of the spruce and the ebony.

The solution was to place the Popsicle brace as they had in the 12 frets. This helped and thus the POPSICLE was introduced into 14 fret models in 1939
so if your neck block is under 1 9/16 use the Popsicle but you only need about 4 inches of this. Use enough to support the fretboard extension with about 1 inch per side.
This is great information!

Some quick measurements says the neck block StewMac sent me in the kit is 1 3/8" and the front brace is 1/2" wide by 5/8" high. So pretty well bang-on for the 1939+ specs just quoted. So it will get a popsicle brace, despite that being left off the plans.

All of the OM kits that StewMac sells are advertised as being 'authentic' copies of the 1933 OM. And (while I have no complaints about the kit) it becomes pretty obvious once you dig in that a lot of the parts are just adapted from their dreadnought model. The neck itself looks identical, but the neck block isn't - the dread neck block had a gentle radius towards the front of the body, the one supplied for the OM is perfectly flat. And it didn't match the width of the OM sides all that well as received. Even stranger, I got an e-mail from StewMac after receiving the kit telling me to check for mis-drilled holes in the neck block (it's a bolt on neck). Mine was OK on that front, but I think they may be having some QC problems with this part.

Anyway, thank you so much for the info regarding the popsicle brace. I'll feel better with it in there!

Andrew
tippie53
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Re: OM 'popsicle' brace?

Post by tippie53 »

there are many changes through the years shape has changed at least 5 times since 1931
brace angle , neck block , transverse brace bridge and bridge plate and list goes on
some things are no longer available for sure. I went so far as to get the original herringbone
remade and the zigzag. These are great guitars. The OM was first in 1929 the Dred came out in 34
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Andy Mitchell
Posts: 58
Joined: Mon Dec 28, 2020 8:54 am

Re: OM 'popsicle' brace?

Post by Andy Mitchell »

Hi,

Is it OK to throw out a few comments about the StewMac OM kit here? A couple of others building similar kits have posted, and I'd love to get their comments.

1. The instructions with mine were just adaptations of those normally shipped with the dreadnought kit, and (as Red Dogg pointed out) are actually really confusing to figure out in places. I'm lucky - having already built the dread I can probably better recognize when something is inappropriate - but it's definitely something that StewMac could improve on in subsequent kits.

2. Mine came with a neck that looked a lot like (but slightly different from) the one in their dreadnought kit. But it's not right I don't think for an OM - it's got a volute, which (in my limited knowledge) should not be there on an OM. Am I correct on that? It'd be easier to leave it instead of grinding it off, but hey, I want to think I'm doing 'authentic' as much as anybody. It does have the 1 3/4 neck width at the nut that John Hall says it should.

3. I ordered an '18' version OM, and I think all the stuff I need to complete the job is there. They sent the expected black plastic binding, but included two choices for purfling - the same preformed herringbone stuff that came with my previous dread kit and three little separate coils of thin white-black-white plastic that I guess you would use if you wanted to do the more authentic 18 style trim. No instructions as to how to use those thin strips (or even mention of them in the documentation). So, a question: how difficult is it to finagle all of that stuff into place when doing your binding? I'll be using weld-on 16 as glue, and frankly, I'm a bit worried about it all melting into each other and/or twisting while trying to get it into place. Pretty sure just sticking the herringbone on instead would be easier... but again, not 'authentic'. Thoughts?

Sorry for hitting you all with this 'authentic' stuff, which I know you probably think is silly (and won't really matter in any functional way in the finished product). I'd have been better off I guess if I had never started reading about all of this stuff and just built the thing the way I liked in the first place. But it is fun to try to figure out what to do for the best.
tippie53
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Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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Re: OM 'popsicle' brace?

Post by tippie53 »

you are correct that valoute or dart was only on 28 series and above
now for the binding herringbone was never on an 18 series but still I like it
so if you do herringbone you don't need the other pieces , and if you take your time
putting all the pieces in at one time isn't that hard. getting it started can be tricky.
I use duco cement . I am not a super glue guy when it comes to binding.
do all the test cuts so you get the channels right. I suggest that it works best if you
set it up so you sand the sides to the binding not scrape the binding to the sides. I am talking
just enough to catch your fingernail
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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