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Martin OM Top Questions
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Author:  Mike OMelia [ Sun Mar 23, 2008 4:50 pm ]
Post subject:  Martin OM Top Questions
OK, got some questions. If anybody has pics of the Martin OM top with bracing, bridgeplate, etc attached (after tuning) I would be very grateful!

(edit: pics are shown in reverse order)

The first pic shows the bracing pattern as it was given to me. Look ok?

The second pic shows most of the parts laid out.

The third pic shows two layout locations that I am unsure of (what part goes there)

The fourth shows the remaining parts (I believe trapazoid part is the bridge plate) but not sure about the rest. Yes, I RTFM, and nothing was in it regarding this stuff. :D

Are the 4 peg holes used for anything (I believe the two at the top are for alignment with the heel block)

Also, as in the bottom, are the braces to be "cut into" the kerfing?

Mike
Author:  jmanter [ Sun Mar 23, 2008 4:56 pm ]
Post subject:  Re: Martin OM Top Questions
of the leftover braces you have:
the 3 small ones go around the soundhole
you are correct about the bridgeplate
the large one is a graft that goes between the neck block and UT brace.
Author:  jmanter [ Sun Mar 23, 2008 5:02 pm ]
Post subject:  Re: Martin OM Top Questions
Does this help?
Author:  Mike OMelia [ Sun Mar 23, 2008 5:24 pm ]
Post subject:  Re: Martin OM Top Questions
jmanter wrote:
the large one is a graft that goes between the neck block and UT brace.


Crosswise? Thats what those two small marks are for? What is UT?

Thanks!

Mike
Author:  Mike OMelia [ Sun Mar 23, 2008 5:27 pm ]
Post subject:  Re: Martin OM Top Questions
Yes, the pic helps a lot! But I cannot enlarge it. I guess what I need is more detail around the sound hole and above the "UT" brace. Is that large brace vertical? It also looks like the three small pieces are mounted vertically. (?)

Mike
Author:  jonhfry [ Sun Mar 23, 2008 5:31 pm ]
Post subject:  Re: Martin OM Top Questions
UT is the upper transverse brace.

the 3 small braces are soundhole reenforcement

and the big wide one is a tone bar. it goes farthest toward the neck end.
Author:  jonhfry [ Sun Mar 23, 2008 5:32 pm ]
Post subject:  Re: Martin OM Top Questions
UT is the upper transverse brace.

the 3 small braces are soundhole reenforcement

and the big wide one is a tone bar. it goes farthest toward the neck end.
Author:  Mike OMelia [ Sun Mar 23, 2008 5:35 pm ]
Post subject:  Re: Martin OM Top Questions
OK, so the tone bar lays down flat. Are the sound hole pieces vertical or flat?

Do (all of) the braces cut into the kerfing (like the bottom)?

Edit: Isee now better in the pic that the tone bar looks like it almost butts up to the UT. Correct?

Mike
Author:  jmanter [ Sun Mar 23, 2008 5:48 pm ]
Post subject:  Re: Martin OM Top Questions
Here is a pic of Martin bracing patterns...
Author:  Mike OMelia [ Sun Mar 23, 2008 5:50 pm ]
Post subject:  Re: Martin OM Top Questions
OK, does this look about right?

Mike
Author:  Brad T [ Sun Mar 23, 2008 6:25 pm ]
Post subject:  Re: Martin OM Top Questions
Mike,

click on the Martin bracing patterns pic above, and it will be a little easier to see. The flat brace closest to the neck block needs to be moved closer to the neck block. You probably should split the distance between the neck block and the large upper transverse, but be sure before you glue it that it will not interfere with the neck block. Your soundhole braces should be flat, but you need to change their orientation like the above Martin picture. As far as inletting them into the linings, you inlet the X braces, and the upper transverse (the big brace that is crosswise, above the soundhole). The 2 long tone bars coming off the lower leg of one of the X braces will probably be tapered down to nothing, prior to getting to the linings. Same taper-to-nothing applies for the 4 short tone bars, but will have some thickness where they come to touch the legs of the X braces. Did you get a set of plans or anything or are you just doing a top for a guitar? Most plans will go into great detail about bracing, and aren't that expensive. There are some more details, like inletting the tonebars into the Xbraces, etc. Also, the uppermost brace (the flat one above the UT) will stop short of the linings. Hope this helps
Author:  Mike OMelia [ Sun Mar 23, 2008 8:12 pm ]
Post subject:  Re: Martin OM Top Questions
Brad,

My plans are the standard from Martin (Bluescreek supplied). That manual is all but useless (not Bluescreek's fault).

SO, inlet the x-braces, and inlet the UT. Got it! I understand the issues with the rest of the braces. I also reconfigured the tone bar after I saw the pic above.

If you have a info source for the OM top, please lemme in on it!

Mike
Author:  Mike OMelia [ Sun Mar 23, 2008 8:15 pm ]
Post subject:  Re: Martin OM Top Questions
One more thing, is there any special consideration when placing the bridge plate? Surely it has to be under the bridge. So do I need to do any measuring? Adjusting? Max distance is already determined by the current size, so it can only go CLOSER to the sound hole, not further away.

Mike
Author:  Mike OMelia [ Sun Mar 23, 2008 10:06 pm ]
Post subject:  Re: Martin OM Top Questions
Aha! After studying the layout geometry and the heel block shape, I finally figured out what that gap (in the heel block) was for. Tone bar tunnel.

Mike bliss
Author:  Cal Maier [ Sun Mar 23, 2008 10:42 pm ]
Post subject:  Re: Martin OM Top Questions
Mike,

Here is a photo of an OM I built before closing the box. It shows the top and back braces, although it was taken a a bit of an angle, you may be able to get a good idea of the placement.

Cal
Author:  Cal Maier [ Sun Mar 23, 2008 11:12 pm ]
Post subject:  Re: Martin OM Top Questions
Mike,

Here is a shot from a different angle that shows the sound hole bracing a bit better. Hope this helps you out. :D

Cal
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