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OM Depth Dimension Question
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Post
Adaboy

Total Topics: 64
Total Posts: 514
I have a question about the depth of a Martin OM at teh end where attached to the neck block. I would also like to know if this depth has changed over time.

I have my sides clamped to the neck blocks and when I placed the neck in the neck block, the neck protrudes 1/2" over teh top of the sides. The neck block is proud of the sides the same amount. I knew something wasn't right.

I have the OLF OM plans so I looked up the dimensions for the sides and the neck heel. These plans show the depth of the neck heel as 3 5/8". I measured my neck and it that is what it measured. The plans showed the sides should measure 3 11/16" wide at the neck end......which is 1/16" wider than the depth of the heel so it seems reasonable. I measured my sides with my dial caliper while they were clamped to the neck/tail blocks so I measured along side the neck block and it measured 3.170". Wow, that is way off......roughly 1/2" off.

I sent an e-mail to the kit provider and he says this is the correct measurement for the sides of a Martin OM. He measured 3 Martin OMs that he owns that were built from the 40's - 60's and he said the side width is within 1/16" of my measurement on all of them.

So how could the plans be right on on the heel measurement and neck block and so far off on the side width? Makes me wonder if Martin has changed the standard depth of the neck area on the OM since the 60's. Anyone know if that is the case?

Is the neck, neck block, abd OLF plan wrong and the sides cut correctly.........or is the plan, neck, and neck block correct and the sides cut incorrectly?

Jan 11, 09 | 5:19 pm
Ken Hundley

Total Topics: 40
Total Posts: 2169
They leave the block way off on purpose so that you may carve/sand off what you need to fit the depth you want....either to mimic an existing design or to fit one of your own. This is where the radius disc or radiused sanding stick comes in very handy. Check the forums, there are a couple real good threads about this topic, and how to handle it. As far as the actual dimension, stick with what your existing plan says, and adjust what you have accordingly.

Jan 12, 09 | 12:16 am
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
Also the plans from ANTES and Mac Rositie are not actual martin specs. I think you also forgot the top and back plates? The width should be 4 1/8 at the tail block when finished and 3 5/8 at the neck. I have seen 000 and OM's vary as much as an 1/8 to this spec.
Older guitars have more variance than the ones produced from the 80's on. The neck and tail blocks are often left long , as you have some fitting to do. Don't forget there as a back radius that needs to be trued and the top has some geometry you need to consider.
Have fun building. The first few are the hardest . You don't know what you don't know till you know it.
john hall

Jan 12, 09 | 4:06 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
What is an OLF OM plan? Who is the artist --- better yet who is the engineer?
Payne, Antes and MacRostie drawings are not replicas of any Martin guitar just similar versions. I have seen Collins and Brune prints that were made to copy a specific instrument.

If the sides you have came from the Guitar Maker's Connection -- which I am almost certain they did, they were cut/profiled with a CNC laser and perfectly match todays version of the OM. (assuming they were located on the laser properly) Lastly, the overall thickness can easily vary 1/16" based on rim sanding, and the final thickness of the top and/or back. I don't know who supplied the parts to you but remember the stuff from GMC is rejected and 2nd quality material -- so find out why your sides were taken off the factory floor.

An OM/00014 is 3 3/8" +/- at the neck and 3-7/8" +/- at the tail block when completed

Ken

Jan 12, 09 | 4:24 am
Adaboy

Total Topics: 64
Total Posts: 509
Thanks for the dimensions guys!

The OLF plan was sold on the OLF forum (now sold through Stewart McDonald)and I think was drawn by Collins. It was originally drawn based on a particular guitar but has been modified slightly since.

I wouldn't be worried about 1/8" off one way or other. The neck heel is 1/2" longer than the sides which is significant. The neck block is also 1/2" longer than the sides. The neck block and heel on my neck match the specs shown on the plans......but the sides are roughly 1/2" too narrow.

To use these sides, I will need to cut 1/2" off the heel of the neck......and remove 1/2" from the neck block. That is a lot of wood to remove.

Thanks for giving me the dimensions you have! These dimensions are very similar to the ones shown on my plans.......and way off from the dimension of my sides. The plans state 3 11/16" for the width of the sides at the neck (not including the top and back thickness) and these sides measure 3.170" wide on my dial caliper.......and the sides don't match the neck and neck block sent in the "kit". (the depth of the neck heel in my kit is 3 5/8" which matches the spec on my plans). I'm guessing I have old spec sides with current spec neck and heel block. The kit provider has offered to take the kit back (several other issues with the kit I've not mentioned here). I think this is being very fair and I'm leaning toward returning it.

Thanks again everyone!

Jan 12, 09 | 5:20 am
Ken Hundley

Total Topics: 40
Total Posts: 2169
If that is the case, I would send it back, and get one from someone you know...(One of the pros here, or from LMII/Stewmac). That way, since they will know exactly what you are trying to build, you will get what you need.

Jan 12, 09 | 5:34 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
I do have a correction -- sorry I should not make entries "BC" before coffee. The depth at the tail block should stated 3-3/8" +/- at the neck and 4-1/8" +

Ken

Kenneth Michael Guitars est. 1978

Jan 12, 09 | 5:51 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
I'd like to see, maybe get a copy of the Stew Mac OLF OM clone drawing -- what's the part/product number. The only one listed is from Michael Payne and that is NOTHING like a real Martin OM/000 except perhaps the basic size and shape.

Thanks in adavance, Ken

Jan 12, 09 | 6:04 am
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
that is who made the drawing for stewmac Ken. He also has the Small and medium jumbo.

Jan 12, 09 | 8:14 am
Adaboy

Total Topics: 64
Total Posts: 509
Ken,

Interesting that the depth stated by Ken and John is 1/4" difference. What should be the depth of the heel on the neck? Mine measures 3 5/8" (matching the plans I have) so it seems logical that the sides would be slightly wider (my plan shows 1/16" wider plus roughly 0.200" more for top and back. Seems the sides don't match the neck and neck block.

Here is a pic:

img]"http://members.cox.net/adaboy/images/Neck View of Sides.JPG"[/img]


Jan 12, 09 | 9:20 am
Adaboy

Total Topics: 64
Total Posts: 509
Oops, try again on the pic:


Jan 12, 09 | 9:21 am
jeremy3220

Total Topics: 29
Total Posts: 242
The neck block is backwards and also remember the surface of the neck that the FB gets glued to sits flush with the top of the sound board.

Jan 12, 09 | 11:55 am
moocatdog

Total Topics: 35
Total Posts: 302
Through communication with your supplier and advice provided here I'm sure you'll work this out. My only comment would be that I wouldn't use the depth of the heel on a neck as any kind of guide, as there usually is excess material there that needs to be removed.

Good luck,
George :-)

Jan 12, 09 | 1:23 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
Before we started manufacturing our own necks this is what Martin sent to KMG L-R



“OM” M&T 3.115 “D” M&T 3.65 “D” DT 4.0
Note that since the tenon is the same size and they can be trimmed down to to shape it is common practice for kit suppliers to send out “D” M&T necks in an OM kit package.

Ken

Kenneth Michael Guitars est. 1978

Jan 12, 09 | 1:53 pm
Adaboy

Total Topics: 64
Total Posts: 509
Jeremy,

Actually, that neck block is positioned correctly (believe it or not). The neck block is for the Martin DM series of guitars and it is made for the combo A and X bracing. That slope had me confused as well and honestly, I didn't want to use that neck block. Here is a picture:



I decided to take the supplier's offer and return the kit.....so it's on it's way back home now.

Jan 12, 09 | 2:34 pm
jeremy3220

Total Topics: 29
Total Posts: 242
"Jeremy,

Actually, that neck block is positioned correctly (believe it or not)."

Wow! I wonder why it's made like that.

It sucks you have to wait for another kit but it's better than using wrong parts.

Jan 12, 09 | 2:45 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
I can see that those side were in fact laser cut so my guess it was pulled of line the because they did not make the grade for this Model --
Martin OM-30DB "Pat Donohue" signature ---- DB stands for deep body. There has been other contemporary DB special models -- I believe this is the only DB being run at this time.

Ken

Jan 12, 09 | 2:52 pm
Adaboy

Total Topics: 64
Total Posts: 509
Ken,

Am I understanding you correctly, that you think these sides are for a deep body OM? Surely I'm misunderstanding.

Jan 12, 09 | 3:56 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
Yep --- I can't be absolutely certain but I think that might be the case. Call Gail at the GMC ask her for the DB side dimensions.

Ken

Jan 12, 09 | 5:05 pm
moocatdog

Total Topics: 35
Total Posts: 302
I think what Ken is saying is that he suspects the sides were orginally intended for a Deep Body model but that they were cut incorrectly (too narrow) and then sold off as kit parts. It's a moot point really, as you are returning the kit and starting fresh.

Good luck,
George :-)

Jan 12, 09 | 5:32 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
You know I re-read your post and mixed up what you said was on the drawing and what your sides mesured -- Sorry again! -- I really believe your side are for a modern OM. But your drawing, if it is the one from Payne it is not a Martin OM, I guess it does not make any difference, but you have not told us more about that drawing. Again, if it is the Payne drawing you are comparing apples to oranges. If you are trying to build a Payne guitar using Martin parts -- well I guess than it would make a difference and not be fair to the supplier.

Ken

Jan 12, 09 | 6:01 pm
Ken C

Total Topics: 30
Total Posts: 554
Addaboy,

You are learning first hand what I experienced as well with the kit I got from the same guy. I am glad you checked everything over before you started building. Returning the kit and getting one from a reputable source will save you a mountain of headaches later. Good call!

Ken C.

Jan 12, 09 | 6:08 pm
Adaboy

Total Topics: 64
Total Posts: 509
Ken,

I'll try once more to explain my concern. As you can see in the pics above, the neck block and neck are built to one spec.......and the width of the sides near the neck were cut to a different spec.

I was trying to figure out which is correct......the sides......or the neck and neck block. I checked the plans I have on hand (which were drawn from measuring a Martin OM) and the dimensions on the plan match the dimensions of the neck and neck block in this kit. The sides in the kit are narrower than shown on my plans.....at least on the neck end. The discrepancy prompted this post to see which parts were built to the correct standard.

I realize these plans are not the defining standard.......but only Martin has that. From what I'm learning on this post, there was a lot of variation till around the 80's so a "standard" is difficult to define.

What I want in a kit is for the parts to be made to a specific standard/design......even if it's non-standard. As seen in the pics above, the sides don't appear to be made to the same standard as the neck and neck block. I realize I could modify the parts and make them work......but I had rather not do that on my first build.

Jan 12, 09 | 7:33 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
I am sorry for not being very helpful regarding this thread, and frankly most likely caused some confusion. However I thought this was the question:

Is the neck, neck block, abd OLF plan wrong and the sides cut correctly.........or is the plan, neck, and neck block correct and the sides cut incorrectly?

So my reponse, based on the measurements that you stated, the checks on similar parts that the supplier made for you and materials I have received here at KMG directly from Martin. The answer to the question would be “The sides are the correct dimensions and the expectation is that the neck block and neck are to be trimmed to size.” And, the OLF/Payne plan is not a true “clone” Martin rendering so comparisons are not valid.

If this were my project and that was my question I’d grab my calipers and drive down to the local Martin dealer and measure a couple of OM’s -- The assumption being that your intention is to build a “modern Martin OM”

Now I realize there has been problems with the supplier you are dealing with, and you are absolutely correct in holding his feet to the fire at all levels of the transaction. But here is where I have to play the “devil’s advocate” – and frankly you totally loose me. If you are trying to build an OM “STYLE” guitar based on a design by Michael Payne – how could one expect that machined “Martin” parts from any supplier will match that drawing? As an example --- surely the Payne drawing does not depict the "A" frame Martin top brace system used with the MT neck block shown in your photo.

Which brings up another issue, as far as I know the KMG OM/000 kits are the only "true bolt on neck" models that use the traditional Martin X brace system and Martin clone profiles consumers are expecting. The point here is that Martin bolt on models are vastly different from their traditional dove tail versions.

Ken
















Ken

Jan 13, 09 | 4:17 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
For those wondering about the strange looking neck block in the above pictures. I believe that is the kind of block used for the Martin High Pressure Plastic guitars. If my memory serves me -- on thoses models the back is not glued to the "full" bottom areas of the neck and tail blocks, only along the perimeter. I suppose it has something to do with expansion and contraction of the very thin plastic and how it would look pinned/glued down to the blocks.

Ken

Kenneth Michael Guitars est. 1978

Jan 14, 09 | 2:53 am
Adaboy

Total Topics: 64
Total Posts: 509
That makes sense Ken.

Jan 14, 09 | 5:13 am
moocatdog

Total Topics: 35
Total Posts: 302
Adaboy,
I thought the figure in the sides seen in your photos above was a little unusual. Were they made from the high pressure laminates Martin uses as well?

Sorry if this hijacks the thread for a bit, but I'm thinking of making a campfire/beach/hiking guitar myself. Anyone have any anecdotes or advice to share?

Thanks,
George :-)

Jan 14, 09 | 5:55 am
Ken C

Total Topics: 30
Total Posts: 554
Ya think we could get a few more Kens on this forum?!

Adaboy, what are you doing for you replacement guitar? Don't let your experience with the SK guitar sour you on a build.

Ken

Jan 14, 09 | 2:30 pm
Adaboy

Total Topics: 64
Total Posts: 509
I'll get another kit.....but it will be a custom kit, no seconds placed together, intended or not. I'm waiting on the refund when the kit arrives to make sure that goes ok. Gives me time to work on my go-bar deck etc. Oh, and I need to learn how to sharpen my scraper so it cuts curls instead of dust.

MCD, I like the idea of laminated sides though I wouldn't want a laminated top and I doubt I would want a laminated back for normal use. On a beater of kids guitar, laminated might be perfect. The sides pictured above weren't laminated.


Jan 14, 09 | 3:55 pm
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
Depending where you got your kit , you can't expect the kit to follow plans from another. Also the neck block is for a dred as is the neck. From CF Martin the mortise and tenon cut is the same but they do use different blocks. You can trim the dred block down to make it fit a 000 or OM.
Martin is selling there cast offs to a few people and they are trying the kit market without understanding what a kit should be, Ebay is often the outlet. The sad truth to this is that often , buyers have no experience and don't know what parts work together and what don't. Those of use that have been doing this a few years know what you need and offer a higher end kit. Ken , myself ,Steve Kovacik for example.
As for plans , As ken pointed out , they are not true to martin spec so you need to do some research. In the long run, you get what you pay for. Martin kits are production off falls. In the old days GMC did see a 1st quality kit but that stopped 8 years ago.
My best advice is to talk to your supplier first and get a feel for his knowledge and service. I do sell martin kits and my own. The economics often drive people for the cheaper kit to start . A good quality kit will cost more at first but as you gain experience building you will see why the custom kits are often the better value.
Good luck and have fun building. Ken , Bill and I are here and will try and keep you from making that big mistake
john hall

Jan 15, 09 | 5:11 am
moocatdog

Total Topics: 35
Total Posts: 302
Sorry if I'm being dense, but I want to make sure I understand what people are talking about here. I'm interpreting the posts above to mean that the kit in question was put together with disparate parts orginally intended for both laminated and solid wood models. Even if this is technically feasible, I don't much like the idea. I'm not looking to start a war or sully anyone's reputation, but I would like to know where this kit came from.

Adaboy or Ken C., if you feel comfortable sharing that information, I can be contacted backchannel at moocatdog (at) comcast (dot) net.

Thanks,
George :-)

Jan 15, 09 | 6:07 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
George I totally agree with you -- a kit should have matching parts, pretty basic premise. The lack of such a product (Stew Mac comes close) is one of the main reasons the KMG "Success Kit" coming to the market place. On the other hand LMII does let the buyer know that there will be plenty of carving and decision making as the build progresses -- which is OK because the buyer knows what to expect if they read the fine print.

Ken

Jan 15, 09 | 6:18 am
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
remember that a kit will still require some work . Fit and finish is up to the builder. Even the best kit can suffer from a poor attempt. No matter how close you make the parts , it is the mating in the assembly where the final outcome will show.
The supplier I am sure supplied parts that would make a guitar. I am not speaking for them but this is between the buyer and seller , and if the seller stands behind his goods , that is all that matters.
john hall

Jan 15, 09 | 7:44 am
Ken C

Total Topics: 30
Total Posts: 554
George, Adaboy will have to confirm, but I assume the kit discussed in this thread is the same one Adaboy advised us he had purchased in the "Finally Purchased A Kit..." thread in the Kit Guitars in General forum. There he mentions the source.

If so, it is the same source as my first kit. Mine had issues, but at least the parts matched better than what Adaboy got. I have commented elsewhere that I was able to make a guitar out of my kit due to much personal help by Ken Cierp--Very commendable as I probably should have bought a kit from Ken in the first place. My kit, and likely Adaboys, came with absolutely no instructions. It would be a tough kit for a rookie even with instructions. The issues with these kits were discussed in another thread, "Martin Kit - Quality Control Issues ??", and I don't want to restart that thread here, but Adaboy's experience is another exhibit for that thread.

Ken

Jan 15, 09 | 7:51 am
Bill Cory

Total Topics: 158
Total Posts: 3584
Every kit I have received, from every kit provider, has had issues - that includes everybody except US Guitars. Any kit provider is free to email me privately (click on my username) if they want to find out what was out of spec or out of the ordinary about their specific kit.

It isnt fair to single any kit provider out. All of us have received kits, many of them our "first kits," that were not perfect. It is the nature of a novice to react differently to this occurrence, because he expects the kit to be "perfect," ready to build with no issues. In a perfect world, this would be the case.

Since we don't live in a perfect world, I must go back to my old advice:
1) Get a kit with good instructions (For Martin-style kits, a manual is available other than the Boak book.)
2) READ all the way through the instructions, and check the kit contents early in the process.
3) Contact the kit provider if there is a problem. All of them will quickly explain, apologize, and replace, as the situation requires.

It is all too easy to sully the reputation of kit providers in a forum, and it should not be done here. Mistakes are made -- some big, some small. A kit provider's feet should be held to the fire by the buyer to correct a mistake, but it should not be done publicly.

This applies especially to other kit providers.


Adaboy -- it's a shame your kit didn't come as expected, but you have gotten satisfaction from the kit provider, and it should be left at that. Everyone else should follow the three points of advice I gave above, and not use this forum to damage or shut down a respected kit provider's business.

Jan 15, 09 | 8:42 am
Adaboy

Total Topics: 64
Total Posts: 509
The kit provider received the kit back today. The kit wasn't damaged and he gave me a full refund. So while the kit did have an issue or two, my kit provider stood behind the kit, offered to give a full refund on the kit (his offer.....not my request), then refunded my money including return shipping. I can't ask for more than that and it says something that he wanted to please the customer.

Jan 16, 09 | 5:50 pm
Ken C

Total Topics: 30
Total Posts: 554
Adaboy, glad you got a favorable resolution.

Jan 16, 09 | 5:52 pm



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