Official Luthiers Forum!

As I understand it, the Andes plans are one size, the Kincade plans another size, and a Martin OM guitar yet another size.

Are Michael Payne's drawings yet another size or do they match the Martin OM?

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Formerly known as Adaboy.......

My body shape, length, depth and sound hole is to Martin specs. My bracing is a simular patter but differnt in X angle, brace thickness, tone bar location and sound hole bracing but not by much.

Darryl,
Funny how things work out in the network of Luthier's on the forum. I just sat down here on the compter from cutting the sound hole and routing the rosette channels from Michael Payne's OM plans.

I highly advise getting a set of his plans from Stew-Mac. They're just a little piece of heaven to work with.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

Thanks Michael and Chuck. Michael, I was hoping you went with the Martin specs for size, good deal. The bracing is probably something I (and probably most here) play with so your ideas will be appreciated. I'm going to place an order, thanks.

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Formerly known as Adaboy.......

I placed the order.....hope it's printed to scale. I've read where some folks have ordered plans (not Michael's plans) and the printouts weren't to scale.

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Formerly known as Adaboy.......

The plans are drawn to full scale. They are printed to full scale on a Xerox process. However any printing process that uses heat, a scale variance may accrue due to heated paper stretch during the process and then contraction as the prints cool. The variance may not be equal in both axis. There is simply nothing that can eliminate small scale variance when using this type of print process. In fact any print process on pulp or bond paper will also have a small scale variance due to changes in the paper caused by ambient humidity and changes. This can be as much as 1.5% of the paper width and height and again may not be equal in both axes. You have to keep in mind that paper is more or les a fabric of random weaves. Both the weave and the cell structure of the fibers are suseptible to heat and moisture.

It is possible to get a pretty much perfect paper print but it is not likely because the Xerox fuser gets hotter the longer it runs and therefore stretches the last print paper more than the first. Most of the time, the out of scale in a given axis or the other will be around 1/32”-1/16” per foot. So the error will be minimal. Unfortunately no printed paper plans on the market are perfectly to scale due to paper stretch and contraction. Just something you have to deal with. When dealing with paper plans.

The longer or taller a part the more out of scale over all it will be but the per foot percentage is fairly constant on a given page. But may vary on one page to another.

Many not knowing that the paper and printing are the culprits blame the drafter. Some printers do not check there scale variance range often Ours does but we still can’t promise 100% to scale due to heat and paper changes. Truth is all plan providers have the same issue. It is rare that the plans are out of scale but the printing process and media have changed the printed geometry. Not the drafter.

The only way to get 100% accurate prints is to plot on Mylar with an X/Y vector pin or inkjet plotter, and to do so raises the cost of printing 400%. (Due to cost of Mylar vs. paper and the cost of ink)

The proofs the printer sent me show that the X (Horizontal) scale varance per foot is .02" per foot on average and Y (vertical) is .01" per foot both on the long side

Yeah, yeah, yeah - excuses, excuses......

Seriously I just wanted to throw in a good word for Michael's plans. I have built with his OM and SJ plans a bunch of times now and the plans are superb. My bracing is different but did not need to be - building as indicated on the plans will produce a superb guitar.

Regarding paper sh*inkage I always use my molds to trace outlines and then center the plan's center in the outline that I captured from the mold. Problem solved.

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Ann Arbor Guitars

Ok, no moderator back talk allowed. Who is moderating the moderator?

Aren't you?

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Ann Arbor Guitars

Perhaps a simple solution would be to print two accurately drawn rules (x and y directions) on each sheet of the plans. That way, the user could measure the printed rule accurately, then apply a calculated scale factor for each dimension they measure off the plans. Right?

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

I assume that the dimensions are notated on the plans. Measure a known x and a known y and come up with your own extrapolation constant.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

This is one of the reasons that I prefer to use scaled drawings. If the drawing is 1/2 the size of the actual instrument, I won't be tempted to measure the drawing. For that reason, I feel it is essential to have all dimensions explicitly noted. That includes the thickness of the tail block, for example.

The only time I like the full scale drawing is when I need to trace the body shape and that is not really necessary since is isn't really hard to scale up a shape using graph paper or a pantograph.

Dang guys??!!!??? Follow the dimensions on the drawings!!!! They don't change with heat and shrinkage every component of my plans are fully and accurately dimensioned!!!!!!!! The only thing is you should not use the plan for is to trace a profile until you have verified the scale variance due to printing or can live with the variance.

Tracing or cutting to make a template is not a good idea with any paper plan set!!!!!

Outside of that what could possibly be a problem with the image being .01"-.02 per foot out?

Here is a little tip from the real manufacturing world. Manufacturing plants do not allow their fabricators to measure a profile, distance between lines or scale any distance on a drawing, period. we fire people for doing this. This rule is in both our QCM (quality control manual) and our ECM (engineering control manual) you read the dimensions listed on the face of the drawing. If a dimension needed is not listed and can not be determined by the product of other listed dimensions then the drafter has goofed. Never trust the image of a drawing printed on paper. Trust the dimensions given!!!!!! This is the proper way to use plan.




All that said my printed plans are really quite accurate. Dimensions are in thousants were that kind of accuracy is required, to the nearest 1/64 wher that type of tolerance is required and to the nearest 1/16" for loose tolerances.

I want to be sure a newbie understands. Paper plans grow and shrink with temperature and humidity. This is entirely normal. And there is nothing different in my plans doing this or the next guys. Plan set are intended as dimensional guides. Not paper doll templates.

If some wants a pin plotted on Mylar body profile tht is 100% accurate let me know I will provide that for the price of Mylar/ink/and shipping. If you have a Cad program and a way to vector pin plot I will provide a DVF file of the body profile for free with proof of purchase from Stewmac.

But again no paper plan set should be assumed good enough for paper doll templates until verified. If the length is good and the major width is good use it.

Michael,

Is the waist curve on your plan the same as used on the Martin OM or is it tighter? Thinking of options for a mold.

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Formerly known as Adaboy.......

I have heard many times that a Xerox copy could not be counted on to be at the correct scale, but did not know why. Thanks for the explanation Michael.

What about blue prints/blue line drawings? Don't see those much anymore, but since it uses a photosensitive paper instead of heat fusing toner to the paper, I would think that they would not have the same problem.

Really, don’t worry about!

For most of us, it is unrealistic to expect everything to line up within closer tolerances to the plans than those of the printing process, as stated by Michael. That is just the nature of hand building these delicate boxes out of several thin pieces of wood, and especially if this is early in your building career. Some things can, and must, be very precisely measured and executed, (fret placement, string spacing, etc) so use the number for those, others things can be less accurate without affecting things much (body shape, etc). The accuracy to plans for most of the assembly is normally somewhere between two, though. How accurate is determined in part by the accuracy of your jigs and tooling, but also by one of the real luxuries of hand building, which is that we can deviate from plans, if we so choose. Learning how and when to do that is the difficult part, of course. If you stick to a proven plan and build as close as you can to that, you’ll be OK.

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Rian Gitar og Mandolin

Surely alot really depends on whether you are wanting to build a 'replica' of sorts of the old Martin OM v your own interpretation? - Kinkade's is his own interpretation, but I wonder how many builders actually use plans for more than say simple outlines and then adjust everything else to suit either their own or their customers desires. Making subtle changes to bracing positions or even adding a few mm to the shape here and there - are kind of what makes your own build unique? I think that's part of the fun really. I would guess if trying to emulate a characeristic 'tone' of a classic OM, would not the choice and quality of tonewoods and the natural aging process have more of an impact on the outcome than a few mm difference in body size and positioning of the bracing?

The body shape is a direct copy of from a Martin I had in shop. and then verified aginst a Blues Creek Martin OM building form.

It is still paper and it move with the environment the ammonia Blue line process is pretty much history these days but the paper was heated by the lamp and then slightly moistened by the ammonia gas so these are not much more accurate.

Under stand ther is no perfict printing process on bond paper! Once again, here is no printing process on paper that can guarantee good accuracy over a large spans. The larger the span the more the paper's movement affects the image. the shorter the span the less affect the movement of the paper will have.The most accurate process to print (plot) is vector plotting where a pin moves in the X and Y axis and the paper is moved in only one axis according to numerical geometry but that is nearing extinction as well.

That's why is prefer scaled drawings. The temptation to measure the plan is gone. I must confess that I do trace the body shape if I have a full scale drawing. The difference between the plan and the "actual" shape is so small that it really doesn't matter. I made a plexiglass template from the Antes 000 plan and laid it against the back of my Martin and it was within 1/32", or less, along the entire perimeter. Frankly, that's good enough. All other sizes and shapes are always taken from the printed values on the plan.

For the OLF SJ, I used John Hall's mold as my template. I'm trusting him to get it right but, if he didn't, the difference is completely imperceptible.

Here is the evolution of the OLFOM plan set.

I have always considered the Martin OM and 000 to be at the top of my favorite body shapes for finger style play. In 2001 I built my first scratch built OM from tracing of a Martin OM-18 I had in house for a re-fret and a Martin OM Kit I had built years ago. Being a professional engineer and a CAD junkie I laid out the build on cad before proceeding. I later reworked the bracing to suit my taste and building technique. I purchased a set of Martin bending forms and assembly molds from John at Blues Creek guitars and finitely refined the shape to match the mold. Truth is there was only the naturally accruing variance in the first place. Since that time all my builds were built off formal plans I drew up as well as my fixtures

In 2004 Don Williams introduced me to this forum. In early 2005 I took my OM plans and put an OLF title block on a copy of my plans and donated that plan set to the forum as a means to provide financial support to the forum and that was the beginning of the OLF Library of Plans.

Since donating the first OLF OM plan set to the Forum little has changed on the OM plans. The Body shape has not changed at all. The bracing layout is still the same though the brace dimensions have changed some.

My OM plan is not a direct Martin copy, It is the Martin body shape but the internals is my layout. It is not a lot different than Martin forward shifted X system but is a tad different to suit me.