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rickoshea

The Apprentice

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My grounding is going pretty well, but should I use stainless threaded bar and tubing? The rate my digging is going I think the props will be well and truly rusted by the time the escape tunnel reaches the Danish coastline. At least having to use a teaspoon for digging purposes leaves one hand free to hold my "Larn yersel Danish" book, so I should have the lingo off to a "T" by the time I get there. :facepalm:

Nice work Rick. :thu: I see your headstock patterns laid out in the background. :thu: Looking gooood. ;)

Dry runs and test drives are a must when you approach a fresh situation, but you soon get a feel for how much open time you have depending on the materials being glued and ambient temperatures. I suppose you could say things begin to go with a flow. It often pays to carefully place parts together, hold them for a second or three and then reach for the first clamp. This allows a degree of capillary action to take place as the glue is drawn into both sets of timber during what's often called "grab time".

Initial "grab" time can be shortened and joint strength improved if you think in terms of less is more. A thin coating of glue tends to work best, causes less problems with parts skidding and sliding before the clamps are applied and improves the overall strength of the joint as long as both surfaces are close fitting and clean. Doing so also tends to reduce cleanup and this leaves you free to move onto the next part of the job in a shorter amount of time.

If in doubt practise on scrap.

Sometimes a little extra glue can help if you need to adjust things after they've been placed and as they're set up, but that generally has to be a judgement call.

Sticky back plastic works brilliantly as a glue barrier when fitted to a mold, clamping caul or work surface (As used when joining soundboard and backplates) and is another alternative to grease proof paper. Old timers used to use waxed brown or news paper and even older old timers used to simply candle wax their workboards and molds.

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I like the candle wax idea mate .... knowing me though I'd have missed a bit and produced a nice "form guitar" anyway lol.

So - the headblock. Now this stage is an important one. This is the fella that the neck of the guitar will be set into so its vital to get it level and dead centre. I thought about going for the niche market and angling it at 45 degrees for those with rubber wrists and/or short necks that prevent them from seeing where they are fretting on a normal fretboard but decided not to be too adventurous with the first build. As always several try ins were done to make sure I could replicate the stages in getting this just right. Heres the all important clamping up and alignment to the marked centrelines (arrowed) :

blocks3-1.jpg

once clamped I set a square against the headblock to ensure it was at 90 degrees to horizontal and popped a level on the top to check it was level (its the only way to be sure ;))

et voila ... everything in place and left to set overnight again :

blocks4-1.jpg

and heres the completed tail and head blocks in place. It was a bit of a nervous time for me as I lost hair over not getting the blocks evenly glued up but all looks good methinks :)

blocks2-1.jpg

blocks1-1.jpg

thanks for reminding me about the greaseproof paper Gary :thu::lol:

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I thought it best to remind you about the greaseproof paper, following a nightmare of a job I had releasing a set of sides from a mold back when Moses was a boy. I honestly don't know who received the most taps on the head block, as it was a toss of the coin between me tapping it or my mentor tapping mine every time he passed my work bench. :lol:

The upside was it never happened again. :thu:

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It's looking real good Rick. I never had all those tools when I built my first guitar. Used a jigsaw, coping saw, purfling cutter, cabinet scrapers, and one chisel plus some clamps and clothes pins. It came out great too.

BigAl :)

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It looks like the tail block will have a large gluing surface area for the top. I think some builders bevel the tail block so the top is free to vibrate, don't they?

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Al, believe me I'm impressed that you built a guitar with minimal tools. I'm trying to do a lot without using power tools, Gary told me he wasn't allowed to use them for 2 years when he started and I reckon it's good for the learning process. Plus, there's more satisfaction doing things by hand :)

gitnoob ... Gary will answer that one better lol. He did tell me some luthiers face the blocks with a hardwood with the grain direction running at right angles to the grain they're made from. I think it was to give a potentially stronger bond to soundboard and back (correct me if I'm wrong mate lol)

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Rick that looks fantastic, you are an inspiration to guys like my self who want to build a guitar :thu:
The pictures are great, thank you for sharing your build with us

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It looks like the tail block will have a large gluing surface area for the top. I think some builders bevel the tail block so the top is free to vibrate, don't they?



Most builders do angle the tail block away from the sides in order to minimise surface and end grain contact between the tail block, soundboard and backplates. The block is angled back to leave 1/4" - 3/8" of gluing surface, but there's a trick I use to achieve this, while also reinforcing the end block to prevent potential splitting. It should become very apparent as the build progresses. ;)

The head block I use is a Spanish/slipper heel type and differs to the ones provided by LMI, Stewmac, Blueridge, etc. This heel design also avoids end grain contact between it the soundboard and backplate and - perhaps more importantly - greatly reduces the potential need for future neck re-sets by virtue of it's form.

The original plan had been for Rick and I to build two guitars (One each) in tandem, but ongoing health issues prevaled and I had to shelve the intended build. I had prepared most of the timbers with this project mind and they're parked up waiting to be bent, profiled, inlaid and carved. It's frustrating on my part because I'd prefer to be of more help to Rick by carrying out the same process as he hits each step, but at least my typing speed is improving and Rick's doing very well. ;-)

------------

Yes, the first two years without being let loose with power tools was standard practice at the shop I was in during my apprenticeship. Although I whinged about not being allowed to use the thicknesser, bandsaw, pillar drill, etc., I think it was a great way to learn the build process in it's entirity. New trainees/apprentices should learn the same manner because it teaches you to read and tool timber from a different perspective and doing so also allows you to become more aware of flaws and how to avoid potential problems. It also allows you to try and perfect each step as you progress from thicknessing & squaring, neck carving & profiling, inlaying, bracing and voicing.

Unfortunately, too many trainee craftsmen seem to want to be able to run before they can walk when it comes to the learning process. It's not their fault, but more a reflection of present day society and what many seem to have come to expect. My views on crafting are definitely not a reflection on the use of kits as a means of entry into luthiery or eventually building from scratch for oneself. I think kits are great.

Luthiery seems to be viewed as an art by some, but in reality it's a craft just like any other. The only difference is it involves stringed instrument building and voicing in order to achieve the best possible degree of playability and balanced sound.

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Gary - believe me you couldnt be more helpful :thu:

the head block (continued :lol:) :

theres a lot to think about when going through this stage, not least the fact that the predrilled neck needs to be aligned perfectly with the corresponding bolt holes in the neck block and the truss rod channel :

headblock4.jpg

You also have to allow for the thickness of the soundboard which has to be level with the surface of the fingerboard and on top of which will rest the fretboard when all is finished. Then there's the dimensional measurements of the body of the guitar to take into consideration ... of concern here is the measurement from soundboard to backboard at the tail and the neck ends.
Its always a great idea to give yourself as little work as possible when it comes to this step. This is where I made the first weeeee mistake lol.

Before starting the reduction of the sides to the required dimensions a try-in (or try-"on") of the neck was in order. As I said the block face and sides need to be on a level and 3mms (to allow for the soundboard in this case) below the level of the fingerboard. Heres the try :

headblock5.jpg

I need to remove 3mms from the face of the head block and sides as the level of the fingerboard is flush with this face and side level ... the 3mms are marked on the block in this image :

headblock6.jpg

what I should have done is to set the block with this 3mm above the level of the sides on glueing. Then the sides would have been at the correct level and it leaves just easy block adjustment. It would have saved me a lot of sanding .... lesson learned for the next time.

I did have some fun designing the reinforcing strips that will be set between the kerfling when the time comes. I decided to make them look a bit better than the average ones so have used 1.5mm thick pine strips (its important the grain runs at 90 degrees to the grain of the sides for these), faced with burr maple veneer :

headblock2.jpg

I'll square them up and bevel the sides to make them look prettier before glueing them :thu:

and a gratuitous shot of the workshop ... just cause I like the look of my bandsaw lol. Note the printed e-mail from Gary beside the mold with instructions on the neck try-in as my brain just couldnt deal with trying to envision what order all this should be done in :facepalm:

headblock1.jpg

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Certainly never a problem Rick and you're more than welcome. ;)

I've just noticed the thickness of the email print-outs and no wonder I've been getting typist's cramp. :lol:

Once the fresh rim alignment has been scribed I'd chase the bulk of waste from the rims using the block plane. This is where the solera is an extremely handy tool to have as it allows all round access to your work while mounted (Bolted/securely clamped) at 90 deg to the bench centre. Initally an agressive cut with the plane and more refined as you approach the line following the grain of the rims/sides, while just say leaving a fraction of the white pencil line visible. The remainder of the line can remain or be sanded out when the time arrives for sanding the linings to their finished radii and height.

The reason for leaving the head block proud of the rims/sides is that it needs to be reduced to match the slightly angled plain (1.5deg) that will exist between the shoulders and waist of the sound box. The soundboard radius picks up at the waist and continues down to the tail end of the box. So flat and rising from the shoulders to the waist and radial/arched from the waist to the tail.

The next task will be to flip the rims in their mold and lay out the contour of the fair curve for the back. Rick will take you through this step.

The 3mm discrepancy Rick uncovered is all too easy an oversight to make at this point, but certainly not insurmountable. I'd tend to call it a minor oversight and nothing more, because we've all hit snags at some point. The best thing is it was spotted before progressing further and can be resolved.

Another means of "fixing" a problem of this nature would have been to sweat the head block from the rim, clean it up with abrasive paper and re-set it, but the block is accurate as it stands and there's sufficient meat on the rims that can quickly be removed and faired up using the sanding dish and rod.

Nice work Rick. :thu:

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The 3mm discrepancy Rick uncovered is all too easy an oversight to make at this point, but certainly not insurmountable. I'd tend to call it a minor oversight and nothing more, because we've all hit snags at some point. The best thing is it was spotted before progressing further and can be resolved.



I never consider extra material a problem. Now, cutting too much, that's a problem.;)

The neck joint seems to be the most critical part, correct?

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Ahhhh, I forgot about that.


1.5 degrees of slope? ~.5" over an ~8" run?


I never consider extra material a problem. Now, cutting too much, that's a problem.
;)

The neck joint seems to be the most critical part, correct?



We're not casting off rainwater, but the seemingly insignificant allowance for a 1.5 deg angle over a 150mm/7" distance (The upper bout, from shoulders to mid-waist) provides sufficient lift in the soundboard for adequate neck angle:action and helps avert the dreaded 14th fret hump. In other words this 1.5deg angle allows the fingerboard to continue in a straight line - once the neck's set - without suddenly dropping off the scale and dipping - if allowed to continue - toward the centre of the tail block. Intentional ramping of the fingerboard extention is a different topic.

If the 1.5deg rise weren't allowed for and the neck attached with it's typical offset, the fingerboard would find itself pulled out of line when glued/fixed to the central upper bout.

With sides, head and tail blocks set quarely to the mold the temptation is to radius the entire circumference of the upper soundboard edge of the rims and there's no problem with that, but doing so may not provide the best take off angle for full fretboard playability or string action. Hence the reason for dressing-in allowance for neck angle.

Let's try not to forget the upper transverse brace, soundhole braces and upper transverse graft/Lollipop brace) aren't radiussed, but straight instead.

Yes, it's infinitely better to have extra material than none at all, but a great deal depends upon the original width of the sides set. It would have proven necessary to re-set the head block if they'd been narrower.

At this stage, positioning of the pre-drilled heel block tends to be the most critical element, otherwise it's a case of "Huston we have a problem" when the time for neck fitting arrives and we find the holes arent in their correct positions. The neck angle is amongst the most critical build elements to be pulled together to form a highly playable and well voiced guitar, but - in essence - each element is as important as it's counterpart.

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there you go eh? .... a 1.5deg offset makes one hell of a difference. This wee mistake was in a way a good one to make as I now understand the mechanics of fitting the headblock correctly and the consequences of not getting it exact :thu:

So today the sides needed evenly reduced by just short of 3mms to allow for the correct dimensions at the neck end. To scribe a 2.5mm line I stuck 2 washers together (handily exactly 2.5mms), cut a white pencil in half so it would draw flush then ran it round the sides on the top :

side_trim6.jpg

I popped the mold and sides onto the solera so I had easy access all round, sharpened up the block plane and gently removed the required amount of side wood to just short of the 2.5mm line. It took me a while when I started out using the plane a bit ago to get used to setting it up to get the nice curly shavings you see. Once you gain some degree of proficiency with it though it's lovely to use :thu:

side_trim5.jpg

So now we have the correct dimensions for an accurate neck setting. The line on the headblock below was traced at 3mms. I've left 1mm to allow for removal when sanding in the 1.5deg angle of the block :

side_trim3.jpg

Its been tricky this step, mostly because its my first time and I found it hard to work out how what is done here affects what happens at a future stage. Good learning though :thu:

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At this stage, positioning of the pre-drilled heel block tends to be the most critical element, otherwise it's a case of "Huston we have a problem" when the time for neck fitting arrives and we find the holes arent in their correct positions. The neck angle is amongst the most critical build elements to be pulled together to form a highly playable and well voiced guitar, but - in essence - each element is as important as it's counterpart.



With so many different parts there are many opportunities to misalign. I suspect the instrument will tolerate some asymmetry in places but not the neck to bridge line. Not to slight other parts of a guitar by any means but my approach would be to make sure the neck to neck block is perfect and linear with the bridge and build around that.

Is building a completely holistic approach or is there a foundation around which everything is built to use my example. In my mind a guitar is a fretboard with a soundbox attached to it, not the other way around. In my way of thinking, if you don't get the red lines in my diagram right all the brace shaving in the world won't help.

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I didn't read carefully. When you mentioned slope my mind went to the BACK of the guitar and I did a rough calculation of the amount of slope required to compensate for the difference in thickness from the body's from upper to lower bout and 1.5 degrees didn't seem nearly enough. I checked my guitar and the top didn't appear to have slope confirming in my mind that you were referring to the back. Now I've learned different, it has 1.5 degrees.


With so many different parts there are many opportunities to misalign. I suspect the instrument will tolerate some asymmetry in places but not the neck to bridge line. Not to slight other parts of a guitar by any means but my approach would be to make sure the neck to neck block is perfect and linear with the bridge and build around that.


Is building a completely holistic approach or is there a foundation around which everything is built to use my example. In my mind a guitar is a fretboard with a soundbox attached to it, not the other way around. In my way of thinking, if you don't get the red lines in my diagram right all the brace shaving in the world won't help.



The simplest means of checking the soundboard angle at the guitar's shoulders is to place a protractor with it's flat base against the shoulders, with zero centred on the underside of the fingerboard. Then take a reading using the fingerboard as your guide. A sliding bevel/adjustable protractor is best for a more accurate reading.

Everything is based around a foundation. Namely a centreline and this runs from the centre of headstock and down the neck to the centre of the tail block. The centreline is then sub-divided in order to locate and determine given elements such as scale length, neck length, body length, bridge location, compensation, etc. Building could perhaps be considered a holistic approach if viewing the instrument as a whole and not it's constituent parts, but it's elements - in order to achieve the desired end result - need to be positioned accurately and crafted accordingly.

Your longitudinal line needs to extend through the centre of the tail block, but being marginally off centre would not make voicing impractical or impossible. Mass would still need to be selectively removed from the braces in order to balance the soundboard and it's resonance. Let's try not to forget that soundboard and braces are voiced throughout the process....... from top thicknessing, to bracing, post soundboard fitting and upon completion.

If it were an organic approach, there'd tend to be less paper borne planning, but more intuitive decision making and crafting along the way. This still amounts to planning, but throw away common measuring devices and the instrument would tend to take on a more asymetrical form if deviating from the centreline. Asymetry doesn't prevent/negate adequate voicing.

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Well your doing well Rick been watching your progress + looks good
and i bet you cant wait until the end product to try it out

And shall be like fly fishing much better catching a fish with your own
home made fly as a found out.. though making a guitar is something else
You shall have more so happiness playing your own made guitar im sure
and feel proud in such well done.

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Everything is based around a foundation. Namely a centreline and this runs from the centre of headstock and down the neck to the centre of the tail block. The centreline is then sub-divided in order to locate and determine given elements such as scale length, neck length, body length, bridge location, compensation, etc. Building could perhaps be considered a holistic approach if viewing the instrument as a whole and not it's constituent parts, but it's elements - in order to achieve the desired end result - need to be positioned accurately and crafted accordingly.


Your longitudinal line needs to extend through the centre of the tail block, but being marginally off centre would not make voicing impractical or impossible. Mass would still need to be selectively removed from the braces in order to balance the soundboard and it's resonance. Let's try not to forget that soundboard and braces are voiced throughout the process....... from top thicknessing, to bracing, post soundboard fitting and upon completion.


If it were an organic approach, there'd tend to be less paper borne planning, but more intuitive decision making and crafting along the way. This still amounts to planning, but throw away common measuring devices and the instrument would tend to take on a more asymetrical form if deviating from the centreline. Asymetry doesn't prevent/negate adequate voicing.



I have to remember to keep an open mind. Because this build is symetrical I'm only thinking in those terms but upon reflection there are numerous asymetrical builds, cutouts being the most common example.

The tail block seems to be almost a copy of the neck block in terms of mass, especially if you account for the dovetail/cutout of the neck block. Is the tailblock's function purely structural or does is lend to the overall sound OTHER than just the affect of it's mass? The tailblock on my Silver Creek-feel free be critical of this build, my loyalty is to knowledge not this guitar-seems to be glued to the soundboard.

This question sets the trap for the question of why the centerline needs to progress to the tailblock. Does a centerline from end to end provide only to asthetic quality or is there a tone/playability component? I'm not dismissing the aspect of a proper straight build, I'm trying to ascertain what affects tone. Nothing much to the ergonomics, within reason, to the lower bout in my opinion. I mean ultimately it is a huge box. I wouldn't think there is much consideration given to the body ergonomics compared to the neck, again within reason.

I'm wondering if there isn't room for improvement in the design of the tailblock. If it doesn't need to be attached to the sound board and it's only function is to hold the two ends of the lower bout together and maybe mount an electronics jack or strap button it seems one could get by with a MUCH smaller piece of wood. The block pictured seems to be smaller than the block in the kit and unless there is a compelling reason otherwise most blocks mass could be reduced without compromising strength.

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I have to remember to keep an open mind. Because this build is symetrical I'm only thinking in those terms but upon reflection there are numerous asymetrical builds, cutouts being the most common example.


The tail block seems to be almost a copy of the neck block in terms of mass, especially if you account for the dovetail/cutout of the neck block. Is the tailblock's function purely structural or does is lend to the overall sound OTHER than just the affect of it's mass? The tailblock on my Silver Creek-feel free be critical of this build, my loyalty is to knowledge not this guitar-seems to be glued to the soundboard.


This question sets the trap for the question of why the centerline needs to progress to the tailblock. Does a centerline from end to end provide only to asthetic quality or is there a tone/playability component? I'm not dismissing the aspect of a proper straight build, I'm trying to ascertain what affects tone. Nothing much to the ergonomics, within reason, to the lower bout in my opinion. I mean ultimately it is a huge box. I wouldn't think there is much consideration given to the body ergonomics compared to the neck, again within reason.


I'm wondering if there isn't room for improvement in the design of the tailblock. If it doesn't need to be attached to the sound board and it's only function is to hold the two ends of the lower bout together and maybe mount an electronics jack or strap button it seems one could get by with a MUCH smaller piece of wood. The block pictured seems to be smaller than the block in the kit and unless there is a compelling reason otherwise it's mass could be reduced without compromising strength.



Firstly we need to remember this is a kit. In essence a starting point from which future ventures into building can spring. Parts can be adapted/customised or retained as they are, but the choice is left to the builder to follow whichever plans he/she wishes to follow. Whether or not provided with the kit.

A total removal from the plans included with a kit is wholely possible, but not necessarily practical inasmuch as thinning head and tail blocks and altering given design features without adequate guidance or understanding potential end results. Yes, head and tail blocks on my instruments differ to the ones provided in this kit, but the design being followed was pre-determined by LMI and not myself or another builder.

Please note the tailblock has been trimmed and will be trimmed further.

The main thing is it's a solid starting point from which Rick can adapt his own designs and ideas for future builds without any need for cutting corners. The full contact between the upper and lower surfaces of the tail block on your Silver Creek are indicative of building to fit a given budget. Corners are cut in order to provide the customer with a functional instrument within a given price point and while full contact won't necessarily kill a soundboard's responsiveness, it won't enhance it either. The norm on a non factory build basis is to keep end block contact with top and backplates to a minimum that's often around 1/4".

The head block's overall dimensions are due to the need for an adequate attachment point that's structurally sound and capable of providing an adequate gluing surface for the ribs and bearing the neck via dovetail, mortise or direct bolt-on. The tail block's mass is due - in part - to the need for a structurally sound end point that's often subject to accidental dings and potential counter-balance to the neck. Bevelled edges often lend themselves to a heavier appearance than quarter rounded/pennied edges.

Hitting into in depth theory as to why the egg is shaped as it is isn't necessarily going to pull anyone ahead unless building and experiencing the reaction of parts as they're combined and the effects of given parts and materials combinations.

A centreline is used as a full length guide from which measurements can be taken and parts locations set. Aesthetic in terms of accurate parts placement and this tends to be more pleasing to the eye of the majority of end users. Yes, cutaways are a form of asymetry, but they don't interfer with tonal response, but if your bridge were heavily off-centre/biased to one side you'd tend to find response would be lacking unless compensated for by voicing braces and soundboard. It depends on how severe the mis-alignment is.

Most builder's end blocks differ. I can't honestly comment on LMI's approach to their designs, but an enquiry email would most probably result in an answer to your question.

The question of what makes tone and why given shapes and contours can affect it is beyond the scope of limited forum response. Books barely skim the surface of this topic.

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Firstly we need to remember this is a kit.


Yes, head and tail blocks on my instruments differ to the ones provided in this kit, but the design being followed was pre-determined by LMI and not myself or another builder.


Please note the tailblock has been trimmed and will be trimmed further.


The main thing is it's a solid starting point from which Rick can adapt his own designs and ideas for future builds without any need for cutting corners. The full contact between the upper and lower surfaces of the tail block on your Silver Creek are indicative of building to fit a given budget. Corners are cut in order to provide the customer with a functional instrument within a given price point and while full contact won't necessarily kill a soundboard's responsiveness, it won't enhance it either. The norm on a non factory build basis is to keep end block contact with top and backplates to a minimum that's often around 1/4".


The head block's overall dimensions are due to the need for an adequate attachment point that's structurally sound and capable of providing an adequate gluing surface for the ribs and bearing the neck via dovetail, mortise or direct bolt-on. The tail block's mass is due - in part - to the need for a structurally sound end point that's often subject to accidental dings and potential counter-balance to the neck. Bevelled edges often lend themselves to a heavier appearance than quarter rounded/pennied edges.


Hitting into in depth theory as to why the egg is shaped as it is isn't necessarily going to pull anyone ahead unless building and experiencing the reaction of parts as they're combined and the effects of given parts and materials combinations.


A centreline is used as a full length guide from which measurements can be taken and parts locations set. Aesthetic in terms of accurate parts placement and this tends to be more pleasing to the eye of the majority of end users. Yes, cutaways are a form of asymetry, but they don't interfer with tonal response, but if your bridge were heavily off-centre/biased to one side you'd tend to find response would be lacking unless compensated for by voicing braces and soundboard. It depends on how severe the mis-alignment is.


Most builder's end blocks differ. I can't honestly comment on LMI's approach to their designs, but an enquiry email would most probably result in an answer to your question.


The question of what makes tone and why given shapes and contours can affect it is beyond the scope of limited forum response. Books barely skim the surface of this topic.



Gary,

I agree with an adequate headblock, I'm thinking it's the foundation, it is the tailblock's utility I question. Agreed on the centerline and the alignment of the bridge to it, I just wondered how critical alignment is beyond that point.

I really appreciate your time. You answered the questions I had. This is a great opportunity to really dig into the structure of a guitar so while the hood is up these questions are popping into my head. I understand it would not only be consuming to go into "the shape of the egg" it would also highjack Rick's thread to some degree. Also, I don't mean to imply that anything should be changed in this particular build, I'm just discussing the items in general terms using this kit to point to the specific parts being discussed. I actually thought of the tailblock's mass as a counterbalance to the otherside of the guitar and then my mind started wandering to hollow carbonfiber necks to reduce that weight instead and the next thing I knew my train of thought was wandering all over the universe.:idk:

Rick, thanks to you too BTW for an excellent thread.:thu:
Great job!

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Gary,


I agree with an adequte headblock, I'm thinking it's the foundation, it is the tailblock's utility I question. Agreed on the centerline and the alignment of the bridge to it, I just wondered how critical alignment is beyond that point.


I really appreciate your time. You answered the questions I had. This is a great opportunity to really dig into the structure of a guitar so while the hood is up these questions are popping into my head.


I understand it would not only be consuming to go into "the shape of the egg" it would also highjack Rick's thread to some degree.




You're more than welcome to my time and any help I can offer and I don't suspect Rick would mind more theoretical input, but the amount of ground to cover is massive. I can provide abridged answers here, but it would literally takes pages of information for me to provide adequate explanations.

IMHO The full length centreline is necessary for one to base the build around - asymentric or symetrical. From this you can plot square, angles and distances, which - in turn - help prevent distortion or twists. The centre line is abreviated to given lengths that provide the dimensions for neck, body, scale length, etc.

Tail block's utility as in? Heft, dimensions or function?

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Tail block's utility as in? Heft, dimensions or function?



All of the above. My first thought would be to use a piece of say 1/4" ply just to weld the seam. It should be adequately strong to mount the accesories, reduce weight and give the 1/4" of soundboard mount you specify.

I edited the above post and threw in a few more bits BTW.

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All of the above. My first thought would be to use a piece of say 1/4" ply just to weld the seam. It should be adequately strong to mount the accesories, reduce weight and give the 1/4" of soundboard mount you specify.


I edited the above post and threw in a few more bits BTW.



No probs. ;)

1/4" ply is fine, but has it's flaws. Another answer is to ply mahogany to 3/4" thickness/use 3/4" thick timber and penny round the edges before profiling it's upper and lower extremes or adding an end splice that prevents end grain contact and improves surface to surface glue-up.

One particular drawback with using plywood is the all round presence of end grain and it's effect on gluing stability. One means of improving this situation is to pre-load/prime the ends using hide glue, allow it to cure and then go through the gluing process, because hide glue adheres well to itself. This still doesn't wholely resolve the problem because it proves difficult to avoid end grain contact when profiling ply to rib/rim contours

I generally begin with 3/4"-1.5" thick stock x 5" x 4", profiled to match the contour of the ribs and reinforce it by adding additionally profiled - horizontal - end splices and a central - horizontal - stiffener that accepts the end pin. With classical I tend to use Lime tail blocks. Tail block mass depends on the neck materials, body profile and overall dimensions of the instrument.

It's a case to case, or design to design scenario, but ply has an awful habit of separating from the parts you attach it to unless the end grain issue is resolved.

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on to the curvature of the sides for the back of the guitar now ....

a paper template is made (here of my Crafter DLX-3000S/K) to give the curvature required from tail to head of the body :

fair_curve9.jpg

here it is in all its glory. The lines must be parallel for approximately 140mms from the centre at the head end and 220mms at the tail end, then the curvature takes effect. A line drawn 6mms below the straight edge allows for the thickness of the backboard and soundboard.

fair_curve8.jpg

So now we have the template that can be transferred onto the body.

fair_curve7.jpg

a line is scribed round this template which will allow removal of the required amount of side material in order to arrive at this desired back to front curvature. I checked this with LMI's plans and the measurements match exactly (124mms at the tail and 100mms at the head - including the widths of the soundboard and backboard). Heres what needs to be removed at the head end (I feel blisters from overuse of the plane coming on already lol). You can saw off the excess close to the line but, knowing me, I'd cock it up. I'll play safe with the plane and accept the blisters :thu:

fair_curve3.jpg

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