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Thoughts on untested idea re: laminated linings
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Author:  doncaparker [ Tue Sep 15, 2015 11:52 pm ]
Post subject:  Thoughts on untested idea re: laminated linings
I would like to experiment with making solid laminated linings. I feel good about the linings for the top; while arched, the arch is not that severe (25' radius) and the two ends are on the same plane. However, the back is a different story. These guitars I am building at the moment taper 3/4" from tail to head. The taper causes challenges when dealing with continuous strip linings that are rigid, like these will be. I am concerned about dealing with the back taper.

Here is the idea:

How about bending the lamination strips in a side bender, but doing so such that the lamination strips sit cockeyed in the bender by the amount of the taper? in other words, we normally are careful to have whatever is in the bender line up completely against one edge or the other, but here we could offset the headblock end by the desired amount of taper.

This should allow the strips to fit the taper of the sides pretty well. Thoughts? Thanks in advance.
Author:  klooker [ Wed Sep 16, 2015 6:15 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
I don't think that would work.

Look at a set of plans that show the un-bent sides drawn with the back taper taken into account, i.e. any of the Grellier plans.

The edge has a fairly pronounced step as opposed to a straight line like you're proposing.
Author:  doncaparker [ Wed Sep 16, 2015 6:48 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Maybe I should clarify: I don't expect to be able to do this without needing to trim off a fair amount at both ends after the bend. I just want to avoid needing to either twist the strips after the bending in order to deal with the taper (which would cause gaps), or making the strips really wide to begin with before the bending in order to cut the taper off the head block end afterward. I'm hoping that bending the strips askew in the bender will let them fit the waist area well and provide for relatively equal waste on both ends, which I will trim off both ends.

I guess what I am trying to do is evenly distribute the taper (and the trimming that will have to be done because of the taper) between both ends and have a tight fit at the waist. This seems like it should work. Maybe, maybe not.

I might test it out. It only costs a few scrap strips and some time.
Author:  Pwoolson [ Wed Sep 16, 2015 7:13 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
What you are forgetting is that in order to bend in that Z axis, you have to introduce a twist into the lining. I experience this with my capped linings. The easy(ish) answer is to build them tall and then just sand them off with the body radius. In my opinion, it looks pretty cool when you look inside and the linings are undulating with the profile of the back.
Author:  Clinchriver [ Wed Sep 16, 2015 7:15 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
The two on the bench now have laminated linings, I used 3 X.080 strips 3/4 tall. Initially bent in my side bender then glued with HHG around a mold (OO and a D) ran them through my thickness sander to flush the top and bottom, and through the router table to put a nice 45 bevel on the lower. I scribed a 9/16 line around the top and bottom of the sides, glued to the line which left me about 1/4 proud in the waist used a sharp block plane and finally a radius dish to complete the profile. The linings flexed enough the twist was not a big deal. These really stiffen up your sides.
Author:  doncaparker [ Wed Sep 16, 2015 8:09 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Pwoolson wrote:
What you are forgetting is that in order to bend in that Z axis, you have to introduce a twist into the lining. I experience this with my capped linings. The easy(ish) answer is to build them tall and then just sand them off with the body radius. In my opinion, it looks pretty cool when you look inside and the linings are undulating with the profile of the back.


Actually, I'm not forgetting the twist; the twist is the whole point of this idea. For the back linings, given the taper, bending straight seems like it will require a lot of trimming, whereas bending with the twist in mind might reduce the amount of trimming, or at least make a smaller amount needed in two places.

I'll get a chance to maybe try this out in a few days.
Author:  mflazar [ Wed Sep 16, 2015 8:29 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
I make my laminated linings straight. My top tapers downward as part of an elevated fret board design and the top is fully domed to a 30' radius. The back is a 15 foot radius. When I glue my linings I start clamping at the waist. As I work toward the end I bend the linings to keep them just a little proud of the top. Then plane level and sand in a radiused dish. Never any problems.

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Author:  doncaparker [ Wed Sep 16, 2015 8:36 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
That's encouraging, Michael! How big is your taper? In other words, how deep is the guitar at the tail versus at the headblock?
Author:  Pwoolson [ Wed Sep 16, 2015 9:27 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
doncaparker wrote:
Pwoolson wrote:
What you are forgetting is that in order to bend in that Z axis, you have to introduce a twist into the lining. I experience this with my capped linings. The easy(ish) answer is to build them tall and then just sand them off with the body radius. In my opinion, it looks pretty cool when you look inside and the linings are undulating with the profile of the back.


Actually, I'm not forgetting the twist; the twist is the whole point of this idea. For the back linings, given the taper, bending straight seems like it will require a lot of trimming, whereas bending with the twist in mind might reduce the amount of trimming, or at least make a smaller amount needed in two places.

I'll get a chance to maybe try this out in a few days.

If I'm understanding this properly, what you will gain is that the waist will be "crooked" which is a good thing. However, you'll still have the radius to contend with which will require you to either bend them in the Z axis (what I called the twist) or leave them proud and trim them off, which is what I do.
Author:  doncaparker [ Wed Sep 16, 2015 9:33 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Pwoolson wrote:
doncaparker wrote:
Pwoolson wrote:
What you are forgetting is that in order to bend in that Z axis, you have to introduce a twist into the lining. I experience this with my capped linings. The easy(ish) answer is to build them tall and then just sand them off with the body radius. In my opinion, it looks pretty cool when you look inside and the linings are undulating with the profile of the back.


Actually, I'm not forgetting the twist; the twist is the whole point of this idea. For the back linings, given the taper, bending straight seems like it will require a lot of trimming, whereas bending with the twist in mind might reduce the amount of trimming, or at least make a smaller amount needed in two places.

I'll get a chance to maybe try this out in a few days.

If I'm understanding this properly, what you will gain is that the waist will be "crooked" which is a good thing. However, you'll still have the radius to contend with which will require you to either bend them in the Z axis (what I called the twist) or leave them proud and trim them off, which is what I do.


Leaving the linings proud and trimming them is part of the plan, for sure. I'm just trying to have it be a smaller amount of trimming on both ends instead of a lot of trimming on one end, due to the taper.

Thanks for the input. I appreciate it.
Author:  david farmer [ Wed Sep 16, 2015 11:08 am ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
I think It's a good Idea.

You would have to glue the laminations together skewed as well.

Bending and gluing along the taper line should produce linings that require less fudging or torcher to get parallel w/ the back.

Now you got me thinking about how to taper the jig I use to laminate linings. It's enough to make me long for cad-cam skills yet again.

Let us know how it works.

Oh yeah, and don't forget to skew some the opposite way too!
Author:  Hesh [ Wed Sep 16, 2015 12:03 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Years ago on the OLF Colin Symonds came up with an excellent method to transfer the radius of the dish to the sides so that the sides would be pre-profiled very nearly, but not entirely eliminating the dish sanding. I don't recall the method although I tried it out back then and it worked great and saved me a lot of sanding drudgery.

I also recall that Colin built at least back then with solid linings.

As such I suspect that his method if someone can find it in the archives would be perfect for pre profiling solid linings as well.

Colin is still a member so you might want to shoot him a PM and see if we can repost his method.
Author:  kencierp [ Wed Sep 16, 2015 1:03 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
We always profile the sides before bending and actually use the inner waist curve apex as the main location point throughout the assembly process -- here's how we make our profile templates -- I suppose it could be done with a contoured dish? Ken Casper turned us on to the basic idea years ago.

http://www.kennethmichaelguitars.com/si ... lates.html
Author:  doncaparker [ Wed Sep 16, 2015 1:51 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Actually, getting a good profile line for the sides, assuming a taper and the use of radius dishes and an outside mold, is not hard.

You put the radius dish on the bench, concave side up. You cut some poster stock to be the same width as the thickness of the mold and tape it to the inside of the mold, all along the side. You put your mold on the dish. You prop the tail end up by the precise amount of the taper, measured from the inside edge of the mold at the tail, versus the inside edge of the mold at the headblock. You use something that can allow you to transfer the contour of the dish below to the poster stock several inches up. This can be a set of dividers with a pencil on one end, or it can be just a narrow stick of a few inches' length that you are careful to stand up vertically as you draw along the top of it, scooching it along the inside edge of the mold. However you get there, this gives you a line on the poster stock. Remove the poster stock, lay it flat, and there's your contour line, as measured against one of the straight edges of the poster stock.

Back to this idea of bending the lamination strips cockeyed instead of straight: Another way of approaching this is to recognize that, when working with molds, bending can be an inexact procedure, and with wood as thin as this (I will be working with 0.085" stock, like the normal thickness of side material), the heated bending is more of a general thing to do before you manipulate it to the precise curve of the mold. So, I could just bend the stuff, generally speaking, into the shape of the sides, then clamp it more precisely after that.

Anyway, we'll see what happens. I really do appreciate all the input.
Author:  Alex Kleon [ Wed Sep 16, 2015 2:32 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
I just sanded the radius on the back of these sides.Image
They started at 3/4" tall, and finished at 5/8" at the heel, 1/2" at the neck.
I rabbeted the neck and heel blocks to allow for continuous linings, and a very stiff rim. Image

I like the look of the tapered linings, myself, but I can see how your idea can be desirable as well. I'm trying to get my head around making a glueing form for the linings with the compound curve, though! I'd really be interested in seeing what you come up with, Don!

Alex



Sent from my iPad using Tapatalk
Author:  doncaparker [ Wed Sep 16, 2015 2:42 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
That looks great, Alex. What is the taper on that guitar, if you don't mind me asking?
Author:  Alex Kleon [ Wed Sep 16, 2015 3:36 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Thanks, Don! The taper is 21/32" or 5/8" + 1/32" as per the OLF SJ plans. In reality, I'm about 1/64" shy of that. This is my first, but I've started #2 for my brother's 60th birthday in January. He might end up getting #1 if I can't get it done in time.
Sorry about the big pictures messing up your post, Don.

Alex
Author:  david farmer [ Wed Sep 16, 2015 4:35 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
A lining lamination clamp like mine could be made much thicker, propped up on one end the amount of the taper, run through a thickness sander, and the opposite side sanded parallel.

I think I would hog off most of the taper w/ a band saw or plane.

Then your skewed lams would fit right in there. bliss
Sounds like a lot of work and wasted materiel though. Especially since you'd need a left and a right mold. idunno

But ooooooh.... The fit!

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IMG_3674 25 resize.jpg
Author:  Ken Lewis [ Wed Sep 16, 2015 4:48 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Don, maybe I'm misreading what you are saying about the head to tail taper, but to me it makes no difference if
it is one inch or two or three even. I think the only thing that causes the twist is the back radius. In other words, linings
that are made to fit a 15' back radius should fit with the same amount of fuss no matter the front to back taper. Perhaps I'm
stating the obvious, maybe not? ;) But having a consistent height for the entire length of the lining cuts down on sanding later. I glue my laminated linings like Alex and Michael in that I clamp them to an inside 1/2 mold. I find that if I hold them flush to the top of the mold at the waist and below 1/8 inch or so at the ends, without any distortion, it helps later on. They fit pretty uniformly height wise.
For me though, the most important thing is a good lining to side fit without having to use too much clamping force.
A top notch glue joint is what I'm after. As long as they're reasonably consistent (plus or minus a sixteenth of an inch or so) is ok for me. I like using laminated linings because after glue up there is no spring back, they fit the sides perfectly and therefore are easy to install. Just my take, nobody ever told me I was right, ever. :lol:
Ken
Author:  kencierp [ Wed Sep 16, 2015 5:25 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Rather than trying to bend strips of veneer lengthwise to fit the complex contour of the back I have found it to be much easier to actually use wider strips. Stack'em up and cut the (to width) parallel contours on a band saw. 1/8" thick Walnut bends like butter and two layers is all I use. The sketch shows the 5/8" wide OM 000 14th fret pattern, the blanks would be 1 1/8" The waist curve apex is the locator. Yes there is wasted materials. Hope this makes sense.

Image
Author:  david farmer [ Wed Sep 16, 2015 5:29 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
I think a few folks are misunderstanding the issue. It's not the dish radius. If your bent linings were to fit perfectly along the back, they would have to be glued in parallel w/ the top. In Dons case, the linings would be 3/4" taller at one block than the other.

I thought of a better way to make a tapered lining mold. Lay a plan view pattern on a shaper or router table. put the new mold materiel on top like you were going to copy it w/ flush cutting bit but raise one end by the amount of your taper. The bearing rides on the plan view but the cutter cuts the skew. You'd have your skew cut pattern w/ out wasting material cutting a taper.

I wish I had time to give this a go.
Author:  doncaparker [ Wed Sep 16, 2015 5:32 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Ken (Lewis)--

I think the thing that is the monkey wrench in the works is the waist bend. If you bend the linings for the top, the waist bend is a simple, 2 dimensional section of a circle. For the back, though, the waist bend (assuming a taper and a profile created by a spherically dished workboard) has a 3 dimensional twist. Imagine a section of a spring instead of a section of a circle. This is thanks to the taper. With parallel back and top, you would not have this issue.

This might not matter all that much. We'll see as I start experimenting soon.
Author:  doncaparker [ Wed Sep 16, 2015 5:41 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
kencierp wrote:
Rather than trying to bend strips of veneer lengthwise to fit the complex contour of the back I have found it to be much easier to actually use wider strips. Stack'em up and cut the (to width) parallel contours on a band saw. 1/8" thick Walnut bends like butter and two layers is all I use. The sketch shows the 5/8" wide OM 000 14th fret pattern, the blanks would be 1 1/8" The waist curve apex is the locator. Yes there is wasted materials. Hope this makes sense.

Image


Makes perfect sense to me, Ken. I think I was headed in this direction, one way or another. This provides a tight fit at the waist, the linings maintain a relatively uniform height, and good predictability. I like it as a solution. The one downside is the width of the material needed; I was hoping to get by with smaller. Oh, well. It's only for the back. The top linings can be smaller.
Author:  Ken Lewis [ Wed Sep 16, 2015 6:39 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Guys, I don't like to flog the ole horse, but out of curiosity and to clarify what I'm saying, do you use a radius dish to profile your sides after gluing on the linings? I use one, 15' for the back, I use the same one on every guitar no matter what the tail to front taper. I think a lot of other guys do the same. Think about it. The dish profile doesn't change. idunno Also, when I place my freshly laminated linings upside down in the dish they fit pretty close with no prep work so there must be some merit to what I'm saying, ...Just sayin'. [:Y:]
Ken
Author:  kencierp [ Wed Sep 16, 2015 6:59 pm ]
Post subject:  Re: Thoughts on untested idea re: laminated linings
Yes I contour and bevel the back of the rim with our Mega Mold which of course is like the factory process. I won't speak for Don -- but I believe that has little to do with the OP, its about getting the linings to follow the contour without extreme force and "clampage" while having them end up the same width all along the perimeter.
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