Back & Binding Jig

Last Sunday, I had some time, and the scrap left from my molds, so I began my binding jig.  The construction is less complex than it looks.  I began with the plastic that would serve as the router mount, and cut it to size.  In the picture, the router is mounted backward, and I still have some work to do on the mounting plate, but it's width is correct and that was the crucial dimension.

Next, work on the interior box.  On the material for the interior box (3/4 MDF) I cut the groove for the mounting plate on the table saw with a dado blade.  It took a bit of fussing with shims to get the width of the groove correct, but I wanted a tight fit.  Next, I cut the sides to width, about 2 1/2 inches, and length.  The drawer glides determined the length.  With the mounting plate in the side grooves, used that to get the measure for the width of the back.  I used a simple butt joint, then glue and brads to build the box.  You can use the mounting plate to keep things aligned.

The next step was the exterior box.  Again, I cut the sides to width, about 2 1/2 inches.  Again, the interior box and the drawer glides determined the height.  It is set so the router, at the lowest level, will not bottom out its bit.   A word on the base.     You can see in the photo above and to the left, that it is flush with the front, but extends back.  When the jig is in use, I plan to clamp it behind to one edge of my bench, and you can see from the photo that it supports the weight of my router without the clamps.

I built the exterior box in the same way.  The width of back was determined by the interior box, with the drawer glides.  I then used a simple butt joint with brads and glue.  I cut and installed the base last.  When the glue had dried, and I'd rounded over all the edges, I installed the drawer glides.  Make sure you get the orientation right, but basically the interior box slides up and down like a drawer in and out.

Next, I need to fuss a bit with the router mount, and build the guitar cradle, but on the whole, this project went together better than I would have anticipated.

I had ordered the back and side plates from LMI.  I was side tracked a bit.  Originally, I had intended to use mahogany, but got side tracked by the idea of black walnut, a domestic wood.  It arrived on Wednesday, so I was able to get a start on the back of the guitar.

I brought the thickness down some with my toothing plane, and my thickness sander.  With the toothing plane, I only worked the interior surface.  It's quicker than the thickness sander alone.  There was a bit of tear out, but the thickness sander removed it along with the toothing plane tracks.  

The center stripe is maple from the local hardwood store, with black/white perfling on either side.  The stripe, as you can see from the back view goes all the way through, and is not an inlay.  I prefer this to an inlay, particularly since the joint is reinforced.  The assembly needs a little fussing to get it all lined up in the lattice jig, but then I don't need to worry about sanding through the inlay.  I used scraps from the soundboard redwood to make the reinforcement strip.  Once I had glued it in place on the on the go-bar deck (using every go-bar I had to insure even pressure along the length) I planed it level, then planed a slight bevel on either side, which is rounded over when I sand it.  Today, I will work on the bracing for the back, which I intend to make from walnut, also purchased from the local hardwood store. 

A Bit More Progress

Another bad weather day -- about a foot of snow, but I was able to make a bit more progress.   In the photo at left, you can see the bending mold, now on a stand with the clamps installed.  I made them from scrap oak, but just about any wood will do.  The clamp at the waist has been contoured on the bottom to fit the waist snugly.  I did this on the bench sander, just rocking it back and forth, and checking it against the mold until it was about right.  Although it is not visible, the far post passes through a slot, not simply a hole.  When I had drilled the holes for the posts, I simply cut down with a gents saw into the hole.   This allows one to position it more quickly, a necessity if you are using the Sloan method of bending -- essentially boiling the sides until they are pliable, and clamping them into a bending mold like the above.  I have cracked several sides attempting it, and wouldn't recommend it, but then again Sloan has built more guitars than I will likely ever build. 

In the photo at right, you can see the completed mold.  I decided against the strap clamp for a couple of reasons.  First, they were too stretchy.  As I would tighten the extenders, it opened up the mold.  Second, the arrangement visible in the photos gave the mold greater stiffness.  Basically, it is simply a piece of 1/2 birch ply, tacked and glued on one side, bolted on the other with a 3/8th inch bolt.  Perhaps not the most aesthetically pleasing arrangement, but it works like a champ.

You can see the extenders below.  It is a simple arrangement as well, and a number of luthiers use something similar.  Essentially, it is a 3/8th by 16 threaded rod inserted into a 1/2 steel tube.  Both are available at the local hardware store.  At either end, the rod and the tube are epoxied into the blocks.  When the wing nut is tightened against the steel tube, it extends and puts pressure against the side in the mold. 

To make them, I laminated three scraps of 3/4 MDF, and from that cut six blocks to size.  Using the mold, I marked the contour on each block, and again shaped them on the bench sander to match the contour of the mold.  I then drilled the 3/8 inch hole on one side, the 1/2 inch hole on the other, about 2/3 of the way through the block. 

I then epoxied the steel rod into the 1/2 hole, and cut it off at about the center line of the mold, or where the two halves of the mold come together.  Since the holes were not precisely to the same depth, this worked well, and kept a sense of symmetry.
For the threaded rods, I did the same.  I epoxied one end into the block, then marked it at about one inch in from the opposite block.  In other words, the rod extends into the tube to about one inch in from the tube-side block.  This allows for enough rod in the tube to keep it straight, but also enough in and out play to remove the extenders when the kerfing has been installed on the side. 

The contoured end of the blocks were covered with cork.  The inside contour of the mold was also covered with cork.  It not only makes it all prettier, but smooths out some of the differences between the three layers of the mold and provides a protective cushion.  It's probably not necessary, but I do it regardless.  The cork comes in a roll and can be purchased in places like hobby lobby.  I cut the strips over-sized by about 1/4 inch.  Although the cork came with an adhesive, I still sprayed the interior of the mold with contact cement, waited for that to dry, and installed it carefully.  I then trimmed the excess away with a sharp exacto knife, and rounded it over with a file.        

A Wee Bit of Progress

Yesterday, I spent on yet another household project.  My wife does not like the arrangement of the living room, so I spent the day hanging a cabinet and the TV from the wall to free up floor space.   the challenge was not so much the hanging as the hiding of all the cords that support the electronics.  I have to admit, it looks much better, and she seems pleased, which is good enough for me. 

Today, however, is not a good weather day, so I couldn't move the vehicle out of the garage into the drive so I could get access to most of my tools, particularly the table saw.   I did make a bit of progress over last week on the bending jig.  In the picture above, you can see the hardware set for the upper bout and waist clamps, and the picture below, you see the hardware set used for the lower bout hold clamps, and in the last picture, the half-finished jig.  The stand is a piece of black pipe with two flanges.  The lower flange will be attached to a base.   I needed access my table saw in order to make the base.  

The upper and lower bout clamps are spring loaded, the waist clamp is shaped to fit the waist and is brought down with the two wing nuts.  As I said, I bend the sides first, freehand, then put them in the jig to rest, so speed isn't particularly crucial.  I do like to let the sides rest over-night, particularly if they are still wet from the bending process.

Next week-end, I hope I will have access to my table saw, and I will make the base, the clamps for the bending jig, and the spreaders to complete the mold.  More details to follow.

The Assembly and Bending Molds

I had a little more time to work this weekend, because my wife is out of town with the kids and grand-daughter.  She was a finalist in her school spelling bee, and grandma had to see it.  I'm a bit disappointed that I didn't get to see it, but we have an aged dog that doesn't travel well, so I am dog-sitting.  At any rate, the soundboard is as complete as I can make it for the moment, and I  don't have the plates for the plates for the sides and back.   So, wife away and at am impasse on the guitar itself, I decided to make the molds.  Since it involves MDF, it's also a hellacious messy, dusty job, something my wife fusses over the whole time.  What she doesn't see won't bother her, so long as I clean up well before she returns, all will be golden.  SAFETY NOTE:  wear a respirator. 

To be honest, I forgot to take pictures when I made the primary pieces of the mold, but the idea is fairly simple.  I used my router, a 1/4 upcut bit, and a brass bearing.  I took my initial template, clamped it first to a piece of 1/4 MDF on top of a piece of 3/4 MDF.  I clamped it my bench, tightly -- that's important, tightly -- and cut around the perimeter of the template.  I set the depth so it cut through the 1/4 inch MDF on the first cut, then another 1/4 inch into the MDF below.   Since there is a slight off set between the brass bearing and the initial template, the 1/4 MDF becomes the new template.  I set it aside, and cut around the template five more times, just 1/4 inch into the 3/4 MDF.

A couple of notes of caution.  When you cut left to right following the template, the router has a tendency to drift away from the template on the right side of the cut -- in the picture above, on the lower bout side.  Position yourself so you can keep good pressure between the brass bearing and the template.   

On the 3/4 MDF with the guitar shaped groove, I used my jig saw and cut along the groove, being careful not to cut outside the groove.   You should have twelve pieces, six for the outside perimeter of the guitar, six for the inside perimeter of the guitar.   Each of the six pieces should have a smooth contour left by the router bit, and a rough contour left by the jig saw.  I used my pattern bit, mounted in my router table, to trim off the excess left by the jig saw, running the bearing against the smooth contour, the blade against the rough contour.  I glued them up three at a time, trimmed the edges to make everything neat, and installed the dowels. 

Another couple of notes of caution.  My initial template extends a couple of inches beyond the center line.  Mark the center line.  When trimming the ends where the two halves of the mold come together, you want to hit the center-line mark precisely so the two halves of the mold come together symmetrically.  The dowels are there to keep things aligned and to keep the mold from folding up like a book when the band clamp is tightened around it.  There are a variety of ways that one can bind the two halves together, but after considerable experimentation in the past, this works well.  I have the band clamp.  It provides sufficient resistance for the extenders that hold the guitar against the mold.    So there you have it, an assembly mold.  Next weekend, I'll make the extenders. 

I did get a start on the bending mold.  I'll explain it in more detail, but you can see that it is basically the pieces that are cut out of the center of the mold.  You can see where I've drilled for the hardware.  Since it is six sheets of 3/4 MDF thick, I don't have a drill bit that will penetrate that far, so I carefully clamped two together, and drilled through them.  I glued up the bending mold, three sheets at a time, first using one drilled piece, then the other drilled piece.   Next week end, along the with extenders, I'll install the hardware and make the various hold down for the bending mold.  By the by, I do not actually use this for bending, though if one had a heat blanket, one could.  I bend freehand, but clamp it into the mold to finish drying and to rest.  It's also useful for holding bent binding while it's waiting for installation. 

Radius Cutter

I found a little time to mess around in my shop this morning, and I came up with this radius cutter that I will use to cut my rosettes.  I was able to get into the school shop, and we have a great band saw with a re-sawing blade.  It cut the redwood like butter.  I will begin work on the soundboard, beginning with the rosette.  I have something in mind, but don't know how well it will work.  I'll give it a whirl and let you know if it does. 

The construction of the radius cutter is fairly simple.  I had some 1/4 inch oak scrap left over from the bench, so I cut a 1/4 in dado in the sides of the cuter, and at the same time, cut for the end pieces and the slide, but did them on both sides.  The pieces are laid out on my bench.
 

The slide works fairly well.  I took a section of what I'd cut for the end pieces, enlarged the dado slightly.  I drilled a 5/16th hole for the blade, and squared it off with my 1/4 inch chisel.  I drilled a 1/4 inch hole for the carriage bolt, then cut it in half with my gent's saw, pushing the blade up against one side of the dado.  The slide is held in place by the carriage bolt, which pinches the two pieces against the interior slats, and the blade is held in place with a small shaped piece of the slat.  It all pivots on a 1/4 metal pin that goes in the hole on the right. 

The blade is made from an old jig saw blade.  I did some very preliminary work on the grinder, but it will need some additional shaping.  I have in mind a chisel point so I can turn it in both directions, and will work on some when I get up in the a.m.  I should be able to do that without waking my wife and our guests.  Even with the point only partially sharpened, however, it did cut a good groove in a scrap of birch ply, at about 1/32 of an inch wide.

Re-Sawing Prep

I didn't spend a lot of time in the shop on Sunday.  Lora wanted to get out of the house, and so we went for a movie (the new Sherlock Holmes movie -- fun, but no depth) and Chinese food (a moment of nostalgia for the restaurants in Chicago -- so much better). 

I did, however, put together what I will need to do my re-sawing.  On the left, is a tall fence.  I used it in making the raised panels for apothecary cabinet as well.  I clamp the panel to it, then run it across my table saw with the blade set at a 15 degree angle or so.  For re-sawing, I clamp it to the bandsaw fence, adjust the table so it is perfectly square to the blade, then back it away 3/16ths or so from the blade and slowly, slowly, slowly feed the stock.  In front of it are my thickness calipers (will be buying a better soon) and a push tool.  The push tool I put together from off cuts left from the bench.  Next is the piece of redwood that I hope to re-saw, the template, and scrap perforated hardboard that I will tape over the re-sawed plates to protect them.

The redwood I found at Owl lumber back in Lombard.  It was originally intended as decking, but someone recognized the grain and set it aside (and marked it up).  When you rap the plank with your knuckles, it rings, so I believe it has good acoustic properties.  It book matches beautifully, and finishes well.  I don't know how it will go, re-sawing the wood at my school, but we'll give it a shot.  I want to make some progress on an actual guitar.  I'll also check on the parts for my bandsaw today.  It should be relatively quiet at work -- most people already away for the Christmas holiday.  Peace on earth, good will toward people. 

Lattice Jig

Granddaughter and kids went home yesterday.  We went to Lowe's where Lora bought a white Christmas tree (something she has always wanted) and I bought a quarter sheet of birch ply (something I can always use).  I adjusted the platen on my thickness sander, and put a coat of poly on the drum.  I will put another coat on today, then during the week, I'll install the sandpaper, and all is for the good.

The lattice jig is really a rather simple affair, though it is somewhat ingenious, and I don't know who to credit for that ingenuity.   I took my design from LMI, and simplified it.   It is used for joining the plates for the back and soundboard.  I'll picture its work when I get to joining the plates for my next guitar,

It consists of two lattices, each of which consists of two rails (thinking of the rail road analogy again) and three ties (with a bad pun on ties).  It is assembled using standard wood-working techniques.  I cut 2 inch strips to length, then set up my dado blade to cut over-lapping notches.  I cut them slightly deep, at about an inch and an eighth, so I could keep it all perfectly flat during glue up.

The bottom lattice required the most work.  Between the notches for the two rails, I removed enough material to accommodate 1/4 inch MDF and some sheet plastic.  It provides the base against which the top rails bear, keeping the plates flat at the seam.

On one side, the rope is knotted into a single hole, and on the other, once it is crossed back and forth over the plates, it is snaked through the three holes pictured.  Drill the holes before assembly.  I glued and pinned it on my table saw, so it would be perfectly flat, threaded the rope and tested it on some scrap 1/8th ply.  It worked as advertised, so I can actually begin work on the guitar.  I will need to dig through my wood, but I believe I salvaged the mahogany for the back and sides, along with a book-matched piece of redwood for the soundboard.

If not, I will need to wait for the pieces needed to repair my band saw come from the manufacturer, and there is another project that I can tackle -- a circle cutter to define the rosette channel.  For that, I need a 1/4 inch brass rod (about 12 inches).  I have the necessary screws and inserts -- those I did salvage from the flood -- and the body I can make from oak off-cuts left over from the bench.  I could also continue making my shop cabinets.  I have in mind a router cabinet and another to hold my hand held power tools.  Never a lack of things to do.         

Thickness Sander and Lattice Jig

I have given this some thought on and off over the holiday, between games with my granddaughter, and remembered something that was implicit in my design for the thickness sander all along, though I wasn't completely cognizant of it. The cross member that holds the hinge is not structural and was unintentionally, or perhaps intentionally behind the white noise that usually fills my head, set up to allow for adjustment. Consequently, I have resolved on the plan to withdraw the screws that hold the hinge support in place on the out-feed side. With the adjustment screw fully extended, I will then bring the hinge end of the platen up until it touches all the way across the drum, and screw the hinge support back into place. I've taken a straight edge to the drum, and it reasonably flat along its length all the way around its diameter, so to continue down my current path would simply distort the drum, making the radius smaller on one side than on the other. I will do this Saturday, when the kids and granddaughter return to Boise.

Also, in the meantime, I have been giving some thought to the first step in actually building the guitar, the plate joining for the soundboard and back. I have used the method that Sloane describes. After getting a good light-tight joint, on a work-board, one places a dowel or metal rod under the plates, taps nails along the two edges of the plates (not into the plates, but abutting them), removes the nails and presses the plates flat against the work-board, places a caul over the joint, and then weights that down. For weight, I used edger bricks wrapped in duct tape, but about anything suitably heavy would do. This works reasonably well -- that is to say, it works -- but I wouldn't necessarily recommend it. A couple of reasons, the most important being that you can't really see the joint as it is coming together and its difficult to get even pressure along the length of the joint with the caul, so there have been occasions where plates, perfectly thicknessed, have not come together sufficiently flat at the seam. I have had to cut them apart, re-joint the plates, and go through the steps again.

Consequently, I have been thinking about jigs to join the plates, and the one that holds the most promise is the lattice jig. I call it that for lack of a better term, but it is the jig sold by LMI. Though it has nice features, the price is a bit steep, and I think LMI, in particular, sets prices on such things as if to say, "look, if you're too lazy or impatient to build your own jigs, then you shouldn't be building guitars." Regardless, my next project will be the lattice jig. I will build it from birch ply, cutting strips about 2.5 inches in width and about 22 inches long. It will consist of basically two lattices (think a section rail road tracks with three ties) put together with interlocking notches. On the bottom lattice, on the ties, between the notches for the rails, I plan to remove about 3/8ths. This will accommodate 1/4 MDF and sheet plastic, that will provide a solid flat surface. On each end of the rails, I plan to drill three holes, large enough to thread rope. The three holes should provide enough friction to lock the rope in place, but if not, the exposed loop can be clamped to hold it. To use it, the plates are sandwiched between the two lattices, rope is crossed over the rails, locked into place, and then to provide clamping pressure, a wedge is tapped under the crossed ropes. The lattice holds the plates flat while the ropes provide pressure not only against the edges of the plates, but also to lattice. The trick to this will be keeping the lattice perfectly flat during construction.

A quarter sheet of birch ply should provide enough to build the lattice jig, with enough left over to build the jig that will build the radius dishes for sanding and gluing the braces on the sound board and backs.

The Great Flood

I have, or had, all the tools to build guitars. I say had because we have recently moved from Lombard, IL, a suburb of Chicago, to Draper, UT, a suburb of Salt Lake City. The move itself was not a happy one. It was motivated by the loss of my job and set in motion by a flood. It put our house, and my shop, under about six foot of water, and left chaos as it ebbed. I was able to salvage many of the tools, but not all. The motors on my table saw and band saw seized solid with rust. I've replaced the motor on the table saw, and with patience, and plenty of WD40 and wet-dry sandpaper, I've brought it back almost to new. The same with the band saw, with the exception that, as I write, the motor is on back order. All of the templates, jigs, and molds, however, were lost. In effect, I am starting from scratch, and will approach my path to the perfect guitar with a beginner's mind.

Perfect Guitar

I have resolved recently to build a perfect guitar. It's silly, really, when you think about it, but I try not to think about it too much (I already think about too many things too much). I doubt, of course, that I will bring my resolve to any resolution. Perfection is an elusive standard, particularly when there is likely to be no consensus up front on just what would count as perfection. No matter, it is my resolve, and it is what it is, and one must begin any journey with a bit of faith that the destination is out there to be reached.