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Hey there Dave, that was intensely cool!
The laser cutting of the top sandwich was amazing!

Rob

Hi Rob! Great to hear from you.

I've got a couple of these experimental top guitars on the go at the moment - my ESJ1 with a thicker top, no braces, and no smooth bevel, and this challenge one, my ESJ2 with a thinner top (with just one center brace) with bigger hexagons cut out of the inner layer, and with the smooth bevel thingy. I think I could get enough strength with a thinner top (like the ESJ2) with no braces if I change the hexagon cut out pattern a bit....we'll see when I make ESJ3...

I have no idea how these things are going to be sound-wise, but it's great fun experimenting with them, and the closed bodies sure tap (boing!) nicely! We'll know in a few weeks!!

Stay tuned - I'm going to video the CNC'ing of this fretboard - it'll be my first one on my Shopbot, which I've had for over a year now, but which I'm still learning to use properly...

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

That is looking great Dave , wish I had a few of your toys I do seriously like the head stock . great design.


BTW are you any relation to the great actor Barney Fifield ? JK !

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Don't you mean Barney Fife Wud? I'd not heard of him before, but checked him out on the interwebs - funny fella! No relation, thank goodness!

Well, it's taken me quite a while to get my CNC design for a compound radius fretboard done....but with a bit of help from Andy Bikro I eventually worked out how to route the fret slots without breaking $18 0.023" bits all the time!! Here's a long boring vlog of my Shopbot cutting first the fretboard compound radius surface, then the outside shape of the fretboard, and finally the blind fret slots:



After a little sanding (hardly any!) here's what the fretboard looked like:





I messed around with lots of ideas for inlay on the fretboard, but none of them looked right....just didn't fit with the "theme" of the instrument, so in the end I settled for some simple maple dots that I inlayed using my laser:



I then fretted the board all but frets #3 and #12 (since I use tiny steel rods in those fret slots to locate the fretboard on the neck - the drills/rods come in a kit from LMI), and glued the fretboard in place on the neck:





And here's how it turned out after I'd pattern-routed the sides:



Then I set to the neck with my "Surform" shaper tools, Nickleson (sp?) files, and sandpaper:





I then trimmed the bottom of the heel and added some nice matching walnut to it (although you really can't see it very well in this photo, sorry!):



And that's where I am on it right now....I need to set the center line of the neck straight with the body (fine-tune the neck joint and body fit)....right now it's pointing off to one side by nearly a quarter inch at the bridge! The neck and heel are dead straight, but the top of the body has a slope on it (not sure how that happened!).

More tomorrow - after I've added some side dots and fit everything nicely...

Cheers,
Dave F.

_________________
Cambrian Guitars

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

Looks great. I'm a little disappointed at your lack of a laser guided dust collection system for the CNC, but I suppose I can let that slide since I don't even have a real shop and you have laser beams!

_________________
http://www.CostaGuitars.com
PMoMC

Using hand tools to carve the neck? That's a little old fashioned isn't it!

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Yeah, sorry about that! I'm working on an independent AI dust collection system based on a heavily modified Roomba robot with a laser guidance sub-system for bit avoidance, but progress is slow

Until I get it working I'll have to rely on the Armstrong method (when I want to see where the bit is cutting) or the Shopbot's old-style (pedestrian) dust collecting shroud thingy.....

Cheers,
Dave F.

_________________
Cambrian Guitars

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

Pedestrian indeed. I trust you will have something very advanced soon enough. Meantime, I'm still wedged in between a 1964.5 Mustang and a snowblower.


Posted from the future using Tapatalk

_________________
http://www.CostaGuitars.com
PMoMC

Yup, but I don't have time to develop a 3D CAD model of a neck and then work out all the tool paths for the CNC for this build. I will just about get time to do the CAD/CAM work for the bridge, but that's about it. I'm planning on building a proper spray booth the week of Thanksgiving, just in time to get this build finished and recorded by the end of Nov!

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

Got a couple of hours in the workshop tonight, so I flossed the neck joint and in addition to making the joint nice and flush with the body (for a change!), I got the center line of the neck to point almost exactly down the center line of the body

I'll finesse the neck shape and fine-sand it later. Here's the guitar with the neck bolted on:











I'm working on the bridge now....shouldn't take too long....ha-ha....famous last words....

Cheers mateys,
Dave F.

_________________
Cambrian Guitars

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

She's a beaut, Dave!

Excellent work . That one will be in the running for the prize for sure !

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Thanks guys! I'm not counting on winning anything, although it would be very nice. For me the fun is in the participation. It doesn't hurt to have a deadline to work to either!!

I've been messing with the CAD for my bridge, but not cut anything yet - probably get to it this weekend.
I did make a fairly big decision to build a proper spray room in my workshop. There's a 7' x 7' area that's closed off on three sides and has a proper ceiling that I was going to make into a kitchenette, but I decided it would be better to put my spray equipment in there instead. I will have to build a wall with a door in it (all dust-proof, of course!), seal off a few holes in the wall, close off an old A/C vent that's no longer used, etc., and I will end up with a very airtight little room indeed! At the moment, the area is filled with "stuff" that needs to be sorted (keep, sell, throw away kind of thing). Here's a piccy of the space as it is right now:



I will make a work bench with lazy susan, ceiling hangers, etc. for spraying up bodies and necks separately, with a wall of air filters behind the bench, all feeding an air plenum behind the bench. I have ordered a 20" Jenny variable speed explosion proof fan that I will mount in the ceiling at the top of the air pelnum, with the exhaust venting straight up to the roof (about 6' straight up, no bends). I'll put more filters in the new front wall/door that I build to let clean air in. I have a UV curing booth that should fit into the spray room also, so the plan would be for the guitars to get sprayed, then put into the curing booth without ever leaving the clean area. Even though the UV cured polyester finish is low VOC (some is no VOC), I want to make everything explosion proof as I might want to spray lacquer occasionally. The fan switch/speed control will have to go outside the room, and I will make a sealed acrylic box to put over the florescent light unit to make it safe too.

One of the problems that us UV cured polyester users have been having is with water in the compressed air causing little "volcanoes" in the finish. I've tried dessicant dryers, and they work a bit, but they don't do the job completely, so I decided to invest some of my pocket money in a proper refrigerated air dryer, specifically made for spray equipment. I picked it up from Grainger yesterday and hooked it up (temporarily, just to try it out) tonight. It works very well indeed! I will be moving my air compressor and dryer to the other end of the workshop from where they are right now, so they are just the other side of the wall from the spray room. Here's a shot of my new air dryer:



I'll have more to report tomorrow and over the weekend, hopefully more actual guitar build related

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

Uh-oh, I've got a new self-imposed deadline to meet ahead of the end of November one for the Challenge Build.....I want to show this thing off at the upcoming NCAL meeting at LMI next Sunday!! Cutting it very close indeed!!
I've been busy on it.....finally got a good bridge design/model going in Rhino, and this evening got the tool paths worked out and set the Shopbot loose on a piece of wood! Amazingly, it all worked very well indeed, so after a light sanding to remove the CNC marks, I ended up with a very nice oval bridge for my ESJ2 build.

The material for the bridge was from my $5/lb stuff from LMI's sale. It weighed about 1/4lb prior to turning it into a bridge, so let's say $1.25 for it. I'm not sure what wood it is. Anyone care to tell me? I have a feeling it's a rosewood or ebony. Kind of looks like striped ebony, and it matches the fretboard quite well (which is why I chose this piece). Here are some piccies - don't forget you can right click on them to see the hi-res versions:


A screenshot of the 3D CNC model in Rhino:


The Shopbot in action:


After CNC'ing and light sanding:


Placed roughly where it will end up on the ESJ2 build:


Still have to shape the bottom of the bridge to match the soundboard...


So, tomorrow I'll shape the bottom of the bridge, finish-sand the body and neck, mask off the fingerboard extension and bridge areas, then get busy with putting some finish on it!!
I won't have my spray room finished in time - that's planned to be done Thanksgiving week - and I may have to go to China right after turkey day...

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

It's been a while....I've been busy, but I managed to find time to get the guitar done to show off at the NCAL meeting last Sunday!
Here are some photos of the finishing process, bridge gluing, saddle slot routing, etc. (click on any of the pictures to see the hi-res versions):























Bridge being glued on:


Fingerboard extension being glued down:


Saddle slot routing:


Tuners fitted:


And here she is, (nearly) all done:




There were a few very minor flaws in the finish and one major one (on the headstock - I obviously sanded the edges of the headplates a bit too much at the gel filler stage and didn't see the problem until after the finish was on and UV'ed - DOH!!)

I took it along to the NCAL meeting and told the story of the $150 Challenge build and talked about some of the experimental features of the instrument.
Then, a real guitarist was kind enough to play it for us. It sounded "okay", but not outstanding. Tonally, it is a bit different from other guitars....(not really surprising!).
However, it had only been strung up about 12 hours before the show and tell, so I was expecting it to change....which luckily, it did! I took it into work on Monday and showed it to several of the outstanding guitar players we have there - they loved it, both the action, the sound, and the smooth arm bevel.

"Success!" I thought.....but, not so fast buddy!!......by the end of the day, it was obvious that the soundboard was NOT stiff enough to hold the string tension after all.....
The soundboard was collapsing from the sides of the soundhole to the top of the bridge.....the soundboard below the bridge remained almost in place, but the single center-line brace I'd put on it was beginning to telegraph through the soundboard at the bottom edge of the guitar!! EEK!!
Obviously, it needs some actual bracing - perhaps a modified X brace and/or a UTB above the soundhole. Rats!! I let the string tension off and brought it back to my workshop to cogitate on the problem.... Can I fix some braces in there without taking the top or back off???? After another day of pondering, I'm still not sure what to do about it......any ideas for me??

I'll put up a short partial video I managed to capture of the fellow playing it at the NCAL meeting tomorrow, when I have more time.

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

Well it sure looks good.

As for your strength issue, how hard would it be to get a couple of braces in there with HHG? Once the glue tacks up, you wont need to clamp them so it seems the most likely choice of glue. I'm sure you have a flouroscope in the shop that you can use to x-ray the guitar as you fit the brace inside the box! http://en.wikipedia.org/wiki/Fluoroscopy
What? No flouroscope? Jeez Dave...I'm a bit disappointed at the low budget operation you are running! No laser guided dust collection for the CNC, no flouroscopy equipment. What's next? I bet you shaped the neck for this build with a rasp, didn't you?


Seriously though, a couple of lengthwise braces a la an arch top might solve the problem, though they will change the sound a bit.

_________________
http://www.CostaGuitars.com
PMoMC

When you let the string tension off , did the top spring back ? I would restring with Nylon as a classical and see how the top reacts . If the top handles the Nylon , at least then you have a frame of reference that you can work from . Then again ........ what do I know . lol

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Well, like the others said, it sure looks good. A real shame about the strength issue but that's the way it goes some times with experiments. I'm in the middle of a bit of an experiment myself although I'm not stepping out near as far as you have

As far as the bracing goes I think I would re-top it or pull the back with my preference being a re-top. I don't see how you could add any long-term bracing solution through the sound hole. Of course, that is just my opinion.

_________________
Steve Smith
"Music is what feelings sound like"

I know it is rather late to say this, but I would say the honeycomb core in the soundboard needs to be a lot thicker relative to the inner and outer skins. In my understanding, a core can only add stiffness by increasing the thickness relative to a solid skin, and not adding weight. (does that make sense? ) So the total skin thickness should be much thicker than a normal soundboard, but weigh less than a braced top.
I have no idea how this would relate to the acoustic properties though.

Looks great though!

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Flouroscope is now on my want list Tony! Quite a ways down though....might be a few years yet! I like your idea of using HHG - that would make gluing in some braces easier. I've got to decide whether to go with X braces, A braces, or one or two cross bars like on a classical....

Wud - yes, when I let the string tension off, the soundboard returned to the correct shape almost instantly. I like your idea of moving to nylon strings. I'm considering doing that along with adding just one cross brace under the soundhole (like on a classical). For grins I started putting a set of nylon strings on it tonight, but the nut buzzes and the action is too low. I'll have to make a new nut and re-jigger the saddle height too. Also, something is rattling inside the guitar when the low E is plucked....weird...maybe my single brace has come unglued? It may just be the loose nut (the one strumming it perhaps?)...tomorrow will tell.

Steve - I'm going to see if I can come up with a solution that doesn't involve taking either the back or the soundboard off! If there's a way, I'll find it. If not, then I will take the back off and add bracing etc. to the soundboard from the back. Let's hope there's a solution for me.....

Peter - the center honeycombed piece of spruce is much thicker than the two outside pieces already. I think I posted the exact dimensions earlier in my build log. You are correct though - the thicker the soundboard is, the stiffer it will be (stiffness goes up by the cube of the thickness, as we all know). I have another build (ESJ1) on the go at the moment too. The ESJ1 has a much thicker triple top sandwich with a stiffer center board. I'm going to finish building that one and see how it holds up to SS tension.....I'm fully prepared to rip the back off that one too and add braces if need be.

Cheers for now,
Dave F.

_________________
Cambrian Guitars

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

I have to back off on one comment - I had forgotten the amount of work that went into the top so would not want to re-top that. I would also pull the back if that was the last resort.

_________________
Steve Smith
"Music is what feelings sound like"

I know thats not what you set out to acomplish, but given the work you have in it , it would be an easy solution to a beautifull guitar . Lesson learned and move on . It would make a very Unique Classical and my gut says it would hold up.

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Props for having the guts to go through with an experiment like this Too bad you couldn't string it up before finish. That's one of the things I love about my current shellac style; I can string before I even do back binding, so it's not much trouble to pull the back if need be.

I'd say try to glue a cross strut below the soundhole, with hide glue. Shouldn't be too difficult to hold it in there with your fingers for a few minutes until it gets started drying (do some dry runs, and then heat everything nice and warm so you have plenty of time to get the glue applied and get it positioned). My instinct says there's a good chance it will even handle steel strings ok after that. Cutting a huge hole in the top weakens it so much, and with that one brace focusing the bridge torque right at thee edge of the hole, it's not surprising that it started to cave. And once the forward end of the brace can't go down, the back end will probably stop coming up so hard and telegraphing, too.

Probably don't need a brace above the soundhole, since you have those CF tubes to take the stress off that area.

Another thing that makes a big difference is the string height above the top. I assume you're currently around 1/2"? If you drop that to 3/8" or even 1/4", there'd be a whole lot less torque on the bridge. Of course that does change the tone, and requires changing the neck angle, but something to consider going non-standard with on future experiments. My coral snake guitar (small classical, 11 1/3" lower bout, no fan braces) has the strings at 1/4", and is holding up just fine at about 7 months old now. Sounds great, too.

Good luck, and never give up

Oh nooooo! Bummer. Get a video quick for the competition and just call it as is

Well, you do have till the end of December now. I can't imagine trying to brace the top from the inside but maybe you can pop the back off.

They are great tools. From helping the doctor aim the needle for the steroid shots in my spine to taking a quick pic of my kid's leg when he broke it, they do it all. Now they can help you position braces! Perhaps an app is in order? I hear you know some people at Apple.

_________________
http://www.CostaGuitars.com
PMoMC