2nd scratch build - Carpathian over EIR

Take us through building your guitar step by step. Post pictures and tell us what you're doing.
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nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

I know it's been awhile but I've had some time and need to do something therapeutic. Playing guitar or riding my bicycle usually helps but so does this. I've done a lot in the last couple of weeks to where closing the box could happen within a month. Considering that I kicked this project off in early 2012 that's pretty significant

When last I posted I was bracing the back plate, the rims were kerfed and I was shifting attention to the rosette. Well, the rosette is finished. It took two attempts to create a radial rosewood out of scrap east Indian rosewood because my Dremel skills weren't up to speed but I did it. I even put a central abalone ring of Zip Flex in - which I admit could have come out better (I hadto sand it which took away a lot of the luster) but live and learn.


The sound hole and outline of the sound board are now cut out and I have bracing ready to install and carve. OT, I've also taken an interest in videography with my iPhone. My band saw isn't the best but it's sufficient and I wanted to share the with my non-handy friends (which I still consider myself to be) so I filmed a brief montage. I love iMovie; I was able to add backing music (which isn't the best and frankly a bit annoying but I can always record myself in Garage Band), trim and speed up the footage, add subtitles and upload to Youtube all on my phone. Twenty years ago I spent $6K on a computer setup that couldn't do that.



I've also glued and trimmed the headstock veneer of bookmatched ziricote. The way the abalone used to shimmer in this picture fills me with regret.



Note that the fretboard extension is now cut to the desired length and has an arched end. What you can't tell from this image is that I've also trimmed the width in order to add binding - of which I intend to use flamed maple. The end piece will have to be bent slightly but dry fittings have shown there to be little resistance; the mitering is the only sticking point here.



I've also begun to shape the profile of the neck at the 1st fret and refine the volute. I'm sharpening my scraper and block planes to reduce the thickness of the headstock so that I can install the tuning machines. I bought a set of chrome Gotoh 510 midsize tuners with an 18:1 ratio off Amazon. They were cheaper than buying off Stewmac of LMI.



Today I hope to put the side braces in the rims. I have a lot of scrap spruce from my back braces that I can use for this. I'm toying with the idea of installing a sound port but figure I have time to talk myself out of that. I can also work on carving the braces on the back. This week I intend to brace and voice the soundboard. Things are really starting to progress.
Last edited by nkwak on Thu Jul 06, 2017 11:11 pm, edited 1 time in total.
~ Neil
John J
Posts: 296
Joined: Wed Nov 26, 2014 7:52 pm
Location: Saint Paul, MN

Re: 2nd scratch build - Carpathian over EIR

Post by John J »

It's looking very good. The details you're adding will really make it special. Keep it up!
Learning every day.
joseph d
Posts: 53
Joined: Tue Mar 01, 2016 5:10 pm

Re: 2nd scratch build - Carpathian over EIR

Post by joseph d »

That's going to look great!
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

I carved the braces on the back tonight.



...and I'm doing a dry fit of gluing in the X Brace:



I don't think I have enough cam clamps though.
Last edited by nkwak on Thu Jul 06, 2017 11:12 pm, edited 1 time in total.
~ Neil
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

In order to attach the back and top to the sides I have to sand the kerfing to match their radius. As i understand it, the radius of the plates is determined by the underside arc of the bracing. To do that, I purchased preradiused jigs from LMI at are only 16" across. The length of the body is 20" though and I wasn't willing to pay $75 for a radius dish - let alone $150 for two of them - so I had to get creative.

In my basement I have a 2X4, a chop saw and a bandsaw. I also have a pencil and some rules but that should be a given. Long story short, I cut two 2 foot long sections of the 2x4 and marked the centerline of each as well as the centerline of both the 15' and 30' radius jigs. I traced the arc of each on a 2x4, extended the arc by overlapping the jig over the drawn line and voila! a 24" long radius. After an hour or so of slowly and painfully trying to stay true to that line with the bandsaw and planing/scraping/sanding it as true as I could get it I had two sanding cauls for the rims:



For my birthday I got some spending money and I went to Harbor Freight with a 20% off coupon and bought myself a little 8" drill press. I marked the centerpoint and using the biggest drill bit I have I drilled a hole in the middle of each sanding caul. I also marked out the center in the top of my homemade gobar deck/work table and drilled a hole. I clamped the rims and mold to the table top then I searched in vain for a threaded metal rod but ended up using the drill bit to mount the caul over it:



I grant you, it is imprecise and unwieldy but it works well enough as long as I'm diligent. I monitored the depth of the imaginary "dome" by finding the lowest point in the revolution of the caul and wraped the bit with some painter's tape. Using a block plane I smoothed out the high points then I found some 80 grit sanding belts and a stapler and went to work "driving the bus" as John Hall puts it. It's not perfect but I think I did a pretty good job on the back plate. I have yet to set up the 30' radius caul for the topside rim. Doing the back was exhausting enough. Still, even though the back rim is ready I will wait to glue on the top plate first when it's all braced up.
Last edited by nkwak on Thu Jul 06, 2017 11:12 pm, edited 1 time in total.
~ Neil
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

Moving along in a slightly different direction in order to keep up on momentum - and not concentrate on a life issue that I will not discuss here - I shifted focus back to the neck. As you know, I had been focusing on the profile of the neck at the 1st fret and reducing the thickness of the headstock in order to accept a set of midsize 18:1 ratio Gotoh 510 tuning machines.

Well, I got the headstock as thin as I was willing to go and using a caul and my new drill press I drilled out pilot holes for the tuners and used a reamer as a bit to widen them out. The placement isn't perfect as the drill press is a bit small and clamping the headstock down with cauls on either side is tricky so I aimed to get things "close enough." This is a hobby so I have no delusions of perfection. Here's how things came out:





I would like to note a couple of things:

1: using a reamer and drill press generates a LOT of heat. In fact, there was smoke. It appears that it is very easy to scorch ziricote and it almost appeared to have melted around the edges of the hole. Gladly, there was no charring and a couple of passes with a card scraper smoothed things out fine.

2: the tuners make the headstock VERY heavy. From experience with my first build, this neck is going to be very heavy, though I have also noted that on my first build the mahogany/cedar body is very light in weight. The EIR rims OTOH already feel heavier. The entire guitar is going to be heavier. Hopefully there will be a better balance between the body and the neck.
Last edited by nkwak on Thu Jul 06, 2017 11:12 pm, edited 1 time in total.
~ Neil
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

Moving right along to the neck profile, I put some protective tape on my inspiration for the neck profile: my trust Larrivee OM-03R which is very comfortable to play.

Image

Using a cheap profile gauge I took a measurement of the Larrivee's 1st fret and overlaid it at the same area on my neck:

Image

As you can see, the area is pretty close to being finished. Next is to take a similar measurement of the Larrivee neck at the 10th fret and set to work on that area on my neck blank. As with the basswood on the kerfed linings on the rims things are proceeding pretty quickly but I have a ways to go before I get there.

Still, I think I've made some decent progress this week.
~ Neil
Talladam
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Joined: Mon Sep 21, 2015 9:43 pm

Re: 2nd scratch build - Carpathian over EIR

Post by Talladam »

I love the zircote headstock plate!
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

Thanks! I think I may have to put a matching plate on the back too though; the headstock is a bit on the thin side. I "eyeballed" the thickness to accommodate the tuning machines. There's about 3/32" of "wiggle room" that I think a matching ziricote back plate would solve from both a functional and aesthetical point of view.

Also, I've been mulling over two other issues: sanding the kerfing and the bracing of the top.

With regards to the kerfing, I now understand why a dome is preferable to a sanding bar such as mine - but I think I have a solution. When you sand with a dome you know you're done when there is 100% contact all around. With a sanding bar, you have to constantly monitor its height because if you don't there will be high points on your rim. My sanding bar is mounted using a drill bit and I drilled a hole in the middle of everything so that the bit acts as a mounting pin - kind of like with you do with a circle cutter. This also creates some "play" in things that should at least be minimized. On John Hall's tutorials, he uses a steel pipe nipple and a section of pipe that does not move; my drill bit is short so it "rocks" and slides in and out of the hole, making for high points on my rims. I was using a piece of colored tape to denote my target height but the tape was not cooperating and coming off.

My solution seems overly simplistic but I have a section of threaded steel rod that is the same diameter as my drill bit so it fits in the hole perfectly. It's also longer so that I have more room to adjust for height. I just need to head to the hardware store and get some nuts and washers to hold it in place.

Now with regards to bracing the top, the issue is this: my top may be too thin and slightly less stiff than ideal. Using a thickness sander is an art unto itself which I struggle with and I went a "skosh" too thin - especially on the edges. After cutting out the sound hole I measured the center of the plate and it's .105" with the outer edges coming in .098". It's not noticeably floppy, but the tap tone is what I'd consider to be "deep" and it "potato chipped" after I had left it clamped to a work board for a few days. On the bright side, it returned to a flat shape but I was still concerned.

As with my first build, I asked my friend, luthier Tim Mcknight for advice. I even showed him my soundboard (after I'd routed away for the rosette but before I'd installed it) and he expertly analyzed it. He gave me specific instructions and bracing materials - so in a way this is sort of like a kit. I'm trying to understand the thinking behind it though. I also broke some of the materials (it was very delicate) so I have to try and recreate a portion of it on my own - which affords me the opportunity to experiment with voicing, even if I am not equipped to do deflection testing or do Chladani testing. Suffice it to say, he felt that I needed to use an oversized bridge plate made of maple with a rosewood patch and to use a sort of "closed" bracing pattern (which broke) in order to focus the lower bout. I'm going to end up making a secondary X brace of reduced thickness and height with the hope that I can recoup some of the trebles I may have sanded away.

My main concern is that bridge plate though. Given that my rosette is so thick and made of rosewood I'm wondering if it might have sort of reinforcing effect on the structure of the top in that area. That seems like something that bears its own separate discussion though. In this case though, I'm wondering if the large bridge plate is even necessary. I wish I knew how to check for that.
~ Neil
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: 2nd scratch build - Carpathian over EIR

Post by nkwak »

Here are the modifications I made to my kerfing sanding jig:

Image

Image

3/8" x ~10" threaded steel rod through a hole drilled through the exact centerpoint of the work table. 3/8" hole drilled completely through the radiused sanding board. The mold is positioned as close to the center of the guitar as I can eyeball it. I bought a couple of wingnuts, and a variety of washers and locking rings. I have a regular bolt sitting atop a locking washer and an oversized washer/rubber washer anchoring underneath the table and a similar setup but with a wingnut atop the table surface to anchor it into place. The rod now passes completely through the sanding board and I have washers/locking washers and a wingnut to set the upper limit of the height of the sanding board.

I rotate it by gripping either end of the board until I find the lowest point of the circle and use that to set the target height for the sanding board. The locking washers keeps the threaded rod from moving up or down and keep the sanding board from moving above the set height. It required a bit of effort to sand down the high points of the rims so I eased up on the height of the board a little until I was close, then I locked it up. It holds things pretty firm so there's little "play" with regards to the height of the sanding board.

Now need to take the sides out of the mold and sand a 1.5 degree angle into the top of the neck block assembly.
~ Neil
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