Ozzie Built 17" Archtop

[charangohabsburg]

Just an example for the "cube rule":

If you make a bar 20% wider it will be 20% stiffer (in vertical direction). No "cubes" involved here.

But if you make the same bar 20% higher it will be 1.2 x 1.2 x 1.2 times stiffer (also in vertical direction). That's 1.728 times stiffer, or 72.8% stiffer.

Oh, and btw: this is going to be a beautiful guitar. I agree that this archtop model by itself is aesthetically very pleasing (if it's sexy or not depends a lot on each guitar, but this one will be it for sure!)

[ozziebluesman]

Thanks Markus. Very interesting example there on the cube rule. I didn't realise that there was that big a difference.

Cheers

Alan

[P Bill]

Alan ,ditto what Nick said. I found B.B.'s method of tapping the top plate and feeling for uniform vibration all over the back plate ( after glueup )very useful. I shaped a small scraper and cork to suit and worked the entire recurve till it seemed right, tapping constantly.
re. the tone bars. My top was imported toona . I carved it marginally thicker than specs and my bars were halfway between B.B.'s max and min specs.Hope this helps.
How can you tell if a watermellon is ripe ? Just tap it.

[Nick]

How can you tell if a watermellon is ripe ? Just tap it.

I thought you hit it with a claw hammer Wondered why I wasn't getting much of a helping

[ozziebluesman]

Thanks for the tips Bill. It is difficult to understand the re-curve process by reading about it. Just a matter of doing it to get a feel of what needs to be scraped off! I have been tapping the top and back all the way through the process so steady as she goes. I am looking forward to the experience of tuning the body.

Cheers

Alan

[ozziebluesman]

Yesterday morning I fine tuned the neck joint and checked that the tool I had made up by a mate would allow me to tighten the neck bolts securily. All good so in the afternoon the box was closed. This morning the back was sanded flush with the body. Here are a few pictures:


I am not binding the f holes or the body on this first effort. I want to chamfer around the body and the f holes. Any suggestions how to do a nice uniform job?
Thanks for looking
Cheers
Alan

[rocket]

Nice effot with closed box there Alan, those F holes look nice and neat.
I don't know how big a chamfer you want to put on it but you could use a jig like most use to cut a binding rebate but instead of using a rebate cutter you could put a bevel or chamfer cutter in it, that will give you a nice even chamfer!!
Cheers,,,,
Rod.

[Nick]

No turning back now Alan. Should look good binding-less, I would say make a little radius or bevel template out of cardboard & just careful application of file & sandpaper applied to the corners will suffice, won't take much on the spruce anyway.

[charangohabsburg]

I'm not an expert but I'd also say that the f-holes look perfect without binding (just like violin family members). If bevelling at all, according to my personal taste (you may have a different one) I would only do a tiny one - no idea how. I probably just would take care that when touching the f-holes there would be no chance of blood staining the top because of too sharp edges.

[rocket]

Alan, The viol family as you know have the back and belly overhang the ribs by a couple of mm, to creat a uniform rounded edge on a violin build i made this little scraper in the profile i neded, works well, baybe you could try something similar for your aplication.
Cheers
Rod.

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[ozziebluesman]

Thats a great idea Rod. Looks like you have used an old mover blade to make the scraper tool out of. Doing a round over by hand I reckon always looks unfinished. The uniforn edge is what I am looking for. Thanks heaps for the idea.

Cheers

Alan

[ozziebluesman]

Tried out the neck bolt tool today and all works well! Here is a picture.

Cheers
Alan

[H3ytm@n]

Looking great!!!

[ozziebluesman]

Thanks Mike.

Some more progress this weekend. The tailpiece has been made, fingerboard fretted and side dots inlayed. The bridge is from stew mac but I have bought parts to make my own bridge so will see how that turns out. The guitar edges need to be chamfered and the re-curve has to be scraped. Getting close now!

Here are two progress pics:


Thanks for looking
Cheers
Alan

[kiwigeo]

Thats a really nice looking archie Alan.

[Dominic]

Alan, nice work with the archtop. Are you going to string it up before you finish it? That way you can still make adjustments to the top and back to get the sound you want. It could be the pictures but your top plate looks pretty thick on the edge and in the F holes but you said it was to spec so perhaps its just the pic. Should about 5mm down to 3 mm in the recurve. Anyway, if it sounds a bit flat you can attack it with your scraper while strung up and aim for a looser top and back and get immediate feedback. I found on my first one that the back sounded a bit tight/stiff under the tail block when tapped so I worked that area until it had the same boing as the widest part of the lower bout. It made the sound richer and more interesting as I went. I've had this thing strung up with no finish for over a year now, I couldn't bring myself to pull it apart again because I love playing it. But I have it in the workshop now ready to spray. Still undecided on colours. Do you have ideas for yours, sunburst or natural?
Anyway, good luck with it.
Dom

[ozziebluesman]

Thanks Martin for the encouragement.

Dom: I planned to string it up after the re-curve had been scraped to fine tune. I still have to get my head around the re-curve stage and make a scraper blade for the job. The top is 5mm uniform except the bridge area and I followed the book specs and made it 6mm. I will go ahla natural and do a french polish. Thanks for your comments.

Cheers

Alan

[Dominic]

Alan, must be just the perspective of the pic. To scrape the recurve I cut a 60mm x 80mm bit of the end of a large scraper and created a tight radius and a gentle radius curve on each end on the grinder. No need to over think it. Start scraping and tapping and away you go. As Bob mentions in his book, the recurve is more important on the back than the top.
I would suggest you have it strung up while you do the recurve so you can hear what is happening and get the tone you want.
Again, good luck.
Dom

[ozziebluesman]

Finally got the tailpiece sorted. I took Rocket's suggestion and made a one piece tailpiece. Strung the guitar up again today so we will see if it hold on this time.

Here are a few pics:



I want to let the guitar settle for a little and then the recurve will be scraped. I did a temperory wiring job and soldered an input jack on the pickup so I could have a little listen. The sustain is great and the tone, warm and woody.

Thanks for looking

Alan

[kiwigeo]

She looks beautiful Alan......

[charangohabsburg]

Great! (Looks even better now, with strings on ).

[ozziebluesman]

The shellac process is now finished. The guitar has been drying two weeks now. It has been very unusally dry here so that has aided the drying process. I reckon she will be ready for final fit and setup very soon.


Cutting the recurve was an interesting experience. I have no experience using scraper blades and had lots of trouble going across the grain. I ended up making a shaped sanding stick to carve out the recurve channel. This worked well but took sometime! I enjoyed building this guitar and am about to start another using Shane's spruce and some Queensland Kauri.
Cheers
Alan

[woodrat]

G'day Alan, Its looking great!.....

Great Work!

John

[ozziebluesman]

Thanks John, I am very pleased with this effort!

Cheers

Alan