Making a guitar with Roy Courtnall

Construction and repair of Classical Guitar and related instruments
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tom0311
Amateur luthier
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Re: Making a guitar with Roy Courtnall

Post by tom0311 » Thu Sep 14, 2017 6:51 am

Malto069 wrote:
Wed Sep 13, 2017 10:40 pm
I've often looked to alternate sources of information and approaches in starting my first classical, but find I keep coming back to Roy's book - the other sources of information confuse the issue more often than not ;-)
The combination of this forum, the Courtnall book and the Cumpiano book have really helped me. Mind you all the pros (and a lot of the amateurs!) on this forum are producing ridiculously good work that sometimes makes me want to give up :P Make sure you take into account the neck angle on the Courtnall solera - I think in the book it is 3mm which might have been an error. There's a thread on here somewhere about it... if I remember correctly the thread is called "let's talk about neck angle". I think the recommendation was to shim that neck angle up to 1mm. Les Backshall put a good formula into that thread which helps you calculate correct neck angle, too.
“There are two means of refuge from the misery of life - music and cats.”

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josswinn
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Location: Lincoln, UK

Re: Making a guitar with Roy Courtnall

Post by josswinn » Thu Sep 14, 2017 7:12 am

Great to know this thread is of interest and use to people. Expect more photos and notes by the end of Sunday.

Recently, Roy posted about the solera error in the earlier printing of his book.
About the 3 mm solera slope - that was an error that somehow got missed. (Corrected in a recent re-print.) 1 mm is enough, or even perfectly flat. It does depend on the height of the dome at the bridge, and how much this collapses over time, if at all; and if the neck moves (less likely with a CF rod inserted), and so on. A flatter neck angle makes it easier to fit the fretboard.

Abel Schmitt
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Location: Deutschland

Re: Making a guitar with Roy Courtnall

Post by Abel Schmitt » Thu Sep 14, 2017 7:22 am

Wonderful work, Josswinn! Must be exciting to work with the likes of Curtnaill.
I'm very curious to see the continuation of the making... update us!!

Jlrexach23
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Re: Making a guitar with Roy Courtnall

Post by Jlrexach23 » Fri Sep 15, 2017 11:07 am

Simply awesome! Looking forward to see the finished product!

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josswinn
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Re: Making a guitar with Roy Courtnall

Post by josswinn » Sun Sep 17, 2017 6:44 pm

Day 8 (Courtnall book pp. 209-10; 229-232) Today, we began by laminating the back with the cherry and walnut veneers that we glued together last week. Using a scraper and abrasive paper, I ensured the joint was clean of glue and smooth, as well as sanding the cherry veneer to ensure a good flat gluing surface. Then, having pencilled the plantilla outline on the area of the walnut veneer which will show through the soundhole, I sanded it to bring out the grain. It was important to get the centre line of the burr walnut veneer in line with the centre of the back so that when looking through the soundhole, the grain of the walnut veneer was correctly placed. Because I am laminating the back, there is no need to strengthen it with a cross-grain reinforcing strip (pp.221-2). Here's the burr walnut veneer, already glued to the cherry, which was then glued to the walnut back. I think it will look nice when polished and viewed through the sound hole.

ImageSanding the walnut veneer for the laminate back by Joss Winn, on Flickr

Next, I bent the walnut sides, constantly checking the shape against an outline of the plantilla. I'm using the Friederich body from Roy's book.

ImageBending the walnut sides by Joss Winn, on Flickr

ImageChecking the ribs against the plantilla outline by Joss Winn, on Flickr

Again, you can see from the image above that the centre line of the guitar was marked on the template and I've almost got the rib bent to shape. I've yet to cut the wood to the correct length.

Once the ribs were bent to the correct shape I clamped each of them to a separate jig to help retain their shape:

ImageRibs bent and clamped until use by Joss Winn, on Flickr

Next, I cut a block of quarter sawn spruce into 23 strips for the struts and harmonic bars. As I said in an earlier post, there are 18 struts for the lattice. The struts will be further planed and carved to the correct size and shape and then reinforced with carbon fibre strips. Today, they were rough cut at 12 x 4 mm but the final width will be 2.0 to 2.5 mm. The height will vary, from 6 or 7mm over bridge tapering down slightly towards periphery.

ImageSpruce struts cut prior to shaping by Joss Winn, on Flickr

Finally, throughout the day I was attempting to create the log for the motif of the rosette. As I said in an earlier post, I wasn't happy with the first attempt because the ends of the square lines in each plank didn't align correctly due to them not being uniformly 1mm square. I'll post specifically about this next week when I have removed the glued log from the clamp and can compare it to the first attempt.
Last edited by josswinn on Sun Sep 24, 2017 7:04 pm, edited 1 time in total.

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josswinn
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Re: Making a guitar with Roy Courtnall

Post by josswinn » Sat Sep 23, 2017 7:39 pm

Day 9 (Courtnall book pp.201-207) Today I inlaid most of the rosette. As I mentioned on day 6, the first attempt at creating the log for the rosette motif was a failure. This was due to three reasons: My inexperience, the nature of the design, and being supplied with square lines that weren't uniformly 1mm.

I had asked my 10 yr old daughter to come up with a simple design for the motif. She decided upon our initials: J G S. When drawn on 1cm square graph paper this amounted to 11 columns and 5 rows plus a column at each end for spacing, so the finished log would be 13 x 1mm square lines across and five planks deep. Roy said this was not as simple as it seemed because it was wider than a typical motif and there was more opportunity for misalignment of the square lines. Furthermore, unlike an abstract pattern, the familiar lettering and monochrome (walnut/sycamore) tones made any mistakes immediately obvious. To add to this, the square lines were badly cut by the supplier and so I was dealing with variable width materials. You can see the first attempt on the right in the picture below with the second attempt on the left.

ImageThe rosette motif. 1st attempt (right). 2nd attempt (left) by Joss Winn, on Flickr

The second attempt was improved mainly because I asked the supplier to check the materials they sent me the second time around and I double-checked with a vernier caliper too. I also glued one plank at a time rather than all five at once, which helped me check the alignment at different points. I finished the second log off with sycamore veneer on the top, bottom and one side to provide more spacing when cutting each piece to fit the rosette circle.

I then cut each piece off the log, cut two circles, and chiselled out the waste.

ImageChiselling the 8mm rosette motif circle. by Joss Winn, on Flickr

Here are all the pieces glued in place:

ImageThe inlaid pieces of the rosette motif. by Joss Winn, on Flickr

And here they are having chiselled and sanded them flat with the sound board:

ImageSanded and ready for veneer inlays. by Joss Winn, on Flickr

I then cut the outer circle 5mm from the existing pieces:

ImageCutting the outer circle. by Joss Winn, on Flickr

Here I am chiselling out the waste again. This was probably the most nerve-racking task so far in making the guitar! I was scared of going outside the outer circle because it could mean I'd have to extend the width of the rosette further to rectify the mistake. I was also nervous about going too deep into the soundboard. Fortunately, it all went fine.

ImageChiselling the 5mm outer ring. by Joss Winn, on Flickr

I decided to decorate the motif with simple concentric circles of walnut and sycamore. Here's the outer veneer inlays glued into place and the inner veneers held in place to show you what it will look like. I didn't have time to finish it all off today but will do next weekend.

ImageAn indication of what the finished rosette will look like. by Joss Winn, on Flickr

I'm quite pleased with the rosette. It has my daughter's input, was technically demanding but instructive, and looks OK, too. From a distance, the lettering looks like an abstract pattern but also has personal meaning.

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