#2 Build N. Silky Oak Classic

[Alastair]

Finally got out from under the worst of the house/kitchen reno load, and decided that some "me" time is on the cards leading up to Xmas.

Following the qualified success with the trial Uke build I WIP'ed here, (st*ff-ups constrained to less than catastrophic, and instrument adopted by my daughter) it's time to start a replacement for my wife's aging entry-level Yamaha.

Once again using SO, which I got from Greg Ward, together with an Englemann SB which was kindly supplied from Sebastiaan56 stash. Neck is some Q Maple I got at SWWWS some years ago, together with the Queen Ebony for the fretboard and bridge.

I had my care package from ALS arrive this week with tuners, fretwire, bracewood and bone blanks, so no more excuses

While I don't think I have the energy to do another detailed WIP, I'll keep this thread going as a bit of a blog, to post progress and occasional pics, (and also hopefully as incentive NOT to let things get put on hold all the time, as they did last time)

To start:

Drafted up full size plans from Cumpiano book, together with templates and workboard.

Neck, headstock scarf and heelblock have been assembled. Heel has been slotted to take sides, and I have just glued up the headplate and veneers. On to carving the heel, and headstock.

Soundboard has been thinned to 3mm on my homebuilt drill press sander, and jointed up and glued. Same for the 3-piece back. Next is to cut outlines, and plane to final thickness.

Sides have been sanded to 2.4mm, and will now be scraped to final thickness. Bending to follow.

I'll keep posting as progress is made, (and when there is something to show)

regards

[stevemc32]

Looking forward to this one Alastair, definitely need some photos.

[Alastair]

Weekend update:

Heel carved. Used the tablesaw shaping method from Cumpiano website. Very effective, and goes a long way to ensuring a symetrical result. I really do prefer this traditional heel profile. Remainder of the carve done with chisel, scraper and hand sanding.

Headstock roughed out, and marked out for tuners. Can't measure for sh*t.
Got the spacing wrong, but fortunately miss-drilled the centre hole off by the same error, which meant I only had one hole to plug. Repeat slid in like silk. Now for the second side, without repeating the error

Cut out the back and SB, and after an upgrade on my sharpening, have started on the planing.

Nothing worth piccies yet.

regards

[Alastair]

Wasn't planning on an update, due to limited progress, but with limited time this week, due to work, will do a short one, to keep the continuity.

Completed the re-drilling of the tuners, successfully this time. Plugged hole is invisible in the slot.
Drilled out and cut the headstock slots, and chiseled them close, finishing off with a purpose built sanding board. Also finish sanded the headstock profile. Can now put this aside until I’ve finished off the plates.
Finished the planing of the SB and back. Back at 2.4mm consistent, but will come down a hair with scraping and sanding. SB is consistently 2.3mm, scraped and sanded. Hope I haven’t taken that too far. I believe that there is a bit of safety factor built into the book, anyhow.
Rosette is again minimalist, with segmented Yellowood, framed with Imbuia, and turned on lathe, and then bound with Imbuia, bent on the hot pipe.
Soundhole laid out ready for the “Paddle Pop router”
Got the ring assembled, and the bindings cut, thicknessed and bent. Next is to turn it down to fit, and glue in.
Hopefully some pics next time

regards

[Alastair]

Finally got my act together, and have some pics to post of past (and present) progress:
Headstock and Spanish heel detail. Neck set to one side now, until soundboard ready for attachment.
Attachment 187711 Attachment 187712
3-piece back. This will get a centre inlay before bracing.
Attachment 187713
Soundboard and rosette complete, ready for bracing
Attachment 187714 Attachment 187715
Sides were scraped to 2mm, and bent on the hot pipe. These will be touched up dry, once I start fitting them to the top.
Attachment 187716
An interesting phenomenon I found with these. Soaked the sides in a hot bath before bending, and probably did not have the pipe as hot as it should have been. The sides bent slowly, but with no tendency to fold or crack. However, they seemed to suffer strongly from spring back, and after I had repeatedly tried to push the bend further, only to have it go back after a few minutes, I gave up, intending to have another bash later, after they had dried out.
Lo and behold, when I came into my sun-warmed shed next morning, they had NOT sprung back; they had in fact increased the bend as they dried, even to the extent I’ll have to do a bit of straightening to get back to the template.
Any ideas?

Bracing pattern has been laid out, and the rosette grafts glued. All bits now into the “dry-box”, while I spend the week preparing braces, ready for gluing, and carving.

regards

[Sebastiaan56]

An interesting phenomenon I found with these. Soaked the sides in a hot bath before bending, and probably did not have the pipe as hot as it should have been. The sides bent slowly, but with no tendency to fold or crack. However, they seemed to suffer strongly from spring back, and after I had repeatedly tried to push the bend further, only to have it go back after a few minutes, I gave up, intending to have another bash later, after they had dried out.
Lo and behold, when I came into my sun-warmed shed next morning, they had NOT sprung back; they had in fact increased the bend as they dried, even to the extent I’ll have to do a bit of straightening to get back to the template.
Any ideas?

The only times Ive had major problems with springing back is when the timber has been a bit on the thick side. 2-2.5mm is sufficient for most timbers but I havent built with Silky Oak so it may be different. What thickness did you go to?

Looking good Alistair, I like the rosette a lot. The timber is from Fraser Valley in Canada Martin, part of a lot I grabbed with some very nice spalted maple.

[Alastair]

Thanks Seb,

The rosette is a throwback to my w'turning skills.

Sides were taken down to 2mm. As said, it was quite strange. There was significant springback straight off the pipe, but then as they dried out,overnight, they moved back to, (and past) the point I had taken them to .

Again my thanks for the top; It has scrubbed up well. Only problem I have had was with a couple of small patches of grain reversal, which took some care to remove by scraping and sanding. As a result, I have gone a bit thinner than I intended, (2.3mm), but with Cumpiano's reputation for conservative bracing, and the fine spacing on the top, I hope I'll be OK.

regards

[Sebastiaan56]

You should be OK, Ive heard of classical guitars, Lutes and Ouds with soundboards of 0.9mm and they sound fine. Conservative bracing allays my fears, but I overbuild anyway.

[kiwigeo]

Ive taken spruce tops down to 0.085 on occasions but generally only around the periphery of the lower bout to "free" it up a bit. If the bridge area is very thin then I'd consider a bridge patch if one is not already on the plans.

Lute tops can go down to less than 1mm but keep in mind that lutes have alot more bracing than a classical guitar....particularly around the rose area where the top is thinned right down to make punching out of the rose easier.

[Alastair]

Hi Martin,

Top is (I think) planed very accurately down to 2.3mm. (I have only miked it round the periphery, so if it varies across the bout, it has to be slightly thicker in the bridge area).

Using a standard Torres copy pattern, so it has a 1/16th spruce bridge patch which intersects the 2nd and 6th fans. The Engleman seems very soft (to my untutored feel), but is extremely fine grained, and perfectly on the quarter. Runout is small, and confined to a couple of areas of minor variation.

Given comments frequently read regarding how conservative C & N are with their bracing specs, my intention was to build to their minima anyway, so I should be OK.

The instrument is for family use, so risk is mainly around criticism from no. 1 son, and my own perfectionism

regards

[heytman]

Looking good Alastair!!

FYI I built a small bodied steel string using SO for back and sides earlier this year.

https://www.woodworkforums.com/f98/build-1-a-136439/

I also noticed that the wood seemed to want straighten after bending... until it was dry. I solved the problem by clamping in my molds overnight. Can't remember exactly but think my sides were about 2.4mm.

[Alastair]

A fair bit of work done, but not a whole lot of visible progress this week, and while I’ll get a bit done in the evenings, coming w/e is likely to be blighted with a return to snag-listing in the kitchen, as Mrs. has guests coming the following week.

So what did get done?
All braces have been cut and then sized on the thickness sander. The curved templates for the LCS, and the back braces were developed, and these braces shaped on the disc sander.

The back has been routed and a centre imbuia back strip glued in, and scraped down. I have done this to inject symmetry into the 3-piece back. I did not feel happy with 2 strips, so went with the centre. I am trusting that with a shallow depth, and liberal gluing it will be OK, as I do not intend to do a 3rd seam graft.

With the wildly fluctuating humidity during the week and w/e, I have so far only glued on the fans and finger braces, which are effectively aligned along the grain. I am busy peaking and carving these ATM, and will wait for the weather to settle before I start the transverse top and back braces. Even so, I think these will have to be done one by one, with the plates going back into the dry-box in between.
More, and pics, when there is something to see.

regards

[Alastair]

Progress has been compromised this week, with the rain and humidity making bracing a risky business. The components sit in the dry-box overnight, and get taken out to glue on a brace, and as soon as the clamps come off, back in it goes. It may not be the “green” thing to admit to in a dry country, but I’m seriously over the present weather.
With the bit of a break on the w/e, I have made some progress, however:
The soundboard is complete. All braces glued and carved and sanded. Ends trimmed back to the outline, and the soundboard top cut back, ready for me to attach to the neck.
The back has been troubling me a bit. After I inlaid the back-stripe, it decided to take on a “back-bow” along the line of the inlay. Obviously related to shrinkage in the imbuia after gluing, but I really did not think a ¼” x 1mm strip could cause so much grief.
Rewetting and clamping has improved a bit, but not completely. It flexes back to convex with slight hand pressure, and with no sign of cracking or glue failure, so I have gone ahead with the bracing.
The twin back grafts were cut from WRC left from the uke build. One bonus with the 3-piece back; it made clamping on back braces a breeze. Braces are located in 2 places by the grafts, and don’t have to be chased around the back as you snug down the clamps. So back braces are complete, carved and sanded.
Once completed, the back-bow seems to be gone, except for a trace at top and bottom, and as these will be glued to the shaped head- and tail-block, should be OK. I can only trust that a problem doesn’t bite me in the butt down the road.
I’ve been slack about pics again, but will post the above ones next week.

In Melbourne Thurs/Fri on business, and finishing LOML kitchen on the w/e, so I don’t know if I’ll have a chance to close the box for a week or so, but I’ll be preparing linings and tailblock, and trimming and coaxing the sides to fit.

regards

[Sebastiaan56]

Progress has been compromised this week, with the rain and humidity making bracing a risky business.

I must admit that I am a fair weather luthier. Did you build your dry box with incandescant lamps? or do you use silica gel?

[Alastair]

I must admit that I am a fair weather luthier. Did you build your dry box with incandescant lamps? or do you use silica gel?

Hi Seb,
I'm not using a heated box, just a dessicant. Box is the biggest I could pick up cheap at reject shop.

Attachment 190129

Big enough for the uke, and for a soundbox, but I don't think I'll get workboard with neck in there, so may have to find "plan B".

Dessicant isn't SG, just using one of the cupboard products, which seems to be a NaOH type, as it changes to a deliquescent liquid towards the end.

Current one has been in the box for a (very wet) year, and will probably need changing after Xmas.

regards