Thread: Mini Jumbo build number 1

So, finally managed to get back to the workshop for an afternoon over the weekend... Had planned on a very busy afternoon with lots of progress shots. It didn't quite work out like that. 5 minutes in, while trying to adjust the router table to do the truss rod slot, the router dropped to the floor having relieved itself from the restraining clamps on the table. Approximately 2 hours later it was back in position and ready for action. This was on a lovely hot humid pre-thunderstorm Rockhampton afternoon.... My mentor and partner in crime may have learnt some new words in the process but eventually it was back together and aligned. Back to work and I got the truss rod slot routed with a beautiful firm fit - no need to force it in place and no movement once there. Very happy with the job. the headstock design I'm using required a bit of extra width so I cut the neck taper on the bandsaw and used the waste to add the extra width to the headstock. Glued it up and clamped it ready for shaping next time. I also took the advice given to me on the forum and used a sharp chisel to remove some of the bulk/width on the braces - I actually enjoyed this process and will do a bit more on it when I get back into the workshop. The next thing I did was to see how the truss rod lined up with the bracing once the neck was in place. (truss rod access will be through the soundhole, not the headstock) Big problem here in that the truss rod was in line with the soundboard, so back to the router table to take it another 3mm deeper. I was aware that there's not much timber left under the channel so I tapered the channel from it's original depth at the nut end down to the new depth at the soundhole end. The heal block under this section will more than compensate for the lack of timber. Hopefully will get some more progress next time, but decided to call it a day. I didn't get many photos but here's a couple of the neck and headstock.20131116_174735_resized.jpg20131116_174704_resized.jpg20131116_174650_resized.jpg

So, it's been a bit over 3 months since I was last in the workshop due to a very tight schedule with my work but I finally had the chance to do some work over the last 2 weekends!!. 1st job was to taper the neck and headstock 20140216_111301_resized_1.jpgthen fit a veneer to the headstock using the original back (the one that split). I glued this in place and then cut the headstock to shape and sat back happy with my work. 20140216_130657_resized_1.jpgThe veneer fit beautifully and the only part of the neck joint now visible was on the side of the headstock and you had to look hard to find it. Then I happened to check how the truss rod fit now that the neck was tapered and of course it now sat about 3mm proud of the neck... bugger. So with that, I set up the router, secured a fence to guide the cut and worked out how to set the tapered neck so that the channel would be the correct depth for the whole length. Of course this is where things get messy in this one step forward, two steps back process. The router fence wasn't secured properly let go leaving the router to go on it's merry way cutting a nice curved channel. 20140216_144230_resized.jpgAt least I now have a headstock to practice my inlay and binding. Feeling quite I started a new neck from scratch and thought ahead and got the routing done properly at the start while I was still working with square edges. This time everything seemed to go well and I'm pretty happy with the result. I also did it in about a quarter of the time the original took - this makes me a little bit happy knowing that the next guitar will be much quicker than this one and I will have essentially done everything at least once and more than likely twice. Anyway, I got that finished over the weekend 20140223_113841_resized.jpgand also managed get the heal block fitted and cut to shape - remembering this is a spanish design. (no photos - will have to get them next time) I also got to glue in the radiused back braces and this went off without a problem. 20140223_104655_resized.jpgI then had a couple of hours to play with before I was expected home so I decided to play with the new bending Iron that had arrived. Holy crap this stuff is stiff. After about an hour of spraying and bending and spraying and bending I would have put maybe a 15 degree bend in the damn thing. this is going to be an exercise in patience, so I took the bending iron home and will have a crack (hopefully no pun intended) at it one night this week after work. fingers crossed I won't have to start these again. I've also done some research on this timber and everything I can finds clearly states that it's not suitable for steam bending - this should be fun...

Originally Posted by JSmyth

Then I happened to check how the truss rod fit now that the neck was tapered and of course it now sat about 3mm proud of the neck... bugger. So with that, I set up the router, secured a fence to guide the cut and worked out how to set the tapered neck so that the channel would be the correct depth for the whole length. Of course this is where things get messy in this one step forward, two steps back process. The router fence wasn't secured properly let go leaving the router to go on it's merry way cutting a nice curved channel.

Another option might have been to rout a shallow channel in the underside of the fretboard....you'd first have to check how thick finished fretboard would be. Because I install a wedge in between my neck and the fretboard on my classicals I rout channels in the neck and also in the wedge.

That is going to be a beautiful instrument!

I actually wondered about routing the underside of the fretboard - Oh well, at least I can practice the binding and inlays on this one. The replacement neck is well underway and I think it's actually better than the original.

Ok, so last night I got home from work and had a go at bending the sides. I let the iron go up to around 220 degrees, sprayed some water each side and proceeded to work on the curves. This stuff won't bend!! I patiently managed to get the lower bout done in around an hour each side, then had a go at the waist. I got barely enough of a curve to suit a dreadnaught let alone a jumbo. I reckon I tried the waist on one for close to an hour - it has cracked in places and developed a couple of nice splits as well. no scorching though even given the high temp. I think these will have to be scrapped and after working on them for so long, there is just no "give" in the timber at all now. so, Do I try to use this same timber with a different method or choose something different? I have a cole clark with different back and sides and it looks ok but I really had liked the look of this aussie rosewood. Feeling very deflated. anyone got a suggestion?

Thanks PLD, will be very nice if I ever get it finished!! This timber has such a deep lustre - the photos don't tend to show it all but it ranges from gold to red to chocolate. Even if it sounds like mud it will go on the wall as an art piece.

I'm assuming that 220F? The ideal temp for bending sides is between 350-400F. What iron is it?

Stewmac has a great guide for side bending:
http://www.stewmac.com/shop/Tools/Sp...b=Instructions

It going to look great when finished.

Ross

I discovered while recently bending the sides for a cutaway dreadnaught that heating the piece a little bit the wrong way first then flipping it over and bending it back the right way worked really well for tight curves of the cutaway. Albeit it was with tasmanian myrtle, a timber that bends well. But I believe it may help enough to get the timber to bend. I can only speculate but I figured cracking (which did occur for me before I tried both side heating) must be to do with the fibres on the outside of the curve not being flexible enough, so by heating and flexing and stretching them when u turn the timber over the timber u just heated is now on the outside of the curve and bends much easier. Hopefully that might help you

220 Celsius for sure. It was hot enough for water to vaporise on contact. Good idea on heating the outside first, I'll have to give that a go next time. This set is buggered. I'll have to see what timber I have to cut a new set of sides as I have a feeling I don't have long enough piece. Any suggestions on another species that would suit the colour

After the last effort at bending the sides I decided to go with either Black Wattle or Qld Maple for the sides. I had picked up some of each from another local who had a stash and went about cutting another set of sides. before I spent too much time I trimmed a 2mm piece from the side of each 30mm board and tested it on the bending iron. The Black Wattle was my favourite but it was incredibly hard to bend - even such a small piece, but the maple was really easy. so with that I spent yesterday morning cutting a new set from the maple and then spent a few hours on the bending iron - taking my time and not trying to force it too much. The result... perfect. Still need to tighten the bends a little but very happy with the result. And check out the maple.. next guitar is definitely Qld Maple. Just about ready for the assembly now.qld maple sides.jpgqld maple sides 2.jpg The big blue bucket I used to cover the iron while it was heating up. I found it got up to temperature much quicker and whenever the temp dropped I covered it for 5 minutes and was ready to go again. It's a cheap chinese piece of crap but does the job. I also found that wrapping the timber in a wet chux helped a lot - as well and quickly heating the outside of the curve. I also managed to get some of the binding bent as well so keen to get back into it next weekend.