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How To Do This End Graft
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=30754		 Page 1 of 1
Author:  Pat Hawley [ Mon Jan 17, 2011 7:23 pm ]
Post subject:  How To Do This End Graft
Hi all,

I've just done up a rim set and I didn't pay enough attention to aligning the grain pattern in the wood so it looks disjointed where the two sides meet at the end. So I want to make an end graft that will "smooth out" the transition as best possible. I have the off-cuts from the sides and I found that by flipping one over, I will be able to create an end graft that almost will join up the grain pattern so it may not look too bad. Anyway, the end graft I have in mind will be like this (sorry I can't give credit to the builder, I found this picture without a name):

Image

It's more ambitious than other end grafts I've done and I've been pondering how to do it and get all the mitres in place. My thoughts at the moment are to:

1) put in the central wedge,
2) rout the binding ledge around the guitar, thereby trimming the central wedge to correct height
3) rout channels on either side of the wedge and install the vertical binding/purfling, initially tall
4) trim the vertical binding/purfling taller than the central wedge and sides to allow for mitring of purfling.
5) install the purfling on the top and bottom of the central wedge
6) install the binding/purfling around the top and bottom of whole guitar, adding the mitres as required at the end graft area.

Does this approach make the most sense to people? If anyone has suggestions to do this easier (i.e. without the use of a router) I'd appreciate suggestions.

Thanks,
Pat
Author:  Rod True [ Mon Jan 17, 2011 8:19 pm ]
Post subject:  Re: How To Do This End Graft
I would prepare the wedge with the purfling lines first, get that wedge how you want it as well as the wedge purflings.

Cut the channel for the wedge and purfling
Install wedge and purfling dry to ensure no gaps, fix if required
Glue wedge and purflings in place
Trim to top/back of tail block
This is assuming you don't have the top/back on yet, if you do, trim to the top/back and continue.

Cut binding channels, ensuring it's elevated at the tail on both the back and top for the side purflings
Trim side purfling channel to wedge outer/inner purfling
Mitre wedge purfling
Install inner side purfling (between the wedge purflings)
Install long side purflings at least at the tail end
Trim the long/wide purfling (looks like Koa in the picture) flush with the side purfling
Install bindings

Oh and the only router use I'd have is in cutting the binding channels. An easy way to raise the router for the side purfling lines is to glue a length of the side purfling onto the top/back which will lift the router up the thickness of the purfling line right when you get close to the mitre location.
Everything else you can cut with a razor saw, by hand.
Author:  Pat Hawley [ Mon Jan 17, 2011 9:54 pm ]
Post subject:  Re: How To Do This End Graft
Thanks Rod. I think I know what you mean, however, just to be sure, I have some questions for clarification:

1) When you say "inner" or "outer", what do you mean?
2) In the step where you say to trim the long, wide (looks like koa) purfling flush to the side purfling, I don't see why this step should be necessary. Shouldn't it be already flush from when I route the binding channels (raised up by the width of the side purflings in the end graft area).

Pat
Author:  Rod True [ Tue Jan 18, 2011 1:01 am ]
Post subject:  Re: How To Do This End Graft
Pat Hawley wrote:
Thanks Rod. I think I know what you mean, however, just to be sure, I have some questions for clarification:

1) When you say "inner" or "outer", what do you mean?

The "inner" in the picture would be the w/b/w purfling line beside the rosewood wedge. The "outer" in the picture would be the w/b/w purfling line beside the main side piece. Hope that makes sense.

2) In the step where you say to trim the long, wide (looks like koa) purfling flush to the side purfling, I don't see why this step should be necessary. Shouldn't it be already flush from when I route the binding channels (raised up by the width of the side purflings in the end graft area).

Yes, you are correct here

Pat
Author:  TonyKarol [ Tue Jan 18, 2011 7:55 am ]
Post subject:  Re: How To Do This End Graft
Maybe Iam missing something Rod .. I dont see where in the process you are trimming the centre rosewood wedge to binding AND purfling depth ... if you install and glue the wedge(s) and purfs to the top of the block, and then route the binding, remembering to raise the route by the height of the purfs at the tail wedge - you wont have the centre rosewood wedge at the right height - it will be left too tall to have the purf that sits on top of it mitre into the bwb side purfs .... so how would you cut the little sliver off the top of that centre wedge, and not disturb the bwb sticking up at each end as it has to be mitred ???

I think the centre rw wedge is glued in first, the routed for full binding/purf height. Then the two purf slots are routed where the joint would be for the centre rw wedge, and then the centre koa piece is trimmed for a tight fit inot this slot with its side purfs .. anyway, thats how I would do it ...

But, I am sure there are other ways too ...
Author:  Pat Hawley [ Tue Jan 18, 2011 9:28 am ]
Post subject:  Re: How To Do This End Graft
Tony/Rod,

I wondered about that as well but took it to be the step Rod listed as:

"Trim side purfling channel to wedge outer/inner purfling"

My interpretation was that with this step you trip the top and bottom of the wedge thereby making the "side purfling channel". I figured you would have to do this carefully with a chisel to get it right and not wreck the B/W/B purfling. Sounds tricky if this is what you meant Rod, but I have a feeling my interpretation was off.

The method you proposed, Tony, is what I was trying to suggest in my first post however I currently do not have an appropriate router bit (or jig). However that can be corrected if need be.

Pat
Author:  Pat Hawley [ Tue Jan 18, 2011 9:44 am ]
Post subject:  Re: How To Do This End Graft
Filippo,

I don't think even Doolin's bender would have helped me with this one. I realized too late that the sides I received must not have been exact bookmatches. They were either not adjacent pieces of wood, or trimmed separately after having the original board had been resawed. Being the observant kind of guy I am, I did what I always do and just taped them together and cut them to profile prior to bending. I saw what happened before I bent them but by then it was too late.

Jigs help, but you are still obliged to pay attention and think. The sides may not have arrived as being exactly bookmatched, but they were generous enough in width, that had I been paying more attention, I could have re-trimmed them myself to get a perfect match. Lesson learned.

Pat
Author:  Pat Hawley [ Wed Jan 19, 2011 10:06 pm ]
Post subject:  Re: How To Do This End Graft
For those interested, after more pondering I think I've decided how I'm going to approach this end graft. This seems simplest to me. Assuming what's used in the picture is koa, I can describe what I intend to do as follows:

1) For the B/W/B koa B/W/B trim on either side of the wedge I'm going to shoot for a width of 1/4", that is 1/16" each for the B/W/B and 1/8" for the koa. So I will make two temporary spacer sticks 1/4" wide.
2) Cut the wedge the size I want from the off-cut.
3) Using the wedge and the spacer sticks on either side in position on the end of the guitar, score lines on either side along the outside edges of the spacer sticks.
4) Saw into the scored lines with a razor saw then route out all the wood between the saw cuts. That will be a wedge shape pocket large enough to take the whole end graft pattern.
5) Glue the wedge in place using the spacer sticks (protected by wax paper) to position the wedge centered and at the right height.
6) Remove the spacer sticks so the wedge remains with a 1/4" channel on either side.
7) Route the top and bottom binding ledges thereby also getting the wedge to the correct size top and bottom.
8) Install the B/W/B koa B/W/B on either side of the wedge. Start with the koa too wide and sand until there is a tight fit. Install tall on top and bottom.
9) Trim the B/W/B koa B/W/B correct heights to allow for mitres.
10) Install B/W/B on top and bottom of wedge.
11) Install bindings around guitar, doing remaining mitres at the end graft.

I think this should do it. If anyone see any problems with this approach, let me know. It will probably be next week before I can get to it due to other commitments. When I do, I'll let you all know how it went.

Cheers,
Pat
Pat
Author:  CWLiu [ Thu Jan 20, 2011 9:07 am ]
Post subject:  Re: How To Do This End Graft
I usually make my end graft from either of the offcuts, but my purfling mitering is much simpler. If I were to do this, I'd probably:

1) Joint the bottom ends of two side plates in where one inlay(koa with purflings attached at both sides) will be. Choose the most apparent grain to align, like sapwood or dark lines. Better do some drawing on the side plates in advance.
2) After closing the box, route out two angled slots for the inlays. Now there's a wedge.
3) Route out binding ledges.
4) Glue the over-length inlays into the slots.
5) Trim the ends of koa and cut all eight miters. Or cut miters first then trim.
6) Fitting two mitered purflings to two ends of the wedge.
7) Proceed as my usual binding job...
Author:  tlguitars [ Thu Jan 20, 2011 4:32 pm ]
Post subject:  Re: How To Do This End Graft
Check this build thread out. Page 4.
http://www.acousticguitarforum.com/forums/showthread.php?t=184999&highlight=olson+guitar&page=4
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