Official Luthiers Forum!

Hey guys,

I decided to start my build today, as I finally got some time off. So with only a soundboard and a back to work with I figure it would be a good idea to glue the halves together. Made a shooting board, as is expected. My camera's out of order right now, so this MS Paint drawing will have to do.



* Not drawn to scale, measurements refer to the red block

That extra 1/16" gives my plane blade just enough clearance to cut only what's on the sooting board, and my spruce boards were just a hair wider than 8". I know the side of my plane that it rests on is perfectly flat and straight, as well as the sole of my plane, and both edges of the shooting board as well. Yet every time I check to see how I'm doing, the middles of the boards fit snug, but the top and bottoms of the center line open up. I've tinkered with it for hours and it still happens. On a whim, I decided to do my back and sides (rosewood) and I got a perfect seam. Then I messed up the glue joint, but that's a story for another day. Anywho, point is I cannot get my spruce to cooperate. I'm nearly positive my shooting board is fine, but I'm at a loss as to what it is I'm doing wrong. Help me out here guys?

So, the red piece represents the soundboard halves, and the brown piece under it and the upright are parts of the shooting board, yes? As shown, I don't see how this jig could work. The edges of the soundboard to be planed needs to overhang the shooting board, I have a feeling you may have mixed up where the 1/16" should be. The purpose of the bed of the shooting board (the part where your sound board is resting), is to elevate the work piece off the table, so it can be planed.

I'm including a picture of my shooting board to give you a general idea, these jigs can be both simpler and more elaborate than mine.




If your plane is adequately long, well tuned and sharp, my guess is that the other problems you are having most likely have to do with technique. You need to shift your pressure on the plane during the cut, or the it will cut too aggressively at the beginning and end of the cut, resulting in a joint like you describe. Make sure your pressure is on at the toe of the plane at the beginning of the cut, and at the heel as the iron exits the work piece. Find some scraps and practice, and this will shortly become second nature.

_________________
Rian Gitar og Mandolin

Hi Dan

I too went through this process at the weekend and ended up chasing my tail, plenty of wood being removed but not in the right places.

In the end I leveled both pieces by taping them together and running them through the table saw. I then did a couple of fine cuts with the plane and then taped 120 grit to my plane (blade retracted) and very very gently ran across the edges. I am not experinced enough to say it was pefect but there was no light and it glued Ok.

I will be experimenting with a jointing sanding jig to see what works best, Campiano claims sanding edges is not good for jointing

John

Dan,

In my first guitar, I started with the sand paper method but now in my recent build I have tried the shooting board. I invested one afternoon to perfect my technique and the final result was almost perfect.
Some tips: with a pencil draw many close vertical lines all along the edges of the 2 halves of the top.
shoot one pass with the blade and see what happens; you should notice where the lines disappear first .Mark the lines again and try again compensating the areas the lines still remain.
When you reach the point where it seems that all lines disappear at the same time, you should make one or 2 passes just in the middle section leaving 5-6 cm on each extremity. This should create a kind of a hollow in the middle.
Then you should again make a pass all along the edges again (and check each time with the light test)until it is perfect. You can ear the blade cutting more each time.

Hope this is clear.
Good luck

I found it hard to lead in, the blade wanted to dig in at the start.

I also had some areas which seemed to tear, I know may blade is sharp enough.

As you say the method needs perfecting, its not as easy as it looks.

John

I'm with Todd on this one. Though I don't use the method, they don't call it "Scary Sharp" for nothing. While I use my own "Wicked Sharp"[tm]<g>(there is a best friend story on my aversion to Scary Sharp), a plane blade really needs to be sharp enough to take a .002, nearly transparent shaving. If it POPS the hair off your arm, it might be sharp enough. A truly sharp plane with at least a closely set chipbreaker and closed up mouth will forgive most any other "flaws" in the plane itself.

I'm still confused about the 1/16th" aspect of what was built. A shooting board does not have to have a little "stand off" to keep it from chewing away the vertical guide edge. That small part of the mouth that does not go completely through each side to the cheeks makes the indexing "mini-ledge" in the first few strokes.( I have seen some high tech shooting boards where a piece of 1/16th' UHMW is sandwiched into the build for the plane to ride against-unnecessary in my book-adds an unneeded variable)

Even with a perfect shooting board, there is technique- Arnt hit it first; the stroke starts with pressure(which is such a relative term in this context as to be useless-sorry)on the toe of the plane and smoothly transitions to pressure on the middle of the sole on the stroke and finishes on the heel at the end of the stroke. By marking-at least at first when you are still new to the process- you see where you must "amend" your pressure technique to accomodate to individual wood characteristics. It can take a couple of hours to get it and turns a dread top set into uke material, but there is an(a) "Eureka" moment awaiting. The other challenge is setting up so that the pair returns to exactly the same alignment each time the pair is checked and returned to the board. My board uses a 1/8th" pin-it is removable- the bookmatch pair is positioned on the board and a drill bit of 7/64th" is passed from the back of the shooting board through the boards and then the pin gently pushed through-makes a tight fit. That pin and the 90* stop block across the top form a triangular index that is "home plate" for the process. I start out with about 1/8th" of overhang to remove to get to a "no-light passed" joint. On a good day I may get it on the second stroke and the plane never touches the vertical. I credit luck like that to my #9 box-miter LN-the way it is gripped to shoot seems to command the pressure sequence.

It's almost certainly a technique thing.

If you notice from Arnt's photo, the plane does not index against the shooting board. It can in some designs but it's not essential to make good joints and in fact, may make it worse for seams.

Even though you're planing what should be really straight grain, it will never be perfectly parallel to the joint so if you've got the board facing the wrong direction, it will pull the plane in right at the beginning before the back of the soul starts tracking. The solution is to flip the board (both boards) end for end so you won't get that grabbing effect.

Once you have the boards in the correct orientation, the plane won't dig in at first and you'll be able to shift pressure properly to get a good joint.

One last point is that you don't have to shoot both boards at the same time. They can be done one at a time but just make sure you book match them properly when shooting to make up for any out of square issues your plane may have.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Wow, thanks for all the help guys!

It did take a bit of effort to get the plane started, so it probably does need a good sharpening. Meanwhile, I'll keep tinkering with the shooting board while I wait for some more wood to come in.

You're the best guys, thanks!