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Soundboard joiting troubles
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=33980		 Page 1 of 1
Author:  crazicarl [ Sat Oct 22, 2011 6:03 pm ]
Post subject:  Soundboard joiting troubles
So, I'm trying to joint my soundboard and the middle is good and tight, but it's like I'm digging into either end of the boards leaving a small gap about 2-3 inches long on each side. I'm using an old second-hand plane.

So, is my problem most likely my (lack of) technique or my plane not being entirely true?

Any help would be much appreciated, good people. Also, this is my first build and I'm loving it.
Author:  Michael [ Sat Oct 22, 2011 7:23 pm ]
Post subject:  Re: Soundboard joiting troubles
I am still working in my plane technique. I have never been able to get a perfect joint with the plane alone. I've only been able to get a good joint by finishing up with my 2' level with 80 grit paper glued to it. I use the same setup as I did with the plane. That is just me and I realize the with the proper skill and tool I would not need to use the level but this works for me. Maybe you could give it a try and continue to work on you plane technique. I have no open seems on anything I have built. I just finished this Harp Guitar last Month.

Image

Michael
Author:  lespaul123 [ Sat Oct 22, 2011 9:26 pm ]
Post subject:  Re: Soundboard joiting troubles
I dont know if you have a table saw but this is how I join my tops and backs. First I will run them through my jointer to get them close. If you dont have a jointer you can use a router with a top bearing bit and clamp a straight edge to the top and route them close. Once you have your top or back close then take some 120g PSA sandpaper and stick it to the deck of your tablesaw. Make sure to stick the sandpaper along the fence of your saw. Then take the fence a move it over a little so it is resting on top of the sandpaper and lock it down. Now with even pressure hold your top with one hand against the fence. Use your other hand to push the top along the fence. The tablesaw fence maintains your top to be square and the sandpaper on the deck of your table saw "joints" your top. Hope this helps it works for me
Author:  Fred Tellier [ Sat Oct 22, 2011 9:37 pm ]
Post subject:  Re: Soundboard joiting troubles
Get a couple cheap low grade top sets and practice planing the joints, like Todd says light cuts and a real sharp plane iron. It is a learned skill and the only way to get good it to do it. I was doing the same thing on the ends and it took a bit of time to get the hang of it. If you get it close a few swipes with the sanding techniques also mentioned is ok, but it is better to learn to use your plane. It feels real good when you get it right, I am getting more and more use out of hand planes and the more I use them the better job they do.
Author:  Nils [ Sat Oct 22, 2011 11:55 pm ]
Post subject:  Re: Soundboard joiting troubles
I use a router, some clamps, and a straight edge. I just put the boards next to each other and use the straight edge to cut down between where I want to join. Works great almost every time.
Author:  Trevor Gore [ Sun Oct 23, 2011 12:31 am ]
Post subject:  Re: Soundboard joiting troubles
Check how flat your plane is. If you can see daylight between the bottom of your plane and a straight edge (that is really straight), particularly in the mouth area, meaning the plane sole is concave, you'll get exactly what you describe and no amount of "technique" will fix it.

Flattening an old plane will make it work, but it won't necessarily stay flat if it has not been properly stress relieved.
Author:  John Bartley [ Sun Oct 23, 2011 6:41 am ]
Post subject:  Re: Soundboard joiting troubles
Nils wrote:
I use a router, some clamps, and a straight edge. I just put the boards next to each other and use the straight edge to cut down between where I want to join. Works great almost every time.



Ok, this (above) is how we jointed laminate/veneer/ply in the cabinet shop I used to work in. We needed invisible joints, and one router pass between the two halves did it. We used a trim router with a bearing guided straight cutting bit, and separated the two pieces by slightly less than the dia. of the cutter, before passing the cutter between the two halves.

cheers

John
Author:  John Coloccia [ Sun Oct 23, 2011 6:57 am ]
Post subject:  Re: Soundboard joiting troubles
This is a common problem. One way to get around it is:

1) make an intentional hollow in the middle
2) plane full length until you get one full length shaving and stop

What finally got me over the hump to do it right, though, is to imagine the plane as flexible (it is is a little, actually) and to have these thoughts going through my head as I plane

1) at the start of the board, I try to flex the tote upwards, i.e. I'm trying to bend the whole rear of the plane up and off the board
2) relax the bending pressure as I get by the edge of the board
3) at the other edge, I try to flex the front of the plane upwards by pulling up on the knob

In practice, it feels like a scooping motion, almost like I'm trying to intentionally hollow out the middle (which is another good thought to have).

So I know the plane isn't flexing that much, but what it does is forces me to put pressure in the right spot at the right time. As I pull up on the tote at the beginning, I HAVE to push down on the knob to keep the plane on the board. As I pull on the knob at the end, I have to push down on the tote. I find this much easier and more natural than thinking to myself "Put pressure here...no, now here". That's very unnatural to me, but flexing the plane seems very natural to me.
Author:  crazicarl [ Sun Oct 23, 2011 4:46 pm ]
Post subject:  Re: Soundboard joiting troubles
Thanks for the help, guys. I know I'm new to posting, but I've read a few hundred posts that you have made and I really value the input. I guess I'll keep plugging away, aiming for better technique. My block plane is well tuned, so I'll stick with it.

I've got about another 1/2" on my plates before I run out of room and have to buy a new set or make a parlor. Whatever--I got a cheap set to begin with anyway.

Thanks again guys.
Author:  crazicarl [ Sun Oct 23, 2011 5:40 pm ]
Post subject:  Re: Soundboard joiting troubles
Ok. I went back out to the garage and gave it another go with some marked success. I have some gap around where the sound hole would be, but since it'll be cut away anyway, it shouldn't matter.

What did it for me was this. Before I stood with the plates positioned in front of me and I moved my arms from side to side. As I thought about it, this would create a radial motion (my shoulders as the axes), scooping out the middle, so I decided to stand behind the plates and using one hand to shoot the plane. This works much better.

By behind the plates, I mean behind the motion of the plane. The movement of my arm is one of my arm extending out in front of me instead of from side to side.

It makes sense in my head and it seems to work. I know there are plenty of ways to walk to the post office, but this stance change seems to have done the trick for me.

Thanks again for the help and encouragement, guys.
Author:  Nils [ Sun Oct 23, 2011 8:05 pm ]
Post subject:  Re: Soundboard joiting troubles
Nils wrote:
I use a router, some clamps, and a straight edge. I just put the boards next to each other and use the straight edge to cut down between where I want to join. Works great almost every time.


By the way, does anyone else do this? I dont think I've heard anyone mention anything on this board before about doing this before. Is there some reason not to? It seems to work really well.
Author:  Bryan Bear [ Mon Oct 24, 2011 3:06 pm ]
Post subject:  Re: Soundboard joiting troubles
I do the one handed push forward too. I bend over, rest my left forearm on the plates and push the plane forward with my right arm (holding the frame of the plane just behind the blade. This may sound strange but I close my eyes. It seems to give me a better feel for my stroke (I'm sure it is all in my head, but I won't tell me if you don't).
Author:  Lindamon [ Tue Oct 25, 2011 8:29 am ]
Post subject:  Re: Soundboard joiting troubles
I use the same technique as lespaul123. My small bed jointer tends to put a mild hollow in the middle of the boards and sanding them on my table saw just the right amount takes it back out, works great.
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