Official Luthiers Forum!

Hello all --
I'm brand new here. I'm finishing up my first guitar and I've started
on a couple more. The question I have is in regards to the back
plates I have. First -- they're walnut. My dad's a carpenter and he's
been sitting on these boards for over 20 years. It was from this nice
big tree in our back yard when I was a kid. So, the boards are air
dried and the pieces he cut for the backs and side sets are
quartersawn. The back sets are bookmatched and the figure on
them is really really cool, and also really really busy. I've thinned out
one set to 3mm and now I'm trying to get a good seam and this just
seems to be taking forever. It didn't take this long on my first guitar
(it's mahagony, with a sitka spruce top) First of all, they're curving/
warping now -- which I'm atributing to the fact that there is a lot of
end grain where that seam is going to be -- can you guys help me
on that? Does that cause too much of a problem? It seems that from
what I've read, a lot of builders really recommend straight grain --
Is there too much figure -- or is the grain a little too crazy? Should
the plates NOT have any end grain in the seam? We've all seen
guitars with quite a bit of figure on the back. I've run them through
a jointer, and I've tried sanding them with stick-on sandpaper stuck
to a level and I've tried shooting it with a hand plane -- the hand
plane isn't too big though (I think Cumpiano recommended a size 3
plane or bigger in his book). What do you guys think? What are
some of your methods for joining the back plates -- and the top
plates for that matter? I didn't have this problem with the tops --
they're Cedar -- and they came out fine, with the method I just
described. Also -- what kind of jigs do you use for gluing them
together? Any help would be GREATLY appreciated! Thanks -- and
this seems to be a great site from what I've read so far -- lots of
good ideas and friendly dialogue. Thanks, Ben Klebba

Brock Poling to the rescue....

First of all welcome the the forum...

Brock uses a technique for joining backs and tops which includes two holders with wingnuts on either side. Then with the bookmatch set together, and using a stationary straightedge, you run a router which simultaneously cuts both joining edges.

I'll have to look for the photo, maybe Brock will come along....

Welcome Ben. Consider investing in John Mayes' DVD's. They are quite good in learning about a lot of processes you'll need to learn.

_________________
JJ
Napa, CA
http://www.DonohueGuitars.com

Hopefully Brock comes along with that info...
Who is John Mayes and where would I be able to fine his DVDs. Also
-- What do you think about the grain pattern -- should it really be
more straight grain than not? Should there be end grain where the
seam is going to be? Or is it alright as long as there's not too much?   
Thanks.

Ben

Ben, sounds like you got a tough one to join right out of the gate. Twisting grain pattern, means some will be more likely to tear out. And even with a router method you are likely to get tearout. You can mitigate that somewhat by using a downcut spiral router bit. Brocks setup is perfect for dealing with difficult wood.

Two main ways for making joins that I'm aware of is 1.)the jointer, I have a six inch model that's got to be fifty years old, yet quite frequently I can get a good join with it.

2.) Another way is to use a shooting board and it incorporates a jointer plane, like a number Seven Stanley, but you could use a six or 8 Stanley as well. What's most important is a razor sharp and well set blade. Back when we used to roll our own cigarettes there was cigarette paper which is very thin. If you can get shavings like that you've got it right.... grin.

None of this stuff is easy, or we'd all be masters when we started out. but you keep on doing it and eventually you'll get it. Take your two halves to an outside window and lay them tight together. when you can see no daylight in the join, it's ready to glue up.

Some others will be along by tomorrow and throw in their perspective and what works for them.

Link discussing my version of a plate jointing jig

You can see something about it there (you may need to scroll up in the thread to find my first post and a couple of pictures of the jig).

Additionally, I also have a document that explains how I jointed & joined the top and built the rosette for Lance's OLF guitar. If you want that shoot me your email address and I will be happy to mail it to you.

bpoling38375.9986458333

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Send it to me also Brock, bdickey AT cswnet.com Thanks, I'm gonna try this system. A little time is all I need, got the materials laying around. Where did you learn this?

No need for all that machinery chaps, a shooting board and a sandpaper plane makes perfect joints I have been useing this technique for years
Roger
zenguitars.com

Brock, I have a board just like that, I use it for the back srtip. It never occured to me that it might make a joint. My jointer usually gives me a light tight joint.

_________________
Tickle your guitar daily, and it'll tickle you back.

john lives in ok, you can find videos on ebay or contact him at his website. that can be found in the luthier bio page

I built one of those router plate jointing jigs a while back, it came from the book Lutherie Tools. Works exactly like the one we’ve been talking about here. In my opinion it’s not worth the time it takes to build it. I have never been able to take the plates right off the jig and glue them, you have to use the hand plane to get a good enough seam. Now days I don’t even use the jig, I just run them over the jointer to get close, then put them on the shooting board and plane them to get'em perfect.

P.S. I also bought a brand new spiral downcut bit for the jig.

Well Colby, it's good to hear others experience, like yours, even if it's a thumbs down. Okay, that puts us back to ground zero on this setup. One thumbs up, one thumbs down.

I know my old Atlas jointer has a worn bearing housing. something causes it to occasionally take an extra few thousandths off the last two inches of the cut. Not always but occasionally... So, that's when I set up the shooting board after a few trys on the jointer.

Hoffman said something similar regarding the jointer, when it's set up and working right, it's hard to beat, but when it just refuses to cooperate, a shooting board is another option.

There is one more method of using a router as a jointer, it involves setting an infeed and outfeed fence of a router table, off by a few thousandths, as the cut passes the router bit, the outfeed table catches it at the new dimension and carries it through straight, just like a jointer only turned 90 degrees. I tried it unsuccessfully, but it would work well if set up perfectly.

Like I said earlier, if this stuff were easy, anyone could do it.

Zenguitars, okay, let's see your setup. I think all of us are interested in not just a good method, but the best....

What grit and type of sandpaper are you using?

I'd also think a router wouldn't leave a good enough edge, but I haven't ever tried it. Seems like overkill for an otherwise simple (if sometimes time consuming) operation. I just use a stanley #7 with hock blade (can't say enough good things about those blades) and a shooting board.

Figured woods are easy with a well sharpened blade. You can also carefully true up an area with a long and sharp file if need be, and then a slight pass of the plane. The time put into tuning the jointer plane well saves a lot of time and a sharp blade is probably better for joints than anything.

Regards,
Joshua

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Instagram: @jfrenchluthier
Web: https://www.jfrenchguitars.com/

Certainly, I am not professing my was as the ** best ** way. It was merely something that I made because (at the time) I did not have a good jointer.

For those that have made this and had trouble, let me say this. I was ULTRA ULTRA ULTRA fussy about the guide being installed dead flat. And in retrospect I wish I would have used something heavier for the guides.

The guides are tight against the router so there is no chance it will "wander" off the guide -- not even by a little.

I will tell you that 9:10 times this thing will joint plates where no light passes through them. And on the one where I get a little light seepage about 5 - 10 unidirectional strokes with a long (longer than the plates) dead flat sanding block will do the trick.

It is very easy.

Again, I am not trying to convince anyone that this is the "best" or "only" way to go. I am simply saying that it works, it is easy, and that the results are reproducable.

_________________
Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I'm glad ice cream and methods for joining are not limited to one flavor... Any method that works acceptably is good. Ben got a good run for his query in this thread, now we need some pics of the other setups for it to be complete.

I know I got a revelation on gluing plates recently. Using five pieces of tape like Mario and BobCef.... It squeezes out all unneeded glue, cleans up easily, and is so quick. I quit using wax paper too, because there is absolutely no glue exiting the backside if the join.

Five pieces of tape on the other side as Mario suggested and you can actually pick it up and move it aside for another, that baby is joined.

Hello Guys!

I?m using for joining the plates a Stanley #7 and a shooting board. Most important thing is a very sharp blade. For the glueing I use a board with small wedges ala Cumpiano to get the seam tight. After thirteen guitars no problems with opening seams, even in extreme (25% RH) weather conditions.

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http://www.hl-guitars.at

Here is how I make a perfect join:-

Place one side of the plate on a 30" stepped shooting board trim the edge with a stanley no5,take an old hardwood 30" spirit level one edge has a strip of 150 grit glued on, the other edge 80 grit, gently work against the plate edge in long smooth strokes, do the same with the other plate hold the two together against a strong light to check the join is tight and glue up as soon as possible, as long as you keep the shooting board and level nice and square a perfect join is assured and of course because its silent you can talk to the wood.
Roger
zenguitars.com

One thing I do if additional needed after joiner(not often) but method used at Galloup also is use one of the long alum bars used for fretboard leveling and other uses. Use shooting board and have self adhesive 220 on side. Take very short strokes and check about every 15 or so strokes.

Thanks for all the advice, people. This is what I did -- since I was worried about the warpage from the grain pattern being so crazy and endgrain going into the seam, to keep it dead straight, I sandwiched it between two 1"X6"X24" pieces of pine, screwed the pine boards together, then ran the whole sandwich through the joiner -- this worked pretty well, but I still had a gentle concave gap when I held them to the light. So, I used a level with 80 grit sandpaper stuck to one edge, and lightly sanded away those high spots -- it looks much better now and I'll be gluing it together tonight. If I had a bigger plane, I'd really like to try the shooting board method, but alas, I only have a small hand plane. Regardless, what I've come to will definitely be a solid seam. Thanks again. Ben

I made a similar jig to the router jig in the photo above; however I found that it doesn't work perfectly. I have a couple of curved battons and four DeStaCo clamps to hold the carriage in place and lock in the boards. I also have a couple of indexing blocks that look like inverted "T"s. They key into the slot in the base that the 1/2" downcut spiral carbide bit makes. They've got a maybe .040" rabbited from each side with about 3/4" full thickness to key into the slot. Placed into the slot the plates index off each side of these blocks. When the fixture is locked down, I slide the blocks out of the way and remove them. This way the router always takes the same amount off of each plate.

The problem I have with the fixture is that it tends to cut more from the ends. I believe this is the result that in order to apply reasonable clamping pressure from the carriage onto the plates to keep them in place, there is some distortion. Consequently, I'm rethinking the fixture to have a vacuum platen on each side to hold the plates down firmly and the carriage can just be locked in place without worrying about it distorting.

2005-01-27_213212_Top_&_Back_Clamp_Jig.jpg

Here's my jig I use to glue up tops and backs.

_________________
tim...
http://www.mcknightguitars.com