Official Luthiers Forum!

Hi,

I'm brand new to guitar building--I just started my first guitar last month. I've been lurking around this forum for the better part of a year; I've read up on every part of guitar building, and finally got to the point where I just had to jump in and do it myself. I followed the standard recommendation--I purchased Cumpiano and several other books, and read up all over the web for advice before starting each task. However, as much as I've read and looked around, my lack of experience is kicking my butt right now... I'm working on the joint for the top plates.

I subscribe to the opinion that a joint that's cut (with a hand plane or planer) is superior to a sanded one. I've also decided to use hand tools where practical. That leads me to my present problem--my joint is concave. When I hold up my plates to candle the joint, it's pretty tight at the ends, but there's a gap in the middle. The gap is widest at the center, where it is 1/32".

I am using Hesh's shooting board setup (from the picture tutorial -- the one with a straight edge at the bottom to guide the plane). From what I've read, it seems that I am not properly putting pressure on the toe of my plane at the beginning of the cut, then transitioning it to the heel at the end. I've been making an effort to do so, but can't seem to get a straight cut (despite the straight edge).

So, any advice would be appreciated. A video demonstrating correct technique would be nice--I haven't found a good one yet...

Oh, and I've spent hours lapping my plane sole flat, filing out all the rough spots inside, and flattening the part of the chip breaker that contacts the blade. I've used the scary sharp method and the blade is extremely sharp. I'm using a Anant Kamal #5 jack plane, which isn't top of the line, but seems to work fine. I am getting great, wispy, long shavings off my redwood top, but the cut is concave. I've still got 1.25" of material to play with before the boards get to narrow, but I'm thinking I may need to seek out a jointer if this goes on much longer.

Thanks in advance for the help and for all the great info on the forum--resources like this convinced me to give luthiery a shot.

Corey Ritter

Hi Corey and welcome to the OLF!

It sounds like you have the guitar building bug and it's great to have you here.

I don't use the straight edge for shooting anymore but something that I did notice that can impact your results is if the surface that the plane side is riding on, in my case a bench top, is not very level. If there is the slightest bow in the surface that the plane is riding on that can cause what you are seeing. These days I pick a very flat area on one of my benches and then candle where I am clamping the plates for gaps and when I find gaps I shim accordingly with post-it notes to get is as close to flat as I can.

This has improved my results.

It sounds like your plane is well tuned and I use a #5 too so that is a good size for the job. The transfer of pressure through the stroke is tricky but after a while you will get the hang of it.

Also I clamp the plates between two boards as shown in the toot and it's a good idea to try to have the clamping well distributed along the plates and equal too. Set-up for shooting seems to be pretty important IMHO.

Try leveling the shooting board/surface as best as you can, nix the straight edge, work on the pressure being applies and where and see if that helps.

Hi Correy,

Welcome to the OLF

If your plane is true, I would suggest first off that you sand the edges straight with a spirit level and sand paper. This will see you set to shoot with minimal passes waisted trying to re straighten the edge. Next I would securely clamp your No5 onto it's 'side' on top of a smooth flat surface (edge of a bench with a largish off cut of melamine is good).

You can then place another flat board, (another piece of melamine is good) onto the first which is clamped under the side of the plane, this will act as a carriage board for the plates. Hold the plate flat to the carriage board with the edge to be jointed just over hanging so that the plate edge alone will make contact with the sole of the plane. Now push the carriage board past the plane watching carefully that the plate edge maintains contact with the sole.

The big tip, set the cut for very, very light shavings and work methodically without pushing too hard. As soon as you get one continuous pass, ur done.

Cheers

Kim

Here is an image I found of the setup I am talking about originally posted by Eben Atwater.



Cheers

Kim

hey corey, welcome to the forum. i use a shooting board to joint the edges of the top plates and something that i have found helps a great deal is to use a sacrificial board under the plates that extends 6" or so in either direction. this gives the plane something to ride on both as you approach the plate and as you exit the cut. hope that makes sense. i think i might have picked that up from todd stock. good luck.

_________________
sweat the small stuff.

Wow, thanks for the quick advice. After asking my question last night, I gave shooting another shot (hah) and widened my 1/32" gap in the middle to a 1/16" gap, which was certainly not an improvement.

Hesh, I think I am going to drop the straight edge--I was having problems getting it to help much. However, I don't understand why the flatness of the surface the plane rides on matters. I've got a 1.5" piece of birch plywood screwed in to my bench top as the base of my shooting board, and it does bow a little bit where one of the screws pulls it down in the center (maybe 1/8" off flat). But it seems like the problem I'm having is in the other, well, plane (spatially--hah). To clarify, the bow in the base of my shooting board is in the y-plane and the concave shape in my plates is the x-plane... Could you explain why that matters? Thanks.

Kim, I do think I will sand the plates back to straight, then try to plane the already-straight edges. So you just paste some sandpaper on a level and run it along the plates? How do you ensure the sandpaper and the plates are at a 90-degree angle? I've seen the jig LMI sells for that, and I've got a couple ideas, but I reckon y'all got it figured out.

I think I'll try to make my shooting board more useful and shoot it like normal first, then try Kim's technique of clamping the plane and moving the plates.

Again, thanks you guys-

Corey

Hi Corey - I am not sure that the levelness of the shooting surface does matter for folks with good technique of which I don't profess to be one....

What I noticed on my wimpy benches is that they flex a bit when I apply pressure and I think that this happens when I am using a big honking plane too - again because of poor technique on my part.

So if the shooting surface is not level and flexes things move slightly - that is what I am trying to say. If you start with a level surface at least that much of the potential flex is taken out of play. But there is no substitute for good planing/shooting technique.

I'm not Kim but I have done the level thing too and it works great. Just check your level, I use a 24", against a straight edge first - they are not always straight...... With a level you can circle the places that are making contact while candling and concentrate the pressure on these places and work toward closing the open gaps.

If you do use a level with self stick on it be sure to use new, clean sand paper especially when doing the top. If the same paper was used on the back plates you can contaminate the top's joint with darker wood dust and end up with a visible line when the top plates are joined.

I shoot all my top/back joints on the table of my Unisaw TS. I built a simple clamping jig that secures the plates, and I clamp that to the TS top. Then with either my LV low angle smoother or low angle jack (both rehoned at 45 degrees - plus the 12 degree bed - 57 degree attack) whichever is shaprper at the ime !!!! I go ahead and shoot ....

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Sometimes I have trouble with the ends, and the sacrificial board sounds like a good idea, if I sand the ends down a bit, the boards will sometimes go together.

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Here is what a Parlor Guitar is for!
http://www.youtube.com/watch?v=oEa8PkjO6_I

Some tips for jointing wood:

First I assume you know to joint both pieces together, folded up like a book.

I recommend that you do NOT use a guide on your shooting board for the plane to bear against. That just adds another source of potential problems, and is totally unnecessary.

Whether using a hand plane or a powered jointer, the first thing you need to do is study the edge for concavity/convexity and grain runout.

With nice quality instrument wood, runout is not often a problem, but you should be aware of what the grain is doing at all points along the edge so you can watch for chipping.

If you see concavity or convexity, then work on the high points first, until the edge appears pretty straight. In your case, place the plane in the middle and work off the high spots at each end. Don't expect the plane to work a miracle just by running it the full length all the time.

Then take a few strokes the full length. You really don't even need a shooting board, it works almost as well to just clamp the pieces in your vice sandwiched between some thicker stock to keep them flat together. Again, the guide that you have on your board is not your friend. Let the plane do the job of truing the wood, that is its job.

Good luck!

Is your plane a perfect 90 degree angle?

I made a new jig (shooting board /holds), only took ...3....hours this time, and I am shooting boards like rabbits in the spring. Pop in, pop out, I also use a snap clamp to clamp the top of the 2 instrument plates when I look for light, because sometimes the wood may be slightly warped together and when you look for light, they flex slightly opposite, so you may have a good line if this happens anyway.

I would like to make this more adjustable so I am not using the same part of the blade though.

_________________
Here is what a Parlor Guitar is for!
http://www.youtube.com/watch?v=oEa8PkjO6_I

I've got a suggestion. I ran into this when working on my first set. I was pushing a bit too hard in the center of the board, thus altering its pressure across the length of the board. What I did was to take my push pads for the jointer and held the board down flat against my bench and pressed evenly with both hands against the plane.

Three passes and the joint was dead even.

Edit: I also used a piece of plate glass with 120 self stick sandpaper on it to reset the edge. That helped a lot too. I used the above technique with the sandpaper first, then the plane.

Hi guys,

Thanks for the tips--I finally managed to get an acceptable joint for my top last night. I greatly improved my plane technique by toying around with the depth of cut, the amount of pressure I used, etc. I also taped some 120 grit sandpaper to a 48" spirit level and used it as a plane of sorts to get the boards level prior to shooting with my plane. I left the boards clamped in my shooting board and ran the level across them just like a plane, moving in only one direction. I found that running the level in one direction reduced the rounding on the ends of the joint (another tip that I read here at the OLF). I moved on to the back, and it only took me 20 min to do what took about 4 hours on the top.

Hah, I worried about 3 inches off each half of the top trying to get that joint right... I bought my materials as a kit from LMI, and I decided to go big and get a nice redwood top and figured walnut back and sides. I figured if I couldn't make a good sounding guitar, then at least it'd be pretty. Watching my redwood top slowly disappearing into curly shavings and dust was pretty stressful!

This is my first woodworking project since high school, so I expected it to be quite a learning experience. Thanks for all the advice. I'm moving on to gluing tonight, and I'm reading up on all the techniques on the OLF. Also going to make some plans for a mold, a go-bar deck, and radiused dishes. Any suggestions on those topics would be appreciated.

Corey

Seems one of the reasons to joint bookmatched was to eliminate the need for a perfect 90°, which would be a good tradeoff for doubling the error in straightness when we use this method.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

One plane I have is mostly 90, but it is off, and can tip around, maybe I mean perfect flat side face.

_________________
Here is what a Parlor Guitar is for!
http://www.youtube.com/watch?v=oEa8PkjO6_I

Ahhh. Yes, that IS important.

_________________
formerly known around here as burbank
_________________

http://www.patfosterguitars.com

Corey
Im glad youve finally surfaced here! - I thought I saw someone lurking in the bushes
Anyhow I was just starting out building and collecting luthierie tools a couple years ago.... and like yourself decided to go with hand tools wherever practical... I found this to be a very prudent decision as an asthmatic who's condition has worsened.. its far better to make shavings than dust IMO...
Well in my case specifically...
Im now upgrading my dust collection, and trying to increase dust collection efficiency on all my dust making tools.. and also switching to shaving maker type tools where I can,, i.e. using pattern shaper (cutter type) on drill press to make duplicate parts from templates - rather than routing with a pattern routing bit.... and things like that.
However that said... using handtools is a higher strain on wrists and hands and arms for those who struggle with carpal tunnel, tendonitus, or other like issues - Im sure that it would be much better for them to use power tools that do jobs dustily, and with much less effort on wrists etc....
Its really a matter of personal need....
Looking forward to your progress....
Cheers
Charliewood

Corey wrote:
"I finally managed to get an acceptable joint for my top last night. [snip]
I'm moving on to gluing tonight...."

Oops.

You will get a much stronger glue joint if you do the gluing within 15 minutes of cutting the joint. When you remove wood you are breaking chemical bonds, and there are open bond sites on the surface for a while. If you present them with some glue they will link strongly onto it; if you don't they will pick up what they need from the air and not bond as strongly when you do get around to gluing.

I would think this would be especially important with redwood. I've noticed from time to time that redwood can be hard to glue. It's almost as if it had some wax in it or something; if you don't get a good tight joint, clamp it properly, and allow it to dry thoroughly it can just fall apart. Not ALWAYS, mind you; just once in a while, but that's more often than I like. Redwood is funny stuff.

I use hot hide glue for top center joins, partly because it is practically invisible if you do it right, partly for lack of creep, and partly because it's the easiest to fix if there's a problem. I start the glue warming up before I set up to joint the plate, and it's usually warm by the time I need it. The parts go right from the vice (I don't usually use a shooting board) to gluing.

Something I've always wondered how to handle...
One of the members here said to always plane your boards together (at the same time). It's one of the first rules of thumb and makes a lot of sense for obvious reasons. BUT...... Ever since I received some tops in wedge form I've been wondering how that will be possible. BTW, this is for an archtop build. So, if anyone here has ever ran into this problem please let me know how you dealt with it. So far the best I could come up with is to do them separately and just make sure my plane blade is super-duper sharp and every surface involved is as near to flat as possible. Corey, sorry for veering off topic a bit.
-John