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jointing tops/backs, machine vs. hand
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Author:  Stefan [ Thu Jun 14, 2007 3:41 am ]
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Hi folks,

I've spent a few frustrating hours this morning with a hand plane (jointer length) trying to joint a top and a back.  I've been following the C.M book method.  I think the top is good enough.  The candle test shows only a tiny crack of light at one end of the joint.  This part can go under the finger board, or it will end up getting trimmed off.  The mahogany back isn't there yet, and the wood likes to chip, ah.

Pretty soon I'm going to own a machine jointer.  My question is; with skill can a better job be done with a hand plane?  Do any of you guys use machine jointers for this purpose?

Any advice much appreciated.

Stefan
Author:  Michael Dale Payne [ Thu Jun 14, 2007 3:55 am ]
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I do suggest you do true all areas so they do candle properly. a week spot small as it may be is the starting point for problems. The whole joint is only as good as the weakest point.
Author:  Wade Sylvester [ Thu Jun 14, 2007 4:02 am ]
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Stefan,
Hesh has some great advice there.
Also, as you shoot, turn the knob on your plane to back off the blade slightly for the last few shoots.
Another tip came from Colin who uses a few extra "rails" of wood that are longer than the top wood seam. He sandwiches the rails along the outsides of the top. This giudes the plane and makes your plane stay streight for the shoot.
You will be less likely to have gaps this way.
Good luck,

Wade
Author:  JohnAbercrombie [ Thu Jun 14, 2007 4:20 am ]
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Stefan-
I don't have much to add beyond the advice you will get in books and in the archive here. There is a difference of opinion on how long the optimum hand plane for this work should be- I've used a jointer plane but many say that something shorter works just as well or better.
A razor sharp plane and very light cuts help to get to an acceptable joint before you run out of wood (ask me how I know this!- changed a jumbo top to classical size once). It can also help with the chipping problem.
Also, changing pressure during the cut can help to 'fine tune' the process. I find I usually have gaps at the ends and have to take one 'swipe' in the middle only as the next-to-last pass.
Though I use my machine jointer for 'getting close' to a good joint if the edges are a long way from straight, I use the hand plane at the end. Getting a machine jointer set up to cut straight is a whole other story, and even at the best, the resulting edge is a series of fine scallops, not a true straight surface.
If you can rip up some 'scrap' for practice, it can be cheaper and less stressful than refining your technique on an expensive set of guitar wood.(!).
Keep us posted here on your progress!
Cheers
John
Author:  csullivan [ Thu Jun 14, 2007 4:23 am ]
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Hi Stefan,
even though I have a heavy duty 8 inch Powermatic jointer, I prefer to joint
guitar backs and tops by hand. I have an old no-name 24 inch wooden plane
I keep just for this purpose. I clamp the plane on its side to the top of my
table saw (any good flat surface will do). Then I clamp a large, flat piece of
good plywood or MDF up against the plane. Sometimes I stack two or three
pieces to vary the area on the plane I will be using. This extends the time
between plane iron sharpening. Then I push each top or back half by hand
across the plane. I find a little "body English" as you pass the wood across
the plane helps to correct small discrepencies that show up when candling.
Just make sure you plane each piece so that any angle discrepency from 90
degrees is complemented on the matching half.
Craig S.
Author:  John How [ Thu Jun 14, 2007 5:52 am ]
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All good advise you received here, so I cannot add a thing but I will say that an electric jointer while a very handy tool when it is set up, can be just as troublesome as a hand plane when it's not set up properly.
I guess what I'm saying is there's no guarantee that it'll be an easier job with a jointer. I typically use my large flat Granite block with attached sandpaper.
Author:  davidmor [ Thu Jun 14, 2007 7:10 am ]
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I use a level with sandpaper on one edge.  I sand both edges at the same time to get a good tight joint.  
Author:  LuthierSupplier [ Thu Jun 14, 2007 7:39 am ]
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Great question Stefan, and perfect timing! I have a jig that is about to be released next week sometime that will solve this problem. It was designed by Edward Victor Dick, and is used in his guitar building school. He has built over 355 stringed instruments, and has been jointing tops this way for the past 15 years. It is basically a fence with a flat surface(glass) with sticky sandpaper on it. He uses 80 grit sandpaper, but 100 or 120 will work fine too. He is usually done in 5 minutes, and is a really fool proof way of jointing anything. Because the jig is so simple, we will be selling it for $40. We are not making much off of it, but then again, our goal is to make products that make your job easier.

Anyway, here are some pics of the jig. Feel free to make one yourself, but if you can wait a few weeks, you can own one like this. Good luck!



Tracy
Author:  Michael Dale Payne [ Thu Jun 14, 2007 7:39 am ]
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Yep I have to retract my comments on the gaps. I reinforced by the FB then there is no issue. I did not read good enough and missed putting them under the FB
Author:  KenH [ Thu Jun 14, 2007 8:23 am ]
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I use something similar to the jig posted above, only mine is a piece of marble instead of glass. I am usually done in less than 5 minutes and have a perfect joint every time.
Author:  LuthierSupplier [ Thu Jun 14, 2007 8:40 am ]
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Thanks guys! Hesh, good point, and that is the purpose of the bolts on the end. You loosen, lift the fence up and slide the glass in or out for a fresh section of sandpaper, then tight down again. Works like a champ!

Another cool tip, sometimes people tend to sand more on the ends, leaving a gap in the center. Add some tape to the bottom of the glass in the center and tighten down the bolts. This raises up on the middle area and allows for a perfect job. I'll have video of this process and adding tape once I get the page up, so you can see it in action.
Tracy
Author:  paul harrell [ Thu Jun 14, 2007 11:26 am ]
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Sorry to be old school guys, but check out the pictures of abraded (sanded), jointed and planed surfaces in Hoadley's book and you will see that a razor sharp hand plane is the tool for this job.

                      Peace, Paul
Author:  Alan Carruth [ Thu Jun 14, 2007 12:00 pm ]
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Paul's right. Back in WW II the Forest Product Labs did some research to find out why laminated wooden propellors were coming apart at the glue lines. It turned out that it was the ones where the laminations had been sanded to thickness; the planed ones held up better. No more sanded laminations in props.

Learning to plane a center joint properly by hand is a skill you can learn, and, I'd argue, one you should learn. Once you do you'll find it is seldom a problem; these days I worry if it takes me more than about 15 minutes. In most cases, when it takes too long, I find that the problem is a dull plane. I won't deny that it takes time to learn, but, after all, if you're not in this to learn, what are you doing here?
Author:  Kelby [ Thu Jun 14, 2007 5:48 pm ]
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I joint all my tops and backs by hand. And not for any of the noble reasons articulated above; it's just a lot faster than the alternatives.

I hope I don't offend anyone with the following comments, but I believe them so I'll throw them out there. A skilled craftsman can skillfully perform any given woodworking task any number of ways. He can sharpen his plane blades and chisels to a razor edge freehand on his sharpening stones or jigged on his Tormek. He can saw a straight line with his handsaw, bandsaw, tablesaw, or a dozen other saws in his shop. He can make a perfect joint with a jointer plane, jack plane, smoothing plane, power jointer, router, or sanding block. The question for a skilled craftsman is not "what method will give me good results," because he can get good results with any method; instead, the question is "what method will give me good results most efficiently."

I would encourage you to take the time to learn how to get good joints with handplanes. It's a useful skill to have, and there will be many times you find it easier and faster than the alternatives.

I don't know enough about your methodology to say what's causing your problems, but here are a couple of pointers:

(1) Your plane blade needs to be super-duper sharp. It should be sharp enough to clean-shave the hair off your hand or arm in one pass without applying pressure. If you try it and there are any hairs left where the blade passed, your blade isn't sharp enough. (Don't cut yourself. To state the obvious.) The single most important trick to handplaning is learning how to sharpen.

(2) Tune your plane. The sole of the plane needs to be perfectly flat. A thin cut, a narrow mouth and a well-seated chipbreaker (if your plane has one) will minimize the chipping problems you mention. There are plenty of good websites that discuss how to tune your plane.

(3) Build a good shooting board. I once heard a renowned woodworker say "working with handtools does not mean working freehand."

(4) Buy some scrap pieces of mahogany to practice on. Mahogany is a hardwood, but it is pretty easy to work with handtools, and it's cheap. Don't ruin a perfectly good back and side set practicing.

(5) It can be very difficult to joint a board that has a convex edge, because the plane tends to curve along with the edge. If you have a problem with this, try taking a couple passes planing everything but the very ends (so you get a concave edge). Then, plane the whole edge a couple of times until it's flat.

(6) It's easiest if you joint both pieces at the same time, one on top of the other, bookmatched faces together.

Good luck.
Author:  Brock Poling [ Thu Jun 14, 2007 10:29 pm ]
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[QUOTE=LuthierSupplier] Another cool tip, sometimes people tend to sand more on the ends, leaving a gap in the center. Add some tape to the bottom of the glass in the center and tighten down the bolts. This raises up on the middle area and allows for a perfect job. I'll have video of this process and adding tape once I get the page up, so you can see it in action.
Tracy[/QUOTE]

Something I have found that works with this method (I have a similar jig that I sometimes use on my granite block when I struggle with the plane) is to only sand in one direction. That seems to minimize the gaps on the ends.
Author:  CarltonM [ Fri Jun 15, 2007 5:36 am ]
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[QUOTE=LuthierSupplier] Add some tape to the bottom of the glass in the center and tighten down the bolts. [/QUOTE]
Bending glass?! Danger, Will Robinson!!!!!!

You've apparently done this without breaking the glass, Tracy, but in my experience glass doesn't like to bend. I snapped a piece just by laying it on a non-flat surface and applying some pressure.
Author:  Carey [ Fri Jun 15, 2007 12:59 pm ]
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It's been said above, but is worth saying again: make sure
the sole of your plane is flat. Most aren't. If you use
wooden planes, a *slight* lift, or convexity in length, can be ok, as it will yield a naturally sprung joint. YMMV.
Author:  Carey [ Fri Jun 15, 2007 1:02 pm ]
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PS: should have said "a slight lift aft of the blade.."
Author:  j.Brown [ Fri Jun 15, 2007 1:09 pm ]
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I usually use a #5 or a #7 hand plane to joint them, but when I had access to the grizzly jointer with the carbide spiral blades.....whoa, mama! That thing will joint the tops and backs perfectly with one swipe. An incredible thing to experience with that blade setup. takes about 30 seconds total, assuming its setup correctly.
-j.
Author:  Marc [ Fri Jun 15, 2007 10:42 pm ]
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[QUOTE=Kelby]
........... (5) It can be very difficult to joint a board that has a convex edge ......[/QUOTE]

Exactly, I was going to say since your gap was at the end you may have a high center which is sometime tough to get out of, it tends to repeat itself with each swipe of the plane.
Author:  crazymanmichael [ Fri Jun 15, 2007 11:00 pm ]
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i learned to do the jointing if the top and back by hand, and aside from a brief flirtation with the jointer back in the 80's have remained a confirmed plane user. as i have reiterated in several threads, the #5 jack is my preferred plane for the task. i find the #7 too large, heavy, cumbersome, and unwieldy for work on stock this size.

if you are getting tearout, i would look at the set up of your plane, e.g., sole flatness, degree of polish on your iron, the frog setting, iron and chipbreaker setting, as well as the direction of orientation of the grain in your stock as you shoot. all are factors that can lead to tearout.

that being said, many use a power jointer and are happy with the results.

but the objective research supports the proposition that a single, smooth shaving leaves a better gluable edge and other things being equal, a better glue joint.
Author:  Alan Carruth [ Sat Jun 16, 2007 8:14 am ]
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I think it's time to point out that most planes you buy should really be regarded as 'plane kits'; a set of parts that can be made into a decent plane with some effort. Some of the high-end ones won't need work, but most average ones will. You will usually need to true up the sole, and the surface of the frog, at least. Once you get it set up correctly, almost any plane will make a good joint. I've used my #4 Record for many years, for all sorts of things.

It's common with any tool, plane, sandpaper, or file, to snipe the ends. with the plane you just more or less think about taking more off the middle, and, if it's set up correctly, you'll end up with just the sliver of a gap that can be closed with hand pressure.

Tops are harder to joint than backs, usually, in part because the latewood grain is so much harder than the earlywood. The plane wants to skip the hard parts, just like the rest of us. The remedy for this is to have the cutter sharp.
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