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Scarf joint cut and join problem
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=9716		 Page 1 of 2
Author:  alambert [ Fri Dec 08, 2006 1:43 am ]
Post subject: 
I decided to make a mock run on cutting and joining the headstock to the neck. I went to Lowes and got a 4”x4”x4’ Pine board for $3.50. I made a simple jig for my bandsaw to make the sled jig to make the cut.

Then I clamped one on top of the other to plane the cut smooth. Just like this.



One I got done, I unclamped them and I test fitted the scarf joint. I found it to appear high in the middle. So I stacked, clamped and replaned again. Repeated several times with the same results.

At this point I used my table belt sander to try and get the “high” spot out. Same results!! What gives?

I’m also getting a bevel/taper on the joints. See the rough diagram.



Also my real neck wood is 3.5 inches. Should I just rip this down to 3.0 on the table saw before I make the joint?
Please help.
Author:  letseatpaste [ Fri Dec 08, 2006 1:54 am ]
Post subject: 
Are you checking your progress with a square? That should tell you what areas to work on with the plane, and you shouldn't have to unclamp everything until you know everything's square and flat.
Author:  nathan c [ Fri Dec 08, 2006 1:58 am ]
Post subject: 
I'm getting close to making the scarf joint for my neck so I can't help too much with that problem. I did, however, want to give you kudos for an excellent diagram.
Author:  Michael McBroom [ Fri Dec 08, 2006 2:03 am ]
Post subject: 
What Jon said. I check the scarf with a machinist square frequently while planing. I also prefer a smoothing plane for this procedure, rather than a block plane -- the larger sole seems to help keep things flat across the planed area. I also will plane the surface at an angle (maybe 30 deg. to the grain or so) for some of the strokes, because this seems to help prevent high or low spots. I would also leave it at 3.5" and then trim off the excess after the scarf is done.

Best,

Michael
Author:  alambert [ Fri Dec 08, 2006 2:11 am ]
Post subject: 
[QUOTE=nathan c] I'm getting close to making the scarf joint for my neck so I can't help too much with that problem. I did, however, want to give you kudos for an excellent diagram.[/QUOTE]
I borrowed it!
Author:  alambert [ Fri Dec 08, 2006 2:12 am ]
Post subject: 
What I dont understand is why its still high after I put it on the sander?
Author:  letseatpaste [ Fri Dec 08, 2006 2:31 am ]
Post subject: 
If it rocked just a little bit on the belt sander it'd be real easy to make a high spot.

Use a machinist square to draw a line across the blank where you want the scarf to start and try working to that with the plane. Then you have a reference while you're working with the plane, without having to check it with a square all the time.
Author:  letseatpaste [ Fri Dec 08, 2006 2:37 am ]
Post subject: 
Also... I know you're still collecting tools and trying to keep it within a budget, but if you don't have them already, you will not regret having a nice set of squares... I have this set and use them all the time. They're even on sale...link to Woodcraft squares

Author:  gozierdt [ Fri Dec 08, 2006 3:01 am ]
Post subject: 
What Jon and Michael said. Check often with the square, and use the plane at an angle. Also be sure you are taking very light cuts, and that the plane iron is very sharp. If you have to push hard to start/end the cut, you will inadvertently push down as well as along the cut. If you keep having problems, you can also make a flat sanding board that's about 1 inch wide, and finish off the high points with that.

Gene
Author:  alambert [ Fri Dec 08, 2006 3:17 am ]
Post subject: 
[QUOTE=letseatpaste] Also... I know you're still collecting tools and trying to keep it within a budget, but if you don't have them already, you will not regret having a nice set of squares... I have this set and use them all the time. They're even on sale...link to Woodcraft squares

[/QUOTE]
I bought this same set last week for $29!!! but thanks for the tip.
Author:  Dave White [ Fri Dec 08, 2006 3:26 am ]
Post subject: 
Alan,

The other thing to look out for when making these joints is that the underside of the neck where the scarfed peghead piece sits is absolutely flat and true. In fact it is best to make sure that the the two pieces are as square and true as possible apart from the two surfaces that you are planing. Otherwise when you try the joint dry there will be annoying gaps and wobbles - dimhikt

If it's a belt sander you are using the I find there is always some "cushioning" on the plate. You press down thinking it is sanding flat and square and then test it with a set-sqaure and find it isn't.Dave White39059.4775231481
Author:  Shane Neifer [ Fri Dec 08, 2006 3:41 am ]
Post subject: 
Alan,

There is some great advise. To summarize:

* Leave it at 3.5 inches, gives you 'wiggle room' also allows for a wider headstock design if you desire.
* As Dave said, check taht your pine board is flat. If it is cupped AT ALL, when you clamp it it will flatten out, you plan it, then when you release the clamps the cup shows up again and your joint will never fit.
* plane on a bias with a very sharp plane. You can also hold the plane at a bias to the grain but push it with the grain for a shearing action. That way the sole of your plane rests on the entire width of the headstock.

You'll get it!

Shane
Author:  crazymanmichael [ Fri Dec 08, 2006 3:49 am ]
Post subject: 
the factors mentioned by the previous posters are all amongst the reasons i switched to doing my scarf joints, the few that i do anyway, on the table saw. clamp blank to jig, cut blank, glue blank. no frustration. whilst i eventually got so that i could get a good, tight scarf joint doing it with the plane, it was never a quick or enjoyable process for me, rather always slow and tedious, check, mark high spots, square up, check, mark, ......, seemingly going on foreever till i was satisfied. granted, i did get faster at it, but never fast, and there was satisfaction in achieving a good joint, but i'll take the table saw route any time. and when i built the jig, it took me far less time to build than it did to do a joint with the plane, and it hangs on the wall, always ready to do its thing again whenever i need, with no relearning curve to negotiate.

p.s. forgot to mention a few other suggestions; first you must start with flat, squared up stock else you will always be chasing your tail, second ensure that your initial cut is as square as you can make it, if possible by using a jig of some sort to keep the face of the stock in a vertical plane, mark your square target line on the stock, and the high points on the joint faces to give yourself initial target areas to correct first. do this after every couple of cuts with the plane. these must be marked by checking both squareness across the stock but also straight along the long axis of the joint surfaces. backlight helps immeasurably. use chalk or coloured pencil or gelpen for easy visibility. and as someone else mentioned, use only a very sharpe iron set for very fine cuts. a dull iron will always lead to the ragged start line you depict in your drawing, as well as uneven cuts in the stroke as you strugle to get the cut started and finished, as well as variation in the cut in softer or harder wood.

ain't learning all this a b....-- oops can't say that can i!!! crazymanmichael39059.5109837963
Author:  alambert [ Fri Dec 08, 2006 4:26 am ]
Post subject: 
[QUOTE=Shane Neifer] Alan,

There is some great advise. To summarize:

* Leave it at 3.5 inches, gives you 'wiggle room' also allows for a wider headstock design if you desire.
* As Dave said, check taht your pine board is flat. If it is cupped AT ALL, when you clamp it it will flatten out, you plan it, then when you release the clamps the cup shows up again and your joint will never fit.
* plane on a bias with a very sharp plane. You can also hold the plane at a bias to the grain but push it with the grain for a shearing action. That way the sole of your plane rests on the entire width of the headstock.

You'll get it!

Shane[/QUOTE]

Thanks again Shane? Maybe run the pine board (I bought several and plan on keeping at it till I get it right) through the thickness planer?alambert39059.5199768519
Author:  alambert [ Fri Dec 08, 2006 4:36 am ]
Post subject: 
[QUOTE=crazymanmichael] the factors mentioned by the previous posters are all amongst the reasons i switched to doing my scarf joints, the few that i do anyway, on the table saw. clamp blank to jig, cut blank, glue blank. no frustration. whilst i eventually got so that i could get a good, tight scarf joint doing it with the plane, it was never a quick or enjoyable process for me, rather always slow and tedious, check, mark high spots, square up, check, mark, ......, seemingly going on foreever till i was satisfied. granted, i did get faster at it, but never fast, and there was satisfaction in achieving a good joint, but i'll take the table saw route any time. and when i built the jig, it took me far less time to build than it did to do a joint with the plane, and it hangs on the wall, always ready to do its thing again whenever i need, with no relearning curve to negotiate.

p.s. forgot to mention a few other suggestions; first you must start with flat, squared up stock else you will always be chasing your tail, second ensure that your initial cut is as square as you can make it, if possible by using a jig of some sort to keep the face of the stock in a vertical plane, mark your square target line on the stock, and the high points on the joint faces to give yourself initial target areas to correct first. do this after every couple of cuts with the plane. these must be marked by checking both squareness across the stock but also straight along the long axis of the joint surfaces. backlight helps immeasurably. use chalk or coloured pencil or gelpen for easy visibility. and as someone else mentioned, use only a very sharpe iron set for very fine cuts. a dull iron will always lead to the ragged start line you depict in your drawing, as well as uneven cuts in the stroke as you strugle to get the cut started and finished, as well as variation in the cut in softer or harder wood.

ain't learning all this a b....-- oops can't say that can i!!! [/QUOTE]

Thanks for your responce. If I read you right are you saying after you make the cut on the table saw, you just glue it w/ out any additinal plane work?
Author:  TonyKarol [ Fri Dec 08, 2006 4:43 am ]
Post subject: 
Alain .. dont use a thickness planer to get something flat - thats not what its for - it makes things an even thickness, but the drive roller will flatten out the bow in the board, run it under the knives, and then on the outfeed the rollers release and the bow will still be there, but the board will be an even thickness - you need a jointer, or do it with a plane- sorry, thats whats causing all your grief in the first place. One of my students scarfed a neck last night .. same thing, planing and had a hump in the middle - lighter plane setting, concentrate on the centre, and we had it in a couple minutes. Once you get good at this, you should be ale to get one dead on in about 5 minutes.
Author:  alambert [ Fri Dec 08, 2006 4:46 am ]
Post subject: 
[QUOTE=TonyKarol] Alain .. dont use a thickness planer to get something flat - thats not what its for - it makes things an even thickness, but the drive roller will flatten out the bow in the board, run it under the knives, and then on the outfeed the rollers release and the bow will still be there, but the board will be an even thickness - you need a jointer, or do it with a plane- sorry, thats whats causing all your grief in the first place. One of my students scarfed a neck last night .. same thing, planing and had a hump in the middle - lighter plane setting, concentrate on the centre, and we had it in a couple minutes. Once you get good at this, you should be ale to get one dead on in about 5 minutes.[/QUOTE]

Gotcha. Taking a stright edge with me to get my "test" wood might not be a bad idea either!
Author:  csullivan [ Fri Dec 08, 2006 4:48 am ]
Post subject: 
You don't want to use a thickness planer, because the infeed roller will
just press any cupping in a pine board flat. When it comes out the other
side it wil just spring back to its cupped state. If you have to use a power
tool, run it over a jointer instead. But you will gain some valuable
experience if you use the hand plane for flattening the board as well.
There's nothing better than mastering these skills. The hand plane is just
so useful for all kinds of luthery work.
Craig S.
Author:  crazymanmichael [ Fri Dec 08, 2006 5:21 am ]
Post subject: 
yep! just as i said on your thread re your plane selection. with a good blade it will produce a gluable cut off the saw. presupposes a good blade, an accurately set up saw of course, and an accurately built jig, i.e. one that holds the stock square to the table.

don't think i am trying to discourage you from learning to use the hand tools. the time spent will be a valuable learning experience. and as is often mentioned, many folks prefer to use their hand tools. i just prefer to get the job done with as little agravation as possible.

crazymanmichael39061.604375
Author:  alambert [ Fri Dec 08, 2006 5:33 am ]
Post subject: 
Unfortently I dont own a jointer(yet) of any planes(yet) except a 60 1/2 block plane that I just bought and i think I just did learn the back from the front on it last nigth! ;)

So guess I have to either buy a really flat board, buy some tools or both.

Im hoping my real neck would will be so flat that I don't have to worry about. But I much rather learn on a $3 board then ruin my real wood before I'm ready.
Author:  crazymanmichael [ Fri Dec 08, 2006 5:42 am ]
Post subject: 
the borg, etc., usually sells finished, that is planed and squared, poplar, oak or red maple in 3x1 or 4x1 nominal dimensions at reasonable prices. one length should allow you to make a number of practice joints to hone your skills and gain confidence before you attack your actual neck stock.

after each planed joint is finished, just cut off the planed surfaces again, and start all over. just make the "headstock" end long enough that you will have enough stock to plne and trim it a number of times. if you get a long length, you can also get multiple iterative practice stacking and carving your heels.crazymanmichael39061.6016898148
Author:  alambert [ Fri Dec 08, 2006 6:39 am ]
Post subject: 
[QUOTE=crazymanmichael] the borg, etc., usually sells finished, that is planed and squared, poplar, oak or red maple in 3x1 or 4x1 nominal dimensions at reasonable prices. one length should allow you to make a number of practice joints to hone your skills and gain confidence before you attack your actual neck stock.

after each planed joint is finishe, just cut off the planed surfaces again, and start all over. just make the "headstock" end long enough that you will have enough stock to plne and trim it a number of times. if you get a long length, you can also get multiple iterative practice stacking and carving your heels.[/QUOTE]

I like you thinking! and infact thats basicly what I did. Bought the 1x4 from what I call the "craft section" at lowes, but apparently I got one that has some minor cupping. maybe I should have gotten the nicer ones.

The cracks Im talking about in my post are about the width of a sheet of paper.
Author:  Shane Neifer [ Fri Dec 08, 2006 6:54 am ]
Post subject: 
Alan,

You can use your planer, just take VERY light passes and check with your straight edge as you go. The guys are right though, a jointer is the proper tool. Since I have started doing the guitar thing I have pretty much parked my 20 inch planer and use the jointer, tablesaw and thickness sander. But back to the point, very light passes through the planer should give you a flat spot on the out side of the cup, once you have a flat spot for about 3/4 the width of the board, flip it over and plane it flat...light passes (did I say that yet?) and you can make it work.

Shane
Author:  Shane Neifer [ Fri Dec 08, 2006 6:55 am ]
Post subject: 
*&^&%*&&%* Double posting thing!!! Shane Neifer39059.6268981481
Author:  Mike Collins [ Fri Dec 08, 2006 7:27 am ]
Post subject: 
What size plane are you using?
I do all my scarf joints with a small low angle block plane.
It gives you better control .
Then I sand with a 80 grit sanding block-takes me
3 minutes tops to get a perfect joint!
And as said before check with a square as you go.

Mike Collins
www.collinsguitars.com
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