Official Luthiers Forum!

Hi

I have tried to cut a scalf joint on my band saw and manually - both failed

I want to use the table saw but my blade height above the table is only 55mm, the total cut depth is 95mm - any ideas how I may achieve this ?

Alternatively my table saw has a manufacturers max blade diameter of 210mm - I bigger one will physically fit - do you think this is an option?

John

John: Have used all three to roughly cut the joint. By hand,band saw,and table saw. Then clean it up accurately with a hand plane.
Tom

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A person who has never made a mistake has never made anything!!!

John,

If you have a disc sander, you can build a mitre jig to hold the neck blank at the appropriate angle and sand the joint. Just rough cut on the bandsaw and sand on the disc with 120 grit paper. If your disc is dead flat, you can go right to glue up. I've done this lots of times with scarf joints up to 30 degrees and it works perfectly. I've used LMI white and Smith's epoxy and both have worked equally well.

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Jimmy Caldwell
http://www.caldwellguitars.com

Many builders use a table saw jig to cut the scarf joint. Kathy Matshusita's side has a picture of one that seems to work. I, however, use the band saw. That works for me because I do almost all of the clean up with a block plane. Cumpiano & Natelson, show how to do this in their book and it works well. Usually, I'm all for power tools but in this case the block plane is pretty easy to use. The first time you try it will take awhile but, if you use a sharp plane, you will eventually get there.

After cutting on the band saw, stack the two pieces such that the two cut faces line up. (see picture). I put the neck on top and the headstock on the bottom with a piece of scrap because my clamps get in the way if I put the headstock on top. Clamp the stack to your workbench. Note that the bottom piece of scrap is just a few mm past the neck and headstock. The end of the bottom piece of scrap will be sliced off with the plane.

Plane the cut surfaces so that they are flat. It is important to make the line between neck and the headstock perpendicular to the side of the neck blank. If it is not, the joint will not fit.

Hi

Thanks for the advice and the tips, you have not seen how bad my band saw and manual cuts are ! - Too much to salvage with a sander and plane.

I thinking of making a router jig, I know I have seen one somewhere

John

My 'two cents worth'...

Estimate the time it will take to make the router jig.
Divide by two.
Take that amount of time to sharpen your plane (and other edge tools while you are at it).
5 minutes with a plane, once you have the work clamped as Mike shows, and you will be done.
Taking 1/2 " or more off with a sharp plane is not a big job- it just takes a few minutes.
(And you will still have sharp tools for the next job...)

I like my power tools, but they're not the answer to all problems.

Cheers
John

I cut my scarf joints by hand with a cheap back saw that came with one of those plastic miter boxes. They look like this when I finish the cut

After a few minutes with a sanding block or a hand plane, they look like this

and work quite well. After shaping/thicknessing the headstock, you'd have a hard time finding the joint.
Here's the finished product




You'd be amazed what can be done with a few simple tools and some perseverance. Don't give up, and don't waste time and money searching for a better mouse trap until you thoroughly try the ones you've already got.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

I cut my early scarfs with a hacksaw... Worked great. Cleaned up with a good plane in 10 minutes. No matter how precisely you cut with a saw (table or otherwise) you still need to plane the joint to get it true enough to glue.
IMO... the best single tool investment a luthier can make is the Lee Valley low angle block plane. Get one & practise using it... It'll change your life.

I agree, in principle.

IMO that particular plane (and similar ones) is too heavy for me for comfortable block plane use (I'm going to buy the extra handles to 'convert' to a bench-style plane.)

I like my older Stanley 60 1/2 and especially the LV apron plane.

Any one of the planes mentioned will do a fine job on a scarf- if sharp.

Cheers
John

The jig on Kathy`s site works great for a table saw with a good sharp blade.Like a Freud Diablo 40 tooth.After it`s cut I just sand lightly with some stickum paper on a block of wood.Perfect fit,fast and simple. James

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James W Bolan
Nashville Tennessee

I use two strips of double tape to hold the head to my neck shaft while planing, thus no need of a scrap of the exact same thickness. For easier revomal, I usually contaminate one side of the tapes with my finger oil. I use my bench plane here, too.

When I do a scarf joint ... I dont bother planing the section on the headstock face that is part of the neck itself (after cutting on the bandsaw) .. I get that later. For starters, all I do is clean up the scarf on the headstock extension piece, and glue it on. Then afterwards, I clean up the whole thing, both times using the LV low angle smoother .. wide blade, larger reference surface than the low angle block, which I also have. This way, I need no special clamping arrangement to do both pieces at once .. all I use is a face vice on the bench.

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

I do pretty well the same as Tony - clean up the scarf/gluing surface of the headstock piece, glue it up, then true the entire headstock face up. Except I just hit the entire surface a few seconds on my belt sander and it's ready for veneer.

BTW, I do use a table saw jig based on Kathy M's, which works real well. However for the one I cut last week, I failed to change the 7 1/4" blade out for a 10" before I made the cut, so it didn't go all the way through. Rather than changing the blade out and cutting again, I just finished up with a hand saw like so many are recommending, then trued the surface of the headstock piece on the belt sander. I hit the gluing surfaces with a scraper then glue 'em up.

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Wes McMillian
Santo, TX
http://www.wesmcmillian.com

Thanks for all the contributions, I have decided to get a wider blade for my band saw (5/8") a revisit cutting the scalf with the band saw.

John

John,

What sort of bandsaw are you using? 5/8" is too wide a blade if you are in the 14" world - that's not going to solve the problem because you won't be able to tension the blade, and will then get bowed cuts.

This operation really does just take some practice - make some scarf joints out of 2 by 4's until you get it down, and then the difficulties will be in the past and then move on to the real neck blanks. Hand saw, free-hand band saw, whatever. The cleaning up of the cuts with the block plane is the crucial part.

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Jim Kirby
kirby@udel.edu

I use a sled to cut the head but could also be used to cut a scarf joint too.

Dang Chris, that jig looks nicer than some people's guitars.

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Steve Smith
"Music is what feelings sound like"