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How to cut 15 degrees for a scarf joint?
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Author:  jeff.scott [ Fri Feb 25, 2011 11:00 am ]
Post subject:  How to cut 15 degrees for a scarf joint?

I have been watching many youtube video on scarf joints (headstock) and it seems most luthiers favour the band saw for cutting this.

PROBLEM 1: I built a 15 degree jig, but absolutely cannot get the band saw to bite the wood. I made a little starting groove at a wider angle, but at 15 degrees the blade always bends. Another teacher here (high school) said this it is possible the blade is not wide enough. It is a 1/4" blade. Has anyone been able to cut a 15 degree headstock with a 1/4" band saw blade?

PROBLEM 2: I have also built a jig for the table saw. Some test pieces cut nicely, and some were butchered. I hate to put my maple in there. Anyone cut this on a table saw with success?

PROBLEM 3: One of the best cuts I made was with a mitre saw. I set the blade at 15 degrees and just held the test wood perpendicular to the back fence. Not very accurate, but the best cut so far. Anyone been able to do this?

Author:  Steve Saville [ Fri Feb 25, 2011 11:18 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I use the table saw. You can mess up your neck easily. To avoid that, try a thin kerfed Diablo blade that is sharp. Be sure that your neck is firmly clamped to the sled - both behind and in front of the cut. Make sure your sled has very little play in it. Turn the saw off as soon as you go through the neck.

Author:  Pat Foster [ Fri Feb 25, 2011 11:47 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

If you have a table saw, you can try this jig. Works very well. Kathy Matsushita's site has a some pics and a plan.

http://home.comcast.net/~kathymatsushita/amateurluthier/htmlpages/scarfjig.html

Pat

Author:  peters instruments [ Fri Feb 25, 2011 1:39 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

a 1/4 blade is not going to want to do the job very much, especially if it is a fine tooth blade. if you can get a 3/8 or half inch blade with a fairly low tooth count it will help. 1/4 inch blade could probably do it as well if its in the neighborhood of 6tpi and sharp. if you are using a fine tooth blade it might tend to bind up once you get the cut started anyway.

Author:  jeff.scott [ Mon Feb 28, 2011 9:21 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

All good advice, especially about the guides on the band saw. Thanks.

I have built that same jig for the table saw. As I say, some cut well, others get chewed up. I guess I will have to try a few more practice cuts and then try the maple.

Author:  Darrel Friesen [ Mon Feb 28, 2011 9:38 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

A good Western or Japanese handsaw and a block plane work very good as well.

Author:  Jim Watts [ Tue Mar 01, 2011 12:46 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

A bandsaw and then I clean it up with a hand plane.

Author:  jeff.scott [ Wed Mar 02, 2011 5:22 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I cut my first headstock with the mitre saw. It took a bit of rigging to get the wood perpendicular to the back fence, but it worked. The cut wasn't perfect, so I ran both pieces through the bench sander. Looked pretty good and I glued it yesterday, so this morning I will un-clamp it and check it out. Probably glue on the headstock wings to widen the surface area.

Author:  DennisK [ Wed Mar 02, 2011 8:57 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I'm with Darrel. Mark a 15 degree line and go at it freehand. Still a little tricky to get started, but once you've got a notch to ride in, it's just a matter of keeping it vertical for a few minutes of cutting. Practice on a couple scraps and it gets pretty easy. I use one of these http://www.amazon.com/Tajima-PUL-265-Rapid-Pull-Blade/dp/B0008MGHUM/ref=sr_1_4?ie=UTF8&s=hi&qid=1299073451&sr=8-4. Excellent saw, far better than its price would suggest.

Author:  eugeneparnell [ Tue Apr 19, 2011 1:40 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I have gone through all the same attempts. First I tried making a jig for a miter saw, and it didn't work too well. I tried once with a bandsaw and the amount of cleanup necessary with the plane afterward was too much. Finally I ended up making a jig for my table saw similar to (but not as nice as) the one on Kathy's site (linked above). I've had the best luck with that, although it sometimes comes out a bit out of square.

I'd also second the comment about a good *sharp* handsaw being just fine for the task. The junk saws you get at your local big-box home store aren't going to work too well. A nice Japanese handsaw takes some practice to use, but the blade and its kerf are so much thinner, it cuts surprisingly fast and clean.

Author:  Mike Lindstrom [ Tue Apr 19, 2011 7:48 am ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I used the bandsaw at school. Awesome. Tried at home. Terrible. Used a handsaw. Frustrated. Upgraded bandsaw. Worked better. Regardless of your plan, you will still need to fine fit it with a plane. I also use a granite sanding block. (scrap from a counter guy) For my most recent, I'm doing a multi-scale which requires a compound angle for the scarf joint. On the advice of Mark Mustapick, I went back to the table saw. It was a revelation to me that my jigs and sled didn't need to go under the wood. I can't take credit for it. Saw a picture online somewhere, but don't remember where.

You do want to be very thoughtful of your clamp placement. And don't run your tablesaw with all that stuff on it. Just set it up for the photo.

Mike

Author:  jmpbuffalo [ Tue Apr 19, 2011 1:08 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

Here's the jig I use. It's just a few scraps of plywood. If your saw is well tuned and you have a good blade, you won't need to do any cleanup work.

Image

And, yeah, you don't want to cut through any clamps!

Joe

Author:  Mike Lindstrom [ Tue Apr 19, 2011 5:56 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

Yeah, Joe. That's what I was trying to show. You took a much better picture.

Mike

Author:  Ian Cunningham [ Tue Apr 19, 2011 8:21 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

Draw angle out on neck blank, giving plenty of meat on either side of the cut. Set up your bandsaw, making sure your table is perpendicular to the blade, your blade is tight, your guides are set up close enough to the blade, and that the bearings are set up properly. Cut along the line sloooooooooowly. Clean up the faces with a hand plane, sandpaper on a block, and a square. Always works well enough for me. I use a 1/4" Viking blade from Lee Valley. I think the slowness part is key to solving your predicament.

Author:  jimmysux [ Wed Apr 20, 2011 8:26 pm ]
Post subject:  Re: How to cut 15 degrees for a scarf joint?

I just use a 9" bandsaw with a 1/4" blade and cut across the line I've drawn. Then I use my tabletop belt sander to sand it all flat. Has worked for me flawlessly each time. The only thing is I cut it a few degrees less than I want it, because after sanding it the angle always increases a little.

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