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Message started by Acabooe on Jan 16th, 2008 at 2:08pm

Title: Question about neck scarf joint cutting
Post by Acabooe on Jan 16th, 2008 at 2:08pm
I am FINALLY to the stage where I can cut the scarf joint for my neck.
I decided to use oak as the wood for the neck, because this is my first ukulele and this is just practice to get the feel of building.
I don't have a band saw or table saw.
My question to the forum is which would be best hand saw for cutting the scarf joint?
Miter saw
Japanese pull saw
or regular everyday push it until your arm falls off saw?
Any suggestions would be greatly appreciated.
Mahalo to any who post here.
Bob

Title: Re: Question about neck scarf joint cutting
Post by lefty on Jan 16th, 2008 at 5:59pm
Bob
 I would use the Japanese saw.  You will jave a lot more control than with a push saw.

Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Jan 17th, 2008 at 3:52am
Bob:

Do you have a chop saw?  If you have one of these, or have a friend with one, a simple jig will allow you to cut the 15 degree angle and will save you a lot of hand sanding on the joint to get it to fit together.

If you want some pictures of the chop saw jig I used, let me know.

Don

Title: Re: Question about neck scarf joint cutting
Post by Acabooe on Jan 17th, 2008 at 5:14am
Dear lefty and Don,
Thank you both for your posts.
I was thinking that with the back saw, it might be a little easier. Thanks for the confirmation.

Don,
I don't have a chop saw, ( just starting out in luthier stuff) and I live out in the country so there arn't many people around me, and certianly no luthiers.
If it is not too much trouble, I would like to see pictures of the chop saw scarf jig.
It might help me to figure out how best to cut this joint.
My email is acabooe@yahoo.com

Thanks
Bob

Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Jan 17th, 2008 at 1:49pm
Will send pics as soon as I dig out the digital camera and set the jig up on my chop saw again for photos.  Forgot to take phots when I was making the cuts earlier this week.

Don

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 23rd, 2008 at 12:34pm
I use a 12" power miter saw (much like a chop saw) with a simple jig I made from scraps of pine and oak to do my scarf cutting. I'll have to get some pics of the jig since it can be used with a hand saw if needed, though the jig is set up to allow for the approx. 1/8" kerf of the blade. You'd have to adjust the jig to accomodate a smaller kerf (like the pull saw) so you wouldn't get any wobble/wander in your stroke.

You could also get a smaller miter saw than mine. I figure even an 8 inch saw would work OK and you could get it for fairly cheap. I've found the miter saw to be extremely useful for a lot of other kinds of projects around my shop and home and have probably used it more than any other power saw I own.

The miter saw does the cut very accurately and in about 2 seconds. The trick is to be sure the workpiece is solidly clamped to the jig and the jig is tight against the saw fence. Any movement during the cut will require you to do a lot of sanding to get the joint to fit right...

Jeff

Title: Re: Question about neck scarf joint cutting
Post by Acabooe on Jan 24th, 2008 at 4:57am
Jeff,
Thanks for the tip.
I have a young son, and a wife, so at the moment, I don't really have the money to get power tools.
It's hand tools for me right now, but thanks for the imput anyway.

For those who are interested, I found a cool little jig that you can use if you have a table saw.

If you wanna check it out, go to http://pweb.jps.net/~kmatsu/htmlpages/scarfjig.html


If the link doesn't work, copy and past it into the url bar.

Mahalo again for the reply Jeff.
Bob 8)

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 24th, 2008 at 5:44am
Mahalo for the table saw jig link, Bob! Slick, I may try it.  I printed the drawing. It is very similar to my jig. The main difference is that mine doesn't slide on the table. With the miter saw jig, it and the workpiece stay totally stationary and the blade is pulled down into it. So, if the jig and workpiece are rock solid to the saw table as I mentioned, there is no chance of play and the scarf will be near perfect. I suppose if the table saw has a good quality, accurate fence the same would be true, however.

I still think my jig with slight modification could work for you with a hand pull saw. It is really very simple to make, certainly not rocket science. I'll try to get a picture of it and maybe do a drawing with dimensions ASAP.

I totally understand your situation with the wife and young son. Been there before, more or less. But after 50 years of playing with wood and tools my wife has realized she'd better play along. ;) So Christmas for me is usually at least one really great power or hand tool from her as a gift.

This past Christmas was outstanding. I ended up with a brand new Grizzly 17" heavy-duty bandsaw and a Grizzly 18/36 open-end drum sander! I'm in heaven!

Keep the pukas on the FRONT of your ukes!
Me ke aloha pau ole!

Jeff

Title: Re: Question about neck scarf joint cutting
Post by Acabooe on Jan 25th, 2008 at 11:05am
Hey Jeff,
I would like to see some pics/ plans of your jig.
What I have been doing so far is clamping metal straight edges to the wood and going slowly to make sure that the saw cuts where it is supposed to.
It has worked ok, but I am always on the look out for a more efficient way of doing things.

Thanks.
Bob 8)

Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Jan 25th, 2008 at 11:10am
Jeff:

Please attach them to a note here so others can also see.

Don

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 28th, 2008 at 3:05am
I took some photos of my miter saw scarfing jig yesterday. You can see all of them at:

http://jeffreywbosworth.net/scarf_jig.htm

The close up at the bottom hopefully gives you a good idea of how the jig holds the workpiece. In the one picture of the sample workpiece (#3), it is not the correct size for a neck (I didn't have any neck blanks handy) so doesn't give you a good idea of what the scarf would look like. But it does demonstrate how the workpiece is positioned and clamped in the jig. The clamp would be positioned further out away from the saw blade so the blade will clear it.

Also, the jig itself would be clamped to the saw table.

Let me know if you have questions.










Jeff
P.S. Yes, the saw is set up on its mobile base in my dining room. We're doing extensive remodeling of our old farmhouse and I am cutting hardwood flooring and oak baseboards and trim for our kitchen extension... ;) Like I said, a miter saw is one of the most useful tools you can have.

Title: Re: Question about neck scarf joint cutting
Post by Wood_Butcher on Jan 28th, 2008 at 3:56am
Jeff,

I have built a sliding jig for the table saw, but may need to build a chop saw version.

I'm wondering if you use the 'fall down' that projects through the fence as you headstock?  If so, does it drop away safely from the blade without damaging it?  Not one of those places where I'd like to stick my hand to catch it.

Thanks,

Mark

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 28th, 2008 at 4:29am
Hi, Mark.

That's correct, the "fall down" is the headstock piece. I neglected to say that I put a scrap of wood under it to keep it from actually falling. As long as your blade is sharp, it will be cut without any tear out. Just go slow until you reach the bottom of the cut and then pull it down quickly. Also be sure you start the saw BEFORE you bring it down into the workpiece. Don't let the blade go back up until it has stopped completely.

I've had my miter saw (it's a 12 inch Craftsman Professional compound model) for several years now and it still has its original 40 tooth carbide tipped blade. I've built many things using this saw including a 12' X 28' house addition. All the framing lumber (and more) was cut with this blade. I also used it to cut 4X4 treated posts to build a fairly large pergola. Carbide tipped blades are awesome and well worth the cost!

This saw does have some flaws. I have to adjust the blade's vertical angle when at the left 45 degree setting by 2 degrees or the miter will be off. No amount of tweaking with the adjustments alleviates this. No idea why. Also, the laser cutting guide is virtually worthless...

Bottom line, I haven't had any problems with the headstock piece using this jig.

Jeff

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 28th, 2008 at 5:17am
By the way, the jig's fence also has a 15 degree cut at the end closest to the saw. I made this by putting the assembled jig on the saw table, putting a piece of scrap in as the workpiece and then making the cut. The saw also cut the end of the jig fence to the correct angle. When positioning the jig, align that cut with the side of the blade before clamping the jig to the table.

I ran the small holding piece on the left side through my table saw set at 15 degrees to make the end cut. I positioned that with a workpiece in place on the jig, its rear side aligned with the bottom board's rear edge, so that the block was tight against the surface of the workpiece. I then marked the position and screwed the block in place from underneath, countersinking the screws (all the screws in the jig are countersunk so it sits flat on the saw table).

The only problem with that is that it assumes all my neck blanks will be the same thickness. I should probably modify this jig so that the block can be adjusted for various neck blank thicknesses and then tightened down with bolts and wing nuts.

Jeff

Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Jan 28th, 2008 at 8:54am
I had problems with the first version I built of my scarf joint jig with the free end flying away from the back of the saw, so I modified my jig to add a support and hold down.  My jig sits on a 12 inch Dewalt sliding compund miter saw, and therefore I had more than the normal space behind the blade to work with.

Here are some pics:




Jig on saw after a neck scarf cut.





Jig from front.





Jig from side.  Pine 2X4 cut-offs as hold down for neck end.



Jig from back.  The little plywood block at the end of the neck is a stop block to get the 2 1/2 inches right each time.  It also aids in keeping the neck end where it belongs after cut.



Hope these are of help to others building a jig.

Don

Title: Re: Question about neck scarf joint cutting
Post by jbosworth on Jan 28th, 2008 at 9:28am
Nifty! That arrangement would solve my problem of having neck blanks of different thicknesses, as well.

I must say that your jig looks to be built strongly enough that it could also support an 18 wheeler!! ;D

Mahalo!

Jeff

Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Jan 29th, 2008 at 3:42am
Jeff:

Part of the reason for the double MDF layer is to get over the raised pivot on the back of the saw, but the real reason is I'm an engineer and prone to overbuild.  I hate having a tool/jig flex or bend and not giving me the results I'm looking for.  Also, I tend to use what I have available in the shop resulting in a 4X4 fence.

Don

Title: Re: Question about neck scarf joint cutting
Post by Jeff B on Jan 29th, 2008 at 4:48am
Ha! I understand.

I've become a scrounger, as well, when it comes to making jigs. I also have a habit of saving every little scrap of wood I can. I always see a possibility in it for something, sometime. And after years of doing remodling work on our house I have a LOT of scraps in all different shapes, sizes, and types of wood. The problem is that I haven't taken the time to organize it so it is scattered all over the place in various containers - or not...

;D

Jeff

Title: Re: Question about neck scarf joint cutting
Post by Acabooe on Mar 6th, 2008 at 7:31am
Ok everyone, here is what I did.

I have a table saw... well sort of, it is in really bad working shape, so using that was not an option.
I wanted to see what I could do with my japanese pull saw.
I made the line with a pencil an straight edge, then I clamped the wood down and began to saw.

Things didn't go as I had hoped that they would.
The joint looked absolutely horrible.
I needed to clean it up a bit.

I first tried using 60 grit sand paper, but that took forever + a week, so I resolved to use my rotary tool, and planer.

The planer worked better, but not perfect.
N e wayz, after the joint looked better, I used some spare blocks of wood, and alot of clamps, and I made a gluing Jig.

After gluing, there was still unfortunately a gap at the scarf joint. I guess it will be covered up with the ears.

Then I glued on the heal blocks, and I was done with that step.

I know that it doesn't look great, but I am using this Ukulele project as a learning experience, so I will be better next time.

Hope you like the pics.
Aloha
Bob 8)












Title: Re: Question about neck scarf joint cutting
Post by Matt Blacka on Mar 6th, 2008 at 11:36am
Hi Bob,

Ahhh the joys of trying to get a scarf joint done nicely.....

I have completed one uke about 2 years ago, and am now in the process of doing four ukes at once, which are all a bit different to each other, and I have just finished doing the scraf joints on them.

For my first uke I used a band saw to cut my scarf joint, and then cleaned up with a sanding block. The finished joint was good, but it took a lot of work to get it there.

For the batch of ukes I'm doing now, I made a jig to cut the scarf joints on a sliding compound miter saw (the jig was much like the other peoples' that have posted pictures here, but somewhat uglier).

None of the joints came off the saws perfectly. The jig that I used on the compund saw created a flat but slightly off square cut, which had to be squared up on all four necks with a sanding block. This wasn't a major problem. All four necks moved slightly during glue up, which again I have fixed up using a sanding block. No problems.

In my experiences, getting a good scarf cut and glue up is difficult even with a band saw or miter saw, and requires well made jigs or a reasonable amount of work cleaning up with a sanding block.

You are correct in thinking that the gaps in the joint should be covered up by the ears, at least on the sides of the headstock anyway. Any gaps on the face side can be covered by a face plate, and any on the rear side can also be covered by a plate, if absolutely necessary.
So a few small gaps shouldn't be a major problem, so long as the joint is still strong.

I see that you used one clamp to hold the wood to the table and one across the scarf joint during glue up. I have used significantly more clamps to close the scarf joint than this when doing my joints, like two treble side, two bass side, and one in the middle, plus the one to hold everything to the table. I find that this helps to close any small gaps/imperfections in the joint between the two pieces of wood, as it provides better control on where most pressure is applied. Anyway, maybe this is overkill, and caused my problems with the joints moving slightly during glue up?

Anyways, nice job on the neck blank. One of my favourite parts of the building process is shaping the neck, so have fun with it, and remember its easy to take away, hard to put back.  :)

Matt


Title: Re: Question about neck scarf joint cutting
Post by Don_Orgeman on Mar 6th, 2008 at 5:38pm
Matt:

I thought I was going crazy to try to get my scarf joints adjusted perfectly.  Lots of practice cuts and adjustments with shims and I finally got what I thought would be a perfect cut.  When I cut the actual necks they all came out just a hair off square.  I also had the same problem as you with minor slipping during glue up even though I dry fit the neck into the clamping assembly first.

You are 100% right.  Some 80 grit sandpaper on a sanding block does wonders to correct any problems.  Lesson learned: Don't worry too much about being perfect.

Hey guys, my spelling is lousy.  Is there a spell checker hidden somewhere that I am missing to catch errors in my posts?

Don

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