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scarf joint cutting
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=34975		 Page 1 of 1
Author:  nyazzip [ Mon Jan 16, 2012 2:45 am ]
Post subject:  scarf joint cutting
so i glued up a neck blank....no real tools to cut the scarf with.
got a small table saw: blade doesn't rise nearly high enough("high enough"=70mm plus or minus); got a chop saw, but it only does 45 degrees. got a crappy toy band saw; at that height it would cut a ridiculous wavy line, if it would even allow 70mm....
so: should i try a hand saw? i don't have a decent one, but it is probably about time to get one....
what should i do? and if a handsaw, what should i buy?
Author:  DennisK [ Mon Jan 16, 2012 3:25 am ]
Post subject:  Re: scarf joint cutting
Handsaw for me. I use a Tajima 265 http://www.amazon.com/Tajima-JPR-265DIS-Fine-Cut-Pistol-Handle/dp/B0042BAH6K/ref=sr_1_12?ie=UTF8&qid=1326701682&sr=8-12, although a ryoba saw is probably a better deal as that has cross cutting teeth as well as rip teeth. I use that for just about everything else. Rip teeth may in fact work better than cross teeth for cutting scarfs as well... I just haven't bothered to try it yet since I've got the technique down with the Tajima.

Practice a couple times on scraps immediately before cutting the real thing, to get a feel for where vertical actually is, versus where it looks like it is. And if you start drifting too far off track, you can always flip it over and start a new cut from the other side. As long as you leave plenty of extra on either end of the scarf cut, it's just more block plane work to flatten it out.
Author:  nyazzip [ Mon Jan 16, 2012 5:31 am ]
Post subject:  Re: scarf joint cutting
yep i've been wanting to get a decent pull saw lately. guess i will. i can think of a thousand times i wished i had one
Author:  klooker [ Mon Jan 16, 2012 6:40 am ]
Post subject:  Re: scarf joint cutting
Do you or a friend have an old school carpenter's hand saw? They come with either rip or crosscut teeth.

If you can find a decent one with a straight blade, you can get it sharpened for about $10 & they do work pretty well. I like pull saws also but I prefer the ones that have a back because the blades are so thin. Unfortunately, I don't think you can get one with a back that will cut any deeper than about 2". I find the backless ones a little funky to use.

My $0.02.

Kevin Looker
Author:  Hupaand [ Mon Jan 16, 2012 2:30 pm ]
Post subject:  Re: scarf joint cutting
I got one of these by mistake, but now I use it for everything (almost). It's thick enough to pull a straight cut without a spine.
http://www.ebay.com/itm/BAKUMA-300-FLUS ... 0636145486
Author:  cphanna [ Mon Jan 16, 2012 7:31 pm ]
Post subject:  Re: scarf joint cutting
It is quite possible--actually relatively easy--to get close to your desired ramp with a hand saw. I did my first two with an antique back saw (push saw). When it comes down to the final fit, I always seem to do better with a hardwood sanding block about 8.5 inches long and 2 inches wide, 80-grit paper, and a good try square to be sure I'm staying level and square. The narrow sanding block allows me to correct my leveling process on one side or the other as I go along. I honestly do believe a well-tuned plane would be better for the final leveling, but in all my years of woodworking (and I am probably older than the fathers of most of you who are reading this), I have never mastered that degree of planing skill. My point is simply this: It is totally achievable with the hand saw of your choice and the final leveling method of your choice. Presumably, scarfs have been done that way for countless generations. Don't freak out about it. Just mark out the cut carefully, grab a sharp saw and go for it. You'll be fine!

Patrick
Author:  nyazzip [ Mon Jan 16, 2012 9:32 pm ]
Post subject:  Re: scarf joint cutting
i ended up getting a cheap(relatively) pull saw today at Menards...it was wrapped in cardboard, and i didn't realize it had a reinforced "spine"...so it will only cut about 2" deep!! arg!
so i tried the cut-n-flip method. naturally my cuts were off, so i have a big cleanup to do.......
i do have a hand-me-down carpenter's saw, not sure what its called, classic looking tapered thing. it is extremely dull so i don't use it. i'm going to see if i can sharpen it
cheers
Author:  Pegasusguitars [ Mon Jan 16, 2012 11:44 pm ]
Post subject:  Re: scarf joint cutting
I've done many hundreds of these scarf joints by hand and actually have enjoyed doing it that way. The process was to bandsaw the angle and handplane to get the fit. Pretty easy and gives a nice sense of accomplishment. That said, I now use the chopsaw, which does a very nice quick job of cutting the joint precisely. Only rarely do I need to grab the plane. If I can figure out the process of posting photos, I'll do so following this post. I think they are self explanatory. Just make the jig right and use a good 80+ tooth blade.
Author:  Pegasusguitars [ Mon Jan 16, 2012 11:47 pm ]
Post subject:  Re: scarf joint cutting
Photo2
Author:  Pegasusguitars [ Mon Jan 16, 2012 11:47 pm ]
Post subject:  Re: scarf joint cutting
Photo3
Author:  Pegasusguitars [ Mon Jan 16, 2012 11:48 pm ]
Post subject:  Re: scarf joint cutting
Photo 4
Author:  Pegasusguitars [ Mon Jan 16, 2012 11:51 pm ]
Post subject:  Re: scarf joint cutting
Photo 5 If you have a sliding chopsaw like mine, REMEMBER to lock the carriage so that it can not slide out on you. That's why I use the spring clamps to hold the pieces being sawn, just in case I forget to lock the carriage. If my saw did not slide, I most likely would just hold the pieces by hand.
Author:  nyazzip [ Tue Jan 17, 2012 12:10 am ]
Post subject:  Re: scarf joint cutting
ok, i get it, thanks for the fotos....! i was too stupid to figure out how to make a jig for the chop saw. in my defense, i have actually never used it. i feel better now, i see light! i figure the headstock must be the most unpleasant/unrewarding part of making a classical. at this point i actually haven't declared, "i am making a guitar". rather, i am "just making a neck"..... :D
the side bending and solera and mold stuff seems a bit insurmountable at this juncture, without fully diving in. but if i can pull off a passable neck, then i may go for it
thanks again
Author:  nyazzip [ Tue Jan 17, 2012 3:22 am ]
Post subject:  Re: scarf joint cutting
guess i will show my clumsy results. better next time! i cut in a vice with a backsaw, flipped, cut again, then sand and sand and sand and sand to get a tight joint. i filled in some low areas with cyanoacrylate and dust gathered off the vice. very ugly! but, i plan on covering the top of the headstock with a veneer, and maybe the back. my little block plane made a mess out of the neck, instead of lowering the ebony, it decided to take out the mahogany on either side, instead??? joined with hide glue. a watery mix, i may add, but i am out and i need to order some i guess, if i have decided that i like it...and do i? jury is out

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Author:  Orion Thomas [ Tue Jan 17, 2012 8:43 am ]
Post subject:  Re: scarf joint cutting
The pull saw is a good idea. Anytime your making a deep cut with a handsaw it greatly increases accuracy to use a tall fence (block of wood) clamped to the work piece along the line of cut. Keeping the saw vertical is much easier this way. If you've used a chisel to cut a precise mortise wall the technique is the same.
Author:  Clay S. [ Tue Jan 17, 2012 12:26 pm ]
Post subject:  Re: scarf joint cutting
Hi Bob,
Nice chop saw jig.
Another quick and dirty way is to clamp a square cut block of wood to the fence to use as a 90 degree fence, and set the angle on the chopsaw. Your jig gives a better way to hold the work. Do you use a 12" chopsaw?
Author:  Pegasusguitars [ Tue Jan 17, 2012 5:45 pm ]
Post subject:  Re: scarf joint cutting
Clay - I have a 10" saw and it works fine. My saw will cut 3 and 31/32" deep.-Bob
Author:  truckjohn [ Wed Jan 18, 2012 9:37 am ]
Post subject:  Re: scarf joint cutting
If it were mine (And it's not)... I would disassemble that joint and re-do it...
Gaps in your scarf joint are asking for trouble - and ESPECIALLY with Hide glue... It's not particularly forgiving of thick glue lines or loose joints.

Use the technique that Todd showed - and then, if you can't candle it perfectly flat with a straight edge - sand it flat using a good, flat cast iron table saw table or some MDF....

If you find that you just can't seem to get it perfect no matter what you do - consider using structural epoxy instead... It is strong in gaps where our usual "Woodworking" glues like AR, PVA, and Hide really aren't.

Anyway, here's a pic of how I cut mine....
Attachment:
Oakie Neck 2.JPG


Then, it's gotta be cleaned up and jointed using the technique Todd shows...

Once the fit of the headstock to the neck shaft is perfect - I glue it up with a whole bunch of cauls to back it up and get it all glued tight.

This whole technique is more or less straight out of the Cumpiano book.

Attachment:
Ditson build 89.JPG


Thanks
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