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Yeah, that's why I say there's a possibility I used the spring clamps, since that's what's in the picture, and I've got 'em laying around. I don't remember what I used, but if I saw them in the pic I could have assumed they were adequate to the task.

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Mike

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

This is why I'm reconsidering it's use. I think I'm gonna give it one more shot. I think I have enough wood to build it in the shop, not sure.

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Mike

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

Pete's jig instructions do say just to push the material forward straight through the cut. It says to stop the saw once you have run the piece through, and NOT to reverse it (when the saw is running). Just want to clarify that.

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Kathy Matsushita
San Jose, CA USA
http://theamateurluthier.com
Facebook: https://www.facebook.com/kathy.matsushita

Kathy, thanks for posting the plans. I hope that I can get it working properly for me, as it would be a great help.

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Mike

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

yeah my first instinct was that the forward piece of wood was slipping back into the blade, and with this setup it would start pinching pretty fast. Put some "c" clamps on there and pay attention to the most forward section of the wood to make sure it doesn't tweak when the cut releases pressure that may be on the neck, (although if your jig is straight it shouldn't really be a problem)

The amazing Scarf-o-matic! It slices, it dices!

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Mike

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

You can even cut a tin can with it!

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http://www.CostaGuitars.com
PMoMC

With the exception of my first guitar, where the scarf was cut freehand on a band saw, all of my scarf joints have been prepped on my 10" Delta table saw with a jig very similar to Peter's plans reproduced on Kathy's website. There's a picture of a joint set up for a multi-scale project in the first posting at http://www.luthiersforum.com/forum/viewtopic.php?f=10117&t=41115

From that experience, I would suggest:
1. Check carefully that the fence on the jig and the raised blade are both at perfect right angles to the saw table surface -- otherwise you'll be doing more work later to align the joint. Also check that your blade runs exactly parallel to the table slots. This adjustment should be described in the saw's manual.
2. If the longer rear section is secured firmly to the jig with 2 clamps (as in my picture posted in the above link), it cannot twist to cause burning or kickback.
3. The problem child is the smaller front piece. If you can secure it also with two clamps, then that piece will also stay put and not cause blade burn or kickback. BUT, I'm not able to do that with the clamps in my collection without interference with the blade, so I usually allow it to break away on its own.
4. A single clamp on the front piece can sometimes cause that piece to twist or rotate slightly, and thus become a candidate for kickback. Use either 2 clamps (if you can) or none.
5. An alternative to clamps on the front are a couple of pieces of double-sided tape as insurance to keep the front piece from shifting when it breaks free.
6. As recommended by others, do NOT pull the sled back once the cut is through. Not only will it mess up what should be a perfect cut surface finish (if you have a good blade), but you could also drag the front piece back into the blade and cause it to launch. Just stop the sled once the cut is all the way through and wait for the blade to stop before moving anything.

Have I launched any pieces? No. Use common sense, and I think this is a very good, consistent way to make the cut, leaving a minimum of work to complete prep for glue-up.

Spring clamps work just fine if you have psa sandpaper on the clamping surface of the jig to keep things from slipping.

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http://www.chassonguitars.com

To each their own. If things don't go perfectly, the last thing I want is a large metal clamp 1/4" from my blade. I've made close to 200 necks using spring clamps to hold the blank in my scarf joint fixture. They work fine. If someone's using a poorly tuned saw, a wobbly blade, a poorly designed jig, or anything else that can cause a 5500 rpm mishap, all bets are off on any clamping system.

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http://www.chassonguitars.com

Also agreed that it's safest to let the small front piece be completely free: no clamp and no fence, like Filippo's jig. If there is a fence supporting the offcut but it is unclamped, it could get wedged as it's advanced, as Todd said.

Todd, your jig is slick -- my one concern is that an inexperienced person may clamp too close to the far end of the neck, which could cause the small piece to rotate into the blade after the cut. Perhaps include some guidance on how close is too close.

We use a TS jig similar to Filippo's; I think that style is safest but we do occasionally get a ~1/64" gap in a corner, probably due to the offcut shifting slightly as it's cut. Todd's jig probably trades some safety risk for better accuracy.

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David Malicky

Mine is very similar to Flippos, for my table saw. Two clamps on the rear, the front cut just sits there when free. I also use a Freud glue line rip great finish ready to glue, or super easy to fettle with a sharp block plane.

I made a jig for my table saw that works great and leaves a very clean, perpendicular cut.
The only thing I did out of the ordinary was to spend several hours tuning the blade angle and getting the rip fence parallel (lots of waste cuts).
However, setting the exposed blade as high as it would go was somewhat scary.
This is one of those cuts that requires thinking about everything that could go wrong before turning on the saw.
I use an all-purpose 60-tooth blade.
If I had a jointer or knew how to properly use a plane, I'd use my band saw.

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wah
Wah-wah-wah-wah
Wah

Completely agreed that unclamped in front is a problem if there is a fence there. To clarify, if there is no fence in front (like Filippo's jig and mine), the short end is like any other TS offcut... it just sits next to the blade as others have said.

Also to clarify (for the full-length fence), if the single front clamp is placed too near the end of the neck, the pic below shows the rotation that could occur just after the cut is completed. This rotation increases as the clamp is tightened more; this one is quite tight for the pic. Of course, Todd and most people wouldn't clamp this close, but it might be tempting with a short neck blank or for more blade-clamp clearance.

The full-length fence in reverse orientation is interesting: that may provide some support to the short end for more accuracy, yet it's probably as safe as the 'half-fence'.

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David Malicky

Thanks to all of you who took the time to comment on this. Lots of good info, especially the safety stuff. Can't get too much of that, nor look at that in too many different ways.

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Mike

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

That's similar to the way I've done it... though a freehand cut with a band saw to start then stack and hand plane to true the joint. A jig and table saw is not necessary.

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David Radlin
http://www.facebook.com/radlin.guitars