Tacoma guitars with no binding

[Dave Bagwill]

Rob - so, even on soft soundboard edges, this would be a safe tool - by 'safe' of course, I mean extremely unlikely to pull a chip out of the top? If so, then I can try both this and the hand-sanding methods just to see which works best with my 'skill-set'. The tool is not that expensive, I noticed.

[Robert Hosmer]

Rob - so, even on soft soundboard edges, this would be a safe tool - by 'safe' of course, I mean extremely unlikely to pull a chip out of the top?

Best results are gonna be obtained with:
1. Sharp edge
2. Technique suitable to the application.

1. For most of my edged woodworking tools, I use the "paper test" to check the edge. Clean slice- ready to go. Snag/tear means more work is needed on the edge before taking it to the wood.
Follow their sharpening instructions to the letter, and you should be OK. The tool should come well-ground, but you definitely want to do a honing before first use. I mentioned use of progressively higher grit on the sandpaper, but maybe the recommended 600 followed by a stropping is OK.
Your first few honings should be needed on the back side only. After several honings on that side, you're gonna get a burr on the opposite side that needs removed. That's where it's important to follow the instructions so you don't alter the cut angle (the "grind").
Don't let the sharpening process scare you; it only takes me a minute or so. It's not like a plane blade where you have to set up in a jig, etc.

2. Technique for this would be same considerations for any edged tool- follow the grain.
On a guitar shape, start at widest part of the bout and work to the narrowest part of the waist, then stop and come back in from the other bout.
Once you have the bout-to-waist areas done, cut apex of the bout to the end (stop at centerline).
A technique that would help with the endgrain (besides obvious need for sharp blade) would be a "double pass". You have built-in "fences" on each side of the blade that limit the cut depth; when these are in contact with the wood, they serve as a backer that helps prevent tearout. So a "trick" that may help alleviate any concerns of chipout is to favor the angle on the side of the tool that contacts the soundboard for the initial pass, then come back for a second "straight" pass (45 degree angle to the soundboard). The shavings on that first pass should be very thin and narrow; if you did it correctly the shavings on the second pass will be about equal in size to the first.
By the way, the double pass trick is nothing more than reducing the radius of the cut. If you have the choice of different radiuses, always start with the smallest radius. For this tool, that would be 1/16". Maybe you'll be happy with 1/16" and leave it at that. But if you want 1/8", do the smaller one first. Immediately starting with the 1/8" means a deeper cut, which means more pressure, which means the increased chance of "boo-boos".

I understand your concern about tearout/chipout. I get the same fear when taking off binding tape.
I haven't used this tool on spruce for this particular application, but I have used it on balsa templates with complex curves. Balsa is very soft, open-pored, with a somewhat coarse texture. Any dullness at all in the cutting edge will cause it (the balsa) to be "fuzzy", which is a form of the tearout you mention.
I got a couple of scrap pieces of spruce in the shop; tomorrow afternoon I'll cut some curves in 'em and try things out.
Will let you know how it goes.

As a final note, don't let my long**s post scare you into thinking use of this tool is some unattainable master form of woodworking; once you understand how it works it is much quicker (and cleaner) than sanding.


Rob

[Robert Hosmer]

Dave,

Went ahead and cut some Sitka spruce scrap this morning and tried it out. Also tried it on some WRC just for good measure. The pieces were cut in circles (because I already had the saw set up with the circle jig), so that should be a decent test (3 pieces spruce, 2 pieces cedar).

Everything went fine except for one hiccup- the very first piece I was cutting did get a piece lifting up from the surface. Then I took another gulp of my morning coffee, woke up, and saw the light- I wasn't cutting with the grain! Silly me...

Use light pressure on the cedar; when it cut down to where the fences were making contact with the wood, the fence that rides on the top surface was marking the top due to my hamhanded pressure. It took a fair amount of thinning (sanding) to remove the mark. Considering the softness of WRC, I wasn't surprised.
On the second piece of cedar, I tested the blade on paper before taking it to wood. It cut cleanly, but I went ahead and stropped it anyways. I used lighter down pressure this time and just let the blade do its thing, and had no problems.
No problems with the spruce.

Lots of folks seal the top (shellac, etc.) before cutting, and I do that before routing for binding. I didn't get a chance to do that this morning.

Hope it helps.
Rob

[Dave Bagwill]

Thanks, Rob - there is nothing quite as satisfying as just a good old fashioned test, is there? I appreciate that - for $30 or so I think the tools would be a safe investment, then I can line up some sandpaper and the tools and some scrap topwood and see what I can do.

Before I started this thread I emailed a gent in Australia who really has excellent 'seamless' and binding-less joints between the tops and sides, and he does use jigs and a router, but cautioned me that his is a production shop and the time spent jig-building may not be worthwhile for the uh....individual craftsman :-) .

Thanks to all for the input. When it is done right, that seamless look really enhances the minimalist look I'm planning towards.

[Dave Bagwill]

A pic of what got me started on the whole 'seamless' look.

[Tim Benware]

Dave, I'm not sure how your seams match on your glues up but I think that is more important than the rounding (or how you do it) of the top and back. Here's a pic of what I do to be sure there is a gapless seam around the entire top and back. And since this shot I've added 6 more cam clamps to fill spots and make reaching around the mold easier. I know some will be HORRIFIED at the number I use. But that's OK - no gaps. (Sorry for the edits)

[Dave Bagwill]

Tim - 'no gaps' being the task at hand, your method is logical and works, what more can a fella ask for?
What IS horrifying is finding gaps after the glue-up. :-(