Double Bass Purfling, how far from edge can I go?

[keiranohara]

After a quick survey of the instruments in our shop everything seems to be purfled with between 7 and 10 millimeters from the finished Edge to the exterior of the purfling (examples of many different hand). That being said, how these margins flow into those large corners will make a great bit of difference. [Invalid or Expired Link Removed] does a funky corner to attack the very same issue. How far inboard would the purfling need to be to come to a point on your corners?

 

[bengreen]

Thanks Keiran.

I takes 15mm from the edge to meet at a point. If you look at the pic, there's examples of 10mm and 12mm. I have a pic of 15mm too but not posted.

It's really badly done but towards the top of the pic above, there's c-bout pointing opposite the others in white melamine. I toyed with putting flats on the corners to mimic the blocks. I poo-pooed it as kind of corny looking but after looking at the Hachez, maybe not. Only trouble it'll be like the corners themselves: I thought flats would be easier than violin corners but it ended up that there were 8 joints to make instead of 4! Silly me. But I'm not so afraid of it now that I've tried the pre-glue, fit and wet technique.

I'll try a practice piece immitating Hachez, and see if I can manage it. It actually would solve the problem completely. Think he'd mind?

 

[keiranohara]

I wouldnt do it exactly as he does. But something to fill the space between the two curves.

Another idea would be have the points of the corners meet using the 15mm margin, have the upper, middle of the c, and lower bouts following the 10mm margins. Using a french curve, blend those two curve together over the 20 to 60mm approach?

 

[Ortsom]

it's the white one in the pic at the bottom of the stack with the squared corners facing towards the back of the bench

Somehow I had completely failed to see that one originally, but I feel it is the most natural looking one, coherent with the style of the sideblocks, in providing a clear visual statement emphasising their style. I don't think that looks corny at all. And it would be the most effective one, and allows placing the purfling right above the ribs/linings. It may be a slight outstep from the original Lott design, but so are the corner blocks, and it is a natural consequence of that choice.

Crafty though it may be, I feel the Hachez solution to the issue is a bit forced & may give a needlessly pompous impression.

It is a subjective choice, I like simple lines, but my choices are not necessarily a good benchmark.

 

[bengreen]

Well, here's the lot. Any druthers? Problems I'm not seeing?

Thanks for all of your input.

 

[Ortsom]

The top one is stylistically my clear preference. But it's a subjective choice.

But maybe then also 8mm from the edge, like the bottom Hachez-inspired one (of which I don't like all the extra lines).
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Edited out my comment on bottom part wide (was rubbish, just angle), and fully agree with Chet: take what you like best, it will be great with any choice.

 

[1st Bass]

Well-- I'd vote for the center one, if you are polling. But it will be great regardless. Grab the one you like best and press on!

 

[keiranohara]

Here's an example of a narrow margin (7mm) fading into a point where the margin is more like 11mm

 

[bengreen]

Here's an example of a narrow margin (7mm) fading into a point where the margin is more like 11mm

Thanks Keiran. Looks like he just got out a straight edge and made a bee-line to the center of the corner. But moot now, because...

I made a considered, thoughtful, highly intellectual decision: I flipped a few coins and the flat corner won two out of three. And that's about where my head is too, two out of three, so I'm just going with it. And about 8mm in from the edge.

Have the proverbial two steps back to navigate first, though.

Made a really dumb choice previously about how to angle the edges above the break: I made them perpendicular to the back below the break rather than perpendicular to the plane of the break itself. Was so caught up in aesthetics, totally missed the fact that I'd need a beefy edge (rather than a ramp) to guide on later, whether using the router or a purfling marker. Dumb, dumb, dumb...and the irony being that it would have been a whole lot easier to do it the right way.

Marked it out last night, reducing the edge overhang from 5mm to 4mm to make it work (plans called for 3mm anyway). Heading to workshop now and if it doesn't look glaringly wrong with fresh eyes, I'll get the new edging done today and purfling tomorrow.

Thanks again, Chet and Ortsom.

 

[Ortsom]

perpendicular to the back below the break rather than perpendicular to the plane of the break itself

Interestingly, I remember having made a very similar thinking error... Mine had a 10° break, so it amounts to a maximum error of a little over 1mm near the button/block, which I managed to cover effectively with the mantle of love.

 

[1st Bass]

Good learning experience, Ben, and the finished product will look great regardless. Blessings upon you as you head for Oberlin. Have a great time.

 

[bengreen]

For better or worse...

had to establish sequence due to use of vertical scarf joints



purfling drying after being preglued



and done.

Lesson learned: miters which look tight while purfling is proud of the surface ain't necessarily so when planed down to the surface.

Lesson relearned: everything in woodworking takes at least three times longer than you planned for.

Which brings us to the flip side and the next thread...crossbars!

PS Thanks everyone for your help and encouragement.

 

[Ortsom]

Thank you Ben for showing us your excellent work & most interesting project!