Official Luthiers Forum!

Hi,

I'm getty ready to rout my binding ledge and I was wondering how everybody else does it to avoid chipout.

I know that you want to climb cut as much as possible, but I know there are places where the bit edge is still coming into endgrain, increasing the chance of chipout.

Can I just start, say, at the neck block and just go all the way around in one pass or does it work better to go in sections. I'm planning on shellacing the edge before routing

Also I'll be mitering the purfling at the butt wedge, so I guess I'll have to stop there too?

I'm using a 1/4" carbide downspiral bit mounted in a modified router table. Similar to David Russell Youngs setup in his book. So, I'll be moving the guitar and not the router.

T.I.A.

Kirt

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Horton, MI

Start your cut at the widest part of the bouts and work your way inward. Here's my method:
Widest part of upper bout to neck area
Widest part of upper bout to waist
Widest part of lower bout to waist
Widest part of lower bout to tail
Repeat for other side.

Thanks Paul, that's about what I was thinking.

Since this is my first try with this setup, I'll probably go a little shallow on the first pass and see how things go and then go full depth.

Kirt

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Horton, MI

Thanks Hesh,

I remember seeing that now... sounds like the way to go. Go a little shallow with the fancy cuts, then clean up with on long cut.

Cheers,
Kirt

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Horton, MI

That's ONE long cut.

Bye

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Horton, MI

I've got that Stewmac diagram taped to my williams jig as a reminder. I go full depth on all passes (no mid-operation adjustments to screw up) but I heard a tip that seems to work great - cut as per diagram, THEN clean up the "furr" with sandpaper & make another complete "second pass" (NO adjustments). Yields a clean & nicely machined channel.

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Dave
Milton, ON

I do it like Paul, then make the final pass around the whole perimeter as in the Stewmac sketch.

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Rian Gitar og Mandolin

Thanks Much!

I think I have the courage to try it now.   

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Horton, MI

In reality, the directions shown are only beneficial when doing the purfling ledge - as then you are truly routing into changing grain directions of the back and top - if you are doing the binding, you are routing flat grain (assuming quartered sides) because you are only routing the ledge into the sides, not the top or back (or very little of either, as most of us use binding the same or less than the thickness of the sides) That said, I use a climb cut all the way around, and if need be, route the other way to clean up. If the bit is sharp, the ledge will be clean. I use a new bit every 20 guitars or so ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I should have said that it can matter if you are NOT doing a purfling ledge, as you are routing thru top and back changing grain directions, but I find that climb cutting doesnt tear out anyway - its when you are going upwards into end grain and NOT climb cutting that tearout can be an issue - ie, from the waist towards the top of the lower bout, on the top itself.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Thanks Tony.

I love this place.

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Horton, MI

Kirt-
Tear-out is somewhat less likely when using a spiral bit (like Tony Karol), than when using a straight-flute bit with a bearing (like Hesh).
I just climb cut all the way around, and it usually works OK- using a spiral bit. Even if you have the guide set 'full depth' you can sometimes take shallower cuts, depending on your jig setup. That can help as well.

Cheers
John

Thanks John,

I actually gave it a try last night. But I only went about 3/4 depth. Made a nice clean cut no matter where I started. I did climb cut, but it didn't seem to matter which way I came into the end grain.    

Now I just need to practice a little more to get the coordination down.

Kirt

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Horton, MI

I cut the purfling ledge as per Paul's instructions--all cuts from wide toward the center . There isn't any benefit to climb cutting if you are cutting downhill (with the grain) on a standard cut, and you don't get the potential chatter of a climb cut (although it's such a light cut it may not matter). Then climb cut all the way around for the binding, returning the router the other way to make sure it's clean.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard-
How (bit and direction) do you cut your rosette grooves?
They usually give me more trouble than the purfling ledges.
Thanks

John

I cut my rosettes clockwise, but I think more important again is a sharp bit, again I use a downcut spiral, various sizes - I also french polish the area lightly to stiffen up the fibres prior to cutting the channel(s)

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"