Cutting a scroll binding channel

[Whittle]

For those of you that build F-style mandolin family instruments, what do you use to cut out the binding channel around the scroll. I know that Roger Siminoff makes a Dremel attachment that can get around part of the scroll, but the rest needs to be done by hand.

Doing a little research online and in my books, it looks like the preferred method is to use gouges and chisels to cut the main channel before cleaning it up with micro files.

Would these chisels be appropriate?

What radius of gouge would be best for working around the scroll, or are the micro chisels plenty? Are there other tools you use to do the job?

If you don't mind sharing, what methods do you use to give you the most efficient and reproducible results? How would you describe the process to a beginner? Thank you!

[sunburst]

How would you describe the process to a beginner? Thank you!

Be patient, use whatever tools work for you, take your time, walk away before you get frustrated and come back later, cut the channel as accurately as possible because plastic binding will conform to the shape of the slot, so sloppy work cannot be hidden by the binding. Cut the whole slot to partial depth and continue to deepen the whole thing as you go. If you start in one place and cut to full depth and work your way along, it is very easy to damage the part you've carved while working on the rest.

I've used the Stewmac micro chisels in your link for various things (though not for scroll binding, and I don't own the set), and they would be handy for part of the work, but they wouldn't be my preferred tools for the job. I use pocket knives, small carving chisels, violin purfling cutters (one re-ground specifically for scroll binding), small files, sections of spindle sander sleeves, in-channel gouges, and basically anything I can get my hands on that will do the job. The little Stewmac chisels could be re-ground for scroll binding work. I don't use power tools to cut mandolin binding slots on assembled mandolins.

[David Houchens]

John, just wanting to clarify "the depth". Say the binding is 3/16 x .110, when you say cut the "whole slot to partial depth", are you saying cut the whole 3/16 to part of the .110, or the whole .110 to part of the 3/16? I know it could be done either way but I'm looking to get better results and was wondering which way you prefer.

[fscotte]

Bind the overlay before it's glued to the headstock.

[Whittle]

Thanks John! Here's a couple of videos I found last night that were helpful. Is this how you all do it? How do you accurately mark the width and depth of the binding channel, if at all?

What gouges do you recommend to get the job done?

[sunburst]

John, just wanting to clarify "the depth". Say the binding is 3/16 x .110, when you say cut the "whole slot to partial depth", are you saying cut the whole 3/16 to part of the .110, or the whole .110 to part of the 3/16? I know it could be done either way but I'm looking to get better results and was wondering which way you prefer.

I use 3/16" by .060" body bindings, so my ultimate goal is a slot that size. I sneak up on both measurements. So my first cut will be something like 1/8" (in the 3/16" direction) and around .030" (in the .060" direction). Then I can just keep shaving away wood with light cuts until the slot is done.

[sunburst]

Thanks John! Here's a couple of videos I found last night that were helpful. Is this how you all do it? How do you accurately mark the width and depth of the binding channel, if at all?

What gouges do you recommend to get the job done?

I do mark the curve of the binding slot around the scroll (top or back view), but I mostly just eyeball the line of the side binding (side view). I cut the slot and bind the scroll before it is fully carved, so the binding determines the final carving.

I can't really recommend any particular gouges. The main ones I use for scroll binding are in-channel gouges. One, I bought used somewhere, and the other is one that I re-ground from a standard gouge. The sweep is very close to the curve that I need. I think I posted a picture in a thread long ago. I'll see if I can find it and post it again...

[sunburst]

Found it.

[Jim Hilburn]

I used a "Siminoff" Dremel attachment early on and it will work but because of lack of precision of most Dremels it left a ragged cut so it could be used but not to try to get a clean bottom cut. Also that was before such nice carbide cutters were available. You also had to be very steady to keep it square.
Here are the tools I use now. The traditional purling cutter for the top cut and the one I make for the side cut. If you get those cuts cleanly then cleaning up the wood between is fairly easy.

[Whittle]

Here are the tools I use now.

Thanks! What method do you use for cutting around the scroll, Jim?

Thank you for the picture of the gouge and the advice, John. Looks like I need to do some more hunting.

[Jim Hilburn]

The gouge thing. Flex Cuts are nice. I wish I could throw out the old ones when they get dull and get new ones. They come crazy sharp.
The Stew Mac McRostie video is good for this.

[David Houchens]

I think that my biggest problem has been patience. I us in-channel and out-channel gouges as well around inside the scroll and around the button. Also having these very, very sharp is key. I've handled some of John's edged tools in the past, and he definitely has that skill down pat.
Jim, that perfling cutter is like the one I use. I think I got mine from International Violin. I bought two and have the cutters in each direction so I can swap and cut with the grain runout. I rounded the points on the blades a little too. seems to do better for me. Think I got that tip from John.
I look at Andrew Mowry's binding channels as my ultimate goal. Have not gotten there yet. Ward Elliott was also able to get some very neat, smooth channels. Sharp tools, go slow. I tell myself over and over........

[oldwave maker]

Still on the bench from last weeks bindery, whatever you do, do not watch a Tom Ellis powerpoint on his giant scroll-carving robot, or you may move on to cutting boards and jewelry boxes...........

[Jim Hilburn]

Bill, you could get some new tools. You don't have to use those old worn out ones.

[Jim Hilburn]

Saw some nice ones at Home Depot the other day. Nice plastic handles.

[Jim Hilburn]

Got this set on Ebay long ago. Wasn't Buck or some other name brand so no one else bid on them.

[craigw]

I don't have any in action shots but here is the scroll cutting pin router jig set up that I made for F-5s. The template is shaped with scroll opening and rabbited inset to accommodate the binding channel. The rabbit is cut into both sides of the template/jig so both top and back plates can be accommodated. Bolts with speed handles act as clamps on four locations to clamp the plates down and the bolt holes are recessed on both sides so the template/jig will slide easily on the pin router deck without bolt interference. Prior to gluing either of the plates on, the scroll openings and binding channels are cut in a one step-two part operation. The pin is in a raised position to ride on the thicker part of the template for the total scroll opening and then lowered to the inset (rabbit) position to cut most of the binding channel. I have to do it in several successive cuts, lowering the cutter position each time to get the proper slope and then go back with mini chisels to smooth the slope. The tip of the scroll has to be done traditionally with gouges and chisels but the heavy lifting has already been done. The present jig I have is made from Corian which is quite heavy. At some point I expect to remake one out of a lighter material.

[Whittle]

Thanks for the advice everyone. It's nice to have all of this insight in one place.

Would this set be a good place to start? I have a decent carving knife, just no gouges or high quality chisels.

[Pribar]

Thanks for the advice everyone. It's nice to have all of this insight in one place.

Would this set be a good place to start? I have a decent carving knife, just no gouges or high quality chisels.

Never been a fan of swappable blades myself, check out Narex (a Czech company) they make very good quality chisels and gouges for a beginner budget, you can pick up a nice set of Narex chisels for well under 100 bucks

[fscotte]

Save wear and tear on your underwear next time and do this:

http://millermandolins.com/Construction/Con7.htm

[Whittle]

Save wear and tear on your underwear next time and do this:

http://millermandolins.com/Construction/Con7.htm

Thanks, but I'm talking about the body scroll. I'll definitely look at this for the peghead overlay though!

[Pete Jenner]

Just use your CNC machine like everyone else.

[Whittle]

Just use your CNC machine like everyone else.

Haha. Let me just take out a loan first.

[Bluetickhound]

Late to the game I know but Andrew Mowry did a fantastic article on the subject some time ago. I think it's in the spring 2013 issue of American Luthierie.

[Cush]

I made a holding fixture for my mini mill. Now I just clamp the mando in the mill and cut the channel. It is like a 3D etch a sketch. It takes a while but the result is a square cut channel. These little mills from China are real handy for all kinds of cuts. They do a great job cutting a very accurate truss rod pocket. One of my most favored power tools!