Official Luthiers Forum!

I have read many references to cutting binding/purfling channels/rabbetts by hand using either the Gramil or Sloane type cutters and a chisel. However, I've yet to read/see a detailed procedure of how to actually set up and use those tools. Looks simple enough, and I bought a Sloane type cutter that has two adjustable blades. But now the questions start. How do I adjust the blades? One blade, or two? How to set the depth? Do I cut just on the top, or the side as well? How and when do I use a chisel?
I'd appreciate any comments, directions, or links to instruction, a tutorial would be nice if one exists.
I bought a bunch of cheap/junk spruce tops to use for practice, and have a pile of cedar cigar boxes that are handy for sacrifice too.

Crowduck

_________________
Chris Nielsen
Soquel, CA.

I'd like to add a question to those who've done this successfully...how do you get a consistent and level cut along the sides? Obviously, the Gramil or purfling cutter can't be flipped and used on the sides, 'cause then it would have to register on the domed plates.

This is a picture of binding channel cutters based on what Romanillos uses. The one on the left is for cutting the channel on the sides and the one on the right is for cutting the channel on the top and back. These cutters you can easily make yourself. All you need is a marking knife blade and some scrap wood.
You will notice that the cutter for cutting the sides works like a scraper to score the side. Notice that the arm is not at a 90 degree angle to the blade. This compensates for the radius of the top and back.

Thanks, Robbie! Very interesting. I hadn't thought of using a scraping action on the sides...less chance of wandering.

I have a little marking gauge for that sort of thing. It locates on a very small area, so the tilt or dome of the top or back don't matter.

The double knife cutters are for violin purfling: you'd use a single knife for marking for guitar binding.

I don't actually cut the rabbets with the marking tool; it just scribes a line for me to cut to. I often use a finger plane to remove about half of the material for the rabbet, and do the rest wityh chisels and files. I takes a couple of days to do a guitar, and I need to keep the tools really sharp, but it's possible to do an accurate job.

[QUOTE=crowduck] I have read many references to cutting binding/purfling channels/rabbetts by hand using either the Gramil or Sloane type cutters and a chisel. However, I've yet to read/see a detailed procedure of how to actually set up and use those tools. Looks simple enough, and I bought a Sloane type cutter that has two adjustable blades. But now the questions start. How do I adjust the blades? One blade, or two? How to set the depth? Do I cut just on the top, or the side as well? How and when do I use a chisel?
[/QUOTE]
Chris,

I'm hoping some additional people will join in here, but here's what I know.

As Alan mentioned, just use one blade with the Sloane cutter. To set the depth it might be a good idea to just make a dry run around a guitar (without the blade), and see where the tool meets the top or back. Measure from that point to the tip of your blade, and that's how deep it will cut. As you've probably noted, there are set screws that allow you to adjust the depth and width of the cut. For the width, just measure from the part that registers against the side to the tip of the blade (BTW, you'll want to have a piece of your binding and purfling glued together, so you can check the width and depth of your cut, both initially and as you progress with the chisel).

Make sure the flat (back) side of the blade is against the side of the cut that will remain after the waste is removed. As a reminder, the Sloane tool will only cut in one direction. The Schneider gramil will cut both ways, due to its blade's marking-knife-like double bevel.

Also, don't try to make a full-depth cut with your blade. Use small increments only. The blade will drag and want to wander, otherwise. And, as Alan stated, many people only use the cutter to score a shallow mark, and do the rest with the chisel (and/or planes, scrapers and files).

I know this doesn't cover everything, but I hope it's of some help. Good luck!

CarltonM38955.7331944444

I use the sloane type cutter with just the one blade, as decribed, and then clean the channel with a chisel, it takes not much longer than using a laminate trimmer. Though nowadays I generally use the sloane cutter then the laminate trimmer with a downcut bit. But I always mark the channel with the gramil however I'm going to cut it.

I always build my lutes without using power tools and have built a couple of guitars that way as well, it's very satifying.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Thank you all! The concept is a bit clearer to me now.

After looking at the pics and description of the Gramil at LMI it appears to me that it is intended as a scoring/marking device, and not a tool to cut a channel to full depth. It Does look like it could be used to score the sides, indexing off the top/back, as it appears that the cutting arm is located 'offset' in the black anodized body, so that by rotating the cutting blade towards the 'short end' of the body it could then index of the top/back.

The Sloane type cutter appears to be OK for cutting a channel to depth on top/back, but sides are a problem due to indexing.

My conclusion is that this hand operation will take a Lot of practice to master without some expert supervision or obervation, or a good tape/DVD demo.

Costwise, there's not that much to gain since a Gramil is around $45, a Sloane type is about $35, and I conclude that I would need both tools to accomplish the task, plus a good proper size chisel.

I think I will use the method that seems most popular to first score the top/back with the Sloane, and route to depth with a laminate trimmer. I have read several recommendations for the LMI bearing sets.

I would really like to learn this 'hand operation', but it seems even scarier than using power tools.

CrowDuck
Chris Nielsen

_________________
Chris Nielsen
Soquel, CA.

Right Chris .. it is a great thing to know how to do. SOmetimes, there is no other way to get into some areas, like my jig wont do really tight cutaways, liek the one I made between two necks of a doubleneck, so I had to get out the purf cutter adn go at it. took a bit of time, but works well.

The difference between routing and hand cutting, for me anyway, is tearout vs eveness of the ledge. Takes practice on both counts. Note the words of wisdom in my signature below !!!!

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