Violin Forum/Message Board

mikebee · Junior Member Joined: 03 Mar 2011 Posts: 13 Location: UK

As an amateur maker (but not a particularly experienced one!) I find
that the hollowing out of hardwood backplates can be rather hard-going
at times, particularly for the larger instruments. At the moment I simply use a couple of gouges. Can anyone recommend any kind of power tool that can do the rough cutting out? Do professionals use anything of this sort?

Canuck · Member Joined: 15 Oct 2012 Posts: 29

A friend of mine who calls himself a "luthier" used to use a jig system with a router and an assortment of carbide blades to shape the top and back of the instruments he has built. I have played some of these "industrial strength" instruments, and I wouldn't give you my space in Hades (if you know what i mean) for a boat load of them! His instruments are lovely to look at, but the sound is dead, and they tend to be very heavy! I understand that he is now using more traditional means of forming the top and back. But I don't think I have had the chance to try one of these more recent instruments. I am certain most serious luthiers will tell you that there is no way to rush an instrument, and to meet with success.

polkat · Member Joined: 16 Aug 2012 Posts: 32

Whatever tools you use, sharpness is of primary importance. One technique I found to be particularly good for amateurs. You set up a drill press with a depth stop (can be a simple piece of tape on the drill bit) to bore into the plate on the inside surface to just before the specific graduation depths you want, and then drill these depths all over the inside surface. This makes chiseling and planing away the remaining wood considerable less difficult. Be careful with the depths. You don't,want to drill completely through the plate of course!

You should be able to Google search this process. Here's one example........
http://osnesviolins.com/8.Graduating%20the%20Plates.htm

Michael Darnton · Posted: Thu Nov 01, 2012 6:33 pm Post subject:

http://vimeo.com/13184455
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polkat · Member Joined: 16 Aug 2012 Posts: 32

Pretty cool Michael! Didn't know about that one. What kind of cutting head do you think that is?

Cliff Green · Posted: Thu Nov 01, 2012 8:38 pm Post subject:

That machine looks like an all expense unpaid trip to the ER to me.

polkat · Member Joined: 16 Aug 2012 Posts: 32

Doesn't look too unsafe to me. The cutting wheel is throwing the dust away from him, and I'm sure he watches his fingers (which all appear to still be there). And he's wearing my favorite mini-safety glasses Smile

Definately looks homemade and not too difficult to make. Looks like he carves the top arch in the standard manner first.

I'm just wondering what cutting wheel that is!?

johngia · Member Joined: 10 Nov 2009 Posts: 84

Mikebee,

First: Disclaimer: I am a self taught amateur. I do things in my shop that are unorthodox --- and I am sure controversial. I do not recommend any of my unique procedures.

But to answer your question: My hands ain't what they used to be, and roughing out maple is hard on them. Here's what I did on the last several backs --- both outside and inside surfaces. I used an angle grinder with one of those circular chain saw cutters. King Arthur Tools Lancelot 22 Tooth Part No. 45822 (http://katools.com/carving-tools/lancelot-and-squire-cutters/ )

I left enough material to finish roughing with gouge and plane.

Hand guided. By eye. Very dangerous. Potential for cutting too much wood --- and fingers. I am NOT recommending you do this. But you asked, and that's what I've done.

Been thinking about a duplicating pantograph router set up. I read where some makers have used those. Just for roughing. Still hand final shaped and tuned.

I know. I know. I'm sacrilegious. Shields up. Smile

Michael Darnton · Posted: Thu Nov 01, 2012 9:12 pm Post subject:

A friend of mine contacted the guy in the video. He said it's not really all that unpredictable, but also didn't want to be the one to recommend it to anyone. The cutter is something he and someone else made, themselves.

It sure looks cool, though, and I like the sound it makes.

I have a lancelot. I like it for the outside, but I've never used it for the inside. It is certainly effective. . . too effective if you're the type that doesn't pay attention. It would go right through a back like butter.
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polkat · Member Joined: 16 Aug 2012 Posts: 32

Michael said: >>" He said it's not really all that unpredictable, but also didn't want to be the one to recommend it to anyone."

Well that's certainly understandable, and I don't blame him for saying that. Safety should always be first. But I've always thought that people who don't pay sharp attention to what they are doing shouldn't be working with power tools to begin with, particularly sharp ones.

I thought it looked handmade, and I agree it certainly is way cool! Also looks like a big time saver once one learns it's nuances.

Chet Bishop · Posted: Fri Nov 02, 2012 1:21 am Post subject: lancelot tool

The lancelot tool is wickedly effective, and very dangerous. I have used it for removing large, heavy amounts of hard maple, to good effect. I find it very stressful to use, and don't much like it, but, as johngia said, my hands aren't what they used to be, and I don't expect they will last very long if I insist on doing everything with hand tools. I have also used my 4.5" angle-grinder with a flap-sander disc on it, to good efffect. I use a bandsaw to cut out the plates and ribs. I use an oscillating spindle sander to get the final shape on the corner blocks. How the excess wood came off has very little to do with the final quality of the instrument.

I do all the final work with Ibex planes, gouges and scrapers.

My instruments tend to be quite light, and have good tone. Don't be afraid to use power tools. There is a reason they were invented--in general, with careful use, they do a better job, faster, than one can do by hand. (yes, I am aware that there are exceptions...not going there.) There are also drawbacks to power tools-- your call.
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Cliff Green · Posted: Fri Nov 02, 2012 8:40 am Post subject:

I guess I shouldn't have made such a glib statement, but that tool still has a lot of danger potential. The speed of wood removal is very aggressive so the teeth must be widely spaced and there is not even a remedial guard. My wife is an OR nurse and frequently sits in on hand and arm injuries from woodworking, especially table and chain saw injuries. Not pretty. I've been using all of those sharp spinning things for over 40 years and despite using strict attention and as much safety equipment as is reasonable I consider myself lucky not to have had a severe accident. They happen fast and well, accidentally.

I've never used a lancelot but I have used structured carbide wheels on a grinder for cellos. I've found that a good scrub plane works pretty fast and a lot safer on convex surfaces. For hollowing I set up a 3/4"plywood surface on a drill press table with a 1/2" dowel mounted under the quill. The dowel has a leather pad. I use a 3/4" forstner bit to run close parallel lines the length of the plate and gouge out the remaining wood. My drill press has a very stable stop system on the quill and I always leave a couple of mm excess wood over the finished depth. For final graduation I switch to a 1/2" bullet shaped carbide bur on the drill press. This leaves easy to read dimples for the planing and scraping to finish. For setting the depth of cut I have a graduated wedge by Veritas but previously used stacked feeler gauges.

johngia · Member Joined: 10 Nov 2009 Posts: 84

I was wrong --- I guess I am not sacrilegious and unique as I thought. You guys have used the same or similar techniques.

On using power tools: I say a little prayer every time I start a power tool. Especially my table saw. Saw my Dad almost cut his fingers off when I was a kid. The fence kept his hand from going completely into the blade. Only cut the skin down to the bone.

Michael Darnton · Posted: Fri Nov 02, 2012 2:37 pm Post subject:

Cliff Green · Posted: Fri Nov 02, 2012 4:31 pm Post subject:

The structured carbide disks I used looked like small bits of carbide fused to a shaped metal disk. They came in a couple of grit grades. The coarse ones moved wood pretty fast and sent sawdust everywhere. I imagine the finer grits could clog easily especially on gummy wood but I didn't have any problem with coarse in maple. I only used them on a couple of cello backs before deciding that a better method was due.