New rough carving technique

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New rough carving technique

Postby Brian Evans » Thu Nov 23, 2017 12:53 pm

I am thinking about a new rough carving technique for my next set of plates - I'm building two archtops this winter, so looking to ease the pain of carving extremely figured maple (my hands are cramping up just thinking of it). I usually do the "drill a ton of holes with a depth stop and hack out the waste" technique, but I have to be wary of the extremely figured birds-eye maple I have for one back. I've seen where people use a router to route out waste using contour lines as a guide, but I hate routers in the first place, and really really hate free-hand routing with them. So I thought of a compromise. I think I might make a set of nested templates corresponding to my contour lines, clamp them on the plate and use them to route to. I usually do three depths on a 1" thick plate - 3/4" for the edge, then 1/2" then 1/4", leaving the big middle bit at full thickness. If I can figure out a way to fasten the templates on without harming the plate, I may do this and see how it works.
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Re: New rough carving technique

Postby Simon Magennis » Thu Nov 23, 2017 6:14 pm

Have you looked into the Australian "manly" method of carving violin backs. Should work even better on an arch top. :-)

https://www.youtube.com/watch?v=X2n1W5THyGQ
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Re: New rough carving technique

Postby Jim McConkey » Thu Nov 23, 2017 11:54 pm

I think using a router on highly figured wood is even more risky than drilling, albeit much faster. One improvement I can suggest is to use a fat milling bit (which drills flat, instead of a pointed divot. I use a 10 mm). You can really minimize the hacking. The only drawback is you need a drill press with a deep throat for an archtop. You can see my plate carving for my Birthday Contest mandolins here: viewtopic.php?f=65&t=5146&start=20
After all the drilling, it wasn't 10 or 15 minutes before the insides were basically smooth.

If you do the templates, 1/4" per step seems like a lot. I think I would do more like 1/8". Build yourself a flat stand with either a cutout for the plate shape or blocks to hold the plate in place, with higher blocks at the corners to support your templates. That will keep the body at a fixed position under the templates.
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Re: New rough carving technique

Postby Barry Daniels » Fri Nov 24, 2017 1:37 pm

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Re: New rough carving technique

Postby Alan Carruth » Fri Nov 24, 2017 2:22 pm

I've been roughing archings with a drill press planer all along. It's basically an end mill, with a cut about 2" wide. I draw up a contour map in 2mm steps, and cut out areas of it to allow me to use it as a master to trace onto the plates. Once the bottom side is flat the top is taken down to the maximum height, and the first contour outside of that traced out. The planer is lowered to the correct height plus, say, a half mm, and everything outside of the line is removed. Replace the map, trace out the next contour. Lather, rinse, repeat. I usually leave the edge flat at the 5mm level until the outline is finalized. It takes a couple of hours to get the contours all milled off: I've removed about 90% of the waste. If you're careful, and always leave the line, its not too hard to get the final contours right with arch planes and scrapers.

Note that the one I've got is a Wagner 'Safety Planer', which is not made any more. Using the word 'safety' in referring to any power tool is a stretch. I've been bitten a couple of times (in over forty years of use), but never when I've been roughing arches. OTOH, I had a student who couldn't seem to avoid it. I usually use it to thickness sides, which is relatively safe, since the cutter is down close to the deck, and the lip that overhangs the cutters offers some protection. When roughing contours the cutter is up off the table far enough to get your hand under, and that's scary. Which may be why I've never been bitten doing this (knock wood). You do have to be very aware of where the outside edge of the tool is, and not lose sight of that in concentrating on the cut line. Other than that, my main safety tip is to always keep your fingers pointing away from the tool. You can set your hand right in top of it when it's running with no problems, but no matter how low it is you can get a finger tip in underneath. That smarts.
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Re: New rough carving technique

Postby Beate Ritzert » Sat Nov 25, 2017 7:42 pm

Some people use tools like this

Image

or this:

http://kaindl-woodcarver.de/index.htm?english?einsatz

Here in use by a German luthier - after 1:30 min:
https://www.youtube.com/watch?list=UULV ... BON_YaFyug

Unfortunately i cannot use something like this because the protection of my small grinder is not adjustable. I wish i had it available when i carved the top of my SIX which is highly figured pear...

EDIT: please let me complete this: there is also the Turboplane by Arbortech:

https://www.youtube.com/watch?v=YI6MHTkxv64
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Re: New rough carving technique

Postby Gordon Bellerose » Sat Nov 25, 2017 10:01 pm

I need your help. I can't possibly make all the mistakes myself!
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Re: New rough carving technique

Postby Brian Evans » Mon Nov 27, 2017 3:03 pm

So my decision was to draw out my stair-steps in 1/8th inch increments and use my router free-hand up to each line. Scary but worked fine in the end. My rough carve of an outside back in hardwood would normally take me around 10 - 12 hours with drill press, chisels and routers to get to where I am now. This method took around an hour of routing and 10 minutes with a flap-wheel sanding disc in my angle grinder, so around a 600% reduction in time and a better result. The wood is quilted maple. I still hate routers, though.
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Re: New rough carving technique

Postby Christ Kacoyannakis » Mon Nov 27, 2017 11:00 pm

I basically did the same thing, but with a Wagner Safety Planner, as people have described above. What I did was figure out the absolute highest the arch was at several distances from the edge all around the guitar. So, if the arch at 2 inches in from the edge ranged from 3/16 to 5/16, I set the Wagner to 5/16. I then put a dowel in the drill press table 2 inches from the front edge and just ran the back around to crate a step of 5/16 high at 2 inches all around the edge. Then I used an angle grinder with a Sir Lancelot chain saw ring blade in it to smooth out the curve of the arch. The angle grinder is scary at first, but once you figure out how to use it (somebody described it as petting a Doberman), it actually seems pretty easy to use. After that I used normal curved bottom planes to finish shaping and checking with my arch templates. For the inside, instead of the Wagner, I used the drill press and drill then shaping with the Sir Lancelot in the angle grinder.
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Re: New rough carving technique

Postby Randolph Rhett » Wed Nov 29, 2017 1:24 pm

I have had a hard time with the Wagner un-"Safety Planer" on deep cuts. Always seems to want to "pinch" if I am more than 50% of the cutter head into wood). I find drilling for depth and using one of these in an angle grinder turned the task into an afternoon affair rather than a three or four day ordeal:

http://a.co/8OY2kFy
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Re: New rough carving technique

Postby Christ Kacoyannakis » Wed Nov 29, 2017 1:37 pm

it's always safer and easier to do several shallow cuts with any tool than one big deep cut. I found that if I tried to cut too deep a cut with the Wagner, it would bog down and get stuck (I have a benchtop drill press). So the solution is to take shallower cuts. This keeps the cutter running fast and it is easy enough to run it around the perimeter, check the depth, lower the cutter and repeat.
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Re: New rough carving technique

Postby Randolph Rhett » Thu Nov 30, 2017 2:57 pm

I mean "deep" horizontally. Where the cutter wheel engages only a ledge on the wood I've had no problem. However, when the whole cutter is into the face of the wood I've had problems. I know that is related to how well my drill press table is coplanar to the cutter, but within the usual tolerances of a small benchtop drill press I have not been able to reach the required accuracy.
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Re: New rough carving technique

Postby Christ Kacoyannakis » Thu Nov 30, 2017 8:56 pm

I also have a small benchtop drill press, a Porter Cable. I have used it for very wide cuts, especially thicknessing the back of guitar neck blanks to add a taper. In those circumstances, the entire tool is over the wood. I have not really had any problem, as long as the tool speed is high enough. If it is too low speed, it does get stuck. Maybe I got lucky with a table that is perpendicular with the drill shaft. I can't remember if there was a way to adjust this.
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Re: New rough carving technique

Postby John Clifford » Sun Feb 04, 2018 4:56 pm

I admit I used to scoff at the idea of using an angle grinder on an archtop guitar, but I just discovered the Arbortech Mini Turbo tool, and I think it has changed my mind:

https://www.amazon.com/Arbortech-Mini-T ... mini+turbo

So far, I've only tried it on a scrap of curly broad leaf maple - I'm already at the final carving stage on my current project - but I'm very impressed with how quickly and smoothly it cuts. There was zero tear-out on wood where I tend to get it even with a sharp finger plane. I definitely plan to use this tool to rough out the arches on my next instrument. It should be especially useful on the inside arches. I haven't tried their larger turbo planer, but I think that would be hard to use around the waist areas. The Mini Turbo is just the right size.
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Re: New rough carving technique

Postby Alan Carruth » Mon Feb 05, 2018 2:37 pm

If the safety planer is pinching it could be that the table is not dead perpendicular to the quill axis. I have a sink cutout mounted on my drill press table, which is too small anyway. I used a half dozen screws through existing slots in the table to pull it down onto wedges, and check it for level pretty frequently. For that I use a length of coat hanger wire that has been bent into a 'Z', so that the end tracks around the table in a 12' or 14" circle. Chuck it up, lower it until it just touches the table, and rotate it around, looking for changes in the height, and adjust the wedges until it's perfect. This makes big difference.

I use 2mm steps for roughing the arches, and set the levels about a half mm high just in case I run over the line by mistake. Roughing in a set op plates with this and my arch planes take a few hours, and gives a pretty exact shape.
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