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Scraping violin ribs?


polkat
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Just bought some rib wood that is 2mm thick. I'm looking to make it about 1.2mm thick. I could use a sanding rig, which I don't have. Or I could scrap them. I did scrape some ribs so many years ago that I consider myself new to it again.

What is the best approach to this? Best type of scraper? Someone suggested plaining the wood. Best plane? Scrape/plane along the length? Thanks for any suggestions!

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A well set up block plane and a final scraping if needed is a good approach. Plane or scrape one side to a finished surface. Plane the other side down using either a toothed plane iron or a plane set up with a high attack angle. This is the angle between leading edge of the plane iron and the wood. It's measured on the acute (back side) for some stupid reason rather than as it is presented to the wood. On a bevel up plane like a block plane this is the planes bed angle plus the blades bevel angle. For figured woods, shoot for 50 - 60 degrees (or 140 degrees if measured as it is presented to the wood). This essentially turns your plane into a scraper plane. The more figure, the higher the attack angle.

I use a standard angle block plane. A low angle one should work too.

Either way - toothed or high angle Start with a fresh edge on the iron and take as thin shavings as you can. Increase the shavings very carefully until you think you're at the edge of tear out. Back off if you need to. Expect to sharpen a few times for best results.

If you use a toothed iron, It can be helpful to plane the one side until it is covered with the tooth marks and then measure the thickness. Now scrape the surface until it is just smooth and measure again. This way you can see how much to leave from the toothed plane before scraping. Add a bit of security thickness of course.

All that said, .8 mm of stock removal is doable with a card scraper. I would go to 1 or 1.1 mm final thickness though, unless you have reason. That's you choice. Anyhow, by the time you get one side of the rib finished. you'll be down to .5 or .6 mm needing to be removed. If you use a toothed iron you won't be removing much before you have to start scraping again. It's good practice however you do it.

Hope this helps,

--Joe

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Just bought some rib wood that is 2mm thick. I'm looking to make it about 1.2mm thick. I could use a sanding rig, which I don't have. Or I could scrap them. I did scrape some ribs so many years ago that I consider myself new to it again.

What is the best approach to this? Best type of scraper? Someone suggested plaining the wood. Best plane? Scrape/plane along the length? Thanks for any suggestions!

i like to hold the end down with a clamp or two ,,,,

and a chunk of wood,,

and pull the scraper toward myself,,, or a plane,,,

use a flat surface,,and do several at once,,they stay flat easier and i don't roll the edges.

,,,,,,over a "sharp" jointer works.

wet the wood first with water & alcohol,,just a quick swipe with the liquid right before cutting,,

it lubracates the wood,,,go slowly and cut pretty nice flame. the jointer need to be sharp,,,

factory blades are sometimes not sharp enough,,,they might need a little touchup.

when you see which way cuts the best,,,,,, mark it.. and stay to that direction.

mark a code with stripes on the side of the board so you can put it back together again.

i do a dozen at a time,,,plane all the boards,,,,bandsaw all the boards,,,,plane all the boards,,,,

bandsaw all the boards,,,,plane all the boards,,,ect.

if you get the rhythm just right,,,

you kind of enter a vortex kind of time warp,,,i think eienstein talks about it somewhere.

so one side is left extremely nice,,

requiring afew swipes with a perfected scraper to look authentic....

i like a very sharp 90o razor blade stock scraper,,polished sharp with no rolled edge.

it cuts exteremely clean and smooth.

flip them over and finish the otherside to the thickness as smooth and nice as you deem nessasary.

it helps to cut the edge side of the board close to the final height,,,, first,

then they are quickly ready for the mold.

i wasn't gonna go on,,,

then i think ,,,,,,,,,, :huh: oh!

just one more thing :lol:

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Just bought some rib wood that is 2mm thick. I'm looking to make it about 1.2mm thick. I could use a sanding rig, which I don't have. Or I could scrap them. I did scrape some ribs so many years ago that I consider myself new to it again.

What is the best approach to this? Best type of scraper? Someone suggested plaining the wood. Best plane? Scrape/plane along the length? Thanks for any suggestions!

The quickest and best way to reduce the thickness will be with a sharp block plane, preferably with a fine mouth and a fine setting on the blade. I think if you try to scrape 0.8mm they will turn out pretty wavy, and it will take you ages.

With a sharp plane I can thickness a set of ribs in a short space of time, I have never yet felt the need to use a toothed blade. If you find the wood tears out, try turning it round and work the other way. Holding the plane at a 30 degree angle to the rib will help it to cut cleanly too

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I found the best way is to buy violin ribs ready sanded to 1.4mm and finish with a cabinet scraper. After the linings are in I sand them until smooth, wet them, and repeat.

If you want to do alot of sanding you can invest in a proper floor standing oscilating bobbin sander, has a large cast iron table which takes bobbins up to 5 inches long, with industrial quality loadings of different grit sizes, and a proper dust extractor. It can do Cello blocks, Cello scrolls, etc etc. Prices in U.K. are about £800.

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