Violin Forum/Message Board

[OyvindT]

I have bought some wood for my next violin, and the back came as a wedge, so i have to resaw it and join it.
I do not have a bandsaw or a tablesaw, i can get access to both, i have no experience using them however.

I am not shure how to split it because of the wedge shape, should it be split perfectly down the center?

When it comes to the joining, i have an old wooden jointing plane, but the sole is far from flat, any suggestions on how to flatten it?

[okawbow]

Is your wood sawn or split now? If it is sawn; it is possible that it will not split perfectly.

(I just re-read your post, and noticed you said your wedge was for the back. You probably cannot split the maple sucessfully. The following applies to spruce. You should probably take it to someone with a good bandsaw, using a new, sharp resaw blade, to re-saw the wedge. You could do it yourself, with a very good handsaw and much skill and patience.)

To split a wedge in half......A splitting froe works best. I use an old draw knife. A large, sharp butcher knife would work. Practice on a piece of firewood.
I measure and mark the center line of the wedge on one end. Carefully set the tool on the centerline, and tap with a wooden mallet, or rubber hammer, or piece of wood, untill the tool begins to split the wedge. As the tool gets deeper into the wood; you may need to push down on one end, and tap the other end, until your wedge splits in two.

It will split straight if the wood grew straight.

You may want to take your plane to a machine shop and have them flatten the sole. If you have a perfectly flat piece of granite or steel, you can take out minor imperfections by rubbing the plane sole against the flat surface using valve grinding paste. Start with coarse, and work down to fine, until the sole is flat.

[OyvindT]

Thank you okawbow.

When splitting on a bandsaw, do you just take a slab of the flat side of the wedge, or do you need to split it perfectly down the middle to make 2 identical wedges?

I do not think i will access to a bandsaw with a special resaw blade, is that a problem?

The sole of the plane is about 1.5mm taller in the middle than on either end, so i dont think it is a minor imperfection.

I also need to grind and sharpen the blade, i do have a grinding stone, so that should not be to hard, but i am not shure what angle i sould grind to.

[okawbow]

The two halfs of the back wedge should be as equal as possible. It should be sawed to open up like a book, and will be joined at the but end, so that the re-sawed surfaces are up, and the former outer flats of the wedge are down, and lay flat. Clamp the two halves of the wedge together, with the bottom faces touching. Plane the joint and test the fit until it is perfect.

I suggest you take your plane to someone who knows how to flatten and sharpen the blade properly.

[Andy Gamble]

You said the plane is wooden. That makes it a lot easier to tune up, but likely more difficult to use. If the bottom of the plane is in fact wooden, then you should neither take it to a machine shop nor use valve grinding paste (yuck!).


Here's how I would tune up a wooden plane:

To start, get some sandpaper, 80-grit to about 220-grit. If the plane is made of oily exotic wood (specifically lignum vitae), you'll want to get wet-or-dry paper for the finer grits (at least the 220-grit) and use mineral oil with it as a lubricant to avoid constantly clogging the sandpaper. If the plane is made from something that resembles maple or beech, then that shouldn't be a problem, and any type of sandpaper will do. You'll also need some spray adhesive, or you could simplify the process a bit by finding some adhesive-backed sandpaper. Aluminum oxide sandpaper will also work in this procedure on metal planes. I like 3M's Stikit sandpaper for use on both wood and metal.

Next, find a dead flat surface to stick the sandpaper to. If you have polished granite countertops, you are in luck. If not, see if there is a granite fabricator nearby and ask nicely for some of their scrap granite. A large sink cutout works great. Any piece of granite with a polished surface at least as wide as, and at least 80% as long as your plane will do. Polished granite for use in countertops is almost always more than flat enough to get a plane working nicely. If granite is unavailable, thick (like 1/4" or 6mm) plate glass will do. Stick the sandpaper to it, avoiding any bubbles or irregularities, starting with the 80-grit.

Make sure the blade of the plane is not protruding, and start sanding the sole of the plane. Use elliptical motions, and keep everything as even as you can. Check to see where the high spots are, as indicated by sanding marks on the plane. Keep going with the 80-grit until there are sanding marks at the front edge, the back edge, and immediately in front of and behind the mouth (the hole that the blade comes through). It doesn't matter if there are some low spots in other places.

Once the front edge, back edge, and mouth are all scratched up with sanding marks, switch to the 120-grit until all the 80-grit scratches are gone. Then, switch to the 150- or 180-grit, and so on until the sole of the plane is nice and smooth.


As for as sharpening the blade, the angle on a bevel-down bench plane (which this certainly is) really shouldn't matter, so long as it's not so acute that the edge is weak, and not quite as obtuse as the angle at which the blade is held in the plane. Most planes hold the blade at a 45 degree angle, some at 50 degrees, and very few at 55. Anywhere between 25 and 40 degrees for the bevel would be a safe bet, with the more obtuse angles having the advantage of slightly greater durability. I usually aim for 35, and use a slight microbevel when honing.

If your grinding stone is a powered grinder, be very careful about heat. Keep a bucket of water nearby to dip the edge into to cool it. Grind off small amounts of metal at a time, letting the blade cool often. You do not want the edge to start turning blue: it will become either brittle or soft, depending on what kind of steel it is and how you cool it down afterward.

No matter the angle of the bevel, a course grinding stone will not give an adequate cutting edge for a plane. It is necessary to use finer abrasives to hone the edge. This can be accomplished with fine sharpening stones, or with fine wet-or-dry sandpaper spray-glued to the same flat surface you would use to flatten the plane. After grinding the bevel angle, start at 220- or 400-grit, using soapy water as a lubricant (alternatively, use a stone finer than the grinder). The first thing you must do is flatten the back of the blade. The back is exactly as important as the bevel, and must be treated similarly. Using circular motions, sand the leading 1/2" (12.7mm) or so until the entire edge is flat and shiny. I usually get lazy at this point and put about a 2-5 degree bevel on the back of the blade, mostly to make flattening go quicker. It works.

Do the same thing to the bevel, keeping the angle as close as possible to the angle you ground into it previously. Using progressively finer grits (or progressively finer stones), take both the bevel and the back of the blade up to the finest sandpaper or sharpening stone you can find. 1500-grit does okay, 2000-grit is better. If you happen to have something like a barber hone, used for sharpening straight razors, finish up on that. I think they are usually around 6000-10000 grit, and cut quite fast for how fine they are. That will give you an edge that cuts more smoothly than you might have thought possible.

If you ask 10 woodworkers how to tune up a plane, you will get 20 different answers. This is simply the method I have arrived at by tuning up my own meager collection of planes, and should be taken as neither definitive nor entirely trustworthy.

[OyvindT]

Thank you for the detailed answers, i can easily get some thick glass for a sanding surface.

The grinding stone is water cooled, so heat is not a problem, i also have glass plates with wet sandpaper glued on it to hone the edge, 1000, 1500 and 2000grit.

I will take the wood to the bandsaw next week and try, i will try to make a few cuts on scrap before splitting the wedge.

[Michael Darnton]

Bandsaws can be tricky. If the blade is too loose or too wide, if you press too hard with the wood, the blade can bend backwards, and then sideways (pretend your belt is a blade, and see what it does when you push on one edge, like you're cutting.) You won't see it bow--that happens inside the wood, so much that it's possible to almost come out the side. So make the blade tight and saw slowly.

A friend of mine has split maple using a common handsaw, holding the wood in his vise. It was tedious, but worked well.
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