violin pegs, keeping them round - created 12-20-2010

Ansara, James - 12/20/2010.05:28:16
ObjektLab

have purchased a violin peg shaper and have also made one as ed. herron allen and h.s. wake have described.the cheap? commercial one is adjustable with a thickness knob and blade depth setting,black anodized alu.I have also sharpened the blade to a less acute angle as h.s. wake suggests.the shop made one is acceptable but not perfect. the commercial one a wast of money. my problem is keeping the pegs ROUND and free of chips, any thoughts?Thanks,James

James, please remember to use proper capitalization when you post here. Posting mostly or entirely in lower case can be interpreted as a formatting command by the MIMForum software, which is why your post is in italics. Thanks.

There are posts at some forum somewhere about making the aluminum one work. Maybe in the archives here, maybe at a violin making forum elsewhere, maybe search for Darnton/shaper/aluminum .

To make a homemade one work you have to get the blade geometry right. Absent a decent one to copy, just think in terms of how you would set up a plane to make clean cross grain cuts.

I've made several successful shop made peg shapers on the usual recipe: ream a hole, plane down to the hole so you end up with a tapered slot such that the blade intersects the surface of the peg at the correct angle all along. I clamped on a piece of aluminum with a small bevel to press down on the peg opposite the blade, similar in effect to the mouth of a plane. This may make the difference on yours. You can make this design out of fairly soft wood.

You can also make one out of harder wood and then instead of planing down you can just cut in with a saw and leave wood opposite the blade to perform the same function as my aluminum piece. If you look at good commercial shapers you'll see that they have this feature.

The other important point, regardless of using a home made or commercial peg reamer, is to go easy and not try to turn a peg to final diameter in only a couple revolutions. The harder you push, the more chatter and the less round the peg.

Speaking of aluminum, does anyone know if a normal violin reamer can ream an aluminum block, or will that ruin the reamer? I wouldn't think aluminum would bother a steel reamer much, at least for only a hole or two. I usually make temporary reamers out of maple, but want something more permanent.

Are you making an aluminium violin?

No, I was thinking about drilling and reaming an aluminum block for a peg shaver. Maple blocks work fine for short use, but they do wear, and I recently had one split on me. One of these days when I win the lottery I will buy a set of professional shavers, but I, like many, don't use them enough to warrant a big purchase right now.

But now that you mention it, an aluminum violin might be interesting!

I've seen an aluminum bass in circulation being played regularly and there was an aluminum piano on the Hindenburg zeppelin. But no John Paul Jones to play it.

Maybe Grainger or some other supplier has an actual metal cutting reamer. I cut a bunch of aluminum with a band saw once when I had to fabricate something, the band saw blade maker told me to use wax to lubricate the blade. Maybe that would help with the violin reamer.

Jim,

Commercial peg hole reamers are made from hardened steel, carbon or high speed. These should be capable of reaming many holes in brass or aluminium before needing re-sharpening. The issue may be with the cutting angle which will be optimised for wood rather than metal and this could become a problem, particularly with brass which may grab.

Andres,

I make my peg shapers as you describe, planing down to a reamed hole. I use an old plane blade, G clamped to the body. I like your idea of the clamped bar on the opposite side of the hole from the blade and shall use it on the next job, thanks.

Seasons Greeetings,

Rod

Thanks, Rod. The clamped bar idea sounds great. That is where my last maple one split.

Aluminum will cute well enough on both table saw and band saw, especially if you use carbide-tipped blades. A commercial tool steel peg reamer will be ok, use wax to lubricate it. If you have several reamers, rough the hole with the oldest most worn one.

Machinists dont normally use 1:30 reamers, that taper is normally only found on luthiers tooling.