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JacksonMaberry

Berbuer Wirbelschneider - chatter

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Hey friends,

Last few sets of pegs I've done with the snazzy Berbuer peg shaper have not been as smooth sailing. I'm getting chatter that is creating facets in the peg - no good. The blade was good to go out of the box and the first several sets were no issue. Maybe it's the cheap rosewood, but I'm.worried it's the pricy shaper. Anyone have any tips?

Thanks as ever!

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Can you shave the peg from either side? Maybe the wood "wants" to be cut the other way. Still looking at it from the point of view that it's the peg not the shaver, dry soap (I use ivory) can help with difficult grain.

-Jim

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Paul Sellers likes to distinguish between chatter, caused by a flexing or vibrating blade, and "scudding," where the blade digs into the wood, but is prevented from continuing to dig in by the body it is attached to.

"Maybe it's the cheap rosewood, but I'm.worried it's the pricy shaper."

What's the obvious answer to this? Substitute something else for the cheap rosewood. If it continues to gouge the wood, the shaper is out of adjustment. If it doesn't continue to gouge, burn the cheap rosewood pegs for incense. ;):P

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I do not have that peg shaver (outrageously expensive for the pegs of my violins, always of the same size), but in case of tricky wood I usually wet the peg shaft with water.

Of course just to get close to the final measure, doing the last light final turns dry to avoid shrinkage due to water evaporation.

I noticed that if you make a step (facet) on the shaft, is very difficult to remove it even with the sharpest shaver.

Wetting the wood allows a more uniform cutting.

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I had an adjustable peg shaver (not this one), and it worked well initially, then didn't.  I never could get it to work well again, even after quite a lot of time spent sharpening the blade to different angles, and trying all kinds of adjustments.  So I got rid of it and now I just use a small lathe.

 

Not much help, I know... but that's my experience.  If I didn't have the lathe, I'd probably go for the type that has various sizes of tapered round holes, rather than an adjustable one (I think the adjustable ones have to compromise in stability in order to work with varying diameters).

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I had an adjustable peg shaver (not this one), and it worked well initially, then didn't.  I never could get it to work well again, even after quite a lot of time spent sharpening the blade to different angles, and trying all kinds of adjustments.  So I got rid of it and now I just use a small lathe.

 

Not much help, I know... but that's my experience.  If I didn't have the lathe, I'd probably go for the type that has various sizes of tapered round holes, rather than an adjustable one (I think the adjustable ones have to compromise in stability in order to work with varying diameters).

Do you have a taper attachment for your lathe? If not, how do you make a repeatable taper?

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Adding to Addie's comment, was the blade digging into the peg or was it "scudding"? I might be able to help but maybe you could clarify that first.

I've had the shapers for little while now and have probably done a few hundred pegs with them. Maybe I have to do thousands before they fail. I don't know. So far they still work great. I occasional adjust them but for the most part they work well. I did resharpen the blades a little steeper than how they came. I agree with Don that most of the adjustable shapers on the market are pretty flimsy but The Berbeurs seem pretty stout.

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Just to clarify:

 

Chatter: evenly spaced cut marks caused by a vibrating blade.

 

Scudding: a deep cut of short duration; gouging.  Unevenly spaced and sized. 

Possible causes: cut depth set too deep, blade angle, dull blade, wood grain or density uneven, poor technique/user error.

Those are my thoughts, anyway.  The last cause probably does not apply if you've used the shaper quite a bit already.  -_-

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Just checking in to clarify per Matthew and Addie's question - according to your definition it is chatter. Facets, evenly spaced around the peg, equal in width.

Let's assume user error for a moment (more than willing to entertain that). I'll explain how I've been using the device and perhaps Matthew can straighten me out.

First I ream the pegholes just enough to set the taper. I then use the reamer to set the taper of the peg shaper. Next I score the peg shank just below the collar to prevent the collar being sheared off. I then set the shaper to just barely accommodate the full working length of the peg (all the way to my score line) and shave until no more material is removed, usually just a few turns. I repeat the last step until I'm approaching my correct length from pegbox wall to collar.

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Well, either the shaper is vibrating, the peg is vibrating, or my definitions are insufficient. Make sure you're not pulling or pushing the peg to one side (levering/canting/skewing/whatever) as you turn the peg.

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Addie,

I think you were on to the right thing all along. To be sure everything was stable, I completely reset the device per Berbuer's directions using the included guides. While I had it apart I ran the flat side of the blade across six grades of diamond on granite, from 60m down to 0.1m until it shone like a mirror.

I then tried setting the shaper to the point where about one cm of peg still protruded from the shaper, then pressed the peg in while shaving, repeating in this way while tightening the cone bit by bit. This resulted in a perfect, chatter free peg!

Davide is correct, that once the peg is chattered I can't ever fix it, so I switched to some super hard stuff sold to me as 'tamarindwood'. Much nicer and finished glassy smooth right off the blade.

Photo shows the tamarind before I began cutting it.

post-79096-0-51077600-1474226488_thumb.jpg

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Do you have a taper attachment for your lathe? If not, how do you make a repeatable taper?

 

Most lathes will have a compound slide that can be rotated to an angle.  I'm using a jeweler's lathe that cross-slides that can be set at an angle.  It's was tedious to get the angle right, and I just leave it there as a dedicated tool for pegs and endpins.

 

Davide is correct, that once the peg is chattered I can't ever fix it...

 

I'll take chattered pegs, as long as they aren't torn out too deeply.

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Most lathes will have a compound slide that can be rotated to an angle.  I'm using a jeweler's lathe that cross-slides that can be set at an angle.  It's was tedious to get the angle right, and I just leave it there as a dedicated tool for pegs and endpins.

 

 

I'll take chattered pegs, as long as they aren't torn out too deeply.

My little Atlas armature lathe has such a compound rest. I take it that you cut the entire shaft length at once?

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