Sharpening for Bow making vs Violin repair

[JPherson]

One of the other threads got me thinking. Is there a difference in sharpening for making a bow vs making a violin? If so what are the differences for working pernambuco?

Thanks,

Jesse

[duane88]

Higher angles of the blades. Also, with the chisels, many bow makers use the burr instead of polishing it off.

 

A block plane sharpened to 30 degrees+/- won't last long against Pernambuco.

[A432]

People in Anglo-World, at least, believed that Retford was correct when said (in the book he wrote) that planes like the Stanley 102 had no place in bowmaking. It turned out though that, as Bill Salchow said (BS spent a year learning bowmaking in Mericourt, with a finishing stint in Ouchard's shop), planes like the general 102 type were, in his words, "the workhorse of the French bowmaker." When you attended one of his summer courses @ UNH (I logged four weeks with him at these, 1981 & 1982 sessions) you brought your own -- the other tools (knives and chisels) had had for sale.

What the English apparently hadn't known was that the key to planing pernambucco was to strongly turn the edges of the plane blades/chisels used (ditto ebony). However counter-intuitive this might see, it works, and works like a charm.

Whether this is the case in violinmaking, the violinmakers here can say.

[A432]

Odd -- I posted a followup note to the above but it disappeared.

In short, planing pernambucco & ebony with an un-modidied (low blade angle)102 (& using other edge tools on them) for months without edge maintinance was normal back when I was doing it. Salchow said that Ouchard's own tools "looked like sh*t (no careful treatment). But they worked, which was all he cared about.

Scraper planes would probably be a different story.

[JPherson]

6 hours ago, A432 said:

 

What the English apparently hadn't known was that the key to planing pernambucco was to strongly turn the edges of the plane blades/chisels used (ditto ebony). However counter-intuitive this might see, it works, and works like a charm.

Interesting. Do you turn the edge towards the bevel or away for it?

Ive also heard, weather true or not, is to only sharpen through middle grit. 5/6k or so. Thoughts on that?

[JPherson]

6 hours ago, duane88 said:

Higher angles of the blades. Also, with the chisels, many bow makers use the burr instead of polishing it off.

How steep an angle would you recommend to street with?

[Mike_Danielson]

The Stanley 102 is a 'bottom of the line' plane, but everyone uses it--it does the job.  You can buy a new one for about $30.  

Try about 60 degree on the iron.  The plane is going to be used as more of a scraper because the grain is so squirrelly.  If you use the more usual angle of 25 degree, you will be struggling with tear-out.

I have never heard of turning the edge--I want to know more about this.

[A432]

The edge turns strongly, down away from the body of the plane. I used 220 grit emory paper and leaned into it. Or, imagine your fingers held together like a downward angle salute are the blade. Curling the last digits down further would model what's involved.

Start with no "bite" at all. Tap the nose gently and try 10 strokes. If no curl is pulled, another tap-&-try. You reach the point where the third or fourth pass is starting to  pull a paper thin curl, shaving through irregularities, knots &c as easily as slicing balogna with a deli slicer. That's your working blade protrusion. (A little further for early stage roughing out work, to save time and joint strain).No blade angle modification is needed.

Later stage finishing planes, small in size, have higher-angled bits, but they still cut -- not scrape.

You would only run into tear-out if the blade were sticking out way too far. At least that's what I found, and what you can see on older, gnarlly-grained French bows. Which were definitely planed.

FWIW

[JacksonMaberry]

1 hour ago, JPherson said:

Interesting. Do you turn the edge towards the bevel or away for it?

Ive also heard, weather true or not, is to only sharpen through middle grit. 5/6k or so. Thoughts on that?

That doesn't make any sense to me personally, and while I haven't made bows I have planed a lot of really nasty (but beautifully figured) dense tropical hardwoods. I sharpen (hone) everything the same, but shape blades (grind the bevel) differently for different tasks/timbers. Reason being as that there is really only sharp or not sharp. Sharp is when the two faces of the tool intersect at an infinitesimally small point, and everything else is dull.

Now, it's true that for some tasks (I'm thinking cooking in particular - slicing fibrous vegetables) that a steeled edge - obtained by using a honing rod - is preferable to a polished/stripped edge. This is due to the microscopic chips creating a sort of invisible saw- like effect.

Perhaps this could be valuable in planing very dense, interlocked timber, but my suspicion is that simply setting up the tool correctly for the task, with a nice high angle, and getting it very sharp would be perfectly nice - has been in my experience, anyway. The way a steeled knife moves through the vegetables; that is to say with a motion along the edge (transverse to the fibers, as with a saw), is not the same as planing. In planing, the blade is often pushed in the same general direction as the fibers, less of a slicing and more of a slow motion chop. 

All of which to say - I'm skeptical.

It's easy and fun to make a couple different sizes of wood bodies scraper planes.

[duane88]

17 hours ago, JPherson said:

How steep an angle would you recommend to street with?

His chisels as well as his planes are at 50 degrees. Some of my bow planes approach a scraper plane angle.

[A432]

Cleaning up loose ends, whether it makes any sense (is congruent with a conceptual blueprint) or not, it simply works, needing no justification beyond that (although 225 years of practice in France should suffice).

The blade edge is mounted bevel side up (the usual way) the edge-turned down.

[JPherson]

On 12/24/2024 at 11:20 PM, A432 said:

Cleaning up loose ends, whether it makes any sense (is congruent with a conceptual blueprint) or not, it simply works, needing no justification beyond that (although 225 years of practice in France should suffice).

The blade edge is mounted bevel side up (the usual way) the edge-turned down.

True and I still need to try it out. It’s a fascinating concept especially since it may work. I plan on it this week not that much of the holiday hustle is over. 
 

Jesse

[nathan slobodkin]

A 432 is correct as far as Bill Salchows instructions about sharpening bow tools. He would sharpen at fairly normal angles then turn the edge with a burnisher to get the "bite". I was also in Bill's classes in 1981-82. Care to PM me with your name A432?

[JacksonMaberry]

I think I must be misunderstanding the principle being discussed. If anyone would be willing to dash off a quick pencil sketch of what's going on I'd appreciate it! Though I have been skeptical, I'm always eager to learn and ready to admit when I've been wrong. 

[fiddlecollector]

I assume like this only with a lower blade bevel angle and pushing the plane to the left.(hook is exaggerated) It seems odd but does appear to work when i tried it years ago  but i tend to just used a high angle bevel with a very sharp blade, i suppose its what works for you. Ive always managed to plane pernambuco with a normal edged  sharp blade.

The method described is useful (if its the same as im illustrating with the photo off google images), for areas such as either side of wavy grain or small knots where the grain dips either side of the area  and tear out can easily happen.

 

[nathan slobodkin]

5 hours ago, fiddlecollector said:

I assume like this only with a lower blade bevel angle and pushing the plane to the left.(hook is exaggerated) It seems odd but does appear to work when i tried it years ago  but i tend to just used a high angle bevel with a very sharp blade, i suppose its what works for you. Ive always managed to plane pernambuco with a normal edged  sharp blade.

The method described is useful (if its the same as im illustrating with the photo off google images), for areas such as either side of wavy grain or small knots where the grain dips either side of the area  and tear out can easily happen.

 

No.

My recollection (from 45 years ago) is that the blade was turned the other way and was used on a regular plane with a regular bevel. He also did this with chisels so that the chisel could be laid flat and still cut such as when making the channels for pearl slides or heel plates. I haven't really made bows since about 1986 so I don't sharpen anything like this anymore but I remember that it did work very nicely and watching Bill work was a real eye opener. He did use some scraper planes as above for finishing as well as scratch gauges with square ground blades for fluting baroque style sticks and so forth. I remember watching him make a fluted baroque bow in a single day from beginning to end. A modern bow with hand made ferrule and button took about 16 hours. That is flat metal, a split chunk of ebony, a rough sawn pernambuco stick blank, a rough sawn ivory tip plate, a threaded screw without the button and a hank of hair to polished and playing.

[fiddlecollector]

That image i posted above  was  not mine and not really a good example.. But surely if you turned it the other way on a normal bevel up block plane with a normal for instance 30 degree bevel the hook would be almost horizontal to the direction of travel ????

Maybe im also misunderstanding???

A432 says turn the edge down away from the plane body

[nathan slobodkin]

10 hours ago, fiddlecollector said:

That image i posted above  was  not mine and not really a good example.. But surely if you turned it the other way on a normal bevel up block plane with a normal for instance 30 degree bevel the hook would be almost horizontal to the direction of travel ????

Maybe im also misunderstanding???

A432 says turn the edge down away from the plane body

Still No.

 I don't know how to draw on these infernal machines but the hook or burr was the opposite direction, down towards the flat side of the blade. I cant really explain why it worked but it certainly did. As I said I haven't made bows for a long time and haven't used these style blades but there was no question that being able to use the flat side of a chisel to guide the cut while still cutting was very important to that method of bow making.

[A432]

Nathan --

Tried to PM you yesterday, but couldn't get your name typed into the send-to box. Then wrote a l9ng-ish response to post here but it apparently timed out -- got the usual "Your post must be approved by an administrator" response, but the text tield was empty & it never posted. 

There was an ADHD hyperfocused-with-aspergers-sauce loner there who told outrrageously inappropriate (in mixed company) jokes & turned Bill's 1982 bow's road test into a three hour ConcertoFest. That was yours truly. Having refused any involvement with social media (facebook, twitter, linked in et al.), a name search would only get a 401 result anyhow. 

Glad you've managed to combine luthiery with living in a place fit for human beings (those years here were spent working in a violin shop -- & freelancing -- in a major metropolitan area that's gotten even more toxic since then. 

Cheers & Regards

[A432]

PS (since i can't edit):

404 (not 401)

Overlook small screen wide fingers typos

Close concluding parenthesis. 

[Wood Butcher]

15 hours ago, nathan slobodkin said:

Still No.

 I don't know how to draw on these infernal machines

Draw on a regular piece of paper instead, then take a photo of the drawing, and upload it here.

[A432]

If the cutting edge were turred up (toward the bevel) instead of down it would skate over the surface instead of biting in.

The actual deviation of the turned edge is probably less than 1 % --  just enough to pull the edge of the curl up where it jams against the sole. Forward propulsion after that forces the uniformly thin curl thus produced up into the throat and away.

Just stop trying to model it and try it instead. 

On this end, it's like people obsessing over whether rosin is necessary on bow hair to generate sound when it's so freaking easy to just try it and see, model or no model.

 

[duane88]

Robert had me sharpen, but where a violin maker would polish the back of the tool to remove the burr, it was left in place, both knife and plane. He used the burr to cut as well as the beveled edge. Now, I wouldn't use a burnisher to roll a burr, but did leave the one that was produced by grinding and polishing the bevel.

[JPherson]

18 minutes ago, duane88 said:

Robert had me sharpen, but where a violin maker would polish the back of the tool to remove the burr, it was left in place, both knife and plane. He used the burr to cut as well as the beveled edge. Now, I wouldn't use a burnisher to roll a burr, but did leave the one that was produced by grinding and polishing the bevel.

So far this is what has worked Best for me. Thought I am still learning this method, it’s the closest to what I’m used to. So that may be why it’s working for me. Beautiful, thin shavings of pernambuco with this method. 
Dust and chips when I try to turn the edge. But I will keep trying lol

Jesse

[fiddlecollector]

I,m still no wiser about what has been discussed in this thread. If its just leaving a burr on the blade edge then theres nothing special or unusual about this , most burrs will simply come off after the first use after sharpening without doing anything other that use it , so what is the benefit of that??.  My favourite stone is a double sided norton waterstone that doesnt tend to leave any burr.

Nathan ,Duane and A432  dont seem to be talking about the samething???? A 432 defoinitely mentions turning the edge down away from the plane body,which surely involves the use of a burnisher.