something new to me for wood carving

[Dave B]

I had to go in this weekend for a trama call and figured that while I was in Portland I should stop by the Wood Crafters out let. I ran into a gent doing a carving demonstration on architectural ellements. He had a clasical goddes that he had drawn out on graph paper and a clay 3-D model layed out on a graph bord and the rough cut out profile as done in furniture making. He talked about the fact that no sand paper had touched the ellements he had on the table that were finished. He did it all with scrapers for the final clean up. He then talked about how he put the edge on his scraper. I have never gotten good results trying to use a burnisher to roll an edge over. I can get a very clean edge with a stone but couldn't get the hook. He showed how he would take the stoned edges and push the burnisher in a diagonal just like he was trying to file off the sharp squared corner. He is working the long axis of the tool toward the edge. Only when he has a full burr out on this edge then he puts it in the vice vertically and uses the burnisher as I was taught to knock the hook back down into its correct possition. It works slick.

[davec2]

OK David, I'm really interested in this topic but I'm not overly bright and I didn't get the last part.  I think I understand how he got the hook on the scraper, but I'm not sure I understand about putting "it in the vice vertically and using the burnisher ... to knock the hook back down into its correct position."  Can you explain that last part one more time?

Thanks

Dave C

[Dave B]

Dave no worries, I looked back at my discription and I can see why you had trouble. My editor had already gone to bed .
The burr was first raised by holding the scraper horizontally on the flat of the work bench with only the last eighth of an inch of the edge over hanging. Using a motion like you were trying to file the edge off the scraper, pushing the burnisher down and across the full length of the edge. After this has raised the burr clamp the scraper in the vice verticall so you can use the same motion of pushing the burnisher in the same diagonal filing motion to turn the burr back down to face the way  it normally faces for a pulling stroke.  Here are some drawings to illustrate what I can't explain very well.

[David Rase]

Dave, 
So what do you think is the advantage of putting the burr on the scraper horizontally and then pushing it into position vertically?  The only advantage I can come up with it that maybe you can apply more pressure when the scraper is horizontal.  A disadvantage I see in this method is the possiblity of work hardening your burr from double bending it.   This could cause pieces of the burr to break off due to brittle fracture.  On the other hand, the burr may last longer due to hardening. 
DMR   

[Acer Saccharum]

Well, both sides of the burr get burnished, which may make the cuts smoother, and the burr may last longer due to workhardening.

Neat.

t

[Acer Saccharum]

By the way, thanks for the sketches. They make a world of difference to the comprehension.

T

[Pete G.]

The more I use and learn about scrapers the more I appreciate them. They were used a lot in the 18th century not because they were the only tool available, but because they were the best tool available. Still true in a lot of cases.

[davec2]

David,

Thanks so much for the sketches and second go at the explanation.  I get it now!

Dave C

[Dave B]

Dave R,
I think it is as you say you can apply more force to raise a better burr and work harden the metal. I hadnt consdered the work hardening but did wonder if it would make the burr less durable. I ve got several I will be putting to the test to see how they work.

I have always enjoyed drawing out diagrams it helps make more sence of subject.
Thanks for your commplements.

[J. Talbert]

Well, I'm certainly going to give it a try.  My scraper sharpening results in the past have been very mixed.  I've tried following all the steps as have been outlined to me both verbally and as detailed here and elsewhere in print.  But despite my best efforts I always seem to end up with about 50% sweet spots and 50% not-so-sweet spots.
We'll see if this improves my outcome.

Jeff

[Dave B]

One thing I should add is that he had his burnisher at a closer to perpendicular alignment vs the imression I give in my illustration. You are literally pushing the edge of the burnisher the long axis more so than the side to side

[rick landes]

I do not know if this is a proper technique, but I polish the narrow edge of my scraper to a mirror finish and then do the hook. It seems to give a sharper edge when all is done. I likened it to sharpening a chisel, where polishing the sides was a first before setting the edge.

[Benedict]

I too have had mixed results with scrapers.  When they work it is great.  The drawings help with an understanding of how to burnish the edge.  One thing that noone has mentioned here or in other descriptions is what shape of burnisher to use.  I have a couple different shapes.  One is flat(actually it is 3 sided) and the other is oval.  Which one should I use?  Or is there another shape that will work better?

Thanks,
Bruce

[Acer Saccharum]

I just use a round shank of a solid carbide router bit or endmill shank, stick the cutting end into a wooden handle, and use the shank for burnishing. A HSS endmill will work, too. Drill shanks are normally soft, so they are not good.

Acer

[rich pierce]

A piece of 5/16" drill rod, hardened and not tempered beyond pale straw, makes a nice burnisher.  A flat burnisher has more metal in contact with the scraper, so you can really press on it and not deform things too much.  It's easier to get a uniform edge on a flat scraper with a flat burnisher.  On the other hand a flat one will not be ideal for hooking an edge on a concave scraper.  A round burnisher puts much more "psi" on the edge with a given pressure because the contact patch is very small.  So it's important to modulate the pressure you use depending on whether you're using a flat or round burnisher, and the diameter of a round one.

[J. Talbert]

Rich,
You raise an interesting point...
I never considered the possibility that I was pressing too hard with the burnisher.  I wonder if my inconsistent results could be caused by deforming the edge by using the burnisher too aggressively???
Has anybody here gotten better results after moderating their burnishing efforts?

Jeff

[E.vonAschwege]

When I first started scraping instead of sandpaper, I used a 90* angle only, no burr.  This brings out the texture in the wood, but not as good for smooth finishes.  Next I tried the single burr (only the second step).  Worked better, but not as well.  I've been doing this full method described by Dave for a couple years now and it makes a world of difference.  From my tiny carving scrapers made from hacksaw blades, to the store bought .04mm cabinet scrapers, the wood cuts away in smooth clean shavings.  When the burr wears, you can redo the last step another time. 

Before starting with the burr, I try to get the edges square with a file and then a sharpening stone.  The more you polish, the better the scraped result will be.

If you haven't tried Dave B's description, it's well worth it! 

-Eric

PS, I use an egg section burnisher from Lee Valley. 

[rmnc3r]

Necro-Thread Resurrection

The Drawings that Dave B originally provided are no longer visible - would it be possible to repost them?

My most oft used scraper is a piece of broken Saw Blade, .034 thick,  that is contoured - I can never seem to get a good hook using the traditional methods so I just run the edges on a bench grinder wheel and get a decent sharp edge for rough work.

[flatsguide]

I use a polished carbide rod burnisher of 1/4 dia. And about 6 inches long, shoved into a file handle. It is super smooth and one can develop a sharp smooth hook.
Cheers Richard

[flatsguide]

In my above post I mentioned carbide rod. Here is the source.
R

[Dave B]

here is one of the missing photos. Photo bucket is being obnoxious I cant get the others but you get the drift here. The bur is made by pushing the metal over the edge using the horizontal position. putting the blade with raised burr in the vice and working the burnish her perpendicular to the ege you knock down the burr reflecting it back over into the hook.

[Chowmi]

Aha!!!

Forehead slap!

Norm

[rick/pa]

Thank you. Makes sense to me now.

[flatsguide]

I neglected to post the linktocarbiderods I mentioned earlier.

https://centennialcarbide.com/carbide-rod/?gclid=EAIaIQobChMI__SH7qOA6gIVD6_ICh3_WQuDEAAYAyAAEgIwdvD_BwE

[rmnc3r]

!Munches Grasses! Senor guapo