Kerfing chisel for dozuki?
#11
I've been cutting half blind dovetails lately. It would be a lot easier if the saw kerf went all the way down, like with what Derek calls his "kerfing chisel." Dozukis are made of thin gauge metal, though, and even my card scrapers are too fat too fit. Any suggestions?
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


Web: My woodworking photo site
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#12
I don't think you're going to find a kerfing chisel at 0.015" or less. You could try with the blade from an old, worn out dozuki, but I wouldn't think it would hold up to the task. It's tough duty even for a thicker size.

I suspect that an extra sharpening of your chisel is your best bet unless you want to switch to the thicker saw blade to make a wider kerf. I haven't seen any thicker blades on dozukis that would get to the size range you would need, so i suspect you'd have to switch to a western saw.

If you do try with an old dozuki blade, you could become "Aram, defying the laws of physics" as well.
Fair winds and following seas,
Jim Waldron
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#13
(09-03-2018, 03:09 PM)Jim Waldron Wrote: I don't think you're going to find a kerfing chisel at 0.015" or less.  You could try with the blade from an old, worn out dozuki, but I wouldn't think it would hold up to the task.  It's tough duty even for a thicker size.  

I suspect that an extra sharpening of your chisel is your best bet unless you want to switch to the thicker saw blade to make a wider kerf.  I haven't seen any thicker blades on dozukis that would get to the size range you would need, so i suspect you'd have to switch to a western saw.

If you do try with an old dozuki blade, you could become "Aram, defying the laws of physics" as well.

Thanks. I kinda thought that might be the answer.
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


Web: My woodworking photo site
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#14
Have seen more than one Japanese Craftsman start out half blind dovetail sockets like they were just finger joints.....they saw straight down...chop out that waste, THEN chop the angled parts....to reveal the pins.   Even on full blind dovetails...

They then use either a skew chisel, or the fishtail chisel to clean up back  in the corners...
   
Mitre Joint?
Confused  
   
Not exactly....
Rolleyes  
   
Show me a picture, I'll build a project from that
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#15
They are called "Kerf Extenders" and one type is made by Rob Cosman for the outrageous price of $99.
The theory is to make the kerf plate the same thickness the dovetail saw plate, 0.025 or 0.026 inches. 
 One of LV's scrapers is the right thickness.  You then would buy a piece of folded brass to apply to one edge to bang on and attach a handle. 

Bontz Saw Works makes a really nice one for about $10 more which I bought. It works great, and really saves time. I did not have the skill to attach the handle...so bought one.
https://www.bontzsawworks.net/half-blind-dovetail-tool/

Bontz also makes one that is 0.015 is you just can't let go of those dozukis. The Cosman is 0.026 only.

https://www.ebay.com/itm/Rob-Cosman-Kerf...SwONdbbImW

[Image: s-l1600.jpg]
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#16
(09-03-2018, 11:34 PM)Winterwood Wrote: They are called "Kerf Extenders" and one type is made by Rob Cosman for the outrageous price of $99. (
The theory is to make the kerf plate the same thickness the dovetail saw plate, 0.025 or 0.026 inches.  One of LV's scrapers is the right thickness.  You then would buy a piece of folded brass to apply to one edge to bang on and attach a handle. 

Bontz Saw Works makes a really nice one for about $10 more which I bought. It works great, and really saves time. I did not have the skill to attach the handle...so bought one.

Thanks. I'm sure this works well with western saws, but Japanese pull saws (Dozukis) are considerably thinner.

[EDIT] How about that. I clicked on the Bontz link. They sell thin ones that might work. Thanks for the lead. I won't personally spend $110 on this tool, but I appreciate the link. This gives me hope -- maybe I can make my own.
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


Web: My woodworking photo site
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#17
(09-03-2018, 11:39 PM)Aram Wrote: Thanks. I'm sure this works well with western saws, but Japanese pull saws (Dozukis) are considerably thinner.

I could not get all the pasting (3) into my post so I updated it several times....before I could add that Bontz  makes one that is 0.015 inches, you answered about your special requirement for a 0.015.
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#18
(09-03-2018, 01:20 PM)Aram Wrote: I've been cutting half blind dovetails lately. It would be a lot easier if the saw kerf went all the way down, like with what Derek calls his "kerfing chisel." Dozukis are made of thin gauge metal, though, and even my card scrapers are too fat too fit. Any suggestions?


Hi Aram

I have not measured the thickness of the kerfing chisel I made 7 or 8 years ago. It seems to be about the same as an average western dovetail saw (0.02"), but I have not had any difficulty using it with thinner plates (e.g. 0.015"). I cannot recall using it with a dozuki, but it would not surprise me if it worked just as well.

[Image: KerfChisel_html_m25a489f9.jpg]

Basically, as long as there is a kerf, the blade will create its own extended kerf. 

Here is my article: http://www.inthewoodshop.com/ShopMadeToo...hisel.html

I give credit to Tage Frid for the first use of a blade to extend a saw kerf. I saw a video of his where he used a bandsaw blade. As far as I know, mine was the first attempt to create a tool to do this. Over the years I have used a variety of saws without worrying about the width of their blades.

Regards from Perth

Derek
Articles on furniture building, shop made tools and tool reviews at www.inthewoodshop.com
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#19
DC--thank you for linking your article.

Makes me think that there might be some thin putty knives that could be modified to make such a kerfing chisel.
Wood is good. 
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#20
One thing I might do if trying to push the limit of thinness is to make several tools of different blade depths. The shorter the blade, the stronger it would be. As you run out of depth with one tool, you could switch to the next, and never have much unsupported blade. Obviously, this would be needed only if you encountered problems using the full depth tool to to start.
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