Scraper filing jig

[Tony Zaffuto]

It is difficult to estimate how long the edge holds since the woods I use are very abrasive. Let's say, compared to a card/cabinet scraper, the thick scraper holds an edge about three times as long.

I grind it on a 80 grit CBN wheel (which makes it easier to keep an edge straight), and just enough that there is a flat along a side, and a small burr is raised. I flip the blade and do the same on the other side - in other words, the grind is not perfectly square to the edge.

The thickness of the blade makes it easy to hold and use.

Stewmac make a similar scraper (more expensively!) ...

http://www.stewmac.com/Luthier_Tools/Ty ... raper.html

Regards from Perth

Derek

I have a Stewmac and it does work ncely.....but I find I can do as well with a thicker, (stiff) conventionally availabe rectangular scraper. Why? Probably a mental block when I sharpen the thicker Stewmac on my grinder. Years before I bought the Stewmac, I made (and heat treated) an A2 scraper (I have a heat treat furnace), and put a 45 degree chamfer on one edge. It does a good job and is easier to prepare. Made it to fit a Stanley 80, but works better freehand.

 

[Derek Cohen (Perth Oz)]

I took a couple of pics today as I was shaping the inside of a bow drawer. The shavings peel off this scraper (this is hard, interlocked Jarrah), and leave a fine surface ...

This is how the scraper is "honed" - just grind the edge until there is a slight burr. I am using a CBN wheel here ...

Regards from Perth

Derek

 

[Tony Zaffuto]

How fine is the resulting surface Derek? Finish ready? What size is your grinder? I may have to try one of the CBN wheels.

Thanks,

T.Z.

 

[Derek Cohen (Perth Oz)]

Hi Tony

The wheel shown is a 180 grit CBN. The grinder I use is a half speed 8" I've had for several years, but reports indicate that the speed is less important for CBN wheels as they run cooler. Anyway, I also have an 80 grit wheel, and this one is for quicker grinding. It is also the one I have been using for the scraper in these pictures. For a coarse wheel it leaves a pretty decent surface, not one that I consider finish-ready, but decent enough to finsih with a card scraper - which is what I have done for the inside faces of the drawer fronts. The finish off the 180 grit is better, but also not quite finish ready. Undrrstand that I do not see the role of this scraper as one for finishing, but for rapid work.

The difference between a card scraper and the thick blade is that the card scraper is prepared with a finer diamond stone and a burr is carefully turned. The thick blade is used straight off the grinder, which literally takes me 10 seconds to prepare.

If you plan to get a CBN wheel, and only one, get a 180 grit. I wholeheartedly endorse these wheels. Minimal upkeep for maximum performance. Not cheap, but will last many, many years.

http://www.inthewoodshop.com/WoodworkTe ... SetUp.html

Regards from Perth

Derek

 

[Tony Zaffuto]

Hi Tony

The wheel shown is a 180 grit CBN. The grinder I use is a half speed 8" I've had for several years, but reports indicate that the speed is less important for CBN wheels as they run cooler. Anyway, I also have an 80 grit wheel, and this one is for quicker grinding. It is also the one I have been using for the scraper in these pictures. For a coarse wheel it leaves a pretty decent surface, not one that I consider finish-ready, but decent enough to finsih with a card scraper - which is what I have done for the inside faces of the drawer fronts. The finish off the 180 grit is better, but also not quite finish ready. Undrrstand that I do not see the role of this scraper as one for finishing, but for rapid work.

The difference between a card scraper and the thick blade is that the card scraper is prepared with a finer diamond stone and a burr is carefully turned. The thick blade is used straight off the grinder, which literally takes me 10 seconds to prepare.

If you plan to get a CBN wheel, and only one, get a 180 grit. I wholeheartedly endorse these wheels. Minimal upkeep for maximum performance. Not cheap, but will last many, many years.

http://www.inthewoodshop.com/WoodworkTe ... SetUp.html

Regards from Perth

Derek

Thanks Derek. I'm going to try a CBN on the slow speed Woodcraft grinder I have.