LV Cabinet scraper blade question

[Gary Herrmann]

My wife gave me a cabinet scraper + an extra blade for fathers day. I finally got around to honing the bevel and lapping the face of the blades last night.

Then I read something in the directions that puzzled me a bit - that'll teach me to read directions, I guess.:rolleyes:

"If the scraper is to be used for general smoothing and not fine finishing, it may now be burnished."

The sentence in the instructions seems to imply that you'll get a better finish if you don't burnish the edge. I had planned on burnishing the blades, but I thought I'd ask before I do.

Will an unburnished blade give me a smoother surface? With two, I guess I can burnish one and leave the other alone. What do you folks that have used cabinet scrapers before think of burnishing vs not as it applies to the quality of the finished surface?

Thanks

[Ken Werner]

Gary,

One must burnish the blade in order to form the hook that gives the cutting edge.

Not seeing all the instructions in context, I'm confused.

There is a technique for setting up a cabinet scraper for rough work, in which you use a mill file at about 45 degrees to the edge, and simply leave it at that. The file creates its own burr I guess. I've done it that way, but it's for rough work only, such as removing some nasty glue from a not very important surface. I think there was a FWW article about this several [many?] years ago.

If you're new to using a cabinet scraper, Tage Frid's books have a good section on it. Learning to burnish well takes time, but is, like so many skills, well worth the investment.

Good luck,

Ken

[harry strasil]

Filing at an angle then honing before burnishing , will give you a more severe rolled cutting edge and remove more material.

Doing a double burnished edge is a little harder to do. Some of the old timers just used a piece of broken glass to scrap with.

They say you can't scrape soft woods, but I have pretty good luck with it by skewing the blade to get a shearing action.

[Michael Adelong]

Hmm... I was going to start a new post about what I have learned about sharpening scrapers this week in the evenings after work. Part of what I was going to post, an observation, seems to fit in nicely with this question.

There was a scraper thread on here a few weeks ago, and the discussion turned to David Marks. He wrote or said somewhere that without using sharpening stones on the faces of the scraper, you would never get the correct cutting edge that you need. Without them, you end up with a bunch of tiny hooks going down the edge of the scraper instead of one edge-long hook. These little hooks are weaker, so they dull (or "unhook") quicker. They also prevent the scraper from making light, curly shavings. You get sawdust instead.

After removing the old hooks, and smoothing and squaring the edges with a file, I worked the (narrow) edges on my coarse diamond plate, then a 800/4000 combo stone. After a while, I found it suprisingly easy to work the narrow edges of the scraper on the stones. You can feel the scraper's edge get "sucked" down into the slurry, and onto the stone when the edge starts to get flat. If you move slowly and steadily, you can move the scraper around on the surface of thee stone without tipping the scraper and rounding the edge. Just feel that little bit of adhesion of the scraper's edge to the stone, and do not overcome it. If the edge comes up (and you can feel that easily), stop moving the scraper immediately. I found that this works best, and is easiest on the stones, if I use just enough downward pressure on the scraper to hear a light metal on stone scrape. I slowly make figure 8s around the whole stone. Work the faces of the scraper after that on the stones.

Now, here's the reason that I posted this as a reply to Gary's post. After working the scrapers as I stated, but before burnishing (I am still experimenting with order, angles, and pressure - tips appreciated) I noticed that all 4 cutting edges felt very sharp. They felt even sharper than they did when I bought them brand new and still had the "virgin" LN hook on them (LN 2 pack - 1 thick, 1 thin). Out of curiosity, I tried the scraper before burnishing it. The silly thing made the nicest, lightest, curliest shavings that I have ever seen in my brief time woodworking (maybe 2 yrs). Not only that, but I could actually feel the edge cutting instead of whatever you called what it was doing before I sharpened it(after the LN sharpening died, and I attempted to sharpen). It messed up my learning about the proper way to burnish because apparently, burnishing is an option if the edges have been properly prepared. (That's what I think I learned this week. Am I missing or misinterpreting something?)

If the egde of your cabinet scraper blade is prepared the way I said so that you have 2 sharp faces with a perpendicular (narrow) edge, then the cutting edge will always be in the same place when you mount the blade in the scraper. If you do any burnishing at all, you introduce an unknown cutting angle into the mix. With a hand scraper, you simply alter the angle of the scraper until the hook (or edge) "bites". The blade angle can't be adjusted as easily when mounted in the scaper. You need to adjust, test, adjust, test, and so on. I'd imagine that finding the correct angle would be hit or miss, and finding the optimum angle would be extremely lucky. Once you found it, it would start to change as soon as you used the scaper and the hook wore down or straightened out (what DO hooks do when they dull, anyway?). So, for "fine finishing", put the cutting edge where design of the scraper assumes it will be, or put the cutting edge "in the ball park" for "general smoothing".

Just a hypothesis, though...
Michael

[Gary Herrmann]

Thanks for the responses. I flatted the faces of the scrapers and then honed the bevels using the scary sharp method thru 2000 grit. The edges are extremely sharp. I think I'll burnish one and not the other and conduct my own little experiment to see what kind of shavings and surface results I get.

[Terry Beadle]

I was taught that when you wanted to work on a finish ( like lacquer for example ) you want a very fine hook or almost no hook. It sounds like the water stones give you a no hook edge so that you can smoothe the finish and not take off the finish.

If you are using the scraper on a raw wood surface, then you use a burnisher and put light to heavy pressure, depending on the need for a heavy hook or a lite hook. My2c

[Craig Dempsey]

I went to the LV site and read the instructions. I believe you are misreading the intent of the sentence you quoted. I believe the instructions are to hone 800x/1000x and then burnish for rough work, but for finer work you should hone to 4000x before burnishing.

[Mark Singer]

Honing on the stone is important....then I burnish the face and roll the burr onto the edge....If you roll it over too far you won't get an edge at the correct angle...I hone then all to 3000 or 5000 and then make a small or large burr for rough or fine work....Putting an edge on a scraper is done quickly!