Making a Burnisher and Scraper Sharpening
By D. Greco
Fall 2012

I've been asked by a bunch of people what process I use to sharpen a card scraper. Along with that I've been asked how to make a burnisher out of those carbide bits that were included with the "special offer" scraper sets. So this past week I was on a mission to document as much of the process as possible so that I could write a somewhat comprehensive article on these subjects.

Burnisher construction
Lets talk about the burnisher first. These scrapers (like many that are out there) are made from spring steel with a Rockwell Hardness of 48 to 52. If you are not familiar with that hardness rating, don't worry. Suffice to say that this is pretty hard. In order to draw a burr on this you need a burnisher that is harder than the steel. Otherwise the scraper will be digging into the burnisher

So you start out with a carbide bit. I have these fully carbide bits with a 1 1/4" long shank. They don't need to be real long since you really only use a small portion of their surface. But using them by themselves isn't that practical. You need something to hold them with.

Now there are a lot of woodworkers out there who don't have access to a lathe. So I made a burnisher whose construction was based around a very simple dowel like piece of osage orange. In order to simply the assembly, no ferrule was used. In this instance, it's not really needed. The little twist I added was to include a 10 deg angle (off of 90 deg) to the face. This helps the user to draw the final burr at the "proper" angle.

So we start off with a nice piece of dry osage orange. This particular piece had been sitting in my wood pile since I milled it back in 2008.

Stock
        prep

After surfacing and cutting to size I ended up with a 1 1/4" x 1-1/4" x 6" long blank. I used a shoot board to get the ends perpendicular to the sides and then marked off the center of one end for a 1/8" dia hole. I then used my old pen blank drilling jig to drill the mounting hole for the carbide bit.

driling the hole

I then laid out the 10 deg angle on the blank and was going to cut it by hand. But in a moment of weakness I used my tablesaw to make an template for me to follow. I just tilted the blade over 10 deg and then used my miter gauge to hold a piece of hickory. With this template in place I could start the cut MUCH easier and with a heck of a lot more confidence in the outcome. I started the cut here and then realized that I needed a piece of scrap under the work piece. Other wise I'd risk cutting into my bench top.

cutting the face angle

After I established the face it was a simple matter to chamfer and then round over the corners of the work piece in order to make it more comfortable to hold. I sanded it to about 220 grit and then set the work piece aside.

Now far be it from me to EVER make just ONE of something. So here's how I made some turned burnisher handles.

Once the work piece was roughed to a cylinder I drilled the hole using a steady rest.

drill hole at lathe withsteady rest

I'll be honest with you here, this was overkill. The bit is so thin that it STILL wandered a tiny amount. I could have drilled these at the drill press with the same results.

Once the hole was drilled I just turned a profile between centers. I used a piece of thin walled steel and a piece of copper pipe for the ferrules. I sanded them to about 300 grit. Just because I hate it when wooden tool handle tool gets dirt in the grain, I Applied several coats of TruOil (to seal them) and sanded the work piece between coats. In the end I buffed them with a Beall Buffing System

apply finish

Now it comes time to pay some attention to the carbide bit. You don't HAVE to do this. But I found that by polishing the bit, you can tweak a bit more performance out of the burnisher. It'll slide over the end of the scraper easier and give you a better edge.

I gripped the carbide bit in the end of my drill chuck at my lathe (but you could hold it in the end of an electric drill just as well)

Polishing the carbide bit

and proceeded to sand it using Micromesh.

polish the carbide bit

If you've never used this stuff before, think of it as a super fine cloth backed sandpaper. It's used by pen turners to put a polished surface on acrylics and hard woods. If you wanted, you could probably use some 1500, 2000, or 2500 grit wet dry sandpaper. You are not sanding as much as you are polishing, or refining the surface. I worked my way up from 1500 to 20,000 Micromesh.

Then I used 3M Finese-It Car polish to polish it a bit more.
polish the carbide bit

And here is the end result.
polish the carbide bit

After the handles were buffed, I epoxied on the ferrules and then carbide bit. Here's that they ended up looking like.

finished burnishers



Sharpening a Scraper
Now this is the process I use. I didn't develop this. I merely found a process I liked and stuck with it. If you want to see how others do it, I would highly recommend going on YouTube and typing "Scraper Sharpening" in the search box. You will get a nice amount of relevant links. My favorite ones are from Lie Nielsen.

First off you will need some very very simple tools. I have a flat mill bastard file, a 2" x 10" x 1" thk block of wood, and a Sharpie. And of course, your burnisher.



I hold the scraper in my face vise and then I like to mark the edge with the Sharpie. That way I'll know when I'm removing material


That  2" x 10" x 1" thk wooden block has been milled so that it's face and sides are perpendicular to each other. This block also features a kerf cut along it's length. This kerf is just thick enough to hold my flat mill bastard file securely. Once installed the file will sit perpendicular to the face of the block. That means I can use it as a gauge to get a nice flat edge. Using that file and block assembly, I file the top of the scraper.



Once I have a nice consistent edge filed, I move on to "stoning" the edges. Basically this means that you polish the edge and end up with a nice even burr. However, it you just want to remove some paint, or want to work on coarse material removal with your scraper you can move to drawing the burr right from here.

I like to work on the faces first. Here you can see me using my old Scary Sharp set up to polish the faces. But I assure you, it works just as well with waterstones. I start at the coarsest grit (in this case 80 grit), and polish each side of the face.



I then work my way along and polish the face at the higher grits.


Until I've made it to about 400 or 600 grit.



Then it comes time to polish the edge. Here's where the block comes in handy again. I remove the file and use it to help me hold the scraper upright.



And then I repeat the process of polishing the edge




It's always a good idea to lube the burnisher a tiny bit. I like to use a drop of mineral oil.



After that is done I need to "draw the burr". First I lay the scraper on it's side and run the burnisher across the top. Not a lot of pressure here. I think Charlesworth says, "No more than buttering bread." and I think that fits perfectly.



Do this on both side and then clamp the scraper in your vise again.

Using a 10 deg angle, (or if your scraper has that handle angled face, use that as a helper!) draw the burr.



Do this on both sides, and then you're ready to give it a try!



Thanks,
Dominic