Category: Crucible Tool

My daughter Katherine and I have just completed shooting and editing a short and free video on how I sharpen a card scraper. This technique works for both curved and rectangular scrapers.

This video shows a slightly easier way to deal with the faces of the card scraper. Several years ago when I started studying the burnishing of wood and other organic materials, I started wondering if a carbide burnisher was able to smooth and polish steel to the degree that fine sharpening stones do.

After a few years of experimentation with this technique, I have concluded that it works. And it works really well. I have stopped stoning the faces of my scrapers. So now my technique is to:

1. Burnish the faces of the scraper to fold any hook or burr up onto the edge of the scraper.
2. Stone the edge with a #1,000-grit waterstone to remove the fatigued metal and to cut a square and sharp arris (aka a corner). Then polish the edge with a #5,000-grit waterstone.
3. Burnish the faces of the scraper to polish the steel faces and start deforming the metal up to the edge to make the cutting hook easier to turn.
4. Burnish the edge with the burnisher parallel to the floor and edge of the tool.
5. Tilt the burnisher 7° to 10° to turn the cutting hook.
   

After sharpening hundreds of edges, I can report that the burnisher polishes the steel like a mirror. And the edge continues to improve with every sharpening as the polish improves on the faces of the tool.

I haven’t tried this with high-speed steel (HSS) burnishers, only the carbide ones. So feel free to experiment yourself. I suspect the HSS burnishers will work fine, as long as they are harder than the steel in the scraper.

If you want to see still photos of the process, visit this page we created.

If you want to make your own card scraper with a curved edge, visit this page.

You can buy the Crucible Curved Card Scraper here in our store.

You can buy the ARNO burnisher we use here.

— Christopher Schwarz

Our newest tool, the Crucible Pinch Rods, are now available for sale in our store. The price is $48.

We have been quietly selling these in the store for the last month in an effort to ramp up production and build up inventory before mentioning them here on the blog.

Pinch rods are our favorite way to check an assembled carcase for square. They also help you square up any out-of-square box, and they can be used for transferring measurements from one place to another.

Yes, we know that you can make your pinch rods from two sticks plus blue tape or a squeeze clamp. (You can also make a chisel from a screwdriver.) We decided we wanted to make something nicer.

Our pinch rods are based on an antique example we saw at Roy Underhill’s shop more than a decade ago. After seeing those, I immediately built steel versions for myself. But I always thought it would be nice to have a tool that didn’t look like it was scavenged from home center parts (which mine was).

Our pinch rods are made in Kentucky from brass and feature a custom-milled thumbscrew. The pinch rods come with two No. 6 screws for securing the hardware to the wood, which you supply.

The thumbscrew applies pressure in a concentrated point when you cinch it down. This makes a small indent in the wood, locking the setting, even if you drop the tool to the floor. (We experimented with versions with pressure plates. They didn’t dent the wood but they would easily lose their setting.) We are still using our first pair of sticks from the pinch rods I made 10 years ago with absolutely no problems. But if the wood ever becomes too chewed up in about 100 years, someone can easily replace it.

— Christopher Schwarz

I am pleased to let you know that we now carry the Bevel Monkey and Big Protractor from FirstLightWorks in the U.K. These two tools are essential if you work in angles other than 90°. They are well-made by a small company in Derbyshire, U.K., and are both dead accurate and durable.

The Bevel Monkey helps you set a sliding bevel to an exact setting – even a fraction of a degree. The white markings are easy to read against the black acrylic background.

The Big Protractor is just that – big, it’s almost 12” long. Based on vintage protractors used by geometry teachers on a chalkboard, the Big Protractor simplifies layout chores on furniture-scale materials. And it eliminates the squinting necessary when using a cheap plastic protractor from elementary school.

Both are available for immediate shipment from our warehouse in Indiana. Read more about the Bevel Monkey here. More about the Big Protractor here.

— Christopher Schwarz

It’s winter in the Northern Hemisphere, and the humidity has dropped in many climates. As a result, some customers have reported their lump hammers have gotten loose. Here’s how to tighten it up.

Wedging your lump hammer’s handle is part of its regular maintenance, just like tightening the handles of your handplanes and saws when the humidity plunges. No matter how tightly we wedge the head at the factory, it will come loose at some point due to use and the weather.

We included a metal wedge with your lump hammer for this operation. If you misplaced it, the quickest solution is to buy one at a local hardware store. They are usually about 25 cents.

Re-wedging takes a few minutes and usually lasts several decades. Here’s how we do it.

Clamp the handle in a handscrew and place it on a solid surface – the floor or over the leg of a workbench is ideal. Orient the wedge so it is 90° to the wooden wedge. Tap it in with a good-sized hammer (16 oz. or so). Drive in the metal wedge until it will not go in farther. Remove the excess wedge material at the grinder or with a file. Clean up the top of the head with sandpaper. Add a little oil to the wood if you like.

You should now be set for a long time.

We have just delivered a big batch to our warehouse – you can buy yours here. If these sell out, know that we have a second big batch that is almost done. We just need to do some quality control inspections and package them up.

— Christopher Schwarz