Sunday, February 10, 2008

Potholes

My friend Rich came by the shop the other day and gave me grief for making the jointing in my last post look too easy (I think it was unrolling the shaving!). And he's absolutely right. One of the things that has always frustrated me about woodworking instruction in video and magazine form is that it is limited (for obvious reasons) to showing the correct way to do a task with a lot of basic assumptions taken for granted. It's like a road map that is showing you the correct route, but fails to mention that the bridge is out, the road changes to dirt sometimes and the journey is longer than you think!

I must admit, jointing an edge for gluing took me years to master. But it didn't have to. After much trial and error I came to realize that there are just a few major potholes along the way to avoid, and a couple of essentials for success. Once these are addressed, I can hand the task over to a novice and get great results.






The first major obstacle is of course sharpening the tool properly. In this case, it doesn't just mean getting a sharp edge, but a straight one as well. This can challenge even the most experienced sharpener. The photo above shows a plane iron and a chisel. Of course the plane iron is the tool for the job, but it is a terrible way to learn to sharpen. People trying to sharpen plane irons first are in for a nasty experience (hence all those jigs out there!). The bevel is too thin to easily balance on the stone while moving. Trying to develop the sensitivity and technique with this tool is just too much. So opting for the chisel, with it's much thicker bevel and narrower width is just the tonic. Master the chisel, and the plane iron will follow.


Below is a photo of a sharpening stone. You can see the black areas left behind after a few strokes on the drywall sanding screen. I have read about people using cinderblocks to flatten their stones, but this scares me to death! I find that the drywall screen is the perfect size and the piece of plate glass is easy enough to find.





Of course, the dark areas are the low spots and I keep rubbing the stone until it is one clean color like the image below.





So I've already done two of the most important parts of jointing and I haven't even gone near the wood. By choosing to practice with an thicker tool on a dead flat stone, I've laid the groundwork for success. I am working on a short video to show the proper strokes and grinding technique.

4 comments:

greg said...

I know using drywall sanding screens for flattening sharpening stones is common practice, but it makes me scratch my head. Sure you use them with known flat surfaces, but do you trust that they're manufactured to the flatness tolerance that you want your stone to be? I guess I should mic a sample population before I throw out my concerns here, but my gut tells me these things are cranked out with little concern for uniform thickness tolerance.

Peter Galbert said...

Greg,
I'm not sure that I understand your concerns about the sanding screens. They seem as flat as necessary to get the stones flat. I've never had a problem with them, but again, I fear that I misunderstand the issue.

Anonymous said...

Pete,

re: jointing two boards

Question for you...
Is it necessary to have the plane iron width be greater than the thickness of the board. (eg. Can I use 2" wide plane iron for 2 inch thick wood)

Thanks,
Chris in Colorado

Peter Galbert said...

Chris,
sorry for the delay in responding, I just restored my web access. Yes, a wider blade is much easier to get the results. Having a narrower blade will require multiple passes to level the edge and possibly leave a ridge in the middle. That being said, never say die, do it with what you have, you'll simply acquire a skill that most of us don't have!
Pete