Tuesday, July 13, 2010

It's not the Heat...

It's raining here, finally. We've been in a dry spell lately, and the only rain that we saw for a couple of weeks was dripping of of us as we dealt with near record heat. My student, Mark, and I sweated our way through a continuous arm and learned a little something about wood and humidity.

We pulled Marks stretchers from the kiln (opening the kiln was a punishment in and of itself) and started to do my normal assembly procedure. The only problem was that in the short time that it took us to drill the legs, the tenons swelled .005" or more and the first joint that we drove home made a nasty split down the side stretcher. Granted, the joint may have been a bit tight in the first place, and the mortised piece was drier than usual, but this was ugly.

I'd seen this before, the twisting that we applied to free the tenon threatened to turn solid wood into a rope of separated fibers. It's something to see a complete spiral fracture in hard maple.

So I decided to take the other route, split the mortised piece, thereby saving the tenon, and turn a new side stretcher.

Sometimes getting in a pickle leaves the student more informed and a bit more comfortable with the notion that we all get in a bind sometimes and it isn't the end of the world, or chair.

Below are a couple of photos that were requested by blog readers. The arm below shows that the continuous arm bend is about 72 degrees. With a 7/16" arm, it works out fine.

And Greg, here is the hoop pattern for the childs balloon back. I'll be teaching this chair again in October down at Highland Woodworking.

I do my best to keep up with reader requests, but please forgive me if my schedule delays or doesn't permit my immediate response. Good luck.

Friday, July 2, 2010

More Diamond Talk

So I've gotten a lot of questions about the diamond paste, I guess I let my lack of experience tie my tongue. I got the paste that I used from this link on ebay.com

The photo you see above is the beech with the various grits. As was mentioned in the comments on the last post, I found that the most effective use of the compound was in the final honing or stropping of a tool. I didn't see much point in starting with the rough stuff, but I bought it so, why not?

Like all sharpening, the edge is only as good as BOTH surfaces that meet to make it, so I do polish the flat backs and inner surfaces of the tools with the diamond paste. In the last post, you see a small dowel chucked in a drill that I charged with compound and used to polish the flute of the gouge in the photo. The diamond moves metal, period.

I've also charged my leather strop that I use on my drawknives and noted a huge difference. I used to judge whether a tool was sharp by the waxy surface it left behind when cutting end grain of pine, now the surface looks downright wet.

I've always advocated putting your cash into sharpening gear first, and when you compare the price for this stuff with the cost of a single stone (not to mention the $300 flattening plate that I've been eyeing), it's a bargain.

Thanks for letting me know your experience with this stuff, I enjoy being new to it and learning from you.

Thursday, July 1, 2010

Speaking of Diamonds

I don't know if you caught it, but after my last post, boasting of my brides' lack of care about diamonds, she mentioned that Joseph the goat could use a diamond collar, hrmmph...Well, have I got the diamonds for him. A while back, I was reading Ron Hocks Sharpening Blog about the role of diamonds in modern steel honing and saw the light, as they say.

Old school carbon steel has all the qualities that I want in a tool, save one. It's easy to sharpen because it's soft enough and it can get sharp as you could ever want, but it can rust (which I take to mean that you aren't in the shop enough) and it dulls relatively quickly.

So, with all our technology, we've added some elements such as chromium, to retard the rust process and also to prolong the durability of the edge. The main problem with this is that the edge that we get with traditional cutting honing stones doesn't get these particles properly sharp.

I've come to think of it, with Ron's help, as a chocolate chip cookie. We can sharpen the cookie, but the chips, they need something more.

This is where the diamonds come in. The diamonds can cut the chips and get these ultra durable particles sharp, so I've heard.

To test this myself, I went online (boy you can get anything there) and found some diamond paste for 3 bucks a tube (in China, diamonds must be a seasoning). After the wait for transit, I found that indeed, I was able to get all of my modern steels significantly sharper by simply honing them with the paste. For my plane type blades, I rubbed the paste on an old black Arkansas stone, honed as usual, and was thrilled to watch my spokeshave conquer curly cherry to a glistening finish. I did the same with my high speed steel turning tools.

For my concave spokeshave, I tried something a bit different. I turned a piece of beech that I culled from around my spring (now the spring doesn't dry up in summer) and applied the sequence of pastes down to the finest 1/2 micron, which equals a 30,000 grit stone. I kept the beech spinning in the lathe and carefully rubbed the edge on it. A real revelation, I'd never, in the 11 years that I've worked with this tool gotten it this sharp, with so little effort.

I was doing this during the down time while teaching a student, who couldn't help but tease me as I grabbed every tool in the shop and tuned it. So, I suppose there is a moral to this story, but who cares, my tools are sharper and it's easier to do, what more do you want??...diamonds