The Cobblers Children

The old saying "The cobblers children have no shoes" has fit the bill as far as my most recent chairs go. I have not had the time to make myself one of the cherry chairs with the bent spindles that I have been making for clients. People like to tease me about the amount of chairs that I must have, and it's true, I am tripping over them constantly. The only problem is that the chairs that I own are all of the early ones and I generally watch as my best work goes out the door. Well, finally my shifting of my business plan has afforded me the time to make myself a chair. I have gone from taking orders to taking names on a list that I can call when the time affords. This wonderful piece of business advice came from my friend Curtis (hey, when are you going to start taking your own advice?!)




I decided to use the last of my hickory log to create a dramatic contrast with the spindles. Hickory is one of my favorite woods for spindles. I hardy ever use it for bends, even though it often bends beautifully, because it tends to shrink dramatically and therefore check a lot. In most chairs, I find hickory too strong, leaving the back inflexible. I tend to use it in combbacks where the spindles offer the only support for the upper back or when it's strength is of benefit.
I wish that all spindles called for hickory. Once you get used to the lack of obvious clues (such as the rays in white oak), shaving with the fiber line is easy and no wood has the creamy texture of hickory. My sawyer calls me when he gets a great hickory, and luckily, fall is here and it's time to get a new one (they rot in summer!).
Now my only challenge is to hold onto my new chair, in the face of the mortgage, the insurance, and oh yeah, christmas is coming!

Parting Tool Grinding

Honestly, one of my favorite activities is trying out new parting tool grinds. (Maybe I need to get out more!) There are a whole slew of them and my favorite tends to be the one that I'm using at the moment. The most important factor in parting tool grinding is of course frequency. I grind all the time. At this point I don't bother to hone my parting tool, I simply grind it and knock the burr off by dropping the tip into a block of soft wood and then get back to work.



Above is a photo of my technique for grinding the lower facet of the bevel. By grinding it on its side, the facet will curve (slightly) from side to side. Below is the grind that I use on the top facet. It imparts the curve from the toe to the heel of the bevel. By have the facets curve in different directions and meet at the tip, a slight spur is formed at the corners. The spurs help ensure a clean cut.



It is crucial that the grinding be done square to the axis of the tool. The diamond shape can make this tough to see. I like to look at the relationship of the bevel to the square edges at the top and bottom of the tool. Below is a picture of the (relatively) square grind.


alt=""id="BLOGGER_PHOTO_ID_5119823658096405218" />
To function properly, the two bevels should meet and form a square line across the tip of the tool that seems to connect the widest part of the diamond. It is critical that the actual leading edge be square to the axis so that readings of the dimension of the workpiece not be thrown off by an angled surface. I don't have any absolutes as to the angle of the grind, I tend to freehand the top bevel on the wheel, and then get back to work. The lower bevel only gets ground when absolutely necessary because it takes a time consuming set up. Improving the performance of this tool may seem to be a waste of time, but I have come to see a smooth cut into the diameter of a fresh turning blank as gratifying as the final sweep with the skew.

The Lowly Parting Tool

I am going to focus a couple of posts on the care and proper use of the much maligned parting tool. Here is a turning tool that is most often abused, misused and treated as an necessity rather than a choice. The parting tool sets the diameters for all of the details in spindle turning but gets none of the glory of skewing a perfect surface or cutting a flowing cove. I have seen many turners grit their teeth while jamming a dull parting tool straight into the spinning piece, the vibration, noise , and yes, the smoke! confirms the lowly status of this tool.

I'll talk about the sharpening process later, now I'd like to pretend the tool is in top notch condition and focus on technique. Below, you see a 1/8" diamond parting tool (I am thrilled to find that Sorby still offers these). The diamond shape helps to ensure that the tool won't bind in the groove that it is cutting. The widest point of the tool is 1/8" which helps reduce vibration. As I've noted in earlier posts, vibration begets vibration, and by using the parting tool correctly, this initial rumbling can be avoided.




The key to cutting with the parting tool is to use a shearing cut as opposed to a scraping cut. This is best achieved by rubbing the bevel of the tool against the (fast) spinning work piece and slowly raising the back of the handle until the cutting edge makes contact. At this point a shaving will shoot along the top of the tool. Here is where many go wrong. Don't just continue lifting the handle. This will transition into a scraping cut as the diameter gets smaller. Instead, feed the tool into the cut by pushing forward. The result of this may be that the cutting edge lifts out of the wood and the tool will once again be rubbing on the bevel.
This is fine.
Once again raise the rear handle and engage the cutting edge. When done correctly, the rate of feeding the tool forward and the rate of raising the rear of the handle will keep the tool cutting high enough on the round to maintain a continuous shearing cut. Above is the correct position to hold the tool when cutting a large diameter. Below is the correct position when cutting a small diameter. Notice the different angle of the parting tool, but the relationship to the diameter is the same as far as the cutting edge is concerned. The skill is maintaining that correct angle as you cut from one diameter to the other.
It is definitely better to stop cutting by feeding the tool forward too much than to let the tool scrape. To make the whole process a bit tougher, wiggling a bit side to side as you cut will also help the kerf stay wide enough to reduce vibration.




Below is the scraping position, easy yes, but it will make it hard to love this tool. I have come to enjoy my parting tool now that I shear cut, grind often and give it that funny wiggle. Grinding is next.