Sunday, May 10, 2015

Table Progress - Part V

Last week we left off with half the steam bent parts for the table completed, so one would probably assume that this week I would get the other half done this past week. That would be a good assumption, except that suddenly summer pitched up. Since there is still another month and a half before the astronomical commencement of summer, I am gambling that there will be some cooler weather before then, and it will be much more comfortable to burn my fireplace for 6 hours when the temperature is not 32 (90 F) degrees outside. I did continue working on the table this week, though, and this posting will look at some of what was accomplished.

All central field parts joined now

In part 3 of this series, I began making the table top, but all the segments were not yet joined up. My process was to work it up in stages, joining three pieces at a time. Once these sections were finished, there were two planks left over which were intended for the ends. Upon reaching this stage, I joined two sections of three pieces, and one end piece, creating two halves of the top. The final step was to join the two halves together as you see in the above photo. After these last pins are cut off flush, I will do a final planing of the entire top to get one uniform surface. Once that is accomplished, it will be ready to add the inside and outside frame, completing the table top. In this photo you can also see the two extension leaves, joined, glued, and planed flat.

Another thing I began working on was the turning of the legs. Wood turning is fun and enjoyable, but it can also make a huge mess, therefore, I always do it out-of-doors. The warm weather was perfect for doing this, so I dragged out some pieces that were cut up a few years ago, and have been waiting for something to do ever since.

3 quarter sections of an elm log, rescued from a firewood pile a few
years back.

Unfortunately, these pieces were not quite large enough to get a leg of the size I wanted, so they will have to have a little extra material added. This is much closer to the size I need, though, than what one could get at a sawmill which is only 25 or 50mm thicknesses. (1 or 2 inches) These pieces were too long, which was good, because they had checked (cracked) at the ends; by cutting each end off, I was able to get rid of those problems.

cut to length (yes, with a hand saw)

In order to glue more material on the sides, they need to be planed smooth; in order to do that, I need two flat sides to be able to hold it in the vice. I mark a line parallel the edge, this will be cut off with a saw...

making a square edge

Once the edges are squared up, the pieces can be planed and the inside faces formed at right angles...

truing up the faces

Once these are finished, the additional material can be glued on.

gluing the additional pieces to get the required dimensions

One of the primary reasons most glue joins fail is because someone did not cramp it together well enough. To get a good join, the glue must be pressed into the pores of the wood, and the entire surface on both joining members must be thoroughly covered with glue, (but not an excessive amount). A good way to ensure that all surfaces are properly mated to one another is to use a lot of cramps. Care must be taken though, not to over-tighten them or all the glue will be forced out. If the glue was put on correctly and the cramping was adequate, these parts should remain firmly joined as one until some far distant future when the worms or fire reduce them to dust.

getting ready to turn

One of the hardest things to turn on a lathe is an out-of balance block of wood. In order to get it a little more balanced, I used a draw knife to remove some of the access material from the corners. I don't want to go too deep, though, because when I put it on the lathe, it may not be perfectly centred and then I might wind up with a flat spot on one side. It is rather difficult to find the centre of a non symmetrical piece; the best way is to use a compass set at the diameter you wish and make sure when you draw your circle that no part of it runs off the timber. This will automatically establish your centre point as the point where the compass pivoted. Once the edges have been knocked off, it is time to start turning.

Setting out the base of the leg

The first stage of turning something is to get it all to a uniform cylinder of the maximum size possible with the blank you are working with. Once that is established, I jump right in with one or the other end and start removing everything that is hiding the shape which I know is in the blank. I usually have a stick with my key points marked out as a reference to go by, but do not draw every ring on the cylinder, as they would very quickly get removed anyway; I just keep checking against my gauge as the work progresses. usually, when I turn two like pieces, they are done  together as mirror images of one another, but that requires having one piece long enough to get two parts from, so obviously I could not do that here. (The following picture shows an example of this method, but the photo is not very clear because this was actually a tiny object in the background of another picture)

A (not very good) picture showing
two parts turned in mirror image

Once one end has been established, I then work out the other end, which also establishes the overall length of the object. The material which is left on the ends of the turned object will form a tenon with which to join it into the horizontal members...

setting out the top of the leg

As I said a minute ago, my basic method of turning wood is to remove everything that does not have the appearance of the shape I am looking for; part of this process is to establish the basic shape I want and then refine it as it gets closer to the final dimensions. In the preceding photograph, though the basic final shapes have been established, they all need more material removed to achieve the desired variance between thick and thin elements. Carefully compare the final results below with this picture above to understand the process. In the above photo, the base is essentially the same diameter as the central section, but by reducing it a bit, I was able to get a more pronounced effect to the vase shape of the main body.

final shape; ready for finishing

And here it is, a leg of classical baluster form, with a coat of finish on it to bring out the grain. I used some powdered minerals and charcoal with my oil when I sanded it the final time; this enriches the colour of the wood. Since there are still many other things to do on this table, I will leave this leg on the lathe and continue applying coats of oil until I obtain the desired finish before removing it to turn the other leg.

first coat

Videre Scire

No comments:

Post a Comment