Saturday, April 28, 2012

A Japanese-style mortise gauge

To some of my readers, perhaps only the word "Japanese" makes sense in the title. No matter. All will be revealed in good time. A mortise gauge is a device used to mark out the sides of a mortise. A mortise, in turn, is a sort of trench excavated in wood. In this trench fits a similarly shaped peg, the tenon. M&T joints are as old as the hills. This summer's program includes a brand-new machine storage barn. I am determined to do it timber-framed. None of this nailing commercially milled lumber together. We will cut mortises and tenons and peg the whole thing together. It will last much longer than I will, unlike the ticky-tacky boxes they call "houses" these days.

Anyway, a mortise gauge is a layout tool. It will lay out the long sides of the mortise. If this is perplexing, stay tuned. We begin with the slider; it needs a rectangualr hole. I am using wood from a footstool that had fallen apart and been deconstructed.
What we have to do is cut a rectangular hole in a piece of wood. This is the way I did it. First, the dominant dimension in the scrap wood was 19mm, or 3/4" RGU. So we drill overlapping holes 19mm wide, and chisel out the rest so's it's rectangular. Behold the result above. A reasonable rectangle. Now we make the arms. These are nominally 19mm square cross-section, arbitrarily long. I could have made them much shorter than I did, but here is one of them:
That's one arm. The other looks just like it. In the middle there is an aluminum separator strip. This is to keep the arms parallel. The arms have to be planed so they are a tight, but not impossibly tight, fit into my rectangle. It is much easier to plane the arms than to enlarge the rectangle.
When both arms are in it looks like this:
Now, in the arms go the cutters. These things score the wood, and prevent tear-out when you actually make the mortise. I made them out of an old hacksaw blade (never throw good steel away). They were annealed, ground to shape, hardened and tempered. Then they were sharpened. Tedious but necessary. Now we had to make a slot in each arm to accept the cutter. I did this by drilling 1.5mm holes in a line and cutting out the intermediate stuff with one of my miniature mortise chisels (handmade, of course). When we got this done we had a respectable-looking Japanese-style mortise gauge.
There were some details, in which, of course, the Devil always resides. I epoxied copper rubbing strips to the inside of the rectangular hole, which, by the way, is itself a mortise. A through-mortise to be exact. The arms require wedges to hold them in place. But on the whole I am very pleased with my gauge. It cost nothing. Perhaps in the next episode I will cut a mortise for you to show you how it is used, and it has been used, and very, very useful it is. I have a commercial mortise gauge, but this one is much better, because it scores the wood instead of scratching it. This helps a lot; prevents tear-out when you actually cut the mortise. Next episode I may cut a mortise for you to show how it is done.

Thursday, April 19, 2012

Rustoration Part two

I am very annoyed with blogspot. They cooked up a new, improved interface. It is no improvement. It is a nuisance. I did not want it. I did not ask for it. They forced it on me, and I am peeved. But no rants. Let's get on with posting.

This post continues the previous one. At the Willow thrift store, I picked up an old breast drill for the sum of $3.50. This baby was not in good shape.
For those of you who have not heard the term before, let me explain. A breast drill antedates the electric drill by, ohh, 100 years. At the right end in the picture above is a sort of tang. It is broken. But to drill holes in metal, pre-electric drill days, you put a drill bit in the chuck, at left, and put your breast or shoulder against the tang, putting body weight against the work. Thus you could drill, by turning the crank in the middle of the thing, holes in metal by hand. It so happens I already have a breast drill, in much better shape than this one. But I have plans for this baby. It was frozen solid when I got it, so in this case what you do is take it apart.
There it is in pieces. There, also, is the tool restorer's best friend, WD-40. Many people say that if WD-40 and duct tape were banned, Alaska would come to a standstill. "If it doesen't move and it should, use WD-40. If it moves and it shouldn't, use duct tape," goes the saying. The toothbrush in the middle is to scrape grunge out of the gear teeth. Save them old toothbrushes, I do. Notice the gears. The thing is geared about 4:1. One turn of the crank gives you 1/4 turn of the chuck. When you are drilling metal this is a distinct advantage. On wood it helps a lot with big drill bits.

So all this needed was to be taken apart and cleaned out with a toothbrush. Well, a dental pick is useful too. Observe it at right of picture. There are days when I feel like a dental hygenist. Only it's gear teeth, not people teeth.

I have plans for this elderly gentleman. As I said, I already have a breast drill in much better shape. The plan is to make ol' elderly here into a drill press, hand operated of course. Stay tuned.

Saturday, April 14, 2012


For those of you who might be wondering about the title of this post, a word of explanation. Actually a whole paragraph.

Roger Welsch is an author who lives in Nebraska. At one time he was a regular on CBS Sunday show, AKA "the fat guy in overalls," his words and not mine. His real passion is old tractors. Since old tractors are also a hobby of mine, although not quite as intense as Roger's, we share a mutual interest. You can Google him easily. But the point is, Roger uses the word "rustoration" because he restores old rusty tractors. In my context I will borrow his word to denote the restoring of old tools.

All this began when I stumbled across a reference in a British blog, all about restoring old drill bits and braces. I happen to have a large collection of old drill bits, all of them in deplorable condition, at least for actually drilling holes. A collector would be outraged by my proceedings. Collectors, however , seldom drill holes with their bits. They put them in glass cases. Fie on that. I need to drill holes, and there is no room at Chalupy for glass cases. So I set out to restore the bits. Mr British recommended citric acid, readily available in Britain (not so much in the USA), plus methylated spirits (denatured alcohol to us yankees) plus dish detergent, known in the Isles as "washing-up liquid"). Hmm, said I. A weak acid. What do I have that is a weak acid? Why, vinegar of course. So I made a tray off of the bottom of of a laundry detergent jug, filled it with vinegar, and off I went. I left the bit in the vinegar for four days. I may not have citric acid, but I do have patience. The bit emerged much, much cleaner than before. I am sorry I did not take a picture of the original state. Color it old and rusty.
As you can see, the bit has changed color from very dark brown to something that looks like metal. Here it is, chucked into the Taig for further cleaning. I used the four-jaw chuck because it is impossible to chuck a four-sided object in a three-jaw chuck. The four-jaw is a very good chuck indeed, but it is a pain to set it up. The three-jaw Taig chuck is exasperating, but it self-centers. Sort of. Note my improvised cup center at the right. It is a piece of wood drilled through and cinched up in the tailstock. It holds the leadscrew, obviously impossible with a conical center. An application of sandpaper (the Willow hardware store does not sell emery paper, which would have been much better) the thing cleaned up quite nicely. It is badly pitted. On the pyramid that fits the chuck, we found the number "15," meaning that it is 15/16 inch or about 22mm. Old Gringo auger bits are numbered 4 to 16. The number indicates 1/16s of one inch, about 3mm.

Again, no "after" pic. I wasn't sure it would work. But encouraged by my success, I braved my way out to the shop and collected all my rusty old bits. I bought them for at most a buck apiece. Fresh vinegar and splosh! In they go.
Above is my ex-laundry detergent tray, filled with vinegar. Do use distilled vinegar for this gig; save your wine vinegar for salads. They had marinated about four hours when I took the picture. Be patient. As with other marinades, good things take time. Vinegar is really cheap. After about five days, the vinegar had turned black. Time to unmarinade. The bits looked amazingly like steel.
A bit of work with sandpaper and steel wool, and they are as good as new. Well, not quite. They have to be sharpened. The link will tell you how. The last step in the process is to spray the bits with Teflon lubricant.

There are alternatives to this process. You could use battery acid, which is sulphuric acid diluted, or hydrochoric acid. These are much faster than vinegar. Overnight, in fact. But they are nasty substances, and you have to dispose of them properly. When you live on the north end of a southbound septic tank, as I do, it is highly unadvisable to dump acids down the same. Poison. There is also electrolysis. I may post on this someday. For now I wil stick to vinegar.

Saturday, April 7, 2012

Waiting for Spring

Breakup is slow this year! It snowed this morning, maybe a whole centimeter. Gosh. It is now raining lightly. It seems, this time of year, that the snow will never melt. But the other day we went for a walk. Perforce we go on the road, because the snow, even with snowshoes, is impossible. But off we go. Out the driveway. What's this?
Look! Behold! It's the ground. Bare patch in the driveway! Exciting way to start your walk. So. encouraged, we persevere and get on Beryozova, giving Basargin a C- grade. While we are on it, we note the snow has left the roofs. Why that isn't rooves, I cannot say. English spelling, she is erratic.
The unheated shed still has full snow on it. Today, by the way, I went to one of the unoccupied houses in the village. It is roofless -- collapsed by the snow. On we go. On Bery, we have a pleasant surprise.
Nice big patch of bare ground. We amble down Bery about a about a klick and a half ("klick" is, or was, USAF shorthand for Kilometer) and come out on Crystal Lake road. This is a paved (well, chip-sealed) road, so we expect some melting. Indeed:
We conclude that there are indeed some signs of spring. We return home and have a cuppa, reassured that Nature is really doing her job. It is we humans who get impatient.