Shoot that frame!

Usually one thinks of "shooting" as pointing a gun and pulling the trigger. But this word has a meaning that probably goes back to the Romans. Maybe they made picture frames too, although I doubt that any are left. Most of our extant frames date back to the Renaissance. Those people really did shoot frames. So what do I mean by "shooting a frame?"

When you make a picture frame (think of the last frame you saw, or have hanging on your wall) with miterered corners,  there are three requirements. One of them is that the pieces should be cut at exactly 45 degrees. The second is that the  dimensions of the pieces should be exactly the same. Especially the inside dimensions. The third is that the mating surfaces should be as smooth as you can possibly make them. Otherwise it looks, well, amateur.The big boys -- the pros -- use a guillotine-like affair. This is beyond my means. A miter joint is a really weak joint, you would not like to use it for furniture. For picture frames it works all right. Just.

You could concievably cut miters (Britons read mitres) at any old angle. Say 30 deg. But then the mating part must be cut at 60 deg because the frame is rectangular. The jigs required to get this straight would be quite complex, unless you resort to CNC cut frames. So most of us stick to 45 deg, half the right angle.  I did too.

The crucial step is to build a shooting jig.  Here it is.

It is basically a scrap board clamped in my woodworking vise, which is attached permanently to my dining room table. I have a very small house; everything is multi-purpose, especially in winter. It is really a very simple jig, but it took me all morning to tune it. There is a triangular piece screwed on to the board.  There is a rabbet (Britons read "rebate" which is where our corruption comes from) and the angle between the rabbet and both sides of the triangle is 45 deg as accurately as I can measure it. It took quite a lot of planing (and a very accurate protractor) to get the angles right.  In the rabbet slides my trusty Veritas rabbet plane. Expensive. Worth every cent of it. My frame member is clamped (you can just see the clamp upper left) to the jig. When you plane across, left to right, you shave just a tad -- 0.1mm at most -- of the approximate saw-cut miter. This is called shooting the miter. Adjusting this thing is very difficult. Takes patience. But by George, your miters will be at 45 deg. This is a very old-school technique. Most people use CNC equipment for this nowadays, I suppose.But shooting makes a glass-smooth surface, especially with the Veritas plane which is a low-angle plane.

When I was all through with the shoot, I had a big gap in my frame. Surprise! My dimensions were way off. One piece was a full 6 mm off the other, which is suspiciously close to 1/4". When I laid this out at my daughter's place, I had very primitive layout tools so I suspect I made a mistake because I really cannot deal with RGU. So now I have to take 6mm off one side. I got down to 3mm and then decided to take a break and go back to machining my steady rest. Next post.

A picture frame

As I think I mentioned I spent two weeks in Anchorage. As a project, I determined to make a picture frame. I brought my carving tools with me. I should have brought some more, but that is hindsight. So we went to Home Depot and bought a pre-milled molding. I hate these things, I want to make my own. But needs must when the devil drives, as they say.

First task was to lay out the molding and saw it to size. Later on I found just the tool I needed by my bedside. Too late. So there was a big mistake. I laid out the wrong angle on the molding.  Regardless,  I had to carve it.

Now, carving these thing is not something I am going to tell you about. I am following Chris Pye's book. You can buy the book, or go to his website. I think he even has a blog. If you are going to do carving I think you can do no better. If you cannot follow Chris Pye, perhaps you should take up Origami. No insult intended; some people do Origami very well indeed and it would be very boring if we all did the same things!

This is a repetitive design, and it requires painstaking attention to detail. There are obviously four sides to a frame, and they have to match up. You can see my carving tools. I made them all myself, see my Microforge label on this.  It was difficult in Anchorage, because I did not have any sharpening materials. But my daughter came up with a Japanese waterstone, which saved the day. I will not use anything but Japanese waterstones for final sharpening. If you do carve, you will find you need razor edges and mirror finishes (I use a leather strop charged with rouge for final edges. There is a sharpening label on this blog.) .

So one of the problems of the Anchorage sojourn was that  the corners of  the traditional miter (or mitre, whichever you prefer) were not at 45 degrees. Oops. So back at Chalupy I laid out a 45 deg miter and cut it out with  a Japanese razor  (Dozuki) saw. I hate western backsaws. Clumsy wide-kerf things. In retrospect I should have built a mitre box. Act in haste, repent at leisure. I did cobble up a jig. Not precise enough, as it turned out. I do have a miter box, but it does not coexist with my Japanese Dozukis.

After a while I evolved the improved jig above. This was much better. So I have two decent miters and two bad ones. This is OK. I have to shoot the miters anyway. That means plane them to the exact angle. I will have to build a shooting board, and I am still mulling this one over. If you are going to build a picture frame it had better fit. And, as you all know, I hate power woodworking tools. So some time spent on a shooting board will yield future dividends.

I spent this morning making up some corner clamps. Getting eveything perfectly square meant resorting to Cecil B. De Mille. I milled the things as if they were metal, first cutting them on the bandsaw. Yes, power tools. But I think all means are fair when you are making jigs or fixtures. Get it out of the way! It was an interesting milling exercise, it took me two hours to figure out how to do one of them and then about half an hour to do the rest. The problem is that the corner clamps were much too big for my micro mill. The corner clamps are tensioned by string and ice cream sticks. Be sure to wind the sticks the same way!

At the end there is the provisional frame. There are some huge gaps; I don't think they are so visible in the picture. But they are there. On to shooting the miters. We will overcome. This is a fun change from metalwork, and we might yet have a frame. Stay, as they say, tuned.

Steady Rest, some more

I have been away in Anchorage for the last two weeks. Although I can post from there, the laptop I use drives me to distraction. Most of this is caused by the touchpad cursor; I suppose I could do something about that -- but the laptop also runs Ubuntu Linux, which I hate. Just me. I could fix all these things, but I don't feel it's worth the effort.

While I was in Anch I did some carving, a pleasant change from machine work. That's a future post. I would like to record progress on my steady rest.  All of it before I left for Anchorage.

I finished milling the dovetail slides and for improvised cutting setup it was a very good fit. I was pleased. I will have to drill and tap some holes for fixing screws, but that comes later.



 Next picture: the body of the steady. It will be screwed to the dovetailed piece.This is just drill and tap. I will not show it.

Now comes the really crucial step. I must put a great big hole (25mm) in the vertical plate. The center of the hole must be exactly at center height on the lathe. Once  you get the hole drilled, the center is gone! So I put a sharp point in the lathe chuck, and located the centerpoint by tapping the work with a hammer. That is center height. (The nominal height is 2.5" or about 62mm, but it is not advisable to rely on this.). we have a centerpunch mark. Right where it belongs.

So we can drill a pilot hole on the punch mark.  Now if I could chuck this in the lathe I'd be in clover. I could bore it out with a boring bar. But the upright will not "swing" in the lathe. Obviously -- it is at center height. So we will have to mill it out. The big boys do this on a rotary table. I have no such animal. It costs almost as much as the mill! So instead I built a fixture.

 Somewhere on my walks I found a very heavy piece of steel; whence it comes I know not. But I drilled my work something like 6mm and also my fixture, more or less in the middle. I pushed the work on to the pin. Then I could rotate the work around the pin, with my hand. So the cutter cuts a circle. Keep increasing the Z axis till you go through. This is definitely the pauper's rotary table! But it works. As Tom Lipton says, "we're all heroes in Aluminum".

After this, all that remains is to screw the upright back on, drill and tap the fixing screws, and make the fingers. 

Bought some aluminum to make the fingers. Haven't done a thing yet; busy carving. At least next post will be a relief from all this machining.We'll be doing some carving in wood for a change.

Steady Rest Redux, and some misadventures

I really started out to make a feed screw for the Taig lathe. Really I did. What I have found out about this machining business is that to make A, you have to first make B. However, that entails making C and D and so on, so sometimes you lose track of where you are.

I actually did make a feed screw. It was a 1/4"-20 RGU feed screw, approx. M6x1. It was far too flimsy.  I knew it had worked for Dean over on  http://www.deansphotographica.com/machining/projects/projects.html (look under "feed screw for the Taig lathe") but I found it very wobbly. So I needed a bigger screw. I am limited by ready availability, so maybe M10x1 would do it. Not for sale at Home Depot. Maybe 3/8"-16? This is about M10x0.75. But, here comes the problem, I cannot get a 3/8 screw through the bore of a Taig, so ... we need a steady rest. I made one before, see label "steadyrest", but it is too flimsy, just like the 6mm feedscrew. 

I had used a wood-turning attachment as the base of the old steady. It worked. But not really steady enough for what I want. So first I have to make the slide. This is a 45 degree dovetail slide, about 7mm on perpendiculars. So I set out to make the slide.

I had some 1/2" (12+mm) steel so I traced the outline of the old slide onto the new stock. Then I had to mill it out. And now we come to making C. I wanted to use my new Christmas present, a 4mm endmill. The bigger the endmill, the less work. But Cecil B. de Mille cannot chuck a 4mm bit.The biggest chuck is 3.2 mm or 1/8" RGU.

Now you cannot possibly turn down a 4mm mill shank down to 3.2 mm, even with carbide tools. The stuff is much too hard. But you can grind it down. So I mounted my trusty Dremel on the cross-slide. The adapter you have seen before, it is part of a chainsaw sharpening attachment. It ate the grinding wheel to a nub, but it worked. Sort of. Alas, I had a taper on it. It is very difficult to get the Dremel exactly parallel to axis of lathe. I finally set up a dial indicator.

I am getting far too much runout. (Off-center error), 0.1mm or so.  I actually did grind it down to 3.2 mm at base, but it tends to squeeze out of the chuck. Disaster. Time for another plan. 

I set up the vertical milling attachment on the Taig and put a really big (12mm) bit in the chuck. This is a no-no. You are not supposed to do this. I did it anyway and it worked.  So I "hogged out" most of of the slide by this method. I must say it was a pleasure to take really big cuts. By my standards anyway. So now we can clean up on Cecil. I put the bar right on the table and held it down with toe clamps, just like the big boys on YouTube.

The next job is to cut the 45 deg slots for the dovetail. The big boys use dovetail cutters. I haven't one; and it would never fit in my mill anyway, so we improvise. Using a protractor we tilt the piece to 45 deg and mill straight down.

Here you see the first dovetail cut. I am setting up for the second. Tomorrow, all deities willing, I will start cutting it. Then I can worry about the rest of the steady rest. Then I can worry about the feed screw. Whay did I ever take up machining? Because, in the end, it is fun. Getting to the end may not be so much fun, and is sometimes very frustrating. Life, after all. 

Chain Mail, the coda

So we come to the end of the chain mail saga. I have made enough rings to go around the earth, or so it seems. One last thing to make. It is only fortunate that the recipient does not read my blog. She is much too busy! This number is a fine-mesh, 3/8" or about 10 mm as opposed to my usual 13mm rings. It is harder to do the small rings than the big ones. I have tried 6mm rings and I consider it almost impossible.

 As usual it is a pendant plus a chain. All in 4:1 mail, which means that each center ring links four side rings.

In this piece, the center rings are copper -- salvaged electrical wire -- and the others are steel, 14 gauge fencing wire. Very cheap stuff. I like the contrast. There are two pieces. the pendant and the chain to go around the neck. Here is the pendant. I like the contrast of copper and steel. Picture has a slight yellow cast to it. Sorry. Blame auto-exposure.

 The chain is single-strand 4:1 chain mail. If you were making this for protection you would not use copper, you would use all steel. But I'm making it for decoration. I want it to look nice; protection is merely symbolic.

The wire at the top of the pendant is there to stiffen it up. It does tend to sag, but I think I will remove the wire and just put in two more linking rings into the top.

And I am now really through with chain mail. If disaster comes and we all revert to the middle ages, at least I could make a living as an armorer. Although by now I am quite deft at this, it is very labor-intensive. But then, another word for the middle ages is labor-intensive. No machinery allowed. Glad I did it, but enough is enough. Now back to other things, such as my clock.

The mail must move!

Christmas is over. So everyone has their presents. So now I can show some of the constructions! For my daughter I made a copper/brass mail thingie. Call it a necklace or call it a wall hanging, doesen't matter. Didn't get pictures of it. Here are some of the construction steps for another one.This is for a dear friend. It is a "necklace" of sorts. It could also be used for a wall hanging. It is made out of salvaged copper wire.  And other things.

I made a maltese cross out of sheet copper that I happened to find in an antique shop! In the middle of it is a mandala. Well, maybe it isn't really a mandala. It is in fact a piece  of a defunct VCR player, which I deconstructed. Remember those? Does anyone remember a videocassete? The coil  was so elegant that I knew its ultimate fate was to become a mandala. Sitting off to the right is the neck chain. This is a copper/brass single-strand contraption. In order to be artistic it was very, very slender wire, what bead-stringers use. One uses what one can find in Alaska. It was so flimsy I had to solder all of the brass rings. This was a lot of work, but I couldn't have things coming apart. Unseemly language was used in the construction. Contrrary to popular belief, it does not help at all, but  it eases frustration.

Fortunately my butane torch behaved itself, as it seldom does in winter. I used silver solder, much stronger than the lead solder used for electrical work.

Above, the top of the "necklace" has had a wire rod soldered to it. This will keep it from sagging. The neck chain has been tied in and soldered. I happen to like the intersection of art and technology. Just as well, because otherwise this piece would have driven me crazy.

I really like this piece. It is all proper chain mail. It is also symbolic, but I will leave this aspect to the art critics. They have to make a living too, after all.

A post where I don't tell you anything!

Beacuse if I did tell you what I am doing it would spoil Christmas. I am making chain mail, though. I already told you that, no surprise. Fluffy is getting something different. This chain mail thing is really interesting and has lots of possibilities. But it is really labor-intensive and time-consuming. No doubt armorers in the middle ages got quite wealthy turning out these hauberk things!

But it is all great fun. Be back after Christmas, unless weather intervenes, which it usually does in Alaska. Always safe to talk about weather.

Back again soon. Your friendly armorer wishes you a merry Christmas.