Thursday, February 20, 2014

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.

Friday, February 14, 2014

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.