Stool pigeon part II

We have made great progress on the stool. In facr it is usable as it is. The remaining steps are shown in this post. The next step is to add the braces. The long braces are jointed. The short ones are put in with glue and screws. I had neither the patience nor enough material to joint them.

The next thing to do is to really attach the legs to the top, since I do not trust construction adhesive at all, and note the skirts in place. You can see the dowels I put in. That should hold it. Drilling the holes is of course tricky.

This double bevel stuff is tough. I wonder how the power tool fraternity would do it! OK, there she is. A bit of an error on one leg. Should use two jig triangles. Live and learn.

 After a few days of sitting on this thing I decided a more ergonomic design was in order, so I decided to carve it to fit my seat.

 

I used a fishtail gouge, a cheap Chinese item which I got a decent edge on it. That took a while. The gouge is to the left, mallet in center, and to the left is a scorp. This is a European-made tool, which I bought some time ago. The factory edge would not cut butter. It took a stick wrapped in sandpaper, my diamond hones and a lot of effort to get it to go. But it is made for exactly that purpose -- chair scooping --, and once sharpened it works quite nicely.  So we are almost done. Probably one more post on this one.

New Shop Inhabitant

For several years now I have struggled with HandyBandy, the portable bandsaw which I found abandoned in a pawnshop and which got a new stand, so it served as a cutoff saw. It long since has ceased to work correctly. The blade jumps off the wheels or gets jammed between the thrust bearing and the guides. No matter what you do to the tension. Being, I think, a Harbor Freight saw, all this is not surprising.

It was time for something new. From the "Little Machine Shop" I ordered a new bandsaw complete with stand.

It has a really solid stand and an equally solid vise. It fits the table. On its first run, it cut a chunk off an old torque wrench (or breaker bar) handle very nicely. If you look carefully you will see the chunk at the front. Since 99% of all lathe projects begin with a cutoff, this saw is a gem. And it cost no more than a Milwaukee saw of same size at Lowe's, without a stand!

Our new saw is, of course, named DandyBandy.

A stool pigeon

I am getting old. I think I have lived longer than any other venezuelan Rivero. The price you pay is aches and pains. So I can no longer stand at benches for extended periods. Backache, bad stuff. So I decided to make a stool to sit in front of the woodworking bench.

The first thing is the seat. I planed and edge-glued some scrap 2x6 together to make these, as shown above. At this point, I made a fateful decision. Obviously  if the legs go straight down, the stool will be unstable. Legs are splayed out for that reason. So I decided to splay outward in both directions. This is a double bevel. My bevel gauge is at Chalupy, so I had to pause to improvise one out of a hacksaw blade. This is by far the most complicated piece I have ever made, because of the double bevels.

The next job was to cut out dadoes for the skirts -- reinforcing pieces on the legs. I used my trusty rabbet plane for the purpose, as below.

 I figured that the skirts would fit into mortises cut into the legs. But wait, the legs are splayed! So I had to bevel the  bottom of the skirts so that they would splay outward, as well as cut a bevel on the edge. Then came the problem of cutting the double bevels as well as the mortises to accept the tenons. I had to make some holdit jigs as well, to get the angles right.

Above shows a view of progress to date. Three legs on, one to go.

Above, you can see the thing from the short side. It looks cockeyed but it isn't really. The whole thing is not square to the bench. Looked on square it is OK. You can see the bevel jigs taped to the legs, and I am using constuction adhesive to stick on the legs. Later I will dowel through. By far the most complicated piece I have ever made. I am sure the power saw boys would have done the single bevel -- but I think they would have to build a special jig to do the double bevel. So far no power tools have been used in this build. More later.

A Laser Centerfinder

It has been been while since I posted. I have temporarily abandoned the cutting of the last wheel on the clock, and have been playing in the shop. I have been looking at laser centerfinders ever since I saw Dan Gelbart's video, number 18 in the fabrication series. Also Gadgetbuilder's pages have a simple laser centerfinder. Out I went to OfficeMax and bought a laser pointer.

All these gadgets have a frame holding a cheapie laser pointer, used by presenters. So we cut two slots in a piece of Aluminum. Had to do it in the lathe because the mill is busy. Bigger endmill makes it faster. A 3mm shank is superglued in.

 

So I friction-fitted the laser in the drill press, made a pinhole in the paper taped to the drill table with the smallest drill I have, and tried this out. You must adjust the tilt so that the spot is centered over the pinhole. I found out (a) the laser spot is much too big. (b) Any adjustment you make does not stay put. Unacceptable.

To cure the big spot I made a pinhole from a scrap of soda can. Tried the thing on the mill. Now the spot is just fine, the adjustment still unreliable.

So we go off and make a frame with screws in it to hold the pointer still. At this point I took a fateful decision and cut dovetails to hold the frame together. It is very difficult to do such small dovetails with a jeweler's saw.

One day later and having remade one of the joints, I J-B welded the whole thing together. It worked. The pointer stays put. The peephole makes the spot very weak. You can just see the line I drew around the pinhole. Note the adjustment screws. There are three 4-40 screws, you can only see one.

I now have a working centerfinder. So on to other things. I got interested in soda (or beer) can alcohol stoves. The Internet is full of articles and videos on how to build these things. Mine work. I used Red RTV to seal the cans, could use muffler tape I suppose.

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Spring and Springs in Alaska

So we are a few days away from the vernal equinox, AKA spring. Strangely, I have been working on some projects that involve springs. And we have a surprise ending.

First we have the spiffy new handle on the dividing head.

This is a spring loaded plunger that pushes the prong into the dividing head and holds it steady. The plunger is pulled back to go to the next hole on the plate. It took quite a lot of messing around to get it right. I kept getting the spring backwards! I had to change springs several times; my supply of springs is limited. So that is one spring.

Next idea I had was a vertically adjustable Dremel holder. My first try looked like this:

The Dremel is held in the chainsaw attachment, already described elsewhere. This worked but it was very sloppy, so I spring-loaded the screws.

It works a lot better that way. The Dremel tends to lever it because this stuff is all Aluminum form Lowe's. A casting would be much better but I'm not set up for that. Bit too much slop. Have to think about that. As it is it is a hand-held Dremel router.

Well, that's three springs. While I was at it I clamped the thing to my homemade pantograph.

This worked surprisingly well. I realize now I have a pantograph with adjustable ratios, depending on where I clamp it. Bonus. It is nice to have a vertical adjustment. I hand-made a set of templates, seen at left. I am holding everything down with two-faced tape. Not ideal, but it works. I m encouraged. Springs are  wonderful.

Finally, "spring" also means a season of the year. The Vernal Equinox is March 21 or 22 depending on a lot of things. This is an astronomical datum. Alaska has its own ideas:

About 10 cm or 4" snow yesterday. Biggest snow of the year. Of course we were (still are) in the El Nino hotspot. No snow to speak of, until yesterday. A day late and a dollar short. No skiing. But it was nice to have the snow, and a fire welcome. Observe Miss Mocha curled up on her tuffet at the right of the picture. Right out of Currier and Ives.

And today the temperature went way up, +6C or so I do not expect winter wonderland to last very long. Spring, one way or another, is here.

The 120 tooth saga n the Isaacs clock

The biggest wheel on the Isaacs clock is a 120 tooth monster. As I said before, when I made the pinions I inadvertendly went from module 0.6 to 0.9 and I am unwilling to redo the pinions. I calculated that the biggest wheel on the clock  it would fit on the lathe i.e. I could "swing" it. So it did, but this whole 120 tooth "great wheel" is a monster fully up to Godzilla's standards. I calculated that a 120 tooth wheel would fit the lathe. I had no idea how close that calculation was.

I cut these things out on the bandsaw. Then I turn them down to the exact diameter on the lathe. It is something like (N + 1.76)*M (M is the module and N is the number of teeth, and if anybody is screaming about this remmeber these are cycloidal bears, not involutes). As you can see it clears the little Taig by about 2mm and I had to file it a little to get it to fit!

Next we need a pair of backing disks for  the wheel. I like the kind of board called masonite or its like. It does not matter if it is a lot off-center, its function is to support the wheel in its odyssey on the mill.

Now my dividing head has a height of 50 mm. Unfortunately at Module 0.9, the radius is about  110mm so I am a bit short. What to do? Why, riser blocks.

Above 100 tooth wheel for comparison.

A 100 tooth just barely fits without blocks. So... First I tried putting it on the left side of the mill. Note the riser blocks. Note the clamping. Also note I have not supported the wheel. Two big mistakes in one go. Unsupported Lexan wheels flex and lead at best to inaccurate cuts. At worst to "crunchies" where you wreck the wheel beyond repair. Worse yet, I am "climb milling." the cutter is fed in the same direction as the cutter moves. Sometimes this does not matter. On all the previous wheels it didn't. But this is a huge wheel relative to my equipment. So remove the vise, go to the right side of the mill.

Much better. Now I am "conventional milling" and the cutter moves opposite to the feed. I am still having problems. Stay tuned.

Cutter project II. Getting there

I have been remiss in posting, but other things have interfered. As usual.

So we continue with making four-tooth cutters. We are getting there, but not quite. Still, progress. I am using 3/4" (20mm) supermanium steel from Lowe's. First step is to turn it round. The exact diameter is not critical. Then we slice off a 5mm slice. Hardest part of the whole thing, because The Taig does not like to part 20mm of steel. Then we put it on the drilling jig, and drill four holes in it. Equally spaced, if our drilling jig is up to snuff. I made on the mill, it better be! Then we mount the slice on the eccentric arbor which I have described previously. Here it is. As you see, one piece of the round sticks out. Exactly what we want.

Now we proceed to turn a certain amount of material off. I have to watch the dial on the cross-feed very carefully. I mark the dials with a sharpie. What we want is a sort of square, but with rounded sides. We have to rotate the blank 90 deg after the full cut has been taken. After a while we start getting the shape of a square. Again, sharpie keeps me on track. After a series of cuts, we have to unbolt the piece, rotate it 90 degrees, and make some more cuts. The circle of holes go successively into the pin in the eccentric mandrel.

A closer view. Getting to square.  When I get a sharp corner I am done. Now comes the hard part. We have to form the radius at the bottom of the cutter. For this we use a form tool shaped like the radius of the cutter. It is less than 3mm. The form tool is plunged in. But setting it up on center is very difficult. I have since learned about something called the button method, which I intend to try. The Taig has no way to measure transverse feed. Unless you fit the compound. The Taig compound is very flimsy and I don't think it would work. A dial indicator would be great, but nowhere can I fit one in; the lathe is mostly aluminum. So my radii left something to be desired.

Next we take it over to the mill. I made a fixture -- a square wih a hole dead center -- so I can turn the thing over. Using an abrasive Dremel cutoff disk we "gash" the teeth. I did not get any pix, but it is in the previous episode. In the next pic, I have gashed radially at the corners.

Then we rotate the piece 45 deg and gash again. One advantage of using the cutoff tool is that your cutter faces are automatically sharpened. You can see one of the teeth pointing at you, one in profile to the right, and even see the relief on the teeth. The relief is the sole reason we went to the eccentric arbor and the holes. Without relief, the cutter won't cut.

Still have to work on the radius. But this is much better than my previous attempt. Onward.