WEEKEND WOODSHOP

[lumberjim]

I want to build a Wardrobe. So I can go to Narnia. No, because I have no closets. yeah, that's it, no closets.

I like to watch New Yankee Workshop, and HomeTime and shows like that, but they blow through stuff so goddamn fast, that you really can't learn anything properly. So I thought it would be fun and mutually beneficial if those of us that have some experience with and tools for woodworking could work on a project each weekend and keep track of each other's progress. SInce I know of a few Bob Villas, and at least one TimTaylor I'd like to put a few people on the spot, and directly invite the following:

Happy Monkey
Griff
BrianR
xoxoBruce

Anyone else that wants to.

Does this sound like fun? We could all agree on a certain plan and take pics along the way as we construct it, and compare final results.

[Undertoad]

Can we make a bong?

[lumberjim]

no bongs.....remember tommy chong....

[SteveDallas]

One of you should build a telescope.

[Undertoad]

You can't fool us... that's a bong!

[SteveDallas]

It's a shitty scan. But it is a telescope. Completing it was a moral victory and I now use the factory-made models. But I observed the partial solar eclipse of 1998 with it.

[JeepNGeorge]

How bout a water filled tobacco smoking accessory instead of a bong then?

[Elspode]

You built your own Dobsonian, SD? I am now green with envy.

[lumberjim]

steve, could you teach us to make one? how much do you think you spent in materials for that? what's the magnification?

[Happy Monkey]

Unfortunately, I don't work fast, and I've got projects planned for the forseeable future, so I can't work on an agreed upon plan.

I'd be happy to post progress on whatever I'm working on, though - currently a very large knockdown bookcase, then a Winsor chair.

[lumberjim]

have you begun the bookshelf yet?

[SteveDallas]

Oh, my. The dob. The very fact of its completion is something of an achievement. But yet I never use it, and I have enough concerns about its quality that I'm not entirely comfortable giving it away to someone else.

(For those who are not, like Elspode, clued in on astro jargon, a Dobsonian or "dob" telescope is a newtonian refractor mounted on a simple "alt-az" or up & down mount. The idea is to make a telescope with a relative big aperture, mounted as cheaply and conveniently as possible. (A traditional equatorial mount large enough to support, say, a 6" Newtonian, is very cumbersome.) Named for John Dobson.)

Now the sensible person embarking upon the construction of a dob, will purchase a mirror. The masochist will undertake to grind the mirror himself. The sensible masochist will produce a "slow" or long focal-length mirror. The reason for this is that it's (relatively) easy to produce a spherical surface and much trickier to produce a parabolic surface, which is what you really need. The longer the focal length, the smaller are the deviations from a spherical surface needed to produce the parabolic. (For example, for a 4.5" f/10 mirror, they are so close you can just make it spherical and leave it at that.) The complete moron will attempt to produce a short-focus mirror, and this is in fact what I did. (It was a misguided attempt to have a happy medium between longer and shorter focal lengths, a tradeoff which I now know it is unwise to attempt.) So I pruchased a 4.5" mirror kit from Willmann-Bell (maybe $100?) and went to work grinding. It's a fascinating process, but not one I'm particularly interested in going through again. I ended up with a 4.5" f/5 mirror and sent it to be coated.

Meanwhile, I had acquired the 6" diameter cardboard tube, and I built, with much cursing, the mount. All of the wood is 1/2" thick plywood. The base's upper surface (hidden) is covered with a piece of "Ebony Star" formica, a variety which amateur telescope makers have found to be quite effective over the years. (The goal is to have complete ease of movement when you move it, and complete stillness when you stop moving it.) The "rocker box" on top has pads of teflon on the bottom which rest on the formica and rotate around a central screw. The semicircular cutouts at top of the rocker box each have two more teflon pads. The telescope tube is surrounded by a small box, more plywood, which is placed along the length of the tube so as to provide as good a balance as possible. On each side of this box is a black 4" PVC drain fitting, which lies against the telfon and provides the up/down motion of the telescope.

At the bottom of the telescope is the mirror cell, which is mounted on the back of the scope with 6 screws in such a way that the angle can be adjusted independently in three directions so that the mirror can be aimed or "collimated" properly. To provide maximum freedom from any distortion, the mirror "floats" between three equidistant vertical wood posts, held in place with silicone cement.

At the other end of the tube is the "spider" or holder for the secondary mirror. I forget what I paid for the spider and the mirror, maybe $60 or $70 together. There is also a helical focuser, another $40 or so, to hold the eyepieces.

I have successfully used the scope up to magnification of about 140x. Howefer, it's better suited for a lower power viewing of wider objects.

If you are interested, I recommend Build Your Own telescope and The Dobsonian Telescope, for starters, as well as the Amateur Telescope Making listserv. There are even a couple companies around that sell pre-cut kits, from basci 4" couple-hours projects to massive 20" monsters.

If I really felt like digging in again--and I don't, I don't have the time or the dexterity with tools, as I proved many times during this process--I would make a Schiefspiegler.

[lumberjim]

sounds a little technical, steve....cool, but a little advanced for what i was thinking....maybe we SHOULD start with a tobacco accessory??

Monkey,

i work slow too...i can usually only get about 3 hours or so at a time on the weekend to work on my projects....so i was thinking we would do one step at a time on a common project......i just made a bookcase, but the chair sounds interesting...i really wanted to do a wardrobe, and will whether or not this idea takes hold. I just thought it would be fun to compare notes and tricks with some other cellarites.

anyone else have the time/inclination??....the plans i have for a wardrobe look relatively simple.

[Happy Monkey]

I'm afraid I have - it's near completion (sort of), but I can put up some illustrative pictures if you like. I wanted to do some step-by-step photos, but laziness unfortunately won out.

[SteveDallas]

Originally posted by lumberjim
sounds a little technical, steve....cool, but a little advanced for what i was thinking....maybe we SHOULD start with a tobacco accessory??

I'm making it sound worse than it is. If you're going to buy the mirror instead of grinding it, the carpentry aspects are simple (if you're not a klutz with power tools).