i am building a 3x6 router and i am using 3\8 threaded rod i need a way to hook it to my stepper motors they hasve 1\4 shafts

You can by couplings at http://www.mcmaster.com that will fit both sizes. Or, you can have a machine shop turn the ends of the screws down for you.

natchex-what tools do you have available?

very basic tools

While this isn't a truly ideal coupler, it should work sufficiently well.

Get yourself some flexible "high pressure" hose at Home Depot. The stuff with the fibers embedded in it. Get it for 1/4" inner diameter. Cut off a piece that's about 1 or 2 inches long.

Take a drill and drill out a 5/16" hole in one end. Tap it with your 3/8" tap.

Screw it onto your threaded rod, and just to make it secure, add a worm hose clamp over the threads. Now, slip it onto your 1/4" motor shaft, and use another worm clamp to secure that connection.

Works amazingly well, and costs virtually nothing. In fact, if you find someone nice at Home Depot, they'll often GIVE you a piece that small.

-- Chuck Knight

thanks i will try that

Doesn't have to be worm clamps, either...but they do work extremely well.

My own leadscrew was chosen as 5/16", because it would thread into a 1/4" ID tube...reaming out the inside of one end should allow you enough clearance to get your larger lead screw in there.

Let me know if it works...I haven't tried this with a larger dia screw, so it's untested.

-- Chuck Knight

off the subject for one second. Chuck what are you holdin in your pic. just wondering.

CamIam - that is good advice, except sometimes the Z axis remains problematic. i had trouble with it, so i made a 2-setscrew per-shaft motor coupler.. something I would recomend: get a drillpress! that was my first "machine tool" it helped me so much.. a drill press with a vise can do so much if its all you have! plus, it makes a milling bit into a spiral cutter, and a sanding disc into a small part "planer", and.. and.. other good thigns are a small disc\belt sander machine. i got the cheapo ryobi of both these and am very happy with them for my purposes - acrylic, aluminum, delrin, etc.

One of my interests, nay, passions is geodesic design and construction, and natural geometry. That sort of thing.

What I'm holding in my hand is a small model I built, of a geometric form. 26 sides for a full "sphere." Can't remember the specific name of the form, cause it's been too long...I do remember that it's built exclusively from equilateral triangles, and squares. All edge lengths are identical, which made it both interesting and useful.

One of these days, I'd like to create the forms for a "Fly's Eye" dome, and build one. One of the most beautiful structures I've ever seen...it's so organic. While it's possible to do the shaping with clay forms, etc...this one just calls out for a CNC cutter for the forms, and vacuum forming for the actual parts. People are making them, occasionally, and completely by hand.

Here's a link.
http://www.bfi.org/albums/FlysEyeDome/aaj.sized.jpg

In at least one configuration, its sub components are all identical, and here's one of them.
http://www.wnet.org/bucky/gif/kuhtik.gif


http://www.bfi.org/albums/FlysEyeDome/aaj.sized.jpg


-- Chuck Knight

all the parts of that are the same?!

nope.


how many different parts is it? the big one in the first link?

Yep...every part is identical. In fact, the way they're designed, they're not only interchangable, but can be stacked to reduce volume for transport.

In fairness, a few parts in this dome had to be different. They had to "cut" the lower pieces, to give it a flat bottom...in a full sphere, all the pieces are completely identical.

Here's the easiest way to explain it. Got a soccer ball? Good. A soccer ball can be analyzed as a truncated icosahedron...every part is a regular pentagon or regular hexagon, and they follow a very rigid pattern.

Soccer ball graphic:
http://www.soccerballworld.com/images/telstar1.jpg

Now, look at every "corner" on the ball...where a pentagon and a hexagon meet. There are 3 edges...one pentagon and 2 hexagons...those are the 3 edges in this fly's eye dome. They describe angles of 108, 120, and 120 degrees. (This is 3 dimensional, not planar geometry, so they don't have to add up to only 360) Notice in the picture linked above, that there are 3 legs to each piece...2 are thin, and one is thick. That's the geometry it reproduces...the edges of 2 hexagons and a pentagon. 6 components around a circular window make a hexagon...5 around a window make a pentagon.

Ingenious, isn't it? And pretty, to boot!

Here's a picture of it going up, piece by piece. It's about a 20-25 foot diameter dome...fairly small, but sufficient for a small home. You can see the component parts in the picture, as well as their relationship to the people erecting the dome. Domeraisings are like Amish barnraisings...lots of people around, to help.

http://www.bfi.org/albums/FlysEyeDome/abn.sized.jpg

-- Chuck Knight

P.S. Don't even get me started with tensegrities...floating rigid members, suspended in a tensile web of string, and with no rigid parts touching each other. They're all suspended in a web of string, and tensioned by each other, without touching.

Seriously...it'll give you a headache, trying to figure it out.

http://jimfl.tensegrity.net/tensegrity/P1070005.JPG

off the subject for one second. Chuck what are you holdin in your pic. just wondering.

BTW, I looked up the name of the shape I built. No wonder I couldn't remember it...

rhombicuboctahedron

Here's an animated GIF that shows it, better.

-- Chuck Knight

http://www.mathconsult.ch/showroom/unipoly/anim10.gif

I want one. i have a 3000sft living room. i could put one up as an office area! wow. i even ahve access to a 4x4' professional vacuum former, and a nice AXYZZ router to make the molds..... ... .. .. . ...