[TheForge] Re: Spiral stairs? (Was: horn)

[Mike Spencer]

> What about a platform with a counterweight? If you have the skyhook
> in your shop, it might actually be easier to rig up a simple
> capstan-style winch with a counterweight system and a brake through
> the doorhatch.  Then Peggy can ride in style.

Hah!  That's next.  I'm 63 and no longer ...um... atheletic myself --
jump only small buildings with a running start, dontcha know. :-) Over
the next decade, we'll be thinking about something like that.  For the
moment (and unless my imagination is way better than my skills) I'm
going for a spiral stair.

> Building stairs is a pain, and spirals (as you no doubt know) are
> *really* a pain. How were you gonna curve the spiral up accurately,
> anyway?

Each tread built on an 8" segment of pipe on the bench.  Segments
slide down over central pipe.  Twiddle until in the right place.  Weld
segments together.  Add tread-to-tread links at outer edge.  And I
don't really expect it to be quite as easy as it sounds.

Those pieces of tube, BTW, turn out to be special pipe for something
to do with oil drilling.  Specs include 15,000 psi burst pressure and
withstand 8000 ft-lbs torque.  Some kind of fancy proprietary thread.
You can have some too:

   http://www.networkintl.com/catalog/lotdetails.asp?SLXID=OVJOMA0012MG

What kind of alloys are represented by tubing specs called L-80, P-110,
P-105 or AC-95?  I'm going to have 7' or so left over to play with.

And I infer from scraps found on the net that it (and therefore the
saw chips) are magnetic because there is such a thing as a "magnetic
drill collar" in the oil rig trade.

- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

--