From: karplus@ararat.ucsc.edu (Kevin Karplus)
Newsgroups: rec.crafts.misc,rec.crafts.textiles,sci.engr
Subject: materials question for rebuilding loom
Followup-To: rec.crafts.misc
Date: 30 Sep 1992 18:42:20 GMT
Organization: UC Santa Cruz CIS/CE
Distribution: world
NNTP-Posting-Host: ararat.ucsc.edu

I am repairing/rebuilding/redesigning an 8-foot (2.4 meter) wide hand loom, and need 
some help.

1) the breast beam and slabstock of the loom are too flexible.  They appear to be made
out of fir 2-by-4s (rectangular beams about 4cm by 8cm) that have had one side roughly
rounded.   Leaning against the loom causes the beams to bend alarmingly---I haven't
even tried to put a warp on the loom yet.

For those unfamiliar with the technical vocaublary of looms, the slabstock and
breast beam are the stationary horizontal beams at the back and front of the loom.
The warp threads run from the warp beam, over the slabstock, through the heddles
and reed, and are woven into cloth.  THe cloth then runs over the breast beam
and is wound up on the cloth beam (note: some looms are more complex, but most
handlooms follow this simple pattern).

Because the warp and cloth wrap around the beam about halfway, there is usually no
way to brace the slabstock and breastbeam in the center, and so they are supported
at the ends only.

The bending forces on the beams can be fairly high---a cotton warp may have 20 ends
per inch with an ounce of static tension on each end, and linen warps are usually
woven at about twice that tension.  Dynamic loads are higher, as the warp tension
is increased and the cloth tension decreased whenever the beater hits the fell line 
(the edge of the cloth where the weft was most recently inserted).
Bending needs to be minimized, to keep the tension on the warp threads uniform and
the fell line straight.  

The traditional approach is to use thick beams of stiff materials (hard maple is
a popular wood for loom building).  A maple 2x4 is adequate for a smaller loom, but
I don't know if it would be stiff enough for this wide a loom, and would be fairly 
expensive even if it were.

So---finally my question:  What low cost materials are available as 8-foot long
cylinders that have a stiffness at least as high as a maple 2x4 (in the stiffer
direction) and a diameter not exceeding about 6 inches (15cm)?


2) the loom was originally set up as a two-person loom, with one weaver throwing the
shuttle and the other one catching it.  Unfortunately, my wife does not weave, and
I keep too irregular a schedule to schedule time with another local weaver (much
of my weaving happens when I have insomnia).  I plan to remedy the problem by adding 
a fly shuttle to the loom, but have never built a fly-shuttle before.  I have the
appropriate end-feed shuttles, and have some plans for building the shuttle
boxes, but I don't have power saws, routers, and similar tools, and so would prefer to
buy already built shuttle boxes.  Does anyone know of a supplier for shuttle boxes
that can be adapted?  The only ones I know of are AVL (far too expensive) and
LeClerc (which might be suitable, as the beater on my LeClerc loom is very similar 
in everything but length to the beater on the 8-foot loom).

-- 
Kevin Karplus		karplus@ce.ucsc.edu

Due to budgetary constraints the light at the end of the tunnel is
being turned off.