Andrew Kieran

hello.

I'm a student at Heriot Watt in Galashiels. We have about 20 of these things, in various states of repair

I
read your message and I might be able to help if i can see some photos
of the loom, or preferably video of the lifting box while the loom is
working

off the top of my head i can think of a number of things
that could be happening. first you have to understand the mechanical
function of the loom (all this is assuming that the loom is mechanical
and not using a computerised dobby, in which case i probably can't
help).

when the weaver presses down on the pedal, the lifting bar
is raised. Now, each shaft of the loom is attached to a hook contained
in the lifting box. each of these hooks is in turn horizontally attached
to a metal plate. each of these plates can be pushed forward by a peg
which is attached to a lag which is on a barrel which rotates round each
time the weaver releases the pedal (there is a downward pointing hook
which rotates the barrel one step, thus turning the lagchain once and
putting the next lag in place.

a lag is a little wooden bar, with
16 holes in it (or more, depending on the loom). You program the loom by
hammering pegs into these lags.

now, what could be wrong?

firstly,
if the shafts are failing to lift only on a certain step of the weaving
then it could be that some pegs have fallen out. alternatively, it
could be that the lag chain is loose, in which case it needs to be
tightened because loose lagchains can bend when they get turned into
position.

secondly, if the shafts aren't lifting at all, then
there are a few thing which could be wrong. firstly, the plates which i
mentioned (that the pegs push against, which should be on the right hand
side of the lifting box) could have slipped out of place.

secondly,
the vertical wire to which the hook is attached could have turned
itself backwards (this happens occasionally on poorly maintained looms,
in my experience they're all poorly maintained) which would prevent the
hook from being lifted by the lifting bar.

thirdly, the wires which leads out of the lifting box could have become twisted about themselves.

These are the most common faults.

it
occurs to me as well that sometimes when using 16 shafts, the back of
the barrel can lift up causing the back shafts to fail to lift. in this
case, you should find that there are a couple of holes on either side of
the barrel rest, which you should be able to put nails through to hold
the thing in place.

I hope this helps. Like a previous poster
said, assuming it's a mechanical dobby it's a reasonably simple
mechanism. I understand some people don't have good mechanical sense,
but generally i find i can find any faults in any loom i'm using by
getting someone else to pump the pedal (or hold it down) while i watch
the operation of the lifting box from one side, from the other, and then
from standing up on the loom and peering inside.

it's such an amazing coincidence that i logged on today, i haven't been on this site in months

andrew