Hey Tom
Just found your site on a search. I have a 72" J-comp 24 harness loom.
I
want to know if you have anyone on your e-mail list that has
successfully used it to weave large rugs or weft faced hangings. When
I
ordered this from Dale he did not seem to think I would have a problem,
however it has been nothing but!
Rugs need to be woven under high tension, and the wider the warp the
more tension required in order to get an adequate beat. The loom
woefully underperforms under high tension. Major harness float, which
I
am unable to overcome with the adjustment devices provided. And the
beater is not up to the task. So Dale built me a heavier beater,
reasoning that I would not need the tension if the beater was heavy
enough.
This has not solved my problems, sooooo I was hoping you might have
a
lead on some or someone who has some
(solutions). Or maybe you know of someone who would like to buy a
beautiful cherry mint condition loom :-(
Cynthia Neely
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
From: Tom Vogl
Subject: J-comp Loom Adjustments
Cynthia's query prompts me to recapitulate some of the problems that
I
have had working with high tension (sticky warps and rugs) and how,
with
Dale's help, I have resolved them. The problems fall into three
categories: Problems with the shafts, problems with the tie-up unit,
and
operator error. I did not have all these problems simultaneously,
so if
you have one or more of these kinds of problems, a thoughtful
differential diagnosis (and some experimentation) is required.
What follows is not the last word on any subject addressed. If
any of
you can confirm the correctness of these suggestions or have alternative
solutions, or other problems, solved or otherwise, do write and let
the
rest of us know. If you prefer, write or call Dale or me - we'll try
to
help.
Problem with shafts: Here there can be three causes of problems:
The
black hooks that hold the lifting rods, the balance weight, and the
adjustment of the springs at the top of the cantilevered lifters of
the
shafts.
The black hooks: They look like they are made of painted steel, but
they
are, in fact, plastic. The plastic is soft enough that under
high
tension it can bend and be permanently deformed in such a way that
the
lifting rods can swing free when the shaft is in the down position.
this
problem is exacerbated by the fact that, at least on my loom, the open
side of the black hooks is on the side that the lifting rods would
naturally swing toward. There are two possible solutions, either
of
which will work.
(1) buy a new set of uncut lifting hooks from Dale and use two screws
to
hold them down. (Before dale cuts them, they have a screw eye on either
end.)
(2) Drill a new pilot hole for the hooks in such a way that the hook
faces the other way, but the top of the loop stays in the same place.
Then, when the lifting rod tries to swing, it will swing toward the
closed end of the loop.
The balance weights: If all else fails (see below) one possible solution
to harness floats is to increase the weight of the balancing steel
that
is on the bottom of each shaft. Note that the counterweight on
the left
treadle must be incremented in weight equal to the total weight added
to
all the shafts in order to maintain easy treadling. (If I were
to do
this, I would start by adding weights that I tied onto the shafts (such
as a length of rebar) in order to determine whether this fixed the
problem and how much additional weight is really needed. Only then
would
I consider a permanent weight increase.
Problems with the springs on the lifters: The symptom of this problem
is
that just one or two shafts will either tend to float more easily or
not
lift properly. When all the shafts are in the down position (left
treadle down) it should be impossible to raise a shaft by pushing up
on
a lifter bar. When the right treadle is down, it should be possible
to
raise a shaft by pushing on a lifter, but a definite snap or resistance
should be felt before it begins to move up. If it lifts easily,
without
a snap, tighten the thumb screw on the lifter spring assembly at the
very top of the loom.
Problems with the tie-up unit: Although these problems can produce a
multitude of symptoms, often confusing, the causes are almost always
one
of two things: inadequate lubrication and/or stretched cables.
Inadequate lubrication causes the solenoids to stick which can either
effect random shafts or a group of even or odd numbered shafts. Spraying
WD40 onto the tie-up box, particularly on the shafts that go into the
solenoids, usually cures this problem. Lubrication at least once
a year
is recommended.
Loose cables: If your loom is working fine, *now* is the time to feel
(and remember) the tension in each of the cables both when the treadles
are up and when they are down. The tensions should be checked
(and
adjusted, if necessary) every time you are about to put a warp on the
loom as part of normal loom maintenance. Another thing to watch and
adjust regularly is the cable that runs from the right treadle, through
a pulley and onto the left side of the tie-up box. A part of this is
to
check the size of the gap between the nylon wheels on the right treadle
and the little rectangular box on which they run as the treadle is
raised. If you are experiencing problems with either the odd
or the
even shafts not engaging, or with the cable that runs horizontally
along
the aluminum bars on either side of the tie-up box (and holds the shafts
that go into the solenoids) occasionally jumping off one of its pulleys.
it is time to adjust the tension.
This is how it is done (it is a matter of trial and error to get it
right): The adjustment is done with the four (2 each side) #10 phillips
head screws coming out of the side of the two horizontal aluminum bars.
The adjustment must be made on one front and one back screw, but they
can be on opposite sides. Note that there are also 4 1/4" bolt with
a
nylon crown locknuts - do not use those by mistake. Loosen the
set nut
on at least two of the screws and adjust them so that the hinged arm
on
the ends of the aluminum channel move out (to increase tension) or
in,
as required. Note that if the hinged end holding the pulley moves
out
too far, there is a danger that the bar may sometimes hang up on the
locknut. In that case, rebalance the tension with the other screws.
Changing the tension on that cable may (probably will) effect the
tension on the cable that runs from the right treadle onto the tie-up
box. Readjust that tension by running the nuts up on the eyebolts
that
hold the cable to the treadle.
Operator error:
It is important to remember that because of the 40:1 mechanical
advantage that the worm gears on the J-made provide, that it is very
easy to produce far more tension in the warp that it is possible to
achieve on any loom with a ratchet or friction brake (unless the ratchet
lever is a yard long). I note in passing that the more tension is on
the
warp (particularly if it is animal fiber) the more problems there will
be with shrinkage during fulling.
Equally important, to minimize shaft float, is to distribute the warp
ends as uniformly as possible among all available shafts. For
example,
if the pattern being woven is a four shaft pattern in straight twill,
and you own a 24 shaft loom, then the slaying should be 1, 2, 3, 4,
5,
6, 7, 8, 9, .... 24, 1, 2, 3, ... with shafts 1, 5, 9, 13, 17, and
21
being raised together as if they were a single shaft, etc. This reduces
the total force on each shaft by a factor of 6 and allows for much
higher tension before shaft float occurs.
Hope the above helps solve someone's problem some day.
Cheers,
Tom.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
From: Tom Vogl
Subject: Convergence 2002
Katherine and I are planning to attend Convergence in Vancouver and
we
have high hopes that Dale will manage to come as well. We will
be
staying at the Hyatt (for the pre-workshops as well as the main meeting)
and as soon as we get a room number, we will post a message on the
message board. We think it would be delightful for J-* owners/users
to
get together over a beer or a meal, or just get to know each other
as
time and schedules permit.
If you know you will be at Convergence, send me an e-mail and we'll
see
if we can set something up in advance.
Cheers,
Tom & Katherine.
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