Mysterious Selvedge Error

I have my new-to-me 1985 AVL PDL up  and running.  The flyshuttle was pretty cranky, but we seem to have come to an agreement.  The dobby was repeating sheds; I tightened the left treadle and that seems to have stopped.  The tension is working, the laptop is talking to the dobby; we're making towels.  I had trouble with the edge stitches not always weaving because of the huck floats in the pattern.  This is a huck check from Strickler's 8 shaft pattern book, and makes great towels.  I rethreaded the outside 6 threads on shafts 9 and 10 as selvedges, added them to the pattern as tabby.  They don't always weave properly.  If I just raise the shafts and watch, without throwing the shuttle, I see 9 rise, then 10 rise, etc; which should give me tabby selvedges.  When I start actually weaving, sometimes it works, and sometimes the selvedge threads do not weave.  Any ideas?  After threading selvedges, I really don't want to add a FS, especially since I don't really want to  rig it with this flying shuttle.

Comments

Posted on Sat, 03/14/2015 - 23:29

I have been moving compu-dobbys and have noticed that the adjustments need to be checked & re-checked over the first few weeks.  A dobby adjustment that was perfect on one day was all wrong a week later.  You may want to check your compu-dobby's depth by creating a lift plan of shafts 1 & 16.  If they both lift then your depth is looking good.  I have posted dobby adjustment pictures/instructions on http://fiber.hassel.net/Dobby/

Posted on Sat, 03/14/2015 - 23:30

I don't think you should have to use 9 and 10 as long as the tie shafts are used for the selvedges and they are tied up as opposites as the pattern shaft pairs are opposites, such as for a 5 end huck

threaded                                                          tied up

   2   2                                                             XOOXXXOO

1   1   1                                                           OXXOXXOO

 

Or did you expand the motif shafts and need 9 and 10 for the ties? 

Is a shaft sticking sometimes?

I have Stricklers book here.

Posted on Mon, 03/16/2015 - 00:05

I checked the dobby  and everything seemed to work (I made a draft raising 1-16 individually),  I watched the shafts move as I treadled through a pattern, and found that 10 did not come up often; 9 came up when 10 was supposed to. On the thought that 9 was not being cleared, I looked at the left treadle again, and it was hitting the floor before the dobby bar hit the bumper at the top.  I tied it up higher, and my selvedges are working 85% of the time.  Occasionally, both 9 and 10 are raised at the same time.  Have not figured this out.  When I wove this pattern with hand shuttles, the crossing of the active weft around the carried weft (it's a three shuttle pattern) prevented floates.  I don't like the loops of inactive wefts along the selvedge that the flying shuttle makes, so I may go to hand shuttles for the rest of the towels.

Reed guy, I could thread the selvedges in the pattern shafts.  But I have the shafts to put them on separate shafts, and it's much easier threading.  I don't have to do any extra tie up for the extra shafts, so there's no reason not to. 

I think that a problem may be that the original steel cable treadle tie ups are long gone, and the left treadle has a nylon cord (right is cotton).  Nylone expands with cold and contracts when warm, and my studio is only heated when I'm in it.  I will replace the nylon cord an see if that helps.

Posted on Mon, 03/16/2015 - 00:29

I was thinking since there are already tie shafts with heddles strung across, why not put the handful of extras on the ends of those for the selvedges. Depends on the loom I suppose and heddle placement you already have.

I guess if you got'm (extra shafts) use'm :)

Posted on Mon, 03/16/2015 - 00:52

1) If you push the left treadle down all the way then all the shafts from the last pick will be released.  If not then you definitely have a left treadle problem.  As you surmised the cable that controls the left/right treadles cannot be allowed to stretch.

2) Check to make sure the dobby arm alignment is precise (wires line up with grooves).

3) If 1 & 16 lift on command then the depth is ok.

Posted on Mon, 03/23/2015 - 21:59

Adjusting the dobby and tightening the left treadle did it.  I put it out until it started dropping shafts, then turned it in two turns.  Now very occasionally, #10 will not clear and I have to release the wire from the dobby bar, but this is minor.  I beleive that this loom likes to be warm, and if I let the studio get nice and warm before starting, everything works well.