I have an AVL 40" 16 shaft mechanical dobby folding loom and I have nothing but heartache from it. Aside from the loose tension (which I think is a warping issue) I will weave for a random number of picks at which point the loom will raise random harnesses. I am putting my left foot down consistently and I have adjusted the turnbuckle both tightening and loosening it to no avail. Sometimes the dobby bars hitch up inside of the dobby box. I know there must be a simple fix but I cannot even get a good plain weave with this loom! Any ideas of what is going on? Thanks!
Joy
Joy, is this a used loom that is new to you?
I have a 16-shaft 40" AVL folding loom and used it with dobby bars and pegs for some years, as well as a 60" AVL with bars and pegs. Tension on the 40" has to do with the way the cord is wrapped around and also you do need to move the position of the end of the cord from that used while winding the warp onto the beam. Do you have the manual that came with the loom?
The bars and pegs have always been very reliable provided they are connected properly and everything is assembled correctly. Also you might need to adjust the alignment of the wooden arm that moves when you step on the treadles.
There are two different styles of bars. Older bars are connected by little metal loops. Newer bars (still could more than 10 years old) are connected by a strip of plastic and need two sizes of pegs.
Have you searched Weavo for previous messages and the group on dobby bars and pegs/mechanical dobby looms?
Bonnie Inouye
Yes it is a new-to-me used loom. The dobby bars are of the old type with metal linkages though I use zip ties. I am (trying) to work my way through your book and have a twill on the loom now. I have looked at mechanical dobbys on WeaveTeach and Weavo and have not had much success in finding an answer.
Joy
check the 2 cables for the treadle and the cable with the turnbuckle on it. I have found that if the treadles do not actually hit the floor, things work best. half inch to 1 inch from the floor is great. the treadles need to make the dobby arm go all the way down and all the way up. The arm that comes down from the top frame and connects to the dobby arm needs to be straight up and down. Even a slight variation matters. When dobbys work they are fabulous, but they are persnickety about adjustment. Make sure all your bolts are tight, they seem to work loose quite frequently if you weave alot.
Yes, alignment needs to be correct. That includes the floor! If the loom is not sitting on a level surface, that could change the way the chain of bars hangs down and advances.
Alignment of the wooden arm is something I have to fiddle with occasionally on my older AVL looms. Treadle to raise the arm and put the pin in that holds the arm up. Walk around to the side and see if things line up well from the first shaft to the last shaft, so the cables and balls will fit exactly into the right openings. You can push the arm a bit to the back, right, left, front with your hand and watch what happens. My 40" loom needs a small shim inserted- a folded postcard is about right- to hold it in the correct place. If I move the loom or if somebody bumps into it hard enough, I have to insert the shim again and check alignment again. This is in addition to tightening bolts.
Cable ties, yes, that's what I use.
Glad you have my book. Look for the little drawings of my bars and pegs throughout the book for tips for your loom.
Bonnie
Another factor could be the length of your chains. On my looms, it was tricky to use fewer than 16 bars. With more than 60 bars, I had to watch the chain as it moved up (or down). Before it gets badly messed up, it starts shifting out of line. Easy to fix if you catch it in time. I decided it was better to learn to manipulate the bars back and forth than to peg a whole lot of bars. I prefer long treadling sequences generally.
Bonnie
There is also an adjustment that helps the internal mechanism in the dobby that catches the little metal balls on the cables. the pegs on the dobby bars activate the switches in the dobby. Those switches push the cables and the balls catch in the mechanism. One the front of the dobby box there are two allen set screws that adjust the mechanism that catches the metal balls. I have had to adjust that in/out before. Especially if the shafts that are missing are all toward the front or toward the back of the loom.
Between putting a shim in the dobby bar and realigning the bar with the the allen wrench I was able to weave 6 inches without errors or skipped threads! Thank you so much!
Joy
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