Sunday 23 May 2010

Fan Reed (5)

This morning I managed to take the series of photographs I need to explain how a fan reed works. I have turned them into a Powerpoint presentation but thought I would attempt to turn them into a Picasa Slideshow for this blog.

 First, how does it work? Mine is a 15 dent/inch reed 20 inches wide and 5 inches high. On the centre line, every fan is two inches wide and runs from 1 inch at one side to 3 inches at the other side.
Basically the warp stays constant in position and the reed moves up and down so that some sections of the warp are squashed together while alternate sections are further apart. The 15 dents per inch on the centre line becomes  30 dents per inch at one end and 10 dents per inch at the other.



How you achieve the movement of the reed will depend on the loom you have it mounted in. I rather fancy that an overslung beater is best but that is probably because I have implemented mine on a Louet Kombo. The actual motion is achieved by winding two screws up and down.


This is a SolidWorks drawing of the mechanism. The inner two vertical rods are long screw threads. There are wingnuts under the lower wooden beam for the reed which are manually adjusted together to drive the reed up and down.

Now you have to decide what 'pattern' you want to weave. Suppose you fix a step in vertical reed movement. If you throw a weft three times each time you move a step, you get a linear pattern, looking like a triangle. In practise as you turn round to go back, you will not maintain a sharp kink and  the triangles will be rounded. You can vary the length of a pattern repeat by throwing more or less weft shots per step. I do not like this linear pattern and have experimented with a number of curved shapes. I now use an approximation to a sine curve (computed using EXCEL) which does require a variable number of wefts per step.

There are problems in using the Fan Reed

- you cannot use the whole height of the reed. The top is limited by where the upper threads of a shed are and the need to have enough space in the shed for a shuttle. I bought two tiny shuttles from Bluster Bay specifically to use with the Fan Reed  but I still 'lose' the top 15mm - and to make the pattern symmetric you cannot use the reed to the lowest point but must stop 15mm above the lower edge
- you need a high tension in order to give the shuttle a surface to glide on. And this very light shuttle is not ideal.

I am weaving 60/2 silk and there are additional problems in weaving silk at 48epi with the Fan Reed.

- because the cloth is sometimes warp faced and sometimes weft faced, unweaving is a real problem if you make a mistake. The shafts have to be well balanced and equally hung - and that is not easy on the Louet Kombo.  A tie up system like the LeClerc Voyager which uses Tex-Solv would get rid of a lot of these problems
- it is very slow. I reckon to be an average weaver. I can manage better than 3 seconds per weft throw on my Megado. It takes me 50 minutes to do five inches which works out at 12.5 seconds per weft throw. This is mostly a function of my mechanism and yes, I can see how to automate it using a stepper motor and a lot of money.

It is a waste of time, in my opinion to do anything but tabby with this reed, though maybe you could use twill. I am disapppointed at the number of errors in my weaving. Possibly weaving with a thicker yarn would avoid these errors. Most of what I have done has been 60/2 silk although the first thing I did was 10/2 cotton in a triangular pattern.

I have taken photos of the current cloth at the top and bottom of the reed and at three intermediate positions with the current weaving.  For those of you who are still with me, try this Fan Reed Slideshow.  Click SlideShow at the top left  and then immediately go to the lowest central part and click on the plus sign until the 3 seconds reads 10. Then you can use the right and left arrows to move through the Slide Show at your leisure. I would like to know how readers manage with this Slide Show.

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About Me

I am weaver and - -. I dye my yarns with acid dyes, I paint my warps, put fabric collages and stencils on my weaving. I have three looms, a 12 inch wide, 12 shaft Meyer for demos and courses, a 30 inch Louet Kombo which is nominally portable but has a stand, two extra beams and a home-made device containing a fan reed. And last a 32 shaft Louet Megado which is computer controlled, has a sectional warp and a second warp beam and I am the proud owner of an AVL warping wheel which I love to bits and started by drilling holes in. I inserted a device for putting a cross in. I have just acquired an inkle loom and had a lesson from an expert so I can watch TV and weave at the same time. I am interested in weaving with silk mostly 60/2 although I do quite a bit with 90/2 silk. I also count myself as a bookbinder with a special interest in Coptic binding.