I finally finished my first weaving! So happy! :)
I tried a shawl of 40cm (15.7 inch) width and 180 or 190cm (71 or 75 inch) length. Yarn had more shrinkage and draw-in than I expected (see notes below on using knitting yarn for weaving), so the shawl turned out with a length of 186cm/73.2 inch and a width of 38cm/15 inch.

So glad my calculations worked. Took me ages to understand how to calculate the amount of yarn - I did this first “manually”, following the Rigid Heddle Loom course on Craftsy (by Angela Tong), but cross-checked my calculations with the online weaving calculator by Weavolution.

Sett chart: http://www.fiber2yarn.com/info/sett_chart.htm

Calculations:

Yarn available:
1 skein = 115 gr = 0.25 pound / 355 yards
4 skeins = 460gr = 1 pound / 1420 yards
I have: 345gr bzw. 1065y/973.8 m

Total yarn required (Summary): Warp 484.4 yards + weft 396.5 yards = 880,9 yards = 804,6m

Warp calculation:

• Finished length of one piece: 75 inches (--> final length of shawl: 186cm/73.2 inch)
• Loom waste: 18 inches
• Take-up: 10%
• Finished width of one piece: 15.75 inches
• Width Shrinkage: 10%
• Warp Sett: 10epi
• Yards per pound: 1420 ypp

Warp length is 101 inches (2.8 yards) = 256,54cm = 2.56m

Length to weave is:
83 inches (under tension) = 2.1m
75 inches (relaxed) = 1.9m

Width in reed is: 17.3 inches = 43cm
Number of warp ends: 173 (-> 176) = 88 crosses

Total Warp Required: 484.4 yards (5.5 ozs.) = 443m (442.9m)

Weft calculation:

• Picks per inch: 10 ppi
• Take up: 10%
• Yards per pound: 1420 ypp

Total Weft required is 396.5 yards (4.5 ozs) = 362.5m

Total yarn required (Summary): 484.4 yards + 396.5 yards = 880,9 yards = 804,6m

Production notes:

• March 8, 2015: Warping time: 3h
• March 15: Beaming the warp and threading heddles: ca. 4h
• March 21: Tying warp to front apron rod and weaving header, ca. 2h.
• March 22: Begin real weaving, ca. 1h. …. lost track. Too much knitting in-between.

Questions:
- I’m using a thin and slippery yarn and when I put tension on the warp after cleaning it, the yarn slips back a little through the slots and the tension on the warp which was already on the beam seems to be gone.

• Do I have to keep tension on the warp while I turn the beam and wind the warp onto it to prevent this? I tried gripping all of the cleaned threads with my right hand and putting tension on them while at the same time turning the beam. It works but I’m not sure if I’m doing the right thing.

Lessons learned:
- I don’t need to beat as if I would want to form a brick… ;) … in the beginning, I beat far too strong, so the fabric got a little stiff. This changed during the last half of the shawl, when I beat less hard.

• To keep an even beat, count threads per inch/cm (when the fabric is like you want it to be - mostly between really dense and too loose = you can see your hand through the fabric very easily. Seeing the contours of your hand is okay though) and check this count during weaving repeatedly, to ensure a consistent density of the fabric.

• When tying the warp to the front apron rod, don’t make large bundles of threads as shown in my picture - you need to weave a large header otherwise and the gaping is ugly. Smaller warp bundles are better. I retied them after taking the picture.

• To advance the fabric, loosen the back ratchet first, then turn the front beam.

• Keeping an even tension is really essential. When it’s not really even, your weaving will get diagonal. Happened to me after I loosened the tension for a few weeks where I couldn’t work on the loom and tried to tension it again with turning the front beam. Turning the back beam brought better tension (at least here).

• Using yarn intended for knitting is more difficult as this yarn is spun differently than yarn intended for weaving. Knitting yarn has more twist and is more elastic - which can cause problems keeping an even tension (as I experienced as well).

• This results in a heavier draw-in of the fabric when the warp is very tense - or a shrinkage of the finished piece, when the yarn “springs back” after you cut the piece off the loom.

• To keep knitting yarn evenly tensioned, prepare the warp with only little tension and also put only little tension on the warp when on the loom, just as much to open a proper shed.