Notes on Sliver Processing

All industrially produced sliver has a right end and a wrong end to spin from. Drafting is smooth from the right end, and goes “clump, clump, clump” from the wrong end.

Card Sliver is the first process, where the fibers go through a large industrial drum carder. The fibers emerge from the card as a filmy web the width of the card, are then gathered and fed through a condenser and coiled into a canister. The fibers are not parallel in the sliver, so there is more air space in the preparation. Handspinners find card sliver is the easiest preparation to spin. I recommend it for beginners. The right and wrong ends are not so easily distinguished in card sliver, so it doesn’t really matter which end you start from. Most novices will get the clump, clump, clump because of their drafting technique.

Draw sliver is the next process, where up to 10 ends of card sliver are run through rollers that draft a little from each end. Industry uses this to further blend thousands of pounds from different sources for uniformity of the final product. I sometimes use it on colors or fiber combinations that have not quite been properly blended in the carding, and I also use it to make the striped slivers. Drawing straightens out the fibers so they are mostly parallel. There is still some air space, and experienced spinners do not have any problems spinning it. Novice spinners may find that they get more lumps more often than with card sliver. The right and wrong end are easy to tell apart in the spinning.

Combing removes the short fibers from the drawn preparation. This process yields a very high quality preparation with a uniform fiber length. Because up to 15% of the fiber may be removed, combed cotton is more expensive. Uniform fiber length is the first requirement in creating a yarn that does not pill. The second requirement is proper spinning. Maintain your preparation in pristine condition so that you do not create areas in your yarn where fibers are folded; all of the fibers in the yarn should be straight.

Roving can be made from either draw sliver or combed sliver. Roving is drawn out to pencil thickness or finer and has a little twist added for stability. Roving is used in ring spinning in industry. Because of the twist, roving is better behaved during hand dyeing than sliver.

Sliver is weighed by the grains per yard. There are 7000 grains per pound; a "70 grain sliver" means that one yard weighs 70 grains, and it takes 100 yards to make a pound. I usually ask for 70 grain. The weight will not be exact, so if we estimate an ounce at 6 yards, then if you fill each of your 3 spindles every day using a yard of sliver, then it will take you two days to spin an ounce or 32 days to spin a pound. If you take two weeks off, you should be able to spin a little over 11 pounds a year.