A drum carder is an efficient way to card wool to make a batt from which you spin.
I bought a piece of 120 TPI (teeth per inch) 8" x 8" carding cloth from a vendor on etsy.com for about $30. I often spin angora and alpaca, but for recommendations on TPI for other types of fibers, see the comments below.
These supplies cost about $20 from a home improvement store:
(1) 2" PVC pipe (2ft)
(2) 2" PVC end caps
(1) 1/2" threaded rod (3 foot)
(1) 1/4" threaded rod (1 foot)
(9) 1/2" nuts
(6) 1/2" lock washers
(2) 1/4" nuts
(2) 1/4" lock washers
(1) small paint roller
(1) tube silicone adhesive
The "licker in" brush is a "regular" hand carder with maybe 72 TPI that I had on hand.
Step 1: Prepare the Drum
I bought a 2' length of 2" PVC pipe. To cut it to length, measure inside the end caps and mark it on the drum. Don't actually put on the end caps; if you do, you'll have a heck of a time getting them off. : )
Lay the 8" x 8" carding cloth next to that line (making sure that the margins devoid of teeth are on the outsides and not where they would overlap). Mark the length of the other end cap and cut. Drill holes about 1/2" in from the line to aid in sewing the carding cloth to the pipe.
Trim the carding cloth if it overlaps more than 1", but know that a layer of the silicone adhesive will add 1/16" or so in diameter to the pipe. Don't panic if the ends don't meet completely; you can fill in the seam with more silicone later.
Step 2: Secure the Carding Cloth
Spread a thin layer of silicone adhesive/caulk on the back of the rubberized carding cloth with a plastic knife.
Ask a friend to help you close the seam while you duct tape the cloth on as tightly as possible. The duct tape will not stick to the teeth, so you have to pull it tight just as you stick one side to the other.
If some silicone squeezes through the crack, that's okay; it can be trimmed down later. If you spread it on too thick, however, and a very large glob arises through the crack, take off the carding cloth and wipe the excess off.
Set the drum aside for a day and a half to cure. Poke it gently with a knitting needle at the seam to see if it has cured. If the seam needs additional adhesive, run a small bead of silicone and leave for a while longer to dry.
Step 3: Drill Holes in the End Caps
Drill 1/2" holes in the caps. Be sure that you get them as centered as possible.
Step 4: Make the Wood Ends
Drill 1/2" holes in a a piece of wood. "Wobble" the drill a bit to make the holes just a tad larger; the threaded rod needs to turn easily through the holes. You will need two of these.
The height from the bottom of the wood to the holes should be at least 3" or so.
Cut a 2 1/4" wide strip to serve as the handle connector; I used the same piece of wood. The length of the handle should be at least 3" (any longer and your hand might hit the board you clamp the drum to).
Step 5: Fashion a Handle
A small paint roller works great for the handle. Cut a 1/4" threaded rod to connect the handle to the piece of wood mentioned one step ago. Estimate the extra length you need on the end by imagining a nut and lock washer on one side, the wood for the handle connector and a nut and lock washer on the other.
Step 6: Assemble the "Butt" End
Before you start to assemble the drum, you will need to think about the orientation of the teeth on the carding cloth. The top of the drum will turn toward you. You can orient it so that it's either a left or right hand crank. Mine is cranked with the left hand (and the wool fed with the right), but if you want to do it the other way, plan ahead and make sure the teeth are in the correct direction).
Thread a 1/2" nut and lock washer on the threaded rod. Add your end cap and thread another lock washer and nut on top of that. Leave enough room to add the piece of wood and two nuts on the end. Tighten the nut near the end cap until it doesn't turn any more.
Step 7: Assemble the Handle End
Thread the nut and lock washer on the other side (eyeball where the end cap will fall), thread on the cap, and push securely. Thread another lock washer and nut on that and secure.
Bear in mind that once the end cap is pushed onto the pipe, it will not be removed easily. It would be best to over-estimate where the lock washer will fall (and leave a small gap between the carding cloth and the end cap) than to underestimate.
The drum should not twist on the threaded rod; if it does, you may have to tighten the nuts more. If you tighten the nut too much, the PVC pipe might flex a little and your drum will be closer on one side than the other due to the distortion.
Step 8: Attach the Handle
Thread a 1/2" nut, a lock washer, the handle holder, a lock washer and another nut on the threaded rod (on the drum side). Tighten.
Do the same with the 1/4" nut, a lock washer, the handle holder, a lock washer and another nut (for the handle). Tighten.
Step 9: Mount the Drum and Licker
Clamp the drum carder to a painted board, and screw down a slicker brush or a hand-carding board to serve as the "licker in". Test by feeding in small amounts of wool. If it grabs a large clump, just back it up and pull some of it out.
When you fill your drum, use another slicker brush to "burnish" the wool and brush it a little more on the outside.
When you're ready to pull off your bat, slide a knitting needle under the wool at the silicone seam.
Step 10: Store
The carder could be clamped to a table, but if you have something on which to support the carder (like this old guitar hero drum stand), you could hang the tool with a piece of rope.