Others may have better methods, but since you asked...
When the bin is dryer rather than wetter or before wetting is a good time to harvest. I put vermicompost into a basket with one and a half inch by quarter inch slots in it and shake it. The stuff not shaken out goes back into the flow through for a second time around. I would prefer to have a choice of baskets to try with perfect half inch holes and other sizes. But I don't. The stuff that falls through gets worms removed from it. The light method is sort of fun for me. I put a piece of cardboard over an ex diaper hamper and put a pyramid of vermicompost on top. I let time do the work for me. I use only the light from the room and not a special light trained on the worms. It seems to work quick enough. I sit down to sort and the work is at a good height to be comfortable. It is peaceful and zen. Do not bother me. I am having great fun. The cardboard is square and the hamper bin is round. This leaves spots along the side of the board to push the wormless sived vermicompost into the bin. I turn the cardboard around and drag material off of each side. When the effort to seperate seems not worth it I toss the waggle of worms and small bit of remaining vermicompost into a second container. Future remains also go into this container. So I have many contianers. One is stuff that did not fit through the sive. One is stuff that fit through but waiting to be pyramided. One is stuff removed from the pyramid with out worms (except for a very few that sneak in) and one is the worms with minor bedding. Eventually I take the worms with minor bedding container and dump that pyramid style onto the cardboard. This final seperation yields a hunk o worms that I stand back and admire for a few moments because I started with only a few worms, then toss into the brand newest not processesed at all of my compost bins.

My worms do not seem to grow egg bands or put out eggs year round. They seem to follow the seasons. I have not seen an egg in ages. They are in a cold celar. I hope this spring they will again put out eggs to hatch the very fragile baby worms.

I frequently disturb all my worms to try to understand what is going on except for delicate baby worms.

I have a large outdoor pile and I take my time harvesting. I only do so once or twice a year so it doesn't seem like much of a chore. Gathering some large plastic bins that they put coke bottles in or produce baskets that are plastic (think grocery store hand baskets) I use a pitchfork and fill the basket sitting on top of my worm bed with 3" of vermicompost. Since it's on top the worms dive down back into the pile in a day or so. I harvest 7 or so of these every day for a week then fill a wheelbarrow with it. It gets tossed on the garden beds and I repeat till it's finished.

I do miss some worms or eggs but I've got so many and take care of them well enough that I don't mind a small sacrifice to the worm gods. Screening and harvesting seems to be too laborious otherwise. I don't see a benefit at this point to making a large screen or some rotary version. I can take my time and it doesn't take very long to harvest. Since I only do so once or twice a year it seems odd to want to rush the process.

I think I'd have to monitor the moisture level excessively to be able to harvest it with a screen as well. Seems like a lot of work.

All my dealings with the worms are to make it as productive and non labor intense as possible. Easy and lazy is the way to go, I like for the worms to do the work.

Lazy, but effective: Turn on the light, let the worms go down, start pulling the vermicompost/castings from the top. When you are low enough, pull one side over to the other so that a portion of the bin is empty. Fill in with bedding and some food. Wait a couple days. Many worms will have moved to the food. Continue to scrape the surface of the old side on occasion.

I really like the grocery store hand basket idea because it is already to transport to just where you want it. Also moving it in little easy bits is better than heavy back injuring hunks.

I do mine a lot like equinox, take your time, enjoy the harvest, hug your worms.
If I am harvesting for a more pure casting, Then I go a step or two further. I use an expanded metal screen that is 1/4 inch by 1/2 inch on a one foot square wood frame. all that does not pass is returned to the bin . All the material that passes is then passed through a galvanized 1/8 inch screen also one foot square. Most worms and cocoons will not pass through and are placed in a separate container for inspection before returning to the bin.
The final castings are then placed in a separate container for finishing. Finishing takes about one month I place some food on top I prefer melon or squash, placed skin side up and harvest the small worms that have hatched or slipped through the screen. They will flock to the food and can be scoped out. I think I have seen a video of this finishing on this forum?
For my outside circle trench I simply dig it out with a shovel where I am not actively feeding. Most of the worms are around the food where the moisture is

The easiest systems to harvest are the ones that have multiple trays with holes in the bottom - these could be home made boxes with mesh bases, stacked shopping baskets or commercially produced worm farms etc. The main advantage to these systems is that once the lower tray is composted the worms will move up to the food in the next tray, the lower tray can then be removed and used with no mess whatsoever.The site below has some good information on vermiculture, which applies equally to home made bins as it does to commercial bins.

Here is a link that might be useful: Worm-Composting-FAQ

The weather was decent this weekend, so we took to harvesting a couple of our bins.

I kind of do the burrowing method, but I do them a pie plate at a time...makes things go faster, or so it seems! I do it outside (also gives the bins some time to de-fruit fly themselves), so the sun is over the worms. This is also when we pull the frozen scrap bins out of the freezer to let them thaw before giving to the worms. I try to pick out cocoons as I see them and get them back in the bin, but I'm not overly detailed about that.

We harvest about half the bin at a time, but we don't get really scientific about it. I usually just stop when I'm bored/tired/whatever, then load the bin up with food and bedding, and leave them alone for a month or two. (Or three or four, as was the case this past time, since it's been so stinking cold.)

This go-round, one of our bins had a TON more cocoons than the other, so we put the castings from that bin into a small bucket with a lid (with holes) and a little bit of bedding, and brought that bucket inside, where hopefully the heat will encourage the new wormies to hatch. Then we'll separate again and put the babies in with their parents.

I built my first harvester this weekend, and it has made things much faster. It does take some time to pick the worms stuck in the screens, but it is worth it. I posted a video of my first run, and wanted to give a good look at the set up. I know I watched several videos and did a lot of research to plan. I hope this helps. http://texasredworms.com/2011/02/08/texas-worm-harvester-part-3/

Here is a link that might be useful: diy worm harvester

Your video is well done and She looks pretty enough to me. I like the double screen idea for various size fall through. First time I have seen that. I would have the supply as high as possible so one only needs to push more material in as needed a bit at a time. As opposed to a bucket way down on the ground that each back breaking shovel full has to be individially lifted. It also looked fun to run. Seeing the result I kept thinking I bet the worms would like to eat that. It would be great to put a layer of that great stuff each time fruit fly attracting food is put into the worm bin. You might want to put up a seperate website with this video with no .com on to link to to get feed back from this board. Because a reading of the board posting policy, as on many boards, does not allow linking to a comercial site even if the intent is not to sell. And because to get the best help from this board since the other posters may have products and worms they are not linking to due to the board policy. Thus they have less incentive to reply to your post. They may be the same people with the best information who you do want to reply to your posts. This do not post commercial items is a bit easy to overlook. I bet you had no idea about it and only excellent intentions to share with the board. I post about it here so others with businesses who may have no education intent but are only looking to advertize will be aware. A look back through the posts may show some not so nice posts about the subject. You do not want one of them. The opinions on this do vary greatly. About a month ago I saw at 2 AM one post that was blaintent only advertizing with no educational information at all on the post. Somebody else must also read the boards at 3 AM because in the morning it was gone but I do not think I imagined it. So I'm thinking the powers that be saw it and removed it. As they should have.

I built a DIY separator using 1/8 in hardware cloth and a 5 gal bucket with the bottom cut and them cut into half . I am very satisfied with the way it works. You just have to make sure the material is relatively dry or it does not work satisfactorily. Instructions for building can be had by googling up DIY worm separator.

It's important, when harvesting worms by whatever method, that you don't expose the worms too long to light or to the drying air. Get them out of the old bedding and re-covered into new bedding as soon as possible. As long as they are crawling into the old bedding, they are ok. But when it gets down to the end, work quickly. If you do the shaking method, shake small amounts at a time and dump the harvested worms into a prepared container of fresh bedding.

Here is a link that might be useful: Vermicomposting

I got the following method from Bentley (redwormcomposting.com) and tried it once. I then switched to flow through bins where the harvested material has only a few worms in it and it's not hard to pick the 5 or 10 worms out by hand, so I haven't needed to use it since.

If you have more than one bin, great, use the less processed bin on the bottom. If you have only one bin, prepare a new bin with bedding, food and some stuff from the old bin to get it started with all the right creepy crawlies. You'll want it less than half full and aged so it seems like a better home than where the worms are now (in their own poo.)

With the newer bin on the bottom, put something like fine mesh hardware cloth or (as Bentley suggested), a plastic garbage bag with lots of holes poked in it by a pen on top of the contents of the newer bin.

Dump the finished, worm filled compost on top of the 'separator', wait a week and most of the worms will go down to the new food. I got impatient and would scrape a few inches of worm free VC off the top every so often and put the whole thing in the light during the day. If you've got a bin full of pretty well finished VC and very little time to spend on it, this is a great way to harvest, though I do appreciate the zen of the other methods.

If your VC isn't all really well finished and you still have lumps (for me, it's corn cobs and the like), take one of the suggestions above and sieve through something with largeish holes first to dump stuff that doesn't go through the sieve into the bottom of the two bins before you start. Anywhere from 1/2" to 1" square holes sounds reasonable to me.

If you're interested in how to make your own flow through, check out the link.

Here is a link that might be useful: List of DIY Flow through bin construction descriptions

Harvesting or separating worms from the media to acquire worm castings is the age old question of vermicomposting, and there are probably as many varied methods as there are people who engage in vermiculturing. I enjoy previewing comments on this topic because you never know what great ideas you might come across. My method is different than the previously ones posted here, but a lot like joe_jr's, in that I daily collect spent media from my four indoor plastic tub bins. So for what its worth, here's my two cents worth.

I remove about a half inch of surface material form each bin at feeding time, which is dry enough to be removed with a kitty liter scoop. I simply scoop this material off into a 5 gallon plastic bucket. I then dig a trench on one side of the bin for feeding a blender full of food, and repeat the process on the other side. It doesn't take long me long to fill a bucket full of material which is perfect for germinating and potting mixes. I run the material through a quarter inch screen just before using it.

I should also mention that I keep a four foot fluorescent light fixture on top of my bins which is on 24/7. If I do get a worm or two scooped up with the dried spent media they will crawl up the sides of the spent media storage pail if there is a lid on top. But even if you do get a few worms in your spent media they won't mind being potted up or shipped to the garden. Even after grating the spent media there are worm casings which ultimately hatch out in my seed starting peat pots and elsewhere. No problem there either.

Note: the term 'spent media' is simply my way of looking at the finished product. I don't think the commercial worm castings are any different from my perspective, but that is one topic which gets lots of interesting responses as well. Some people go to great extremes to generate what they claim to be pure worm castings. To what end I don't really know. They are just going to be diluted when used anyway, so why go to all the bother. Please take a chunk out of me for that comment. Seriously I thrive on feedback, favorable or otherwise.

morgan_3: what kind of bins do you have?