i have been reading that a 1/4" mesh for the 1st screening and a 1/8" for the 2nd. hope this helps.

Thanks I think the next wire mesh down is 6mm which is a quarter inch and the fly wire I've ordered is about a 1mm which will have to do the trick. I have a flo through bin so it's practically done in that one by the time I harvest. My other 2 bins are a galvanised bin and a large drum so will harvest using a variety of methods. If I loose a few worms in the process no probs. I will have a compost sifter to cover all bass X thanks again

I made a simple sifter out of 2x4's and 1/4" screening , have used it for years for castings , compost , and whatever else. I have also made a 1/8" screen but that doesnt work as well as its too small. I place my sifter over a wheel barrow , dump my castings onto it then run my hand across it to sift thru the mesh, works fine. My sifter measures OD 30" x 24", hope this helps.

Thanks sounds like I've over complicated it. I reckon the 6mm mesh which equates to a quarter of an inch and even smaller with some overlap.,it's reassuring to,know that the 1/4" inch will do the trick and the 12mm mesh will be fine for the horse poo, garden soil and anything else. As for the fly screen stuff sounds like I might get dust coming through it lol.thanks for your help much appreciated as I continue to learn about this fascinating hobby,

have a great day cheers