I've made 1/2 dozen wooden high seats and can recommend the turbo coach screws sold by Screwfix:
http://www.screwfix.com/p/turbo-coach-screws-m8-x-100mm-pack-of-50/78121
They come in various lengths, are cheap, have self drilling point and I've never had a problem with the wood splitting.
10mm socket for your drill and away you go.
http://www.screwfix.com/p/turbo-coach-screws-m8-x-100mm-pack-of-50/78121
They come in various lengths, are cheap, have self drilling point and I've never had a problem with the wood splitting.
10mm socket for your drill and away you go.