Ibyuma bizunguruka bishyirwa mubikorwa bishyushye, byahimbwe kandi bikonje.Icyuma gishyushye kizengurutse gifite mm 5.5-250 z'ubunini.Muri byo: 5.5-25 mm ibyuma bito bizengurutse cyane cyane kugirango bigorwe neza mubice byinshi, bikunze gukoreshwa mugushimangira utubari, bolts nibice bitandukanye bya mashini;Ibyuma bizunguruka birenze mm 25, bikoreshwa cyane mugukora ibice byubukanishi, umuyoboro wicyuma udafite icyuho, nibindi.