I need to drill 16mm diam holes in a reinforced concrete slab.
14 holes each 150mm deep.The holes will be used to resin in anchor studs, and then right angle straps are being bolted to slab ... the vertical portion of strap will then be secured to vertical studs of timber frame walls.
I have an SDS drill and a new 16mm bit.
When I have drilled SDS holes before they tend to wander about until a cm or so into the material.
Any tips on doing this .... some options I have thought of are :
#1 use a non SDS pilot hole, before using SDS drill ... although I recall someone posting here that SDS bits should not be used with a pilot hole, due to way they work.
#2 bolt straps to vertical studs first and drill through the clearenance holes - risk here is damage to clearance finish, and this is external job so need the protection.