Why are my Anka screws jamming securing Pine to concrete?

Manooks

Hi There - I cant work out for the life of me why my Anka screws are jamming up with about 20-25mm to go.  im trying to secure treated pine to concrete.  Ive double checked all the specifications (bit size, 10mm larger hole) ive worked the hammer drill in and out to clear up any debrief and the problem persists (some sites have recommended an air pressure cleaner!!!)

With every failed attempt as get more frustrated, i keep threading the screw heads making the matter worse.  I've got both a pillips head and a star head, even bought 2 different sizes with same results

Hoping someone can shed some light on this for me.

Thanks.

Manooks 

 

JDE

Ive always found ankascrews need quite a bit of force to get the last couple of turns. I use a small bottle cleaning brush and my car compressor to make sure the holes are clear of debris. Using the drill alone will not always totally clear the hole. I have once used a vacuum cleaner wilth straws taped to the end to clear holes. Suggest making sure your hole are deep enough. Make sure no debris left in holes. Personally I use the ones with a bolt head they allow using a spanner so you get a lot more leverage and the head doesnt chew out like a Phillips. If you choose to persist with the star and Phillips ones make sure you are holding your impact driver square on and with pressure.

JDE