I have 5 soloway horizontal nipples and I made my waterer yesterday. I'm using a 1" PVC pipe and I've seen others use the same thing with the same nipples. I drilled the holes exactly the size I read that I should (3/8). For the life of me (and my husband) - cannot get them in! We push and turn and push until our thumbs feel like they're going to fall off haha. Should I just drill the hole a little bigger? We can get them in half way and then they'll pop back out... so I really think the hole must be too small.