I'm using a 1/2" rock chuck, so I have to use the 1/2 to 1/4 adapter just about all the time. I got a couple new "V" router bits with 1/4" shanks (can't seem to find any with 1/2" shanks, anyone know where to get them?). I used the 90 a couple times with no problem, but when I tried to use the 60 bit there was a problem. It was hard to get into the adapter so I sanded the shank a bit and got it in, but when I tried to put it in the chuck the adapter would not go all the way in. It got stuck about 3/8" from being all the way in. I sanded the shank a bit more, made sure everything was clean with the chuck and adapter but still no dice. So I went back to the old bit and it was fine. Anyone have this problem before? Variation in the shank diameter on the bit perhaps? They were on sale at Menards, perhaps that's why LOL.