I have installed some new toilet paper holders in my house. They came with cheap plastic wall anchors without a collar on them. I threw them away and used different anchors, because every time I try to use the ones without a collar I push them into the wall. Is there a trick I am missing for these anchors without the collar? A lot of stuff comes with them now, and apparently I am not smart enough to use them.
Plastic anchors come in different quality flavors and having the collar or not doesn't correlate with that.
I use a locally manufactured (I'm outside of US) series of anchors without a collar - their diameter is slightly smaller than that of the hole and they have small relief dots extending from the surface so that the outer diameter is slightly bigger that that of the hole. They require some force to be driven into the hole - either pushing them with a hard tool or gently hammering with a hammer. My experience with these anchors is very good - they almost never slip given the material is hard and doesn't crumble while drilling.
At the same time I saw a lot of anchors both with or without collar that slip in the hole. So I'm pretty sure it's not the collar itself that matters.
That said another very important factor is how precise the hole is drilled. It has to be of exactly the required diameter. Drilling must be performed in such manner that the drill bit doesn't exert side load onto the hole walls - otherwise the hole is milled and the anchor won't hold there.
Also usual plastic anchors can only be used in strong solid materials that don't crumble while drilling. There're special "hollows anchors" (not sure of the exact term) that can be used for slightly bigger holes and for hollow materials - they tight into a knot when inside a hollow.
Finally the anchor diameter must be properly selected depending on the screw diameter. Otherwise you're screwed.
I really hate the anchors that come with most wall accessories. I always throw them away and opt for my own anchors. I love the self tapping screw in type. They look like an over sized masonry or self tapping screw. So easy to use, simply insert the sharp point on your mark, no drilling required and use a #2 phillips screwdriver to screw them into your drywall. They come in different weight ratings. I use the 40 pound rated ones for most everything. They tighten snug to the wall and accept a #6 or 8 screw of your choice.(the kit comes with three different color screws) I buy them at Lowes, but unfortunately I don't have any original packaging with the brand name on them, but I will find out and post it in a comment later. They also work great when you have an existing hole from a previous anchor failure, as long as the hole is not much more than 3/8 inch in diameter.
You're probably just drilling too big a hole. Use a slightly smaller drill bit, and only push them in flush with the wall.
When you're screwing into them, you should also probably watch how much pressure you use to push on the screw (you don't need much), as if you push hard enough, the screw will just pop the anchor through the wall.
I've used them a few times when I was too lazy to go downstairs to get something else, and they seem to work just fine.