When making one of the bucket feeders with the PVC elbow near the bottom maybe the best elbow to use is a 4' 90deg street elbow drain pipe that looks real similar to this,

The one in the picture is schedule 40 pvc and only a 45 degree elbow but the most important part are the two ends anyway, but you have to use the 90 deg ell. The small end is called the spigot end and the large end is the hub. For the elbow to put in the bucket feeder make your first cut at a 90 degree angle to the spigot end so when you put the spigot in the bucket it rest about 1/4 to 1/2 inch from the bottom. I had a hard time trying to figure out how to do this cut but I finally took a framing square and laid it across the spigot end and moved it till it positioned correctly on where to cut the elbow, I then held the square in place and used it to guide the saw for the first cut. (I need someone to come video it for me so I could post the video). Next I cut the hub end off the scrap piece I removed with the first cut, I cut it just at the end of the bevel that is on it.
Using the first piece with the spigot end I marked and cut my bucket (I used a cat litter bucket with square sides), then interested the spigot from the inside until the flange stopped it from going any more. Finally take the hub end you cut off and press it over the spigot end outside of the bucket.
If you made your cuts straight and smooth and cut your circle out of the bucket nicely the hub will tighten up on the spigot and keep it all in place without using and glue or fasteners of any kind. If you goofed it up you can still take it apart and modify it or make adjustments until you get it the way you want. When you buy the elbow at the home improvement store it will be with the light weight drain pipe PVC and mine was less than $5. it is called a "90degree street elbow hub & spigot". I got the bucket for free when I bought cat litter and the elbow was less than $5 so I've got a feeder that will hold probably 20 to 25 lbs of feed for 5 bucks plus labor. Its already in the coop being used but if I get a chance I'll take it out and try to get a few pictures to show you in the next couple days.
The one in the picture is schedule 40 pvc and only a 45 degree elbow but the most important part are the two ends anyway, but you have to use the 90 deg ell. The small end is called the spigot end and the large end is the hub. For the elbow to put in the bucket feeder make your first cut at a 90 degree angle to the spigot end so when you put the spigot in the bucket it rest about 1/4 to 1/2 inch from the bottom. I had a hard time trying to figure out how to do this cut but I finally took a framing square and laid it across the spigot end and moved it till it positioned correctly on where to cut the elbow, I then held the square in place and used it to guide the saw for the first cut. (I need someone to come video it for me so I could post the video). Next I cut the hub end off the scrap piece I removed with the first cut, I cut it just at the end of the bevel that is on it.
Using the first piece with the spigot end I marked and cut my bucket (I used a cat litter bucket with square sides), then interested the spigot from the inside until the flange stopped it from going any more. Finally take the hub end you cut off and press it over the spigot end outside of the bucket.
If you made your cuts straight and smooth and cut your circle out of the bucket nicely the hub will tighten up on the spigot and keep it all in place without using and glue or fasteners of any kind. If you goofed it up you can still take it apart and modify it or make adjustments until you get it the way you want. When you buy the elbow at the home improvement store it will be with the light weight drain pipe PVC and mine was less than $5. it is called a "90degree street elbow hub & spigot". I got the bucket for free when I bought cat litter and the elbow was less than $5 so I've got a feeder that will hold probably 20 to 25 lbs of feed for 5 bucks plus labor. Its already in the coop being used but if I get a chance I'll take it out and try to get a few pictures to show you in the next couple days.