For a bird feeder project I want to have an adjustable, sliding metal sleeve fit snugly over a galvanized pole (7’). Will a 3/4” L-type copper pipe fit over a 1” galvanized pipe? From online chart, the copper I.D. should be 1.025” and the steel pipe O.D., 1”. The outer copper sleeve would be about 2’ long. Would the copper pipe actually fit and be movable or is the fit too tight? I’ve read elsewhere on SE suggesting steel/steel alternatives with set-screws but I’ prefer something closer to this if possible. Thanks!

  • 2
    If you have a local hardware store then visit them and manually try out your idea.
    – MonkeyZeus
    Mar 3, 2021 at 19:17
  • If you're trying to learn about pipe diameters then the terms you need to research are nominal versus actual.
    – MonkeyZeus
    Mar 3, 2021 at 19:18
  • 3
    if it's 1" OD it's not a 1" pipe.
    – Jasen
    Mar 3, 2021 at 19:18
  • 4
    If this is going to be outside, galvanic corrosion will by your enemy! The copper and steel will react with each other and reasonably quickly you'll have corrosion "welding" the two pieces of pipe together.
    – FreeMan
    Mar 3, 2021 at 19:19
  • 1
    As noted you will have corrosion. I think corrosion products will block the annuluar space and you will not be able to slide one tube over the other. Mar 3, 2021 at 20:39

2 Answers 2


Instead of trying to source your own parts that fit together, I suggest you find something that already exists. A telescoping pole, such as a paint roller extension pole or a pool brush pole, would probably serve your purpose.


Copper and galvanized steel will corrode where they come into contact with each other; do not mix. I believe a 1" schedule-40 galvanized pipe will fit nicely inside a 1-1/4" of the same.

P.S. I upvoted Longneck's answer for suggesting finding something suitable off the shelf.

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