[TowerTalk] Increasing the Inside diameter of a 1 inch outside diameter Alum pipe.

[Grant Saviers]

The spec numbers on the ASME B36.19 steel pipe tolerances for up to 1.5"NPS
+/- 1/64" for the od.
+20%, -12.5% for the wall thickness

At the spec limits, there is OD/ID interference 1" to 1-1/4".  Luck and 
manufacturers probably making the wall as thin as possible might be why 
it often works *if* there isn't much flash inside the 1-1/4" from the 
welding seam.  Galvanizing Zn is usually spec'd at oz per sq ft which 
according to the galvanizer is 0.003" to 0.005 thickness (added to the 
tolerances) when I've had a tower regalvanized.  The process can leave 
some significant flash and bumps on surface.

I couldn't find a spec for steel pipe ID flash or roundness or 
straightness all of which can make a telescoping fit difficult. Or it 
was made in China.

The specs I've seen for PVC pipe are tighter, since it is extruded and 
thus much more like DOM steel tubing.

Grant KZ1W

On 8/31/2022 15:49, Richard Karlquist wrote:
> I'm not sure why you had trouble with 1" into SCH 40 1 1/4".
> 
> That is a piece of cake with PVC, and it has also worked for me in
> galvanized.
> 
> YMMV.
> 
> ---
> Rick Karlquist
> N6RK
> 
> On 2022-08-31 13:56, Grant Saviers wrote:
> 
>>> Some pipe trivia:
>>>
>>> Any Schedule of 1" trade size has O.D. of 1.315"
>>>
>>> Sch 40 1 1/4" trade size has I.D. of 1.380"
>>>
>>> Yes, there is one *almost* fit of ham interest (1 to 1-1/4 sch40), IF the pipe is round and the weld seam inside is small.   I've done the boring bar and od turning make them fit, but sure don't like doing on the dirty crap steel of welded  pipe.  6063 pipe is a less PITA.
>>>
>>> Grant KZ1W
>>>
>>> On 8/31/2022 09:48, Richard Karlquist wrote:
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