On 12/9/16 6:00 PM, Gene Smar wrote:
-----Original Message-----
From: TowerTalk [mailto:[email protected]] On Behalf Of
jimlux
Sent: Friday, December 09, 2016 12:08 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [TowerTalk] Which Thrust Bearing to Use
On 12/9/16 8:53 AM, [email protected] wrote:
<snip>
Your 2" hole that just clears at -40 will be 2.02" at +60C. I don't
think you're going to have a big problem with that 10 mil extra
clearance.
I don't agree. If the hole is large enough to just clear at -40C, when
heated the entire mass will increase in volume. The OD will get larger and
the hole will get smaller and become tighter against the mast.
The hole expands more than the mast, because the CTE is larger for the hole
It's slightly counter intuitive - at first glance you'd think the
material "grows" between the outer edge of the plate and the hole, and
pushes the hole smaller. But in reality, the outer edge of the plate
moves out more.
Consider if you sliced the plate with the hole in half and shoved a shim
in there that's 10mil. Then slice it on the 90, and shove in another 10
mil shim. etc. by the time you're done, the hole is 20 mil bigger in
diameter.
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