[TowerTalk] Which Thrust Bearing to Use

[Grant Saviers]

Sure.  But since most machining isn't done at -40 deg C, the hole does 
get smaller when the temperature is lower than when the hole was bored.  
I think my calc was correct from a 65 deg F machining temperature.  And 
the CTE of steel is 20 times less than UHMW so it doesn't matter much in 
the tolerances.

On 12/9/2016 18:45 PM, Thomas Noel wrote:
> Absolutely. The circumferential expansion far exceeds the tiny inward radial expansion.
>
> Thomas W Noel
> KF7RSF
>
>> On Dec 9, 2016, at 6:23 PM, charlie at thegallos.com wrote:
>>
>> <anip>
>>> 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.
>>>
>>>
>>> 73 de
>>> Gene Smar  AD3F
>>>
>>>
>> I guess your science teacher "Back when" didn't do what mine did.  He had
>> a steel ball (on a handle, and a steel ring (ditto).  At room temp, the
>> ball would NOT fit through the ring - maybe 1/32 of interference.  You
>> then took the ring, put it in a bunsen burner, and hot it hot (didn't even
>> need to be red) - the ball fit though perfectly
>>
>> Yep, the way materials expand the hole gets bigger.  We do it in the shop
>> ALL the time, heat a gear etc to make the hole bigger to drop over a shaft
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>