[TheForge] consider shrink fit tool holders

[Dave Smucker]

Yes Terry, a ring expands when heated as anyone who has used a bearing heater to shrink fit bearings knows.  But this is not what we have been talking about -- we have been talking about heating only the area around a hole and not the whole piece.  We have also been talking about heating steel into the plastic range.  When the OD of the heated area of a hole is constrained by cool metal (below plastic) we force a major portion of the expansion to make the ID smaller.  The expansion has to go somewhere -- only two places it can go, smaller hole and upset (thicker) portion of the plate.  These are very small changes when the parts again cool, but plastic deformation has taken place and there will be a difference.  

Dave Smucker
Brasstown, NC

-----Original Message-----
From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of terry l. ridder
Sent: Friday, August 12, 2016 9:03 PM
To: theforge e-mail list
Subject: [TheForge] consider shrink fit tool holders

hello

any machinist here?

the shrink fit tool holder is an excellent example of the hole gets larger. upon air cooling the tool is held by thousands of lbs of force.

--
terry l. ridder ><>
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