I'm currently restoring a late 1928 Mason & Hamlin RA Ampico "A".
The shock mounts for the pump motor show a modification not
previously seen in my experience.  Each mount has a cut-out measuring
about 1.125" wide by 1" deep.  A 0.375" diameter by 0.1" thick soft
leather disk has been inserted into each hole for the slide rod to
bear against.  A rubber "doughnut" 1-inch in diameter by 0.750" thick
is placed in the cut-out.

The doughnut is now "flat" on three sides from pressure from the
normal angled metal brackets.  A setscrew collar on the slide rod
bears against this doughnut.  The usual 5-sided metal bearing plates
are in their usual slots in the mounts.

All of this appears to be vintage factory work and not a more recent
modification coinciding with what appears to be a 20-25 year old
restoration.  Opinions?

John Grant
Baltimore, Maryland

 [ http://www.mmdigest.com/Attachments/17/07/07/170707_051817_Isolation%20Mount%201.jpg 
 [ http://www.mmdigest.com/Attachments/17/07/07/170707_051817_Isolation%20Mount%202.jpg 
 [ http://www.mmdigest.com/Attachments/17/07/07/170707_051817_Isolation%20Mount%203.jpg 
 [ http://www.mmdigest.com/Attachments/17/07/07/170707_051817_Isolation%20Mount%204.jpg