[SEL] Question re tapered gib keys

[Jerry Evans]

At 06:00 PM 15/09/2009, you wrote:
>Message: 13
>Date: Mon, 14 Sep 2009 16:36:25 EDT
>From: Germoamer at aol.com
>Subject: Re: [SEL] Question re tapered gib keys
>
>Jerry,
>The tapered key will only work with a hub that has been machined with a
>taper in it.  Interchanging straight and tapered keys will not work at  all.
>If you insert a tapered key into a "straight key" hub it will only  bind up
>at a point to point contact, whereas if it is inserted in a "tapered  key"
>hub it will lock up the full surface of the key thus giving it maximum
>strength.  A tapered key in a straight key hub with the point to 
>point  contact
>will work loose immediately.
>
>It sounds to me that the key slot has worn oversize in either the shaft or
>hub or both.  If it is ok in the shaft and worn in the hub,  you can
>machine the hub to an oversize key and make a step key.  This 
>is  something that
>is commonly done. The other thing that it could be is that  the bore size in
>hub has gotten slightly oversize during removal/running loose  and is not
>properly tightening up around the shaft.  In that case, the hub  has to be
>bored and bushed.
>Tom  Schmutz
>Concord,  Va.

Hi Tom,
         You are a genius. Thank you for that answer because it also 
answered a question that I forgot to put in the original post and was 
wondering about.
         I was wondering if the  keyway in the flywheel was also machined 
at a taper.
         Your answer makes absolute sense to me and now I have a better 
idea of where to look for the answer.
         Many thanks.
Keep the revs up (or down)
Jerry Evans
Near Johannesburg in Sunny South Africa.
Etched Brass Engine Plates made to order:
<www.oldengine.org/members/evans/plates/index.htm>