[DeTomaso] A-arm bushings...should they require machining?

Fri Sep 22 10:53:27 EDT 2017

There is a "starting" chamfer in the outboard a arm bores and on the small
end of the outer shell of the bushing.   The ID chamfer in the a arm bore is
NEEDED to allow the radius of the bushing outer shell transition from fit to
flange so that the flange can be flush to the a arm. 

From: Julian Kift [mailto:julian_kift at hotmail.com] 
Sent: Friday, September 22, 2017 10:30 AM
To: Charles Engles; 'Joseph F. Byrd, Jr.'; detomaso at server.detomasolist.com
Subject: Re: [DeTomaso] A-arm bushings...should they require machining?

Chuck,

I think the difference here is oem rubber style bushings designed to be a
press fit vs. aftermarket poly bushings. We recently had a long discussion
on the merits of each, so won't rehash that, but I'm aligned with Joseph's
thinking that 0.003" would be the expected interference fit for a bushing of
this size. At 0.008" over, I'd probably turn them down or failing access to
a lathe at least spin them up on a sander to lose some of that oversize.

If I recall correctly there is a very slight splay on the A-arms to effect
starting the press fit.

Julian

  _____  

From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of
Charles Engles <cengles at cox.net>
Sent: Thursday, September 21, 2017 6:11 PM
To: 'Joseph F. Byrd, Jr.'; detomaso at server.detomasolist.com
Subject: Re: [DeTomaso] A-arm bushings...should they require machining? 

Dear Joe,

                    I  don't know.

                    I do know that twenty odd years ago when I converted
both Panteras to polyurethane bushings from Pantera Performance Center, they
went in with just finger/hand pressure.  No press needed.   Obviously, they
must have been smaller than yours and I don't understand why there is such a
great difference.

                                      Puzzled,  Chuck Engles

-----Original Message-----
From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On Behalf
Of Joseph F. Byrd, Jr.
Sent: Thursday, September 21, 2017 5:32 PM
To: detomaso at server.detomasolist.com
Subject: [DeTomaso] A-arm bushings...should they require machining?

I have removed the bushings from the front A-Arms and have found their ODs
to be a consistent 1.184".   the A-arm bore IDs varied slightly around
1.181".   this makes sense as the IDs would be 30mm with the bushings
oversized for MY expected press fit of ~ 0.003".

NOW, the new bushing ODs vary around 1.189".   to ME, that is way too much
press and could plastic yield the A-arm bores.   

Is it expected to machine the new bushing ODs?  (Pretty common practice for
new parts to be oversized for field fitting  in the machines I use to work
to allow for possible damage/wear.)

OR

Throw away the micrometers and get a bigger press?

Joe/5177

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-------------- next part --------------
   There is a "starting" chamfer in the outboard a arm bores and on the
   small end of the outer shell of the bushing.   The ID chamfer in the a
   arm bore is NEEDED to allow the radius of the bushing outer shell
   transition from fit to flange so that the flange can be flush to the a
   arm.

   From: Julian Kift [mailto:julian_kift at hotmail.com]
   Sent: Friday, September 22, 2017 10:30 AM
   To: Charles Engles; 'Joseph F. Byrd, Jr.';
   detomaso at server.detomasolist.com
   Subject: Re: [DeTomaso] A-arm bushings...should they require machining?

   Chuck,

   I think the difference here is oem rubber style bushings designed to be
   a press fit vs. aftermarket poly bushings. We recently had a long
   discussion on the merits of each, so won't rehash that, but I'm aligned
   with Joseph's thinking that 0.003" would be the expected interference
   fit for a bushing of this size. At 0.008" over, I'd probably turn them
   down or failing access to a lathe at least spin them up on a sander to
   lose some of that oversize.

   If I recall correctly there is a very slight splay on the A-arms to
   effect starting the press fit.

   Julian
    _____________________________________________________________________

   From: DeTomaso <[1]detomaso-bounces at server.detomasolist.com> on behalf
   of Charles Engles <[2]cengles at cox.net>
   Sent: Thursday, September 21, 2017 6:11 PM
   To: 'Joseph F. Byrd, Jr.'; [3]detomaso at server.detomasolist.com
   Subject: Re: [DeTomaso] A-arm bushings...should they require machining?

   Dear Joe,
                       I  don't know.
                       I do know that twenty odd years ago when I
   converted
   both Panteras to polyurethane bushings from Pantera Performance Center,
   they
   went in with just finger/hand pressure.  No press needed.   Obviously,
   they
   must have been smaller than yours and I don't understand why there is
   such a
   great difference.
                                         Puzzled,  Chuck Engles
   -----Original Message-----
   From: DeTomaso [[4]mailto:detomaso-bounces at server.detomasolist.com] On
   Behalf
   Of Joseph F. Byrd, Jr.
   Sent: Thursday, September 21, 2017 5:32 PM
   To: [5]detomaso at server.detomasolist.com
   Subject: [DeTomaso] A-arm bushings...should they require machining?
   I have removed the bushings from the front A-Arms and have found their
   ODs
   to be a consistent 1.184".   the A-arm bore IDs varied slightly around
   1.181".   this makes sense as the IDs would be 30mm with the bushings
   oversized for MY expected press fit of ~ 0.003".

   NOW, the new bushing ODs vary around 1.189".   to ME, that is way too
   much
   press and could plastic yield the A-arm bores.

   Is it expected to machine the new bushing ODs?  (Pretty common practice
   for
   new parts to be oversized for field fitting  in the machines I use to
   work
   to allow for possible damage/wear.)
   OR
   Throw away the micrometers and get a bigger press?

   Joe/5177
   _______________________________________________
   Detomaso Email List is not managed by POCA
   Posted emails must not exceed 1.5 Megabytes
   DeTomaso mailing list
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   use the links above.
   Members who post to this list grant license to the list to forward any
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   list. They also grant the list owner permission to maintain an archive
   or approve the archiving of list messages.

References

   1. mailto:detomaso-bounces at server.detomasolist.com
   2. mailto:cengles at cox.net
   3. mailto:detomaso at server.detomasolist.com
   4. mailto:detomaso-bounces at server.detomasolist.com
   5. mailto:detomaso at server.detomasolist.com
   6. mailto:DeTomaso at server.detomasolist.com
   7. http://server.detomasolist.com/mailman/listinfo/detomaso