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Re: Tach drive

To: Ron Soave <soavero@yahoo.com>
Subject: Re: Tach drive
From: Chris Kotting <ckotting@iwaynet.net>
Date: Wed, 20 Oct 1999 15:55:24 -0400
Cc: "Hanna, Mark" <mhanna@ball.com>, "'spridgets@autox.team.net'" <spridgets@autox.team.net>
References: <19991020191223.26072.rocketmail@web1105.mail.yahoo.com>
Reply-to: Chris Kotting <ckotting@iwaynet.net>
Sender: owner-spridgets@autox.team.net
Pardon the interruption, but I think you may run into a problem with
this plan:

If the generator turns 4x for every turn of the tachometer cable, then
to get the same effect via a direct drive off of the belt with a
jackshaft, that pulley would have to be 4x the size of the generator
pulley.  

A jackshaft pulley >>smaller<< than the generator would give a
rotational speed >>faster<< than the generator.

The generator pulley is, what, about 4 inches?  You got room under there
for a 16" jackshaft pulley?

Chris Kotting
ckotting@iwaynet.net

Ron Soave wrote:
> 
> That would be a nice solution.  The reduction ratio in
> the gearbox is 4:1, the generator output shaft turns 4
> times for every one turn of the tach cable.
> 
> --- "Hanna, Mark" <mhanna@ball.com> wrote:
> > Hi Ron ,
> > My car will have an alternator. I would like to use
> > the stock Bugeye tach. I
> > was thinking of driving the tach directly from a
> > jack shaft attached to an
> > appropriately sized pulley.  Say 1/3rd the diameter
> > of the main crank
> > pulley. This way I would not need a gear box. Or do
> > I have this backwards ,
> > i.e. the tach has to turn 3 times as fast as the
> > crank ? I haven't spent any
> > time on the problem yet. I will be very interested
> > in what you come up with
> > .
> > Mark Hanna
> > AN5
> >
> > > -----Original Message-----
> > > From:       Ron Soave [SMTP:soavero@yahoo.com]
> > > Sent:       Wednesday, October 20, 1999 9:58 AM
> > > To: spridgets@autox.team.net
> > > Subject:    Tach drive
> > >
> > > List,
> > > I have been working with a machinist in town to
> > try to
> > > come up with gears to replace those in a generator
> > > tach reduction gearbox (it a 4:1 ratio).  What we
> > are
> > > trying to do is find spur gears from, say, Berg or
> > > Boston Gear, that can be modified to work.  Has
> > anyone
> > > done this research before?
> > >
> > > This was spurred by a failure of my gearbox.  The
> > box
> > > is an aftermarket item from "a major LBC part
> > > distrbutor" (begins with M, rhymes with "Toss")
> > with
> > > potmetal gears.  Several teeth just kind of
> > sheared
> > > off, and the machinist said the quality of the
> > metal
> > > on the gears was "expletive deleted."  The
> > machinist
> > > basically felt the entire box could be hand-made
> > with
> > > high quality for what the aftermarket places
> > charge.
> > > If this ends up being the case, you'll be the
> > first to
> > > know.
> > >
> > >
> > > =====
> > > Ron Soave
> > > "You Are What You Remember"
> > > 1960 Bugeye
> > > 1972 BGT
> >
> 
> =====
> Ron Soave
> "You Are What You Remember"
> 1960 Bugeye
> 1972 BGT

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