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Re: Pinion placement within the McLennan gearbox.


Feb 15 8:37 PM

 


----------------------------

#41736 Feb 15 8:37 PM

When modifying the McLennan gearbox, I left the plastic trim that

surrounds the gearbox off and the gears are exposed, permitting viewing

of the gears and the pinion.



After cutting off the nibs of the motor, when inserting the pinion

(which was properly positioned on the motor shaft using the accompanying

spacer tool) into the gearbox, it is apparent that the pinion goes in

too deep and engages the gear just at the very tail end of the pinion,

towards the motor.



As Michael points out, "If you look at the width of the pinion teeth

that engage the narrow gearbox gear that it turns then you will realize

that this is not an issue." I thought so, too, at first glance judging

from what looks like a generous thickness of the pinion. However, that

assumes placement somewhere near the middle of the pinion.



But, with the motor's nibs removed, the pinion meshes very close to the

back edge. When you use a thin piece of rubber (or whatever insulation),

what that does is restore the displacement, moving the motor that much

farther out from the gearbox and the gear now engages the pinion near

the middle of the pinion.



Again, you can only see this from the side with the gearbox cover

removed. I'll try to get pictures tomorrow.



Bottom line: I am recommending a revision to the installation procedure

to cutoff the nibs but insert a thin piece of material (1 to 1.5mm)

which will both improve the mesh and act as sound insulation.



Bill in Gold Canyon, AZ

USA



----------------------------

#41738 Feb 15 10:14 PM

Hi Bill,

I will look for the pictures and have already made gaskets for the

motors. The gear leaves a trail in the grease where it rides, so I can

tell just where it is positioned afterward.

Floyd

--- In Losmandy_users@yahoogroups.com, "William J. Shaheen"

wjshaheen@...> wrote: >

>

> When modifying the McLennan gearbox, I left the plastic trim that

> surrounds the gearbox off and the gears are exposed, permitting viewing

> of the gears and the pinion.

>

> After cutting off the nibs of the motor, when inserting the pinion

> (which was properly positioned on the motor shaft using the accompanying

> spacer tool) into the gearbox, it is apparent that the pinion goes in

> too deep and engages the gear just at the very tail end of the pinion,

> towards the motor.

>

> As Michael points out, "If you look at the width of the pinion teeth

> that engage the narrow gearbox gear that it turns then you will realize

> that this is not an issue." I thought so, too, at first glance judging

> from what looks like a generous thickness of the pinion. However, that

> assumes placement somewhere near the middle of the pinion.

>

> But, with the motor's nibs removed, the pinion meshes very close to the

> back edge. When you use a thin piece of rubber (or whatever insulation),

> what that does is restore the displacement, moving the motor that much

> farther out from the gearbox and the gear now engages the pinion near

> the middle of the pinion.

>

> Again, you can only see this from the side with the gearbox cover

> removed. I'll try to get pictures tomorrow.

>

> Bottom line: I am recommending a revision to the installation procedure

> to cutoff the nibs but insert a thin piece of material (1 to 1.5mm)

> which will both improve the mesh and act as sound insulation.

>

> Bill in Gold Canyon, AZ

> USA

>



----------------------------

#41743 Feb 16 2:59 AM

I checked the position of my pinions (trace in the grease) when I fitted

them. As you say it is close to the edge of the pinion, but still on it, so

I did not do anything about it. The rubber gasket sounds like a good idea.



Mark



2009/2/16 Floyd Blue fblue@...>

> Hi Bill,

> I will look for the pictures and have already made gaskets for the

> motors. The gear leaves a trail in the grease where it rides, so I can

> tell just where it is positioned afterward.

> Floyd

> --- In Losmandy_users@yahoogroups.com Losmandy_users%40yahoogroups.com>,

> "William J. Shaheen"

>

> wjshaheen@...> wrote:

> >

> >

> > When modifying the McLennan gearbox, I left the plastic trim that

> > surrounds the gearbox off and the gears are exposed, permitting viewing

> > of the gears and the pinion.

> >

> > After cutting off the nibs of the motor, when inserting the pinion

> > (which was properly positioned on the motor shaft using the accompanying

> > spacer tool) into the gearbox, it is apparent that the pinion goes in

> > too deep and engages the gear just at the very tail end of the pinion,

> > towards the motor.

> >

> > As Michael points out, "If you look at the width of the pinion teeth

> > that engage the narrow gearbox gear that it turns then you will realize

> > that this is not an issue." I thought so, too, at first glance judging

> > from what looks like a generous thickness of the pinion. However, that

> > assumes placement somewhere near the middle of the pinion.

> >

> > But, with the motor's nibs removed, the pinion meshes very close to the

> > back edge. When you use a thin piece of rubber (or whatever insulation),

> > what that does is restore the displacement, moving the motor that much

> > farther out from the gearbox and the gear now engages the pinion near

> > the middle of the pinion.

> >

> > Again, you can only see this from the side with the gearbox cover

> > removed. I'll try to get pictures tomorrow.

> >

> > Bottom line: I am recommending a revision to the installation procedure

> > to cutoff the nibs but insert a thin piece of material (1 to 1.5mm)

> > which will both improve the mesh and act as sound insulation.

> >

> > Bill in Gold Canyon, AZ

> > USA

> >

>

>

>





[Non-text portions of this message have been removed]







----------------------------

#41745 Feb 16 9:08 AM

Hi Bill, I agree, the gasket is a good mod and probably a good way to

counter the amplification of the sound.

I thought they would send you the 3mm pinions, that is good service!

Floyd

--- In Losmandy_users@yahoogroups.com, "William J. Shaheen"

wjshaheen@...> wrote: >

> Right - I'm not saying it's an essential change and not that one

> should undo a working system. Just an elaboration while making the

> modification. The sound reduction is dramatic since otherwise the

> gearbox cover acts as a megaphone for the noise generated by the

> motor.

>

> By the way, McLennan just responded to my request for some 3mm

> pinions and has posted them to me gratis.

>

> Thanks.

>

> Bill

>

> --- In Losmandy_users@yahoogroups.com, Mark Crossley public@>

> wrote:

> >

> > I checked the position of my pinions (trace in the grease) when I

> fitted

> > them. As you say it is close to the edge of the pinion, but still

> on it, so

> > I did not do anything about it. The rubber gasket sounds like a

> good idea.

> >

> > Mark

> >

> > 2009/2/16 Floyd Blue fblue@>

> >

> > > Hi Bill,

> > > I will look for the pictures and have already made gaskets for the

> > > motors. The gear leaves a trail in the grease where it rides, so

> I can

> > > tell just where it is positioned afterward.

> > > Floyd

> > > --- In Losmandy_users@yahoogroups.com Losmandy_users%

> 40yahoogroups.com>,

> > > "William J. Shaheen"

> > >

> > > wjshaheen@> wrote:

> > > >

> > > >

> > > > When modifying the McLennan gearbox, I left the plastic trim

> that

> > > > surrounds the gearbox off and the gears are exposed, permitting

> viewing

> > > > of the gears and the pinion.

> > > >

> > > > After cutting off the nibs of the motor, when inserting the

> pinion

> > > > (which was properly positioned on the motor shaft using the

> accompanying

> > > > spacer tool) into the gearbox, it is apparent that the pinion

> goes in

> > > > too deep and engages the gear just at the very tail end of the

> pinion,

> > > > towards the motor.

> > > >

> > > > As Michael points out, "If you look at the width of the pinion

> teeth

> > > > that engage the narrow gearbox gear that it turns then you will

> realize

> > > > that this is not an issue." I thought so, too, at first glance

> judging

> > > > from what looks like a generous thickness of the pinion.

> However, that

> > > > assumes placement somewhere near the middle of the pinion.

> > > >

> > > > But, with the motor's nibs removed, the pinion meshes very

> close to the

> > > > back edge. When you use a thin piece of rubber (or whatever

> insulation),

> > > > what that does is restore the displacement, moving the motor

> that much

> > > > farther out from the gearbox and the gear now engages the

> pinion near

> > > > the middle of the pinion.

> > > >

> > > > Again, you can only see this from the side with the gearbox

> cover

> > > > removed. I'll try to get pictures tomorrow.

> > > >

> > > > Bottom line: I am recommending a revision to the installation

> procedure

> > > > to cutoff the nibs but insert a thin piece of material (1 to

> 1.5mm)

> > > > which will both improve the mesh and act as sound insulation.

> > > >

> > > > Bill in Gold Canyon, AZ

> > > > USA

> > > >

> > >

> > >

> > >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>



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