I've exhausted pretty much every avenue to find the belt I need to to get t= >his old friend back working. There is a V belt that drives the shutter and = >mechanism. Standard replacements haven't worked because there is such a tig= >ht diameter on the motor. There are fractional 1/4 inch v belts available t= >hat fit the pulleys, but they can not make the tight turn around the motor = >shaft. They just slip and stutter.. Any thoughts??
Kurt Lofback <kurtlofback@gmail.com> wrote:
I've exhausted pretty much every avenue to find the belt I need to to get t= >his old friend back working. There is a V belt that drives the shutter and = >mechanism. Standard replacements haven't worked because there is such a tig= >ht diameter on the motor. There are fractional 1/4 inch v belts available t= >hat fit the pulleys, but they can not make the tight turn around the motor = >shaft. They just slip and stutter.. Any thoughts??
Are you sure that's a V-belt and not an O-ring belt? Have you looked in
the PRB book yet?
And, of course... has the shutter been lubricated properly and is the pad
for the pull-down cam totally, totally saturated and oil all over the cam?
If the mechanism is stiff, the belt will slip.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
On Sunday, May 26, 2019 at 1:29:28 PM UTC-4, Scott Dorsey wrote:
Kurt Lofback <kurtlofback@gmail.com> wrote:
I've exhausted pretty much every avenue to find the belt I need to to ge= >t t=3D=20
his old friend back working. There is a V belt that drives the shutter a= >nd =3D
mechanism. Standard replacements haven't worked because there is such a = >tig=3D
ht diameter on the motor. There are fractional 1/4 inch v belts availabl= >e t=3D
hat fit the pulleys, but they can not make the tight turn around the mot= >or =3D
shaft. They just slip and stutter.. Any thoughts??
Are you sure that's a V-belt and not an O-ring belt? Have you looked in
the PRB book yet?
=20
And, of course... has the shutter been lubricated properly and is the pad
for the pull-down cam totally, totally saturated and oil all over the cam= >?
If the mechanism is stiff, the belt will slip.
I guess at this point I'm not really sure. The mechanism has a belt tension= >er which wouldn't be necessary with an o-ring. And..If the tensioner isn't = >pulling the belt tight around the motor shaft, the tensioner hits the shutt= >er blades. The pulleys are V shaped for an appx 1/4 inch wide belt. Gates m= >akes fractional horsepower V belts, but they are too stiff, and wont make t= >he tight diameter turn around the motor drive. The photos I have of the mac= >hine with the back opened sure looks like a V belt. It must have been a ver= >y flexible one. Im starting to think of possibly of a poly re enforced sewi= >ng machine type belt. BTW, the entire drive train including shutter has bee= >n rebuilt, smooth as silk. This thing has an oil pump that floods the shutt= >er cam.
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