A Question on Friction ?? (long)
 

I'm having a problem getting my head around this problem..

I have a Lewmar vertical model 1000 electric anchor windlass.

The friction disk that is between the gypsy and the drum is a flat ring of
brittle friction material, ~1/2" wide, ~3/16" thick and ~4" dia. This ring
sets in a groove in the gypsy top surface. The top surface of this disc
contacts a smooth chromed surface on the bottom of the rope (warping) drum.

The friction disc kinda got broken when I backed off to much on the clutch
release nut on top to allow the anchor to free fall. When the gypsy spun
wildly, the friction ring appearently jumped out of that shallow goove in
the gypsy. When I tightened down on the nut to slow the free fall, the
friction ring didn't fall back into it's groove and broke into several
pieces. I managed to get enough metal to metal friction to prevent the total
chain length from running out.

Parts are no longer available hear in the US for this model so I went to a
very helpful brake and clutch shop in Tacoma. The fellow that worked with
me was a blue water sailer and knew exactly what I wanted.

However he recommended that I bond the new friction ring into the groove on
the gypsy top to prevent it from jumping out again. We did this and every
thing works fine 'however'... I can no longer free-fall the anchor until I
have about 50-60 ft of chain out or when motoring astern after the anchor
has taken bit.

Seems like there is too much friction now. Is this due to the new type of
friction material (looks courser) or is it because I only have a single
friction surface (as opposed to the two with the OEM arrangement) that is
free when I release the clutch nut?? Was it a mistake to glue/bond the new
disk to the gypsy, thus eliminating one free surface when released??

OK, How about a couple guys to get your 'egg heads' around this question.
Me? I can even spell physics.

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

Steve wrote:

Seems like there is too much friction now.

Yeah, the new disk is probably little bit thicker than the old one and
it is certainly spaced a little bit further out due to the adhesive so
naturally it will drag a bit.

The friction surfaces are also probably a bit rougher after your metal
to metal incident.

I believe that use will smooth things out and you will have one less
thing to worry about soon.

Rick

A Question on Friction ?? (long)
 

I really don't see where the thickness would have any bearing on this
problem since when released fully, even with the OEM disc, the warping drum
still is in full contact with the upper face of the friction disc. T

The drum isn't lifted off the disc, just less pressure from the engagement
nut. Zero clearance when free running. Sight pressure from the weight of the
drum, to increasing pressure as the engagement nut is tightened.

Thanks

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

In re-reading my post;
Perhaps the term "engagement nut" is incorrect. There is no engagement, as
in a locking situation. Even at full pressure from the winch handle
tightening the nut, there is still only friction binding the two surfaces
and reducing slippage.

However in my situation with the OEM disc, the anchor/chain would free fall
once I powered down until the anchor was off the bow roller. Now I have to
power down to near water depth (~40 ft).

There is no opportunity, in ordinary use, to have the surfaces polish or
smooth themselves. In order to power down, I have to tighten the clutch so
the motor shaft is engaged thru the warping drum to the gypsy.

I've even considered putting a little grease on the disc surface to
encourage some slippage. If it doesn't work, I can always clean it off with
brake cleaner/solvent. (I did this on the rust pitted winch clutches and
brakes on my 50 yr old mobile crane. My seem radical, but it works fine for
my purposes.)

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

Steve wrote:


In order to power down, I have to tighten the clutch so
the motor shaft is engaged thru the warping drum to the gypsy.

So just "power down" with the clutch "loose" it will slip when it's worn
enough ... try lifting with the clutch loose and it will hasten the
running in process.

I've even considered putting a little grease on the disc surface to
encourage some slippage.

That would be a big mistake.

Rick

A Question on Friction ?? (long)
 

I've even considered putting a little grease on the disc surface to
encourage some slippage.

That would be a big mistake.


I kinda expected and deserved the admonishment Rick.

Thanks

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

Don't put grease on the surface face. It won't do what you want it to.
Instead of slipping it will grab. Try cleaning the surface with brake
cleaner to remove any oil and grease.

Jack
"Steve" wrote in message
...
I'm having a problem getting my head around this problem..

I have a Lewmar vertical model 1000 electric anchor windlass.

The friction disk that is between the gypsy and the drum is a flat ring of
brittle friction material, ~1/2" wide, ~3/16" thick and ~4" dia. This
ring
sets in a groove in the gypsy top surface. The top surface of this disc
contacts a smooth chromed surface on the bottom of the rope (warping)
drum.

The friction disc kinda got broken when I backed off to much on the
clutch
release nut on top to allow the anchor to free fall. When the gypsy spun
wildly, the friction ring appearently jumped out of that shallow goove in
the gypsy. When I tightened down on the nut to slow the free fall, the
friction ring didn't fall back into it's groove and broke into several
pieces. I managed to get enough metal to metal friction to prevent the
total
chain length from running out.

Parts are no longer available hear in the US for this model so I went to a
very helpful brake and clutch shop in Tacoma. The fellow that worked with
me was a blue water sailer and knew exactly what I wanted.

However he recommended that I bond the new friction ring into the groove
on
the gypsy top to prevent it from jumping out again. We did this and every
thing works fine 'however'... I can no longer free-fall the anchor until I
have about 50-60 ft of chain out or when motoring astern after the anchor
has taken bit.

Seems like there is too much friction now. Is this due to the new type of
friction material (looks courser) or is it because I only have a single
friction surface (as opposed to the two with the OEM arrangement) that is
free when I release the clutch nut?? Was it a mistake to glue/bond the new
disk to the gypsy, thus eliminating one free surface when released??

OK, How about a couple guys to get your 'egg heads' around this question.
Me? I can even spell physics.

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

1) Is the new friction ring the same material as the old one? Are you
sure?

2) Is the metal surface against which the friction ring rides smooth?
Really smooth, even after your incident?

3) If both answers are "yes" then my guess would be the bonding was a
mistake. Unbond (burn it off, if necessary) and start over if you
have to.

Jim Woodward
www.mvFintry.com


"Steve" wrote in message ...

I've even considered putting a little grease on the disc surface to
encourage some slippage.

That would be a big mistake.


I kinda expected and deserved the admonishment Rick.

Thanks

Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

1) Is the new friction ring the same material as the old one? Are you
sure?

No. the brake material is much courser than the original but it was all they
had available in that thickness.

2) Is the metal surface against which the friction ring rides smooth?
Really smooth, even after your incident?

The drum surface is chome plated and is very smooth with not even a scratch.

I'm considering taking it back to the clutch brake shop and ask them to sand
it smooth. I'm sure they must have some form of surface sander for that type
of business.

Thank.
Steve
s/v Good Intentions

A Question on Friction ?? (long)
 

Steve:

The coefficient of friction is much more related to material than to
surface finish. Consider a rubber eraser -- very smooth, but very high
friction. IIRC the friction material in Swee****er's Lofrans windlass
was a phenolic/Bakelite/Tufnol type of stuff, much less friction than
a brake or clutch lining.

Jim Woodward
www.mvFintry.com


"Steve" wrote in message ...
1) Is the new friction ring the same material as the old one? Are you
sure?

No. the brake material is much courser than the original but it was all they
had available in that thickness.

2) Is the metal surface against which the friction ring rides smooth?
Really smooth, even after your incident?

The drum surface is chome plated and is very smooth with not even a scratch.

I'm considering taking it back to the clutch brake shop and ask them to sand
it smooth. I'm sure they must have some form of surface sander for that type
of business.

Thank.
Steve
s/v Good Intentions