118 replies to this topic

[andylsun]

DEC spins and sounds as good as RA. Tangent arm bolt moves really well in the centre area of the rod. Will pick up new hand control buttons this week.

 

nasty flat spots away from the middle on the tangent arm lead screw, so I’ll grab a die and chase the threads.

 

 

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Edited by andylsun, 08 September 2024 - 06:23 AM.

[andylsun]

Worm screw pulled. Spins freely. Cleaned out the worm itself with acetone and sewing machine oil on the end bushings.

 

not going to do much more to this.

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[andylsun]

Small amount of play (less than 0.5mm) along the axis. Not going to fiddle with that

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[deSitter]

DEC spins and sounds as good as RA. Tangent arm bolt moves really well in the centre area of the rod. Will pick up new hand control buttons this week.

 

nasty flat spots away from the middle on the tangent arm lead screw, so I’ll grab a die and chase the threads.

Wow how did the threads get so mangled?

 

Everything looks mostly in great shape.

 

-drl

[andylsun]

I assume someone clamped something across the threads. Maybe mole grips? I’ve been guilty in the past of doing that. Once you have to repair it then you tend to stop doing that particular bad habit.

[CHASLX200]

Wow how did the threads get so mangled?

 

Everything looks mostly in great shape.

 

-drl

Got beat with something when stored i guess jess.  Them scopes are like old boats and get thrown around over the years.

[andylsun]

RA shaft moves really nicely once the worm was disengaged. Pendulums back and forward under the weight of the DEC shaft.

So probably the only RA task left to do is decide whether to strip down the clutch plate or leave it alone.

It does slip when gentle steering is applied to the mount so it’s doing its job.

DEC hand control buttons and that may be it for the mount for now.

[deSitter]

RA shaft moves really nicely once the worm was disengaged. Pendulums back and forward under the weight of the DEC shaft.

So probably the only RA task left to do is decide whether to strip down the clutch plate or leave it alone.

It does slip when gentle steering is applied to the mount so it’s doing its job.

DEC hand control buttons and that may be it for the mount for now.

I would definitely disassemble and inspect the clutch material.

 

-drl

[andylsun]

Somewhere in my tools collection I do have a thread repair file….

 

a previous owner of a Sherline mill I own had clamped across the spindle threads….

 

Edited by andylsun, 08 September 2024 - 08:34 AM.

[andylsun]

All clean

 

the clutch tension is set via locking washers. Not a huge fan of that and would springs be really that much more expensive. Lock washers very lightly torqued.

 

I think swapping for springs might be a good idea?

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[deSitter]

All clean

 

the clutch tension is set via locking washers. Not a huge fan of that and would springs be really that much more expensive. Lock washers very lightly torqued.

 

I think swapping for springs might be a good idea?

I replaced the cork on my RV-6 by leather and that worked great. Lock washers! No way that is right! Maybe someone else here knows. That drive looks almost identical to similar Cave drives so let a Cave-r give advice here.

 

-drl

[andylsun]

There’s no cork as far as I can tell. Will have a closer look tomorrow.

[deSitter]

There’s no cork as far as I can tell. Will have a closer look tomorrow.

There is usually a soft and durable material between the pressure plates, and the tension is controlled by springs. But maybe this one is designed to be metal against metal, don't know.

 

-drl

[andylsun]

It’s metal to metal with a little bit of grease. Teflon separator between the inside of the brass worm and the steel portion.

 

im not going to do anything to it yet. Will leave alone until the hand controller is fixed.

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[andylsun]

What’s a good sticky grease for a metal on metal clutch?

Half way between super lube and brake caliper grease?

[deSitter]

What’s a good sticky grease for a metal on metal clutch?

Half way between super lube and brake caliper grease?

Nyogel damping grease is what I'd use.

 

-drl

[badback]

DEC spins and sounds as good as RA. Tangent arm bolt moves really well in the centre area of the rod. Will pick up new hand control buttons this week.

 

nasty flat spots away from the middle on the tangent arm lead screw, so I’ll grab a die and chase the threads.

Instead of a die ya' might want to use a thread file: 

https://www.cloudyni...air/?p=10303813

[Kasmos]

I replaced the cork on my RV-6 by leather and that worked great. Lock washers! No way that is right! Maybe someone else here knows. That drive looks almost identical to similar Cave drives so let a Cave-r give advice here.

 

-drl

I bought my mount directly from Cave in 1978 and it only has lock washers for the bolts clutch adjustment. I've seen springs on them but they might have been replacement or an earlier example. I've been thinking of doing the same. The funny thing was, I didn't ask but they never gave me any instructions or guidance on using or adjusting it and it was my first GEM. 

[Kasmos]

BTW, my Cave has a sloppy cut piece of teflon and grease for the clutch.

[andylsun]

Instead of a die ya' might want to use a thread file: 

https://www.cloudyni...air/?p=10303813

Yes I have one somewhere from fixing a Sherline mill thread. Will dig around

[andylsun]

There’s quite a few threads here from 2013 and earlier discussing Cave mounts that recommend leaving the clutch dry. They also have lock washers on the clutch bolts and the worm U doesn’t look as beefy as the one in the Parks.

 

its really interesting to see that Parks basically took the Cave mount and carried on shipping it pretty much unchanged.

 

Hurst motors and a stronger worm U and a RA lock are the biggest differences I’ve seen when comparing to early 70s Cave pictures to mine. Parks then did switch to 12V motors later on by the looks of it and integrated the lunar and solar tracking rates into the RA motor box.

[CHASLX200]

There’s quite a few threads here from 2013 and earlier discussing Cave mounts that recommend leaving the clutch dry. They also have lock washers on the clutch bolts and the worm U doesn’t look as beefy as the one in the Parks.

 

its really interesting to see that Parks basically took the Cave mount and carried on shipping it pretty much unchanged.

 

Hurst motors and a stronger worm U and a RA lock are the biggest differences I’ve seen when comparing to early 70s Cave pictures to mine. Parks then did switch to 12V motors later on by the looks of it and integrated the lunar and solar tracking rates into the RA motor box.

Had all these mounts from all makers but OC from 1 to 2.5" and were slop monsters . Some worse than others.  Had one Cave 1.5" Mount that had so much jitter and flex and the last 2" STARLINER mount was jitter city even with a 8" F/5.  Clutches were stick city kitty when trying to center planets at 450x and up.  Odd that a old 1.5" Edmund mount was smooth as silk and was my 2dn fav mount ever.  My AP800 beats them all by a million miles.

[andylsun]

Had all these mounts from all makers but OC from 1 to 2.5" and were slop monsters . Some worse than others.  Had one Cave 1.5" Mount that had so much jitter and flex and the last 2" STARLINER mount was jitter city even with a 8" F/5.  Clutches were stick city kitty when trying to center planets at 450x and up.  Odd that an old 1.5" Edmund mount was smooth as silk and was my 2dn fav mount ever.  My AP800 beats them all by a million miles.

Yeah. I’m not expecting AP performance. The mount is what it is. Also a great learning experience.

[Bill Griffith]

I like being an optimist on finds. 

 

This instrument already has improvements that you have made.

 

Hope you continue to first light.

 

 

Congratulations!

 

Bill

[andylsun]

First light and beyond for sure.