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Mr. Edmund gets a Drive

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#1 actionhac

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Posted 14 October 2012 - 12:06 PM

Today I'm going to install a drive on my Edmund Scientific 4"f15 refractor.
Feast your eyeballs on this:

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#2 actionhac

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Posted 14 October 2012 - 12:10 PM

Here is the drive. Year/model doesn't make much difference, if you have a 1" Edmund mount and a 1" Edmund drive they should be compatible.

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#3 actionhac

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Posted 14 October 2012 - 12:12 PM

Specs from the drives motor. This one was made 6 (June) 1970

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#4 actionhac

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Posted 14 October 2012 - 12:17 PM

The manual mount. Soon it will be able to compensate for the earth's rotation, automatically and hands free.

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#5 actionhac

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Posted 14 October 2012 - 12:22 PM

I'll see you in a while. I seem to be missing a few parts like the slow-motion cam lever and a small ball-bearing, they could not have gone far.

#6 tim53

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Posted 14 October 2012 - 12:43 PM

That's a handsome scope!

#7 trainsktg

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Posted 14 October 2012 - 12:48 PM

A very nice setup indeed. What keeps the legs from flying apart though?

Keith

#8 bremms

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Posted 14 October 2012 - 01:01 PM

friction with the gound? :question:

#9 bremms

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Posted 14 October 2012 - 01:03 PM

I really like long refractors. Very nice.

#10 apfever

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Posted 14 October 2012 - 01:04 PM

A very nice setup indeed. What keeps the legs from flying apart though?

Keith


The coefficient of static friction on the ground only. I'd get a chain in there.

The RA shaft is short but it should work. The bushing needs to be removed. The RA housing is machined to take the pin assembly and the drive should mount on the exposed shaft after the bushing is removed. Those drives are the same on several different Edmund shaft diameters. They have bushings that adjust for the shaft sizes.

I finally have an original lens on the way to replace the shattered flint in my 57 Edmund 4".

#11 actionhac

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Posted 14 October 2012 - 02:18 PM

That's great you found a lens Neil. You have a ultra cool scope, much older than mine.
I should get a safety chain although the pointed legs do not slip. Those are Astro Optical legs from my 7TE-5. I don't have any original one piece Edmund legs. I am planning on making some.
Here are the missing pieces, the slo-mo lever and the steel ball that retains it:

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#12 actionhac

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Posted 14 October 2012 - 02:22 PM

You remove this collar from the polar shaft. The drive mounts to the newly exposed shaft and the housing where it steps down.

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#13 actionhac

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Posted 14 October 2012 - 02:26 PM

You should do some maintenance like clean/oil this worm thrust bearing and oil the motor output shaft bearings.

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#14 actionhac

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Posted 14 October 2012 - 02:29 PM

There are 2 shaft set screws down through the housing, rotate the shaft within the housing until these are exposed and then you can lock it down to the polar shaft.

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#15 actionhac

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Posted 14 October 2012 - 02:39 PM

Once the pieces are installed adjust the eccentric studs A to remove slop from the slo-mo cam. The 2 thumb screws B are to adjust the slip clutch. Balance the optical tube in it's saddle and then tighten/loosen the clutch till it just holds without slipping.
You are ready now for hands free high power tracking. And extended observation at the eye-piece so your brain has time to process what it is seeing.
Robert

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#16 M Schnittker

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Posted 14 October 2012 - 02:43 PM

Very nice! I built my first telescope in 1969 using an A Jaegers mounted 4 1/8" objective ($69) with Jaegers aluminum tube and focuser on an Edmunds mount ($49?), had a Unitron 40mm finder scope. The had one eyepiece, a Brandon Vernonscope 16mm and a Dakin 2.4x Barlow, I think they were something like $24 and $29 each. I bought the mount version that mounts on a pipe intended for reflectors vice the tripod equipped version thinking it would be more stable, I found a heavy 3" x 5 foot long pipe for it at a junk yard. I still have that scope and mount, great lens. Now I'd love to find the parts to convert my pipe mounted mount to a tripod rig. May end up making the parts myself. Couldn't afford a clock drive at the time, it was 1969 and part time jobs brought in $35 in a good month so it took a while to save up for the parts I did buy. I recall the clock drive was close to $40, something like that. I now have 3 of the 1" shaft Edmund mounts which I use for various scopes and all have Edmund drives, their ID plates have various dates all in the 1960's, there are some differences in the design over the years, can provide photos if anybody is interested. As I get older I find it very fun to acquire items like the Edmund clock drive that I lusted for in my youth but couldn't afford, a circle completed. I really like the old Edmund mounts, would like one of the 1.5" versions they sold with their 8" reflector, THAT was a scope I really lusted for! Seemed so huge then.

#17 actionhac

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Posted 14 October 2012 - 03:18 PM

I still have my first Edmund catalog from 1969. I could only afford chipped lenses and prisms, I wasn't even a teenager yet. I'm making up for it now though.
Actually I bought one of these 4 inchers back in the 70's and have had a few since.
Now I'm sort of doing a mock-up here with this one, it really needs a full restoration but I assembled it and again refreshing my memory over the superb lens. I've had this one a few years but have not used it at all for a while.

It would be great to see any pictures you might have. I'd like to see an older style drive, before Edmund added the slo-mo lever assy., don't know if you have one like that.

Robert

#18 amicus sidera

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Posted 14 October 2012 - 04:43 PM

Excellent thread, Robert, and a fine photo-tutorial! :cool:

I notice that the motor shown doesn't appear to have an oil port in the base to allow for lubricating the gearbox; the reduction gears are the trouble spot on these motors, as the speed reduction needed is so great compared to a 1 rpm, or even 1/10 rpm motor of similar design. If you're interested, there's a CN thread detailing how to go about getting into the gearbox on these old synchronous motors here... properly lubricated, it should last for decades.

Have fun with that fine refractor!

#19 actionhac

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Posted 14 October 2012 - 05:05 PM

Thanks for the link Fred.
This one does not have a lube hole for the gear box. Amazing isn't it we really made some nice stuff didn't we. Almost 1/2 century old and it is as quiet as a church mouse. I didn't even think about all those gears in there.

I need to make a correction. Previous photos show the drive above a tripod leg, that is a error, the drive should be between two legs, thusly:

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#20 starman876

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Posted 14 October 2012 - 07:07 PM

I used to have one of these mounts with that drive. It worked very well. Very nice set up.

#21 actionhac

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Posted 15 October 2012 - 01:04 AM

I have a few extra pictures you might like....
This 23mm finder is small but perfect in every way. Beautifully made. Helical focus on the objective end and also focus for the retical.

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#22 actionhac

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Posted 15 October 2012 - 01:11 AM

With a little tuning this focuser provides excellent performance.

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#23 actionhac

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Posted 15 October 2012 - 01:15 AM

Anyone know who made these lenses for Edmund?
Later on Edmund made lenses in-house.

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#24 trainsktg

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Posted 15 October 2012 - 01:19 AM

I have the same finder on my 4.25" reflector...its a very nicely designed unit.

Keith

#25 actionhac

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Posted 15 October 2012 - 01:28 AM

The only documented information on the source I've found is a 1956 Edmund Scientific Corp. ad stating:

"We found a Japanese optical engineer who designed some excellent astronomical objectives. We place orders with him. He then has these made, testing each one for quality".

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