16 replies to this topic

[M_athias]

Hello everyone,
I own an Edmund deluxe space conquerer 4.25" and unfortunately my telescope mount is missing the extension for the counterweight. 

Can anyone tell me which thread it is? I suspect an inch thread, as DIN screws do not fit.

 

 

Thank you very much for your support

 

Regards

 

Mathias

 

[deSitter]

The shaft diameter is 5/8" so that thread has to be 5/8-11 or 5/8-18. It looks pretty coarse so I would try a 5/8-11 bolt from the hardware store. Once you know, you can buy a 5/8" shaft from McMaster-Carr with the required threaded stud on one end - and also a threaded hole on the other end for attaching a toe-saver stop.

 

-drl

[M_athias]

Thank You, deSitter.

But I rather supsect the thread is 3/8" (pitch unknown) which equals 10mm - this is the value I measured (metric screws did not fit because of the pitch).

btw.: I am located in Europe, ordering from McMaster-Carr is not an option ;-)

Edited by M_athias, 21 February 2025 - 02:49 PM.

[deSitter]

Thank You, deSitter.

But I rather supsect the thread is 3/8" (pitch unknown) which equals 10mm - this is the value I measured (metric screws did not fit because of the pitch).

btw.: I am located in Europe, ordering from McMaster-Carr is not an option ;-)

Standard 3/8" pitches are 3/8-16 and 3/8-24. That mount is trivial to disassemble - just take the sadde/shaft part to the hardware store and fiddle around until you find it

 

BTW I was looking at the large, coarse threads seen in the image looking up the DEC bearing. I refurbished an early example of this mount a couple of years ago, and the DEC shaft was one continuous 5/8" shaft. It was the perfect length to balance the scope. It was not segmented as seen here. I don't remember seeing any examples of a segmented DEC shaft. In fact on closer look, I can't quite figure out what is going on. Maybe a brass bushing on the lower DEC shaft is supposed to go into those coarse threads? I assume those were press-fit.

 

-drl

Edited by deSitter, 21 February 2025 - 03:08 PM.

[ccwemyss]

Mine is also one continuous piece. It looks like someone cut the shaft short, then drilled and tapped a hole so a replacement shaft could be attached (maybe for a different diameter). It would be fine to re-tap it for a metric thread. 

 

Chip W. 

[M_athias]

The DEC shaft on my mount is not modified.

 

Look here at page 9

https://www.edmundop...elescopes 2.pdf

 

 

The Edmund newton (from 1968) was bought in the US  by a German who had lived in the States for several years. When he returned to Germany, he took the telescope with him. A lucky coincidence, because that's how I was able to acquire it ;-)
 

Switch over to the (german) astronomie.de forum - there is a forum entry (with photos) about the acquisition:

 

https://forum.astron...on-1968.375588/

Edited by M_athias, 21 February 2025 - 04:53 PM.

[DAVIDG]

 I have the same mount as your so I measured it so no guessing. The thread count is 24 threads per inch. The diameter of the threaded section is 0.375" and the length of the threaded section is 0.400".  Here are pictures of the threaded section with 24 TPI thread gauge and the 3/8-24 die threaded on the shaft.  A 3/8-24 bolt should fit your mount.   Hope this helps.

 

                 - Dave 

 

 

[apfever]

OH good, thank you David.  That saves digging, dismantling, and measuring. I'm pretty sure the threads are the same across the different versions of the mount.  Determining the right original configuration for a given version might be more difficult than the thread pitch. 

 

Most of these are two piece. The standard DSC on grey GEM pier is two piece. I have not seen a one piece rod on a grey GEM version yet. Some early Edmund 1" shaft GEM mounts (same series as the 5/8" shaft) had a screw in reduction to 5/8". That 5/8" reduction part was very long. The picture in entry #6 looks like a combination of both type mounts, and the picture looks like an original Edmund printing. 

 

What the OP shows in the opening entry is a standard later version DSC grey GEM but on a tripod instead of pier. The earlier versions had different setting circles. There were a lot of versions.  I have all these and will take pictures tomorrow, Sat.  Too late now.  I'll also measure the length of the smooth part of the extension.  

 

Use a little caution. The idea of extending a 5/8" rod with a 3/8" thread, and hanging a counterweight on it, wasn't exactly a top notch idea. For the most part by far -  it works well. I haven't had any issues. However, I have seen some that were bent or destroyed at the threaded junction. 

[M_athias]

 I have the same mount as your so I measured it so no guessing. The thread count is 24 threads per inch. The diameter of the threaded section is 0.375" and the length of the threaded section is 0.400".  Here are pictures of the threaded section with 24 TPI thread gauge and the 3/8-24 die threaded on the shaft.  A 3/8-24 bolt should fit your mount.   Hope this helps.

Hello Dave,

thank You very much!

[Terra Nova]

My old one:

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[apfever]

I tried to limit the camera distortion for the picture. It is an easy read in person over the weight.  The shaft extension is 5-1/2" long. 

The 1" version is on the left. The 5/8" shaft like OP's is the restored one on right.  It is the first version type setting circles. 

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[apfever]

These are basically all tripod mount 1" shaft but with one let down. 

The let down goes 5/8" diameter. Long 5/8".  But then there's op's entry #6 above. Lots of variations. 

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[apfever]

Wow, I haven't dug around back here for a bit, years, well couple probably or something there....anyway this ended up being entry #6 above. It was back by the wall (reflective)  at the upper left behind the black tube. The black tube is the OTA for it. Then I started taking a couple more pictures. This one is an Anchor 4.25" reflector mount that Edmund sold the last inventory.  Edmund bought Anchor Telescopes in the very late 1950's.  This seems to be where the whole Edmund line of these kept going from.  The extension shaft is a Teeny Weeny ....didn't measure it...I'll bet 3/8"  like a long shoulder bolt.  If I don't post now I screw up and loose all this so I'll measure it.

 

Oh and Bugs Bunny episode "Itsy Bitsy Teeny Weeny".  I haven't been able to find it for a while but a classic. 

Oh and this mount and scope stuff can't be reached regular so I use a classic for that too.  Hang on. 

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Edited by apfever, 23 February 2025 - 04:35 PM.

[apfever]

It's a small 3/8" diameter rather long extension and that weight is decent size hummer too. It works well. There are some random pictures of it around this forum. 

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Edited by apfever, 23 February 2025 - 04:53 PM.

[M_athias]

Finally: DIY Shaft extension mounted:

 

 

[YourNotSirius]

Wow, I haven't dug around back here for a bit, years, well couple probably or something there....anyway this ended up being entry #6 above. It was back by the wall (reflective)  at the upper left behind the black tube. The black tube is the OTA for it. Then I started taking a couple more pictures. This one is an Anchor 4.25" reflector mount that Edmund sold the last inventory.  Edmund bought Anchor Telescopes in the very late 1950's.  This seems to be where the whole Edmund line of these kept going from.  The extension shaft is a Teeny Weeny ....didn't measure it...I'll bet 3/8"  like a long shoulder bolt.  If I don't post now I screw up and loose all this so I'll measure it.

 

Oh and Bugs Bunny episode "Itsy Bitsy Teeny Weeny".  I haven't been able to find it for a while but a classic. 

Oh and this mount and scope stuff can't be reached regular so I use a classic for that too.  Hang on. 

Re: Bugs Bunny episode "Itsy Bitsy Teeny Weeny". No such episode is listed. Here are the ones produced in order from 1959 through 1962. Bryan Hyland released the song in 1960 so this brackets its range of popularity at that time. You may have not remembered the title correctly. Please try again. LOL

 

1959
139 Baton Bunny (LT)
140 Hare-Abian Nights (MM) - Starring Sam.
141 Apes of Wrath (MM) - Cameo by Daffy.
142 Backwoods Bunny (MM)
143 Wild and Woolly Hare (LT) - Starring Sam.
144 Bonanza Bunny (MM)
145 A Witch's Tangled Hare (LT) - Starring Hazel.
146 People Are Bunny (MM) - Starring Daffy.
1960
147 Horse Hare (LT) - Starring Sam.
148 Person To Bunny (MM) - Starring Elmer and Daffy.
149 Rabbit's Feat (LT) - Starring Wile E.
150 From Hare to Heir (MM) - Starring Sam.
151 Lighter Than Hare (MM) - Starring Sam.
1961
152 The Abominable Snow Rabbit (LT) - Starring Daffy.
153 Compressed Hare (MM) - Starring Wile E.
154 Prince Violent (Later renamed Prince Varmint for television broadcasts) (LT) - Starring Sam.
1962
155 Wet Hare (LT)
156 Bill of Hare (MM) - Starring Taz.
157 Shishkabugs (LT) - Starring Sam.

 

We are all loony in this life!

 

Q

[apfever]

That is the first time I have seen the nail pointers used on the bottom of the circles.  As long as the extension fix works. What is the sleeve part used to make the 'shaft'?  

Another alternative is to drill and tap the end of a 5/8" rod and use a piece of all thread coupler. I've made extensions this way.

 

 

Re: Bugs Bunny episode "Itsy Bitsy Teeny Weeny".  Here are the ones produced in order from 1959 through 1962. You may have not remembered the title correctly. Please try again. LOL

 

It was Bugs, it was the episode nemesis, it was not chronological to the scope, it takes more time to search than I have.