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Towa EQ mount

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23 replies to this topic

#1 Jaz5833

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Posted 12 January 2021 - 12:24 AM

Can someone explain what function this serves?
(Sears (Towa) 6333-A)

The little, round, chrome turn button.
20210108_221203_copy_979x1305.jpg


Edited by Jaz5833, 12 January 2021 - 12:26 AM.


#2 BillShakes

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Posted 12 January 2021 - 10:30 AM

The small silver button on the lower left of your photo? I believe that it is an attachment point for a spring that holds the optional clock drive against the drive gear.

#3 Garyth64

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Posted 12 January 2021 - 10:44 AM

It is just a little latitude adjustment screw that helps hold the mount at an angle.

 

I felt it was a bit too flimsy, and replaced it with stronger one.

 

adjustment bolt.jpg

 

That is the mount from my Sears 6305a, which has the same mount as the 6333a.


Edited by Garyth64, 12 January 2021 - 10:58 AM.

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#4 Kasmos

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Posted 12 January 2021 - 02:48 PM

"little, round, chrome turn button" grin.gif

 

AKA Thumb screw.   


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#5 Kokatha man

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Posted 12 January 2021 - 05:38 PM

"little, round, chrome turn button" grin.gif

 

AKA Thumb screw.   

I hope your interpretation was correct hmm.gif  - when I read this yesterday I couldn't decide whether the OP meant that - or the worm position adjusting nut on the upper right: as for the other suggestions, I tend to think Bill's is more on the money - not picking on you Gary - but it would be utterly inappropriate (& superfluous) as any sort of secondary locking device...although I suppose it might function as an aid to initially setting the angle before using the large lever bolt to lock this aspect...but you wouldn't want anything loading the mount if you hoped that this was its' intended purpose... confused1.gif



#6 Garyth64

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Posted 12 January 2021 - 07:20 PM

It is not for any clock drive, it is as I said.

 

The op centered the button in the photo, he wasn't talking about anything off to the side. 

 

(don't make me get the mount out of the box again for more photos, lol.gif )


Edited by Garyth64, 13 January 2021 - 08:42 AM.

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#7 grendel

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Posted 13 January 2021 - 07:06 AM

ive always used the thumb screw for the drive motor spring and no, its ot in the ideal place, but it works.



#8 Garyth64

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Posted 13 January 2021 - 08:39 AM

I'm sorry to be so contrary on this, but here is a picture from your post in 2011 showing how the spring is attached for the clock drive:

 

CD spring.jpg

The clock drive attaches on the right side of the op's picture.  The little thumb screw is on the other side.  But the op's mount isn't set up for a clock drive.  He is missing the attachment bolt and the gear.


Edited by Garyth64, 13 January 2021 - 08:40 AM.

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#9 grendel

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Posted 13 January 2021 - 11:48 AM

ooh yes, all i remember is the clock drive went to the thumb screw, looking at that i now see what you mean,


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#10 Jaz5833

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Posted 13 January 2021 - 04:44 PM

20210113_134313.jpg

 

This.



#11 Kokatha man

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Posted 13 January 2021 - 06:58 PM

I'm sorry to be so contrary on this, but here is a picture from your post in 2011 showing how the spring is attached for the clock drive:

 

attachicon.gifCD spring.jpg

The clock drive attaches on the right side of the op's picture.  The little thumb screw is on the other side.  But the op's mount isn't set up for a clock drive.  He is missing the attachment bolt and the gear.

 

 

ooh yes, all i remember is the clock drive went to the thumb screw, looking at that i now see what you mean,

OK - ok - ok!!! Gary must be correct...I don't know whether I posted some of my own strip-downs of these mounts, but I'd better be wary of continuing to challenge him - he'll sleuth down any anomalies anyone makes from the beginning of time as grendel* has found out! rofl2.gif

 

Joking aside, I haven't looked at all the images I took when dismantling one of these mounts, but I do see a much larger threaded hole in the appropriate casting than I imagined that thumbscrew to have when I examined mine a couple of minutes ago - I thought Gary must've opened up the hole & re-threaded it for his heavier duty locker but  a more meaty/stronger one, aka's "Garry's Mod" is clearly an option.

 

* Good to see you are still posting bro - harking back to that old Queensland forum we were both on many years ago now. (the name escapes me atm...Ravenswood or somesuch)



#12 Garyth64

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Posted 13 January 2021 - 07:30 PM

I only was looking for a mount with the clock drive.  I did not know I would find grendel's post, which was perfect for the explanation.

 

"I thought Gary must've opened up the hole & re-threaded it for his heavier duty locker but  a more meaty/stronger"

 

Nope, I didn't do that.  The "thumbscrew" has a 1/4x20 thread, and it is cast, so I just got a stronger 1/4x20 bolt and cut the head off, because the "thumbscrew" on my mount was bent.

 

bolt for mount.jpg

 

I modified the bolt and just screwed it into the mount.  It just helps to hold the mount in position until the large lever tightens it all up.


Edited by Garyth64, 13 January 2021 - 07:32 PM.

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#13 Kokatha man

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Posted 13 January 2021 - 07:37 PM

...yes, I noted that in my post Gary! waytogo.gif (<"I thought Gary must've opened up the hole & re-threaded it for his heavier duty locker but  a more meaty/stronger one, aka's "Garry's Mod" is clearly an option.">) ;)


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#14 Jaz5833

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Posted 13 January 2021 - 10:05 PM

Thanks everyone. It wasn't my intent to start a friendly war. I'll assume, from the lack of certain knowledge, that it's not something I should worry about.
:^)

#15 Garyth64

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Posted 13 January 2021 - 10:33 PM

No warring going on at all, just friendly CN discussions.  smile.gif


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#16 Bomber Bob

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Posted 13 January 2021 - 10:55 PM

It is just a little latitude adjustment screw that helps hold the mount at an angle.

 

Yes, it applies a bit of friction to the latitude adjustment bolt.  In my 1978 manual, the owner sets the latitude BEFORE putting the counterweight & scope on the mount; however, if additional adjustments are needed, that tiny thumbscrew can be used to keep the mount from slamming down on the hub top / azimuth plate until the large bolt is tightened...

 

BIF:  On most of these photos, I don't see the weird-shaped chrome lever attached that is used to swing the drive away from the spur gear so the manual slo-mo can be used...  It kinda gets in the way with all the motor hardware attached, and I bet lots of owners remove and then lose it...

 

Towa 339 EQ P01 - Drive Attached.jpg


Edited by Bomber Bob, 13 January 2021 - 11:01 PM.

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#17 Kokatha man

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Posted 14 January 2021 - 02:09 AM

Yes, just friendly banter & genuine questions/ing Jaz! grin.gif 

 

Bob, this has me wondering because I've seen so many of these electric drive compnents (lever, gear cog specifically) on these mounts but no electric drives I've become aware of over here: how many of these do you think are still around in the US secondhand on a regular basis...

 

The OP's thread has me thinking about this & a quick look through the first 7 pages of the relevant classifieds shows nothing atm..? confused1.gif



#18 Bomber Bob

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Posted 14 January 2021 - 01:47 PM

how many of these do you think are still around in the US secondhand on a regular basis...

 

The Towa 305 & 339 motor drives are RARE, yet the scopes & mounts are common.  In almost 8 years on CN, I've seen less than a half-dozen for sale -- but I don't see every ad.  Total in the USA?  I have no idea, but if I had to guess, maybe 10% of the EQs still in use have the drives...

 

I got a boxed / NOS Tasco-branded drive on eBay at a great price, and held on to it until I knew for sure I wouldn't need it.

 

An Exception:  Meade & Orion both sold Towa EQs about 35-40 years ago, and I have seen some Orion drives pop up -- more often than Tasco or Towa branded units.


Edited by Bomber Bob, 14 January 2021 - 06:20 PM.

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#19 Kokatha man

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Posted 14 January 2021 - 06:14 PM

Thanks for that Bob waytogo.gif  - after posting the above Q. I recalled that I have seen 1 or 2 in interstate ads in Oz over the years but never personally came across one "in the flesh" despite seeing plenty with cogs & levers.

 

That'd probably correlate (very roughly) with the US situatio,n although the far greater volume of mounts sold in your country would mean they were more common there...



#20 Tenacious

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Posted 14 January 2021 - 07:44 PM

Interesting.  I run the spring up to the same post that mounts the clutch lever.

 

Closeup.JPG

 

 

I removed the second image.  It's not mine, someone else (probably another CN member) made the illustration.  I'm not trying to take credit for another's brain-sweat.


Edited by Tenacious, 14 January 2021 - 08:34 PM.

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#21 Bomber Bob

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Posted 14 January 2021 - 08:15 PM

The Towa system looks goofy, but it worked.  On my 1980s Mizar EQs, the drive swings out of the way, but there's no spring & lever to keep the 2 gears aligned when you swing it back.  On my 1964 Sears 6336, the lock lever is a dinky rod that can get in the way of other hardware -- tough to use with gloves on!

 

With my 1978 Tasco (Towa), I left the gears engaged most of the time, and I do the same now with the Mizar.  Just have to keep it all balanced, and I really don't need the slo-mo function on the polar axis.


Edited by Bomber Bob, 14 January 2021 - 08:15 PM.


#22 Tenacious

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Posted 14 January 2021 - 08:38 PM

I use the clutch regularly when changing targets.  Also, the motor shown came with a controller with slow-motion push buttons for scrolling around.


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#23 Bomber Bob

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Posted 14 January 2021 - 09:07 PM

What Brand / Model is that drive?

 

(I'm still looking for a 2nd Mizar drive or compatible for my AR-1.)



#24 Tenacious

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Posted 14 January 2021 - 10:34 PM

Parts.JPG

 

I found it on eBay a few years back.  You can see the aluminum hole in the motor housing which had to be bored one size larger to fit my EQ-2 from Japan.  The drive is a later Chinese model.

 

It tracks well.

 

EDIT:

Oops, forgot.  I also added a longer hex cap screw (next to the motor shaft) that is long enough to engage the clutch lever.


Edited by Tenacious, 14 January 2021 - 10:40 PM.

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