17 replies to this topic

[flyboyu777]

Hey CN-ers, I  am looking for some expert Unitron members to help with with installing a Unitron 142 drive unit.  I am trying to figure out how the drive knob (if I even have the correct item!) is supposed to go on the worm shaft, since the thread diameters don't match up.  Maybe a diagram or pictures of someone else who went through the same process with theirs.  My Unitron is one of the early models from around 1956, if that helps.  Here are some pictures of what I have-I'm still missing the clamp for the base, If anyone has a spare one. . . . . .

 

Jim

 

 

 

[starman876]

I do not recall when the drives came out.   I will look at my selection of knobs and see if there is a difference  between the drive shafts diameters and if any of the knobs with the hex fitting I have will fit the earlier mounts. 

[deSitter]

This seems to be a case of Unitron mixing-matching-morphing. The catalog pictures from 1970 and 1972 show a different knob. In the latter, a deely-bobber slo-mo cable is seen protruding from the knob. Those typically have 6mm or 8mm shaft receivers.

 

-drl

[flyboyu777]

I do not recall when the drives came out.   I will look at my selection of knobs and see if there is a difference  between the drive shafts diameters and if any of the knobs with the hex fitting I have will fit the earlier mounts. 

 

 

This seems to be a case of Unitron mixing-matching-morphing. The catalog pictures from 1970 and 1972 show a different knob. In the latter, a deely-bobber slo-mo cable is seen protruding from the knob. Those typically have 6mm or 8mm shaft receivers.

 

-drl

The bigger knob is the one that was/is on the 1956 mount.  There are 2 identical ones like this.  Makes me think that Unitron used a different worm shaft with smaller diameter threads on each side.  But that's just a guess. . . . .

[deSitter]

The bigger knob is the one that was/is on the 1956 mount.  There are 2 identical ones like this.  Makes me think that Unitron used a different worm shaft with smaller diameter threads on each side.  But that's just a guess. . . . .

Well good news is you have a big threaded thing sticking out and finding/improvising a coupler should be easy.

 

-drl

[flyboyu777]

Well good news is you have a big threaded thing sticking out and finding/improvising a coupler should be easy.

 

-drl

That's the way I'm thinking at this point-find a step-down boss. . . . .

[ccwemyss]

I have the same mount. Tony Costanza at Astronomy Shoppe told me that it's not compatible with the Unitron drive. At the time, he was willing to make me one of his drives to fit it, but the issue is that there is no secondary slow motion on this mount, and you can't use the knob on the opposite side as a manual slow motion because the motor locks it. 

 

I think you could have a custom adapter machined to take the place of the knob, with the hex hole. Perhaps Johann, in his vast supply of parts, has a knob that happens to fit the older thread with the hole for the motor shaft. Unitron did tend to change things incrementally. 

 

I've actually found the mount to be so stable that I can just keep a hand on the RA knob and track quite well for visual use. 

 

Chip W. 

[deSitter]

That's the way I'm thinking at this point-find a step-down boss. . . . .

Yes and you can think about including a clutch so you get manual and driven motion. The worst thing about most classic clock drives is the loss of manual motion without completely decoupling the drive.

 

-drl

[starman876]

The bigger knob is the one that was/is on the 1956 mount.  There are 2 identical ones like this.  Makes me think that Unitron used a different worm shaft with smaller diameter threads on each side.  But that's just a guess. . . . .

Now I think about that is right. The earlier mounts had bigger knobs.   Kind of tells a tale that there was never a drive for the earlier mounts.   When the drives came out the knobs changed a the same time with 10mm hex machined out of the center of the knob.  

[flyboyu777]

This may be where my 3D printer comes in handy. . . . . . If I can make time to figure out what I need. . . . .

[deSitter]

This may be where my 3D printer comes in handy. . . . . . If I can make time to figure out what I need. . . . .

Is there a knob on the other end? Or a protruding shaft? Ideally you'd want to be able to turn the worm from either end, without disengaging the drive. On the 6345 the two functions are separated, with a fixed direct engagement without a clutch, and a tangent-arm style slo-mo on an independent worm. You only have one worm so you need a clutch. On some motorized focusers, there is an inline clutch to allow manual control by spinning the same wheels. That would be ideal here.

 

-drl

[deSitter]

Now I think about that is right. The earlier mounts had bigger knobs.   Kind of tells a tale that there was never a drive for the earlier mounts.   When the drives came out the knobs changed a the same time with 10mm hex machined out of the center of the knob.  

Which model had the large knob with a set screw radially recessed - probably a 4"?

 

The catalog entries for the 3" photo equatorial did not include a motor drive until no earlier than 1971. Was there an option before that? Or are AC motor drives an early 70s thing?

 

-drl

[starman876]

Which model had the large knob with a set screw radially recessed - probably a 4"?

 

The catalog entries for the 3" photo equatorial did not include a motor drive until no earlier than 1971. Was there an option before that? Or are AC motor drives an early 70s thing?

 

-drl

remember seeing the ad in S&T about the announcements of a motor drive.  I thought it was before 1971.   Of course the weight drive came first  for the 4"  Of course there was also a large motor drive that sat on the same weight drive metal shelf and also used the same connecting rods as the weight drive. 

[deSitter]

remember seeing the ad in S&T about the announcements of a motor drive.  I thought it was before 1971.   Of course the weight drive came first  for the 4"  Of course there was also a large motor drive that sat on the same weight drive metal shelf and also used the same connecting rods as the weight drive. 

Right so no 3" option - I remember seeing a shelf for the 3" drive that had blue felt. That must have been the 70s or even 80s.

 

You could buy a 220 astrocamera for the hand-guided 145 photo equatorial $550 for the scope and $70 for the camera.

 

-drl

[gelkin]

I had the same problem several years ago with a late 50s 142. The worm shaft is larger than later mounts and the shaft is also longer. The later shelves to hold the drive are too short. I would have had to shorten the shaft as well as machine it down and rethread it. Not happening. 

Some mounts, I guess photo eqs had a separate tangent arm setup to guide while the drive was engaged. This 4” 160 had it.

[deSitter]

I had the same problem several years ago with a late 50s 142. The worm shaft is larger than later mounts and the shaft is also longer. The later shelves to hold the drive are too short. I would have had to shorten the shaft as well as machine it down and rethread it. Not happening. 

Some mounts, I guess photo eqs had a separate tangent arm setup to guide while the drive was engaged. This 4” 160 had it.

IMG_3324.jpeg

Yes this is the same setup as on the AO 90mm 6345.

 

I remember seeing a knob with a radially recessed set screw of some kind, which seemed to be for gripping onto a stacked knob or slo-mo cable or whatever. I cannot remember where I saw this. You could still use the knob as a plain knob, without anything external attached.

 

-drl

[starman876]

I had the same problem several years ago with a late 50s 142. The worm shaft is larger than later mounts and the shaft is also longer. The later shelves to hold the drive are too short. I would have had to shorten the shaft as well as machine it down and rethread it. Not happening. 

Some mounts, I guess photo eqs had a separate tangent arm setup to guide while the drive was engaged. This 4” 160 had it.

IMG_3324.jpeg

There you go.  Needed to look at the 160 drive I have to refresh my memory.  

[CHASLX200]

Now I think about that is right. The earlier mounts had bigger knobs.   Kind of tells a tale that there was never a drive for the earlier mounts.   When the drives came out the knobs changed a the same time with 10mm hex machined out of the center of the knob.  

They did like my M-160 made around 1955. There were many changes from the 50's on until the end.