115 replies to this topic

[Kasmos]

Back to the Restoration

 

This kit was missiing the tripod hub and it's legs.

Some similar legs from another make of scope will be fairly easy to find,

but an original Atco 1252 Hub would be next to impossible.

 

Here's what a Atco 1252 hub looks like.

The gray ones look just like the black ones but have a straight cut center hole,

while the black ones holes are tapered.

 

The hub from my Kenko is very similar to both types of Actos,

but there's no way I'm going to pirate it from that scope.

 

When I posteded this scope and it's situation in the 'finds thread',

Sean (norvegious) kindly offered a couple of hubs that I might modify.

He also offered 3D printing one but I wanted it to try it using old school methods.

The method would be similar to the one I made for a Swift 839, but not quite as involved.

Swift Hub Link:

https://www.cloudyni...ons/?p=10912288

 

One was from a fairly modern Celestron, the other was from a Towa GEM.

I had him send the Towa.

It's quite a bit larger in diameter than an original 1252 but it's is the best I could do (for now)

 

The first issue was how would I drill out/enlarge the center hole?

I don't have sophisticated machine tools so I drilled a bunch of smaller holes.

This was done by hand from the outside and at an angle...

 

The holes at the clamp bolt channel had to be drilled from the inside.

 

Then all of the holes were slowly enlarged until the center section could be taken out.

 

A new center section was made from materials left over from the Swift hub.

The plastic piece was cut from a PVC pipe coupler and the brass is a drain pipe.

 

I found that if it was cut just right, the inner sleeve had the correct ID when pressed into the PVC coupler.

The ID is the same as the Swift, so I wish I had discovered that on it's hubs build.

 

I used a circle template to score a guideline and filed the new hole to size.

 

Test fitting the sleeve...

 

...and with the collar.

Another coupler will be made and go on the underside.

Edited by Kasmos, 12 September 2023 - 03:11 PM.

[Kasmos]

Hub Remodel Continued

 

The white collar was made from another scrap PVC coupler which will go on the underside of the hub.

It's side hole will line up with the hole in the brass sleeve when slid in place.

The threaded aluminum insert will be installed in the hub to clamp the mount's shaft.

 

This shows where the threaded insert will be JB Welded in place.

The existing threaded hole needed to moved up and enlarged.

 

Just a shot from the inside of the modified clamp bolt hole 

 

This shows how the three center pieces will fit together in the hub.

I checked and rechecked the measurements several times to

make sure everything would line up and be the right height.

 

An outer ring of aluminum was cut from the center piece of a bunt cake pan.

The top of that same piece was formally used for the Swift hub build.

 

The black ring was cut from a piece of 2"ABS pipe.

It will fit between the gray collar and the aluminum outer ring

Each of the three plastic parts were beveled and notched

so that the JB Weld would have more surfaces of contact.

 

This was a test fit before the gluing.

It's hard to see, but the black ring has a small gap at the back because it was slit 

to fit around the gray piece. That gap will be filled with JB Weld.

It was a lucky coincidence that the outer aluminum ring fit perfectly around the black ring.

 

This inside view is after it was all glued together.

The threaded insert was glued in and dry before the center assembly.

That center assemblly took carefull alingment to make sure the clamping bolt will pass thru it's hole.

I then put weights on it while it dried to minimize any push back of the glue.

 

This is how the scope should be stored in the box.

Since this hub is larger than an original, it's fit was roughly checked before all the parts were made

and once again after gluing.

The dewshield's fit was also checked, since it's length was sort of random.

Edited by Kasmos, 14 September 2023 - 03:31 PM.

[deSitter]

Hub Remodel Continued

 

Hub-Parts.jpg

The white collar was made from another scrap PVC coupler which will go on the underside of the hub.

It's side hole will line up with the hole in the brass sleeve when slid in place.

The threaded aluminum insert will be installed in the hub to clamp the mount's shaft.

 

Clamp-Hole-Out.jpg

This shows where the threaded insert will be JB Welded in place.

The existing threaded hole needed to moved up and enlarged.

 

Clamp-Hole-In.jpg

Just a shot from the inside of the modified clamp bolt hole 

 

Center-pieces.jpg

This shows how the three center pieces will fit together in the hub.

I checked and rechecked the measurements several times to

make sure everything would line up and be the right height.

 

Ring.jpg

An outer ring of aluminum was cut from the center piece of a bunt cake pan.

The top of that same piece was formally used for the Swift hub build.

 

Hub-Parts-2.jpg

The black ring was cut from a piece of 2"ABS pipe.

It will fit between the gray collar and the aluminum outer ring

Each of the three plastic parts were beveled and notched

so that the JB Weld would have more surfaces of contact.

 

Test-Collar-Sleeve.jpg

This was a test fit before the gluing.

It's hard to see, but the black ring has a small gap at the back because it was slit 

to fit around the gray piece. That gap will be filled with JB Weld.

It was a lucky coincidence that the outer aluminum ring fit perfectly around the black ring.

 

Sleeve-In.jpg

This inside view is after it was all glued together.

The threaded insert was glued in and dry before the center assembly.

That center assemblly took carefull alingment to make sure the clamping bolt will pass thru it's hole.

I then put weights on it while it dried to minimize any push back of the glue.

 

Fit-Check.jpg

This is how the scope should be stored in the box.

Since this hub is larger than an original, it's fit was roughly checked before all the parts were made

and once again after gluing.

The dewshield's fit was also checked, since it's length was sort of random.

Really excellent work!

 

-drl

[LukaszLu]

As we can see, renovation of classic telescopes can be a creative activity!

[Kasmos]

Thanks guys!

 

Anyway, I could have just glued the center section and been done with it,

but no, I had to make more work for myself.

 

I forgot to take a photo of it before this to show where I'd left off.

I debated for awhile, but at this point I had already dove in by adding

some pieces to increase the slant at each of the leg tines.

 

In theory I was try to make it look more like a Atco (sand cast)

and less like a Towa (diecast), or at least disguise it's source.

 

And next I made these pieces to fill the leg holes to continue with the illusion.

 

They were also glued with JB Weld and held with clothes pins while curing.

It was a bit of a challenge making sure each of them wouldn't slide out of

position when installing one after another.

 

At this point they were all in and the upper body has another coat of JB Weld.

The leg bolt slots will be filled in and then drilled with a hole.

The arrow points to how the rear of the tines will be shaped once this area

is filled.

 

These parts were made to fill that area in.

 

I was so tired of sawing and filing aluminum I decided to fill each of leg slots

with three thinner pieces that could be quickly cut using tin snips.

They will be glued in 3 layers and all at the same time.

Edited by Kasmos, 15 September 2023 - 02:42 PM.

[Kasmos]

The 3rd and final coat of JB Weld

The film can pressed into it served as a handle to keep my hands out of the wet stuff.

 

These are the tools I use for mixing and spreading JB Weld.

The knife's round tip was for the collar's contour.

The thin stainless pieces are for mixing but also for smoothing it out

(can anyone can guess where they came from?) 

Razor blades work really well for skimming and smoothing wider areas.

Sort of like troweling cement or icing a cake.

 

Sanded and ready to prime... finally!

 

Pseudo Sand Cast

The underside is almost as important as the top 

But the lines of the tines had to extend into the center to achieve the look I was after.

 

 

This shot shows the inner extensions of them a little better.

It's also a better view of the newly drilled holes.

To get them centered and even in height, I really had to take my time

measuring each side and then carefully drill them. 

Edited by Kasmos, 16 September 2023 - 02:17 AM.

[Kasmos]

The hub was primed and only a few very tiny areas required spot putty.

 

This shows the pipe that was used to hold it during spraying

It was squeezed into that same film can I used during the gluing.

 

The paint was from a very old can of Zynolite Machinery Gray

and it was applied using a Passche VL airbrush.

 

It came out very glossy and smooth but there are some tiny specks that

are probably due to the paint's age.

 

 

Test shot of how it integrates with the mount

The paint was a good match for touching up my Goto 451 and the Mayflower 814

but it's a lighter shade than used on this Atco.

 

I'm kind of burned out from all the work required on this scope so I haven't repainted it.

One reason, even after all of this effort I may make another hub that's a closer match to the original.

Though it's still a success since it no longer looks like it's from a Towa.

but I'll have to see how much I like it once the rest of the scope is done and set up.

Edited by Kasmos, 16 September 2023 - 05:56 PM.

[oldmanastro]

The hub was primed and only a few very tiny areas required spot putty.

 

Hub-Painted-1.jpg

This shows the pipe that was used to hold it during spraying

It was squeezed into that same film can I used during the gluing.

 

Hub-Painted-2.jpg

The paint was from a very old can of Zynolite Machinery Gray

and it was applied using a Passche VL airbrush.

 

Hub-Painted-3.jpg

It came out very glossy and smooth but there are some tiny specks that

are probably due to the paint's age.

 

Hub-Bot-Painted.jpg

 

Hub+Mount-b.jpg

Test shot of how it integrates with the mount

The paint was a good match for touching up my Goto 451 and the Mayflower 814

but it's a lighter shade than used on this Atco.

 

Hub+Mount.jpg

I'm kind of burned out from all the work required on this scope so I haven't repainted it.

One reason, even after all of this effort I may make another hub that's a closer match to the original.

It's a success that it no longer looks like it's from a Towa

but I'll have to see how much I like it once the rest of the scope is done and set up.

Fantastic work on that tripod hub. It looks a lot like the original. Congrats!  

[jragsdale]

Wow, truly impressive work there! Good job!

[Kasmos]

Fantastic work on that tripod hub. It looks a lot like the original. Congrats!  

 

Wow, truly impressive work there! Good job!

Thanks guys.

My problem, I'm a bit OC so I keep thinking it's not close enough to the original.  

[bill7342]

Thank you for this thread. I have the same missing part for my ATCO 1252. I am going to give this a try. Your final hub looks amazing. 

[Bomber Bob]

Your final hub looks amazing.

 

Yes it does!  Amazing Restore, Chris (as usual!)!!

[Kasmos]

Thank you for this thread. I have the same missing part for my ATCO 1252. I am going to give this a try. Your final hub looks amazing. 

Bill, thanks! It's my pleasure to share this kind of stuff and inspire others to do similar fixes.

 

I've seen your mount, and being the older model, it has a tapered shaft that bolts into the hub. Mine has a straight shaft (no stud and nut) with only an indented ring where the hub bolt locks it from turning plus holds it into the hub. I bring this up since the tapered shaft will make it a bit more challenging to adapt a hub from another scope, so I'm not sure how I'd approach it? Sometimes other mounts have a similar tapered shaft. Case in point, I have a Tasco 19-T mount that's tapered shaft looks like it would fit a Manon hub or a Celestron Cometron hub. 

 

I don't know how strong it is but perhaps the center section could be 3D printed and then glued into a hub. For that matter I suppose you could print the whole thing. Sean had offered to make one but I believe he thought it would still require a sleeve (metal?) in the center.

 

Your final hub looks amazing.

 

Yes it does!  Amazing Restore, Chris (as usual!)!!

Thanks BB 

Edited by Kasmos, 19 September 2023 - 01:08 PM.

[DreamWeaver]

 

[Kasmos]

Mount Issues

 

The mount had both mechanical and cosmetic issues.

 

As found the tube clamp would not rotate 180° in the fork arms without force.

So it was up side down since it rotated better when it's lower side was up.

 

Note how the gap is uneven at the top and bottom.

Because of this, when the mount is assembled and tightened it would bind.

You can also see how the bosses on the clamp don't really line up with the arms.

This can partly be expected with rough sandcast parts.

But it should be machined well enough to work.

 

My TA710 Kenko mount suffered from the same problem but it was completely unuseable. 

And just like the Kenko it was caused by two things:

 

1. The axis was not drilled square in the clamp nor in the fork.

2. The left and right mounting sides of the clamp are not flatly square with it's sides and axis.

 

On both mounts it looks like it was all done by eye without any jigs to square things up.

This makes it hard to remedy (without major reworking) and took a little trial and error to find a best solution.

I didn't want to take too much off but filed some of the

high sides off on both sides of the Tube Clamp Bosses.

 

The right fork hole was irregular and too large and when tightend

it rubbed a couple of high spots in the lower portion of it's hole.

I smooth them a bit but it turned out it wasn't the main or only problem.

 

This shows how it rubbed on the inside of the left fork.

This was also filled some to to help even thing up.

 

This shows the left outer side of the fork.

The scoring is from the metal outer washer not being square with it's face.

It was filed (after this photo), but like all of these surfaces,

it was kept to a minimum so that the gaps between the arms don't open up too much.

A later test found that the single best thing to do was to put a cardboard washer under the metal one.

This alone might have helped the most, but the other things did seem to help.

 

It was disassembled and reassembled several times as I worked it.

Once done it still had a bit of a tight spot, but it will be acceptable in use.

 

Casting Flaws

 

The Tube Clamp had a pretty nasty casting flaw.

 

The Tangent arm did as well.

It had a scrap piece of metal residue that had to be dug out.

 

Both flaws will be filled with JB Weld.

Edited by Kasmos, 28 September 2023 - 03:31 PM.

[Kasmos]

Since Oct. 22nd I had been away so I was unable to post anything new on this project.

Now that I'm back I'll try to get you updated on it's progress and also finish it off.

 

The casting flaw in the tangent arm was filled with a drop of JB Weld.

IIRC, this was the first attempt.

It took me two times to get it right and then sanded smooth without disturbing the surrounding paint.

 

I decided I'd sand the chips and spots of corrosion and try to blend it in with touch ups.

Previously I'd experimented doing this on the Goto 451's hub and liked the results.

 

Early on I had done a quicky touch up of the finder mount but wasn't thrilled with it, so it got the same treatment

 

As I got further into this process I began to question if I had gone to far.

I started thinking maybe I should have left them alone or completely stripped them for a proper re-spraying.

But I could always go that route if it ends up looking horrible.

 

The really bad spots of corrosion were sanded to the metal and the area inside the dotted line was deglossed.

The idea was to try and limit the brush painting to the edges and where the shape of the parts change direction.

This helps hide where the brush painting ends and the original paint starts. 

 

Other than the edge the backside of the fork was mostly in good shape. 

 

The pivot area of the tangent arm was also sanded smooth of it's chips and corrosion.

With all the changes in direction of their shapes, small parts like this take brush painting well. 

 

The casting flaw of the tube clamp was cleaned up for filling with JB Weld.

 

The JB Weld is filled smooth and rest of the top edge was sanded of it's chips and flaws.

This whole quarter of the clamp would be brush painted.

Stopping at the narrow spot above the pivot will hide the brushed paints transition.

 

This is just a better shot of how the area where thumbscrews looked after prep for paint.

 

This side was in much better shape and will only need the bare areas repainted.

 

But again, after everything was preped, I questioned if I had done the right thing?

Edited by Kasmos, 21 December 2023 - 04:12 AM.

[Kasmos]

Well the touch ups went well (if that's what you can call them)

I mixed up a bottle of gray that closely matched the original color so I wouldn't have to do it as I worked.

 

 

The JB Weld repair is right above where the felt is peeled back.

 

The casting is a bit rough in spots so in areas like this it really doesn't show when you use a brush.

 

This side was paint down to the middle of it's side.

As I mentioned in the last post, it really helps if you have a spot where you can stop to hide the edge of last brush mark.

 

A couple of keys to getting good results are having a nice smooth flowing brush and paint that levels well.

During some other trials I'd forgot what brush I'd used and using a nice sable brush really made a difference.

 

Even knowing they are touched up, you really have to look hard and close to see them.

 

Once they were finished I was relived and happy how they turned out.

 

I just realized forgot to get photos of the finder mount. 

Edited by Kasmos, 21 December 2023 - 03:49 PM.

[deSitter]

Well the touch ups went well (if that's what you can call them)

I mixed up a bottle of gray that closely matched the original color so I wouldn't have to do it as I worked.

 

Gear-Cover-2.jpg

 

Clamp-1tu.jpg

The JB Weld repair is right above where the felt is peeled back.

 

Clamp-2tu.jpg

The casting is a bit rough in spots so in areas like this it really doesn't show when you use a brush.

 

Tube-Clamp-02.jpg

This side was paint down to the middle of it's side.

As I mentioned in the last post, it really helps if you have a spot where you can stop to hide the edge of last brush mark.

 

Fork-Tu.jpg

A couple of keys to getting good results are having a nice smooth flowing brush and paint that levels well.

During some other trials I'd forgot what brush I'd used and using a nice sable brush really made a difference.

 

Fork-Back.jpg

Even knowing they are touched up, you really have to look hard and close to see them.

 

Once they were finished I was relived and happy how they turned out.

 

I just realized forgot to get photos of the finder mount. 

Really beautiful work. It's grey-grey! If someone asks, what is grey? It is hard to describe, but you know when you see it!

 

-drl

[jragsdale]

The thin stainless pieces are for mixing but also for smoothing it out

(can anyone can guess where they came from?) 

Nice work on the casting, you're improving it better than stock.

 

As for the thin metal strips, they look a lot like the metal strips that came out of a Questar storage leather case handle. So maybe any leather strap handle would have similar metal strips?

[Kasmos]

Nice work on the casting, you're improving it better than stock.

 

As for the thin metal strips, they look a lot like the metal strips that came out of a Questar storage leather case handle. So maybe any leather strap handle would have similar metal strips?

I found the thin metal strips in the gutter. They came off of the street sweeper's brushes and are stainless steel. I know I'm nuts but I knew they would be useful for something.

Edited by Kasmos, 22 December 2023 - 03:55 AM.

[Kasmos]

I forgot to post photos of the retouched finder mount, so here's some.

 

It shows a few casting blems and some dust but it's a big improvement over what I started with

 

The other side looks a bit better

 

 

 

Here's a preview of the partially complete OTA.

The tube still needs some chips touched up and the objective cell needs to be installed.

 

Edited by Kasmos, 23 December 2023 - 05:04 AM.

[Kasmos]

Mount Hardware

 

Considering the amount of corrosion this scope had suffered, the mount hardware cleaned up very well.

I always use both Nevr-Dull and Blue Magic Metal Polish and it's a slow process to get it to look like this.

 

Cleaning and polishing the screw heads is one of the more tedious aspects.

I usually put some polish on a rag and vigorously rub it's head back and forth against it.

Then do the same to rub the polish off.

 

To clean/polish inside the head, I rub and wiggle the point of a toothpick that was dipped in Blue Magic.

As the point becomes a bit ragged, the better it works. (like the upper end of the toothpick).

(BTW, I make soft jaws for my vice for stuff like this)

 

To clean the polish out of the head, I lay a rag that's been folded double over it. poke it and rub and wiggle in it again.

The rag is doubled so the tooth pick doesn't poke thru it.

I usually do this twice moving to a clean section of the rag for the second time. 

Edited by Kasmos, 25 December 2023 - 01:44 AM.

[deSitter]

Mount Hardware

 

Considering the amount of corrosion this scope had suffered, the mount hardware cleaned up very well.

Mount-Hardware.jpg

I always use both Nevr-Dull and Blue Magic Metal Polish and it's a slow process to get it to look like this.

 

Cleaning and polishing the screw heads is one of the more tedious aspects.

Screw-Polish.jpg

I usually put some polish on a rag and vigorously rub it's head back and forth against it.

Then do the same to rub the polish off.

 

Toothpick.jpg

To clean/polish inside the head, I rub and wiggle the point of a toothpick that was dipped in Blue Magic.

As the point becomes a bit ragged, the better it works. (like the upper end of the toothpick).

(BTW, I make soft jaws for my vice for stuff like this)

 

Toothpick2.jpg

To clean the polish out of the head, I lay a rag that's been folded double over it. poke it and rub and wiggle in it again.

The rag is doubled so the tooth pick doesn't poke thru it.

I usually do this twice moving to a clean section of the rag for the second time. 

Nice work. Always a joy to see. Merry Christmas Kas!

 

-drl

[Kasmos]

Before I could finish the mount I needed to make a locking lever for the new hub to engage the fork shaft.

 

I used two aluminum Binding Post Nuts and and two screws (#10-32 and #8-32)

I've used these same parts before to make some other parts and to make a missing lever.

The large one has 1/4-20 threads so I planned on gluing or soldering the brass #10-32 screw into it.

 

I used a drill as a lathe to machined down and cut the larger one.

When I cut off it's head and started to polish it's end, a small spot started to grow.

This one must have been drilled deeper than others I've used since that never happened before.

It became a hole so I tapped it for the #10-32 screw.

 

On it's outside diameter I drilled two holes 180° from each and tapped them for the #8-32 screw. 

After threading the 1/4-20 threaded section into it, I applied solder to lock it in place.

It took three times to get it soldered right.

 

I ended up using a threaded piece from a scrap #8 brass screw for the lever instead of the stainless one in the top photo.

It was cut to the proper length and threaded into the smaller Binding Post which was also cut to a desired length.

 

After checking it's depth and fit, the new bolt was cut to a appropriate length.

 

I didn't plan on the brass bolt showing but I wasn't going to start over and make another one.

Edited by Kasmos, 25 December 2023 - 11:57 PM.

[Kasmos]

More Mount Preparations

 

Here's some more things I had to do to get the mount back together

Each section or component had to be put together and taken apart several times to adjust how they would fit.

 

When fit into the gear's shaft, the fork shaft had more play than I liked, so I put some tape on it.

I also cut 2 washers from some automotive gasket material.

This was to take up some the up and down play between the two.

Note the white arrow. The set screw of the gear shaft (2 photos) down rides in this groove.

 

This shows where the 2 washers would go, but only one was needed.

Two would fit, but made the worm and gear not line up as well.

It's diameter is larger than the shaft's shoulder since the worm mount (below) also rides  on it

 

This is the screw that rides in the grove of the shaft shown in the top photo.

It's not completely locked down so the gear can rotate on it.

The black arrow points to the grove that the hub locking bolt engages with.

When the locking bolt is loosened the upper mount can be rotated but not pulled apart.

The hub's locking bolt is the only thng that holds the upper mount to the hub.

The earlier 1252s have a lock bolt but also have a bolt on the bottom.

 

This is the worm's mount and cover.

I put a mark on the the threaded retainer where the dimple in the treads were.

This was so I could sight it in the set screw hole when it was threaded in.

 

Note how the worms holder is not even with the edge of the collar bracket.

The worm and gear has more play than I'd like but there's no way to adjust it.

I wish there was a way that it could be pushed tighter against the gear.

 

These counter set screws that hold it are the reason it is not adjustable.

If they were replaced with bolts with hex heads and had slightly slotted holes it might be possible.

The earlier 1252s have hex head bolts and that might be the reason for them.

 

I also made washers for the altitude bearing and the slow motion pivot bracket on the fork arm.

 

This washer helps for two reasons

1. The brass bearing sticks out further than the arm's hole

2. Due to poor macining, the metal washer that goes over it doesn't rest on the arm squarely

 

This shows the smaller washer installed on the pivot bracket screw.

Without it, the slow motion worm had too much side to side play.

 

This is the worms collar/holder and it's set screw.

The set screw rides in a groove on the worm shaft and keeps it from pulling out.

The point of the set screw that rides in it was worn flat so I had to come up with a fix.

 

This drawing shows what I came up with.

I cut a small piece of brass and put it under the set screw and into the groove.

 

Just a photo of the piece of scrap I cut it from.

The piece cut was about 3/32" square.

Being small, the piece it was cut from was held in small vice grips and held in my vice.

It seems to work fine now, but I may make another from some round stock.

Edited by Kasmos, 28 December 2023 - 04:46 PM.