80mm long focal length refractor

[brino]

Argh!!!!!!!!!!!!!! when will it end.

I think we all get that feeling when working on a large project.

I hope it helps to know that your build quality is remarkable.
You will end up with a beautiful and functional treasure when you're done!

-brino

 

[savarin]

Thanks Brino, The phenomenal amount I have learnt and the skills gained since starting this whole exercise have been absolutely priceless so really I shouldnt complain.

 

[ch2co]

The only reason that I really wanted a lathe (and minimill), was to repair, modify, rebuild and make from new, parts for my real hobby, astronomy.
I knew very little about machining before buying my tools. I know that a lathe could turn round stuff and thats about it. I was fortunate enough
to run into a good deal on a well maintained and upgraded G0602 lathe that came with tons of added tooling and including the G8689 mini mill, that
I thought that I would probable just resell to someone. Then after turning a little bit of aluminum, I tried out the mill and not knowing at all
what I was really doing I came up with a decent adjustable laser mount for my 4" f15 Jaegers scope. The learning curve was steep and only
motivated by what I wanted to actually make. No regrets! Just as Savarin said, the whole exercise has been absolutely priceless.
The Hobby-Machinist forum pulled me out of many dead ends that ended up as highly successful pieces of astronomical equipment.

CHuck the grumpy old guy

 

[savarin]

Hi Chuck, any chance of some pictures of what you have made for your scopes?

 

[savarin]

Change of pace today.
Made the pair of holding rings for the finder scope.
70mm dia, marked of and drilled each hole,

Then replaced the drill with the tap, started the thread,

removed it from the jig and finished it by hand.


now comes ---- you guessed it---polish them.

 

[savarin]

I had occasion to try out the shortie finder scope the other night, yuk! coma all around the outer quarter of the field.
I had another 50mm doublet handy of a longer focal length and as luck would have it it fit straight into the original cell.
All I had to do was make a longer tube.

Thats the shorter tube underneath so the new focal length is approx 15mm longer.
Now its a clean image across the field.
The gold tint is reflection from my shirt not brass tubes.

 

[Tony Wells]

You wear a gold shirt? I'm impressed..


Also impressed by your work. You've come a long way in a short time, Sav. Good on ya!

 

[savarin]

Thanks Tony thats really appreciated.
(I thought I had already sent this but cant find it so have done it again)
Made another brass screw today, only 11 more to go. I dislike repetitive jobs so am making them a few at a time.

Also made the clamps to hold the finder to the mounting rods.
They were somewhat roughly chopped out of some scrap and needed too much filing to get into shape so I attempted to remove as much as I could in the lathe.
Bolted together using the rear of the clamps as a register to the chuck body.

That then allowed me to reverse them using the new flat on the chuck body and bring the two to the same thickness.

Back to the other way to face as much as I could from the inside edge.

Now its just a little bit of filing. So after cleaning the remaining ends and face up with a file it was time to round the fat ends.

To get this,

repeat again plus some extra filing for these.

Now to split them from the inside corner to the hole, drill and tap for a 4mm clamping bolt and then its more sanding and polishing again.

 

[savarin]

After splitting the clamps I bolted them to a chunk of ally plate,

I filed a groove for the 8mm shaft to sit in preventing the clamp from spinning round the bolt when I fly cut the profile in the end for the finder rings to sit.
Ask me how I knew that would happen.

both clamps profiled to fit the rings BUT........

Yep, when originally splitting the clamps into two I went too far with the saw and nicked the end.
Never mind, a quick design change and round these ones over. (no I'm not going back to do the others so they look the same)

And now for another design change, sorry, advanced feature.
The finder scope wont pass through the rings now the bolt is in place so I had to shave a little from the screw head, flatten the inside of the ring so the bolt head sat flat and lower and took a shaving from the offending lens cell of the finder.

Next stop powder coating the lens cell and hope I left enough clearance.

 

[savarin]

Have to wait for the powder coating till I get the spray booth finished so I decided to assemble it all and have a quick squiz at the universe.
Saw jupiters bands, 4 moons and it focussed nice and sharp but Wide Angle 15mm was the smallest eye piece I had on hand.I still have to finish off the slow motion controls and add a brace under the support plate as I noticed it flexed a tiny amount.
Here it is with the sun finder, laser pointer and wide angle finder scope.


I rather pleased with its image results. And it looks cool.