Zhumell Z100 100mm f/4 Newtonian

[Alan64]

I'll need to matte-blacken the heads of the screws next.  The acorn-nuts lend a bit of panache and style, eh?

[Alan64]

Presently, I'm working on the dust-cap for the telescope's front opening...

It snap-fitted originally, but with the addition of the aluminum veneer to the inside rim of the cowling, I'm having to reduce the diameter of the cap's flange.

[Alan64]

The cap now fits to where I want it.  It's neither snug nor loose.  Part of the flange will be flocked, and to serve as cushioning as the cap is removed and replaced...

A section of the flange was cut out to accommodate the secondary-stalk and the thicker aluminum used to bolster it.  The center-plug, for the 60mm aperture-stop, cannot be used, as it's too thick and will not fit due to the secondary-hub's adjustment screws sticking out too far; and no, I am not going to revert back to the set-screws, absolutely not.  Instead, I will fill the hole with aluminum sheet backed with black-plastic sheet or other, and add a knob. 

Oh dear, if I do that, I won't be able to use, per the diameter of the secondary-mirror, the 60mm f/1 or f/2 aperture...

It looks like I'll just have to do without that grossly-obstructed aperture; and a dim, 60mm one at that.  

[Alan64]

It appears that I will be able to retain the aperture-stop after all.  The dust-plug for the dust-cap...

The plug is not of hard-plastic as the cap, but rubbery, yet stiff in its own right.  Aluminum bonds to rubber quite well, with epoxy...

[Alan64]

[Alan64]

I ordered two of these, and from China...

https://www.ebay.com/itm/Black-plastic-M4-M5-M6-M8-M10-M12-thread-ball-shaped-head-clamping-nuts-knob-ah/392308035882?ssPageName=STRK%3AMEBIDX%3AIT&var=661295015533&_trksid=p2057872.m2749.l2649

...the 16mm, M5.  They've already landed here in the U.S.  It's only a matter of time.  One will make for a rather complementary knob for the aperture-stop's plug.

In turning towards the tube-rings, I shortened the bolts by about 2mm.  These are the tips that had scratched up the tube...

The tips of the bolts are now flush with the tops of the nuts...

...and now clear the tube.  I then found that the factory-felt of the rings was too thin, and for a secure clamping...

The adhesive left behind at random was removed with charcoal-lighter fluid, the kind used for grilling food outdoors.  It worked a charm, and is also excellent for removing factory glue-grease from mounts.

The new, thicker felt in place...

...much better now.

I removed the camera-piggyback adaptor from the one ring.  Both will have, instead, pointed acorn-nuts attached, which will serve, when called upon, as a finder.

[Alan64]

The telescope itself is completed, save for its collimation, dust-cap and tube-rings...

Edited November 30, 2019 by Alan64

[Alan64]

The high-point acorn-nuts and their screws; glamour shot...

I had to deepen the recesses for the screws' heads...

The screws were cut down to 10mm to 11mm in length.  The tube-rings are completed...

Now to wait on the knob for the dust-cap's plug...

[Alan64]

I still haven't collimated it yet, but no matter.  Tantalising glamour-shots of the innards...

Dead-black inside; that's the ticket.

I had never taken a non-flash shot of the interior, after it had first arrived; only a flash-shot.  Hence, flash-shots, before and after...

Edited December 2, 2019 by Alan64

[Alan64]

A view down the 60mm aperture-stop...

What an obstruction.

It's interesting to note that the aperture, at f/6.7, will be at or nigh to the actual focal-ratio of the doublet of this 60mm "VariPower" achromat...

I never did get round to cutting that tube down and installing a conventional focusser.

Edited December 2, 2019 by Alan64

[Alan64]

The telescope mounted upon my Maksutov's "Twilight Nano" alt-azimuth, and upon which it will spend considerable time outdoors...

It will also point straight-up towards the zenith, then a wee bit beyond and without colliding with the mount...

[Alan64]

This particular online-shopping experience tested my patience; but at the same time it taught me patience...

Again, last late-November, I ordered two of these...

https://www.ebay.com/itm/Black-plastic-M4-M5-M6-M8-M10-M12-thread-ball-shaped-head-clamping-nuts-knob-ah/392308035882?ssPageName=STRK%3AMEBIDX%3AIT&var=661295015533&_trksid=p2057872.m2749.l2649

...and from China, and all that that entails.  I ordered a spare in case one of them got squished out, out of the notoriously-skimpy bag these sellers tend to use, and during transit.

The package arrived in the U.S., the west coast, on December 3rd.  But did I get all excited?  Of course not, as I knew that USPS was not going to be in any hurry whatsoever in delivering it; been there, done that, before.

The bags they use are not unlike those used for packing sandwiches.

All the way from Bishkek, Kyrgyzstan, which is right next door to China, to the west.

Aren't they lovely?

See that screw?  I had gotten that locally, an M5, and round the time I placed the order.  It fits perfectly, but I will have to shorten it somewhat; glamour-shot...

Edited January 6, 2020 by Alan64

[Alan64]

That's J-B  Weld steel-reinforced epoxy mixed up there.  You want to retain the unused portion, and to know when it's safe to handle...

...and in about 16 hours.

After it cures, you'd be hard-pressed to separate the two components, even with two pairs of pliers.

 

[Alan64]

Cake's done...

After the edge was ground, sanded and smoothed, for the application of satin-black, I temporarily installed the knob; glamour-shot...

The reverse...

That won't be seen of course; good thing, too.

It looks like a lid for a jar of sweets; candy...eye-candy.

[Dr_Ju_ju]

After knobs !!  have a look here http://www.wdsltd.co.uk/categories/65/hand-knobs-thumb-screws/?page=2&pageSize=20   will be more expensive than the oriental variety, but probably better quality & faster delivery...

[Alan64]

12 minutes ago, Dr_Ju_ju said:

After knobs !!  have a look here http://www.wdsltd.co.uk/categories/65/hand-knobs-thumb-screws/?page=2&pageSize=20   will be more expensive than the oriental variety, but probably better quality & faster delivery...

Oh, that's just a decorative yet practical knob, static; for removing the plug when I'm bored, and in having nothing else better to do than to observe with that stopped-down, grossly-obstructed, 60mm aperture.

Edited January 7, 2020 by Alan64

[Gina]

That cake looks a bit tough 🤣

Sorry CNR...

[Alan64]

The top and thin side of the plug was primed, then sprayed with satin-black enamel...

It'll be tomorrow before I can even think about handling it.

[Alan64]

The satin-black enamel I use is obviously oil-based, as it hasn't cured quite yet.  Still, I attached the knob, permanently, and in order to handle it for the next step; glamour-shot...

[Alan64]

The next step was to apply clear-gloss enamel onto the flange all round...

On top of that, something else will be applied.  Then on top of that, something else again; but nothing else after that.

[Dr_Ju_ju]

How about some felt, to stop painted surfaces sticking together ??

[RobertI]

This is an epic thread. That scope is going to be worth a fortune! 🙂

[Alan64]

11 hours ago, Dr_Ju_ju said:

How about some felt, to stop painted surfaces sticking together ??

Shhh, you're going to spoil the surprise.

[Alan64]

Aluminum-foil tape was applied round and over the plug's glossed flange, for a smoother substrate for the final application, and of...whoops, mustn't spoil it...

I haven't even collimated the telescope yet.  That will have to wait until the dust-cap and its plug are completed; although, it doesn't have to, but is going to rather.

[Alan64]

The plug is not too loose, nor too tight, just right rather.  Yes, you guessed right, and a final application of...

...felt; hard, red felt.  For this type of shimming, you want the hardest self-adhesive felt you can find; none of that down-soft stuff, no, but it would be better than nothing at all.