Jump to content

sgl_imaging_challenge_6_banner_jupiter_2021.jpg.eacb9f0c2f90fdaafda890646b3fc199.jpg

 

 

A Restoration


Recommended Posts

I've adjusted the vast majority of the slop out, what very little there was, between the RA-worm and the worm-gear.  I did leave a frog-hair's width as a fail-safe.  I can't detect any real movement, only a very slight "knock".  This is being done in the summer.  In winter, it may become slightly more loose, who knows, but no matter as I don't much like observing in the cold, although the night sky is delightfully darker.

I have ordered a brass rod, 0.40"/10mm in diameter, 10"/250mm in length, and to replace these black-plastic clamping "buttons"...

1868888459_clampbuttons.jpg.1202207a305040c953003c0cff7bfb72.jpg

The "buttons" are 0.20"/5.08mm in height, and 0.37"/9.34mm in diameter.

The threaded holes for the clamps are about 0.40"/10.2mm in diameter.  I may have to reduce the diameter of the brass rod slightly.  We'll see.

Oh dear, I've got this to do next...

454088493_DECparts.jpg.cd8cb9f2b3f8bd10ddaba0615a9b688f.jpg

<shudder>

  • Like 1
Link to comment
Share on other sites

It's a shame...

2131590405_DECNTB4.jpg.4b2673fadfe369143492c8abb5f514c3.jpg

...that I cannot place the needle-thrust bearing on the inside of the DEC-axis...

1136388730_DECNTB4b.jpg.06993015ebef6cdf063a0782818107ae.jpg

...resting upon that inner surface at the very bottom...

1519630423_DECNTB3.jpg.78ff4155081827a7c2c0a5cc9359d0a2.jpg

...and lovingly sandwiched between two bronze washers to boot.  But I cannot, as it would throw everything off, wildly.  Although, it makes sense nonetheless, as the weight of a telescope would then rest upon it.  So much for dreams.  

And now, back to the original idea, which will work.  On the opposite side of that inner surface, is the outer surface.  Initially, the bearing had to be snapped in, and was somewhat difficult to pry out...

828183871_DECNTB2.jpg.4740d503622a0af65d521bf546d389dc.jpg

But I don't want to reduce the outer diameter of the bearing itself, so I've sanded and polished the inner surface of the cavity instead...

122711944_DECNTB4c.jpg.205491378dc31e11c8af1dcfb72ae1fa.jpg

1755394123_DECNTB4d.jpg.382e67eb10523a61677292c10065c613.jpg

All of the paint on the inside was removed as a result, and now, the bearing drops in readily...

320231904_DECNTB4e.jpg.da1aee0d3ba7800127dffea1d6b6c991.jpg

...but it does not spin as freely as I want.  Next, I'm going to grind a bit more off of the inner rim...

  • Like 1
Link to comment
Share on other sites

The bearing spins freely now, and with that toothpick...

1211022147_DECNTB4f.jpg.4e918f1308d8b6f6372461026b625677.jpg

The aluminum threads of the DEC-shaft do tend to try to catch the inner rim of the bearing.  I will look into that as well.

In the end, the DEC-axis will have four bronze washers, two thinner and two thicker.  I would love to place even more within, more bearings too, but there are no places to put them.

The poor ole DEC-axis, always taking a back seat to the RA-axis; abandoned, forlorn, neglected, and relegated to a secondary importance.

  • Like 1
  • Haha 1
Link to comment
Share on other sites

I buffed the threads of DEC shaft with #0000 steel-wool and lemon-oil.  The needle-thrust bearing now spins even more freely, and exceeding that of government work.  Mind you, that's without grease having been applied, yet.

The DEC specs for the washers and what-not...

The upper DEC washer, at 0.020"/0.508mm in thickness...

281478965_DECspecs.jpg.a8f60f184ead8d45549f72d448165950.jpg

There's another one of Synta's narrow bearing surfaces again, indicated at right, but that one may not be widened, as that of the RA-axis could've been.  The inner-diameter of the washer must be as snug as possible, as a result, and no greater than 62mm across.  Nor should the outer-diameter be greater, so as not to protrude over the teeth of the DEC-worm gear.

Incidentally, the four large plastic washers, two for the RA-axis and two for the DEC-axis, are 0.0215"/0.55mm in thickness, 0.0015"/0.038mm thicker than the bronze to replace them, although quite negligible.

The middle DEC washer is essentially identical to the bottom surface of the DEC-worm gear, also at 0.020"/0.508mm in thickness...

1930023921_DECspecs2.jpg.1bdb0ce825b9d7f56c3643345654e452.jpg

The thickness(0.0945"/2.4mm) indicated in the following spec(the lowermost washers) is the needle-thrust bearing sandwiched betwixt two 0.008"/0.203mm-thick bronze washers...

101250110_DECspecs3.jpg.e21ef9adb73996fd731d9be59a74651d.jpg

Said bearing and washers are taking the place of the original single plastic washer, at 0.0630"/1.6mm in thickness...

246429614_DECsmallplasticwasher.jpg.e78bb70f82040982bf5692a102dcc4d0.jpg

The plastic washer is 0.0315"/0.8mm thinner than the three parts to replace it, and fits over the DEC-shaft's thread rather sloppily; again, quite negligible, as those are on the outer portion of the DEC-shaft.  There will still be plenty of room for the lock-nut, and the parts for the useless setting-circle.

There may be another washer to be made, but I won't know for certain until I test-fit the thicker bronze washers.  I seriously doubt that it will be necessary, however.

I might make a bronze washer for the setting-circle as well.

  • Like 1
Link to comment
Share on other sites

From this, the washers for the DEC-axis shall arise...

bronze3c.jpg.54b2dc7bb1b575d917c6088f42fbed05.jpg

The section from the roll that I used for the RA-axis was somewhat prettier, and adjacent to the aforementioned...

bronze3b.jpg.4b5b35a552f9c656ad2e39468b472608.jpg

In that Synta was most generous in sticking a 0.060"+ plastic washer at the bottom of the axis, I can go whole-hog too, and make the smaller washers for the needle-thrust bearing from the same 0.020" sheet, instead of from the 0.008" sheet as I had first considered.

Then, they'll be on the outside of the DEC-shaft.  What could go wrong?  :D

After all, this isn't an EQ-1.

For over a week, it's been wet, and damp persisting.  When I went outside a while ago this afternoon, I could almost see the steam rising from the ground, still.  But it is drier, and I may now set up my scroll-saw...

...but at night, and with my friends in the sky watching o'er. 

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

It's almost dark here, and a little cooler, but not quite there.  For tonight's "festivities", I'm getting the washers described beforehand.  Here, the two Xs for the compass-point have been determined...

290348378_DECwashers.jpg.86f8576e0528fac71b5680b986f58f48.jpg

There, above the sheet, is one of the many micro, carbide drill-bits that I have.  I used a common, steel micro-bit for the previous washers, but it tended to describe a circle instead of drilling a hole, until I cut the shaft of the bit down.  I won't have that problem with the carbide bit; but carbide is brittle, almost to the point where a bit may be considered disposable, so care must be taken, if I want to use it again in future.

  • Like 1
Link to comment
Share on other sites

The carbide drill-bit broke just before it drilled completely through the second X, but that's because my small drill-press is not a precision product.  My mini drill-press, which I would've used instead, the belt broke recently.  I can get replacements, but not in time to complete this project.  Still, before the bit bought it, it did make a deep enough hole into the bronze for the compass-point.

The washers for the DEC-axis have been described, and pilot-holes drilled out for the scroll-saw's blade; or blades rather, as I expect one or two to break.  However, I'm learning how to prevent that, but a breakage now and then is inevitable, as this bronze is relatively thick...

1847067525_DECwashers2.jpg.3359ec5eb51504aab36d7be1f18f3273.jpg

  • Like 1
Link to comment
Share on other sites

The Moon, and Jupiter I believe(By Jove!), were riding somewhat high in the sky whilst I worked, sawing the washers out of the sheet.  I didn't illustrate the aftermath of the sawing of the RA washers, but here is what they looked like as well, and fresh from the scroll-saw...

902690158_DECwashers3.jpg.405fca5124b2440ad1dc83238e0eaf1f.jpg

I saw the centres out of the smaller washers first, then the smaller washers out along with their scraps.  That leaves all of the washers ready for cutting, dressing and polishing; no further sawing, thank goodness.  

Now, the bronze pieces appear to be beaten up, but they aren't.  That's only greasy, oily smears here and there.  Incidentally, they appear as brass within that image, smacking of it at least.

I had to douse myself with 40% DEET-based repellent, to prevent anemia.  I prefer the lemon-eucalyptus(non-DEET), but a relation within the household cannot stand to be around me whilst so "perfumed".

I broke only one blade, yet during the last stretch, perhaps an inch left, although I wasn't using those whisper-thin, pin-less, jeweller-type blades(that require an adaptor), but some old fine-toothed pin-type blades that I've had for almost twenty years.  In that I was sawing non-ferrous metal, I thought, "Why not?"

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

When sawing out these washers, I don't get too close to the lines.  The excess can easily be removed; better that than sawing adjacent to or even past the lines.  Such also allows for fine-tuning of the diameters.  The same follows when using shears to cut along the outside of the washers; not too close...

1857159295_DECwashers4.jpg.a9bfdf5a96c2ada0392b239bcf8b4cef.jpg

Note the two outer and inner lines that were described for the larger washer on the right.  That one goes in the centre of the axis, and its exact size is a bit of a mystery.  That washer will be cut and dressed along the outer lines, then to test...

240265618_DECwashers4b.jpg.5633b9a08103538ac8110be0a5e01fcf.jpg

The larger washer on the left must have its inner diameter ever so carefully reduced, and until it drops in place.  It must be as snug as my attempts at an ISO9001 standard will allow, and for its narrow bearing-surface.

After the washers are roughly dressed...

FspCDGC.jpg

...I then use a Dremel tool, along with either a grinding-stone or sanding-drum, to effect the exact dimensions required.  Lastly, the washers are fine-sanded and buffed with #0000 steel-wool and lemon-oil.

Edited by Alan64
Link to comment
Share on other sites

I have a couple of Dremel #407 sanding-drum bits, somewhere, but I can't find them at the moment.  But I did find my late father's, which seems to be a bit on the heavy-duty side...

sanding-drum.jpg.5dab1459706c6c9866923f86dae47474.jpg

The nut screws on in reverse, towards the left, rather than to the right.

sanding-drum2.jpg.ef4740f9a9a75e8084f2c8c4fe24d669.jpg

This sanding-drum will remove the excess bronze without building the metal up at the edge, which would require an extra step to remove that.  I got these grinding-stones recently, and used one for dressing the RA washers...

grinding-stone.jpg.4037bd9a9604f700d8924ff00e41b94f.jpg

They work wonderfully, but the metal tends to build up at the edge.  I'm going to use the sanding-drum at first, to remove the bulk, then the grinding-stone to close in.  The sanding-drum, however, is spent much more quickly than the stone.

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

The bronze washer for the mid-section of the DEC-axis is completed...

451230938_DECwashers5b.jpg.48dcec21e2729973754789e0abde91b4.jpg

1133056880_DECwashers5.jpg.640aa40f46ee9611a11b3047ce210053.jpg

I'm puzzled, as I had to grind beyond the outer line, inward, before the washer would drop in; strange, but all's well that ends well. 

This union is where I thought I would need to add a washer.  I placed a small amount of the blue grease I bought, indicated by the white arrow...

894207330_greasetest.jpg.1d4dbcd6bed4e0d474dbab09859509a1.jpg

I then combined the two sections, with both bronze washers installed, twisted the two sections together a little, then separated them.  Only a tiny smear, and from the top of the glob, was evident on the opposite surface, indicated by the grey arrow.  Hence, there's a gap there between the two surfaces, thankfully, and a washer will not be required.  But I will grease those surfaces nonetheless before reassembling.

Now to prepare the washers for the needle-thrust bearing...

  • Like 1
Link to comment
Share on other sites

I had originally gotten these shears for cutting things related to my shed, but they have become a blessing in being able to cut this thicker bronze...

879459481_DECwashers7.jpg.67aa935ce24f3b629f1ce337f9fea146.jpg

1542166052_DECwashers7b.jpg.131d3d01b0d068340aeb0b1c67f2fc73.jpg

You can see how rough they are round the edges.  I did cut them neatly, and very close to the line.

The washers were then sanded and polished...

1257342228_DECwashers7c.jpg.4d66a8586e87e2125077b55e4c71c335.jpg

477781753_DECwashers7d.jpg.884724d2882d47be8167e6e457f0bc62.jpg

1487476029_DECwashers7e.jpg.537a9d43fc8797048f8c821689f2ef49.jpg

1007051248_DECwashers7f.jpg.aed5668fb1285538c87c17e9ad51ea81.jpg

Plenty of room for the lock-nut...

8636830_DECwashers7g.jpg.4e8421a72166a77dad6127e549a90060.jpg

...and that useless setting-circle.

1216045030_DECwashers7h.jpg.bdd7ce6ae0f561e962b31ffc6f80a6f6.jpg

Next, to re-assemble the DEC-axis...

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

There's a video on YouTube where the author states not to grease the outside surfaces of the worm-gears(for a go-to EQ-5), as that's where a clamp engages same, and to lock the axis, the premise being that the grease would allow the gear to move despite being locked.

I greased the outside of the RA-worm gear, but it doesn't drop in to a tight-fitting cavity, as the worm-gear for DEC-axis certainly does...

1784103967_greasingissue.jpg.aa49a133912632cd73ea07fc904b1a85.jpg

Indeed, the outside of that worm-gear has scratches from placing and removing it several times, most tightly fitting it is, therefore it will have to be greased.  I can see the black-plastic clamping "buttons" giving way, but I'm hoping that their brass replacements will not.  The brass rod, incidentally, is due to arrive in three days, but I won't be holding my breath.

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

Firstly, the cavity for the worm-gear was greased.  I even filled that narrow channel round...

1.jpg.bc82e08f40f5963d8c02095866b989af.jpg

The washer and the worm-gear were totally saturated with grease and set into place.  If you look sharp, you can see a bit of the washer peeking out from the grease...

2.jpg.90a5fd31ea5612112c7b4424d76c5ce8.jpg

The DEC-shaft was greased where needed, then the two sections were combined...

3.jpg.64239db703721f884e34b55f166bff50.jpg

4.jpg.e33efe0fc2267176b8a312d9bea46783.jpg

5.jpg.51a296413059d22ab799f070f0f5b064.jpg

Just as I did for the RA-axis, the lock-nut was brought to a dead-stop, then backed off a quarter of a turn.  The two set-screws were then tightened.

I do grab each axis by their ends, then pull them, and in trying to detect any slop, which I did not with either, none whatsoever...

7.jpg.411f63f809e65a1f0fc24aa84ff68862.jpg

The motions are, well, out of this world.

Now for the worm...

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

I've run into a problem when attaching the saddle atop the DEC-shaft, and just above the worm-assembly.  When the saddle is battened down, it presses on top of the worm-assembly, making it tighter than normal, normal being when I effect the best position of the worm in relation to the gear.  For this section that sticks out over the worm-assembly, I removed the paint and sanded it down...

2054808508_saddlefittingissue.jpg.342df0c4ff1510bf17127cea9acf817f.jpg

That's the section where a motor-drive is attached.  Removing the paint and sanding the section's underside helped a bit, but it still required those washers(at left) on the underside of the saddle to elevate it.  But those washers are not the proper way to elevate the saddle.  This, rather...

2025232562_saddlefittingissue2.jpg.3ec5d215f63b64e5f967b82ec48351a4.jpg

Those three unpainted areas are slightly higher than the painted surfaces surrounding them.  I will need to thicken those three areas instead of using the washers.  1.5mm to 2mm should do the trick.

Now I know why the DEC-axis was bound-up upon arrival.

Edited by Alan64
  • Like 1
Link to comment
Share on other sites

I began to make the larger, single partial-circle, and for the elevation of the mount's saddle...

762738642_saddlefittingissue3.jpg.bdaf0f82203b225e081cce1b9afb6fe4.jpg

The brass there was an attempt to keep from marring the aluminum whilst clamped for dressing.

Inadvertently however, somehow I had cut it down too short in its curved length.  What do you do when you're handed a bag of lemonades, and instead of that Aston Martin you were expecting?  You make lemonade, the two smaller pieces, from the "bag"...

1320572283_saddlefittingissue3b.jpg.b6f2fec1ac2d9092ccfceaa3ab5403a7.jpg

Those are actually much more difficult to make, as they had to be, essentially, sculpted, so it turned out well in the end.  I got those out of the way, first.

The aluminum I'm using is from a narrow strip, and a mere frog-hair thicker than 1.5mm...

680416344_saddlefittingissue3c.jpg.fb8f81f527b5283876bd3ed0e24ee51b.jpg

Yes, it's a great tragedy that I'm having to do this.  I don't think I would've had to have done this to my old Vixen.

Edited by Alan64
  • Like 2
Link to comment
Share on other sites

Incidentally, all surfaces to be joined, including on the top of the DEC-shaft, were rough-sanded, scored with a utility-blade, then cleaned with 100% acetone....

2027376818_saddlefittingissue3i.jpg.85028d9746f7771324d628c6ce72288f.jpg

Never use even 91% isopropyl-alcohol to clean and de-grease when using J-B Weld.

Link to comment
Share on other sites

Incredible; the J-B-Weld set rather hard after just five hours.  I suspect it was due to it being summer...

932451043_saddlefittingissue3ha.jpg.36d441f7fd36bb8f39b87ead5b3810cf.jpg

There's now a considerable gap between the saddle-plate and the worm-assembly...

306831923_saddleplate.jpg.b8824a6cfe61ce854fb74f67df19d518.jpg

Voilà ...

reassembled.jpg.df0a573158beab84411cb6bd1aff3c71.jpg

Just as for the RA-worm, I adjusted that of the DEC where I could detect no side to side movement, but only a slight "knock".  The worm-shaft does not rotate quite as freely as that of the RA-axis, but there's no binding.  I couldn't turn it at all upon arrival.  The DEC-axis itself does not rotate as easily, either, but smoothly nonetheless.  It simply requires a bit more force, is all.  That may be due to the worm-gear fitting ever so snugly within its cavity.  Although, that may be beneficial actually once a telescope is attached to its saddle.   But none of that matters, really, as it's only the DEC-axis.  It's the RA-axis that really counts, and...it...is...superb.  But you won't know for yourself unless you do everything I did.

I can't place the mount-head onto the tripod for a glamour shot, without clamps, as the DEC will drop upside-down.  I may receive the brass rod tomorrow, however. 

But going back when the mount-head first arrived, and without clamps then...

LX70a.jpg.6f620c03f06e45802daed42a13ad8915.jpg  

...I could pose it like that, as the axes were bound-up, stiff.

  • Like 3
Link to comment
Share on other sites

This particular, ordinary brass is type H62(softer than H59), an alpha-beta brass, being roughly 62% copper, and the rest of zinc.  

Moh's...

Copper: 2.5 - 3

Zinc: 2.5, same as gold

Brass: 3

Bronze: 3

Aluminum: 2.5 - 3

:happy72:

After all, I wouldn't want this to happen...

1196248414_sparedamage.jpg.d039f0a36a1f90458ebecca9298f3baa.jpg

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.