View Single Post
  #9  
Old 16-08-2021, 09:12 PM
Eldest_Sibling's Avatar
Eldest_Sibling (Alan)
Registered User

Eldest_Sibling is offline
 
Join Date: May 2017
Location: Mid-South, U.S.
Posts: 136
The main plastic washers of the RA-axis had to go. I'm certain that they slide ever so smoothly over the surfaces with which they come into contact, but I want them out, no ifs, ands, or buts.

The two plastic washers are 0.020" in thickness, a fiftieth of an inch. That meant that I could not use the 0.008" bronze. So, I ordered a roll of the 0.020"...

Click image for larger version

Name:	bronze5.jpg
Views:	83
Size:	79.7 KB
ID:	279276

When I cut the band holding the roll together, the roll unfurled in a split second, and violently. I then cut out what I needed.

Glamour shot <Look this way, my darling! No! Not that way! This way!>...

Click image for larger version

Name:	bronze3b.jpg
Views:	119
Size:	25.6 KB
ID:	279277

It's all about circles, you know, like whilst collimating a Newtonian, rotating an axis, the Airy-disk of a star even, not to mention its whirling, razor-sharp diffraction-rings, but I mentioned it anyway. Hence, I needed a compass...

Click image for larger version

Name:	compasses.jpg
Views:	116
Size:	16.5 KB
ID:	279278

The one on the left won't do, and one I've had for years. So I went out to my local hardware and what-not discount-store, and got the one at the right, a 6", in length. They had a 12", too, but I passed. It's of tool-steel, utterly, and the tips of the legs are very sharp. Indeed, a point serves as a scriber in its own right...

Click image for larger version

Name:	HF compass tip.jpg
Views:	115
Size:	25.4 KB
ID:	279279

Not once did I have to fill its holder with a scriber-pen. I got one of those, too, at another hardware store, just in case. I have used it for describing marks, however.

Instead of measuring the plastic washers for their replacements, I made measurements per the axis's parts themselves, and with this...

Click image for larger version

Name:	Mitutoyo calipers.jpg
Views:	121
Size:	30.1 KB
ID:	279280

The primary-washer, at the teeth of the worm-gear...

Click image for larger version

Name:	RA primary washer.jpg
Views:	138
Size:	49.1 KB
ID:	279281

...and the other, secondary-washer, at the bottom of the worm-gear...

Click image for larger version

Name:	RA secondary washer.jpg
Views:	158
Size:	23.1 KB
ID:	279283

The odd measurements may be rounded off, but not always. There were times when I had to adjust the measurements, but always slightly, either larger or smaller. Indeed, the replacement washers are oft "scuplted" to their final diameters.

Last edited by Eldest_Sibling; 16-08-2021 at 09:28 PM.
Reply With Quote