Notbob's Knobs (for Skywatcher)

[eqcradle]

A thank you to member Nightstalker who posted a link to ...
http://www.smallparts.com.au/store/categories/knob/

... in this thread:
http://www.iceinspace.com.au/forum/s...t=46868&page=2

I just made up some Notbob's Knobs for my Skywatcher 8" Dob - see photos attached.

These are the part numbers from my order for the knobs for the secondary mirror:
3 (EA) SCM040x00250CP-SKT-H M4x0.70 (4mm) 0.85 2.55
3 (EA) KNOB-13.000xM4-Knu-B 13.000 0.85 2.55

As you can see, 3x cap screws plus 3x knobs = $5.10.

For the primary mirror, I only replaced the locking nuts. It isn't quite the full Bob's Knobs experience, but at least I don't need any allen keys now. The part numbers for the primary mirror knobs are:
3 (EA) KNOB-16.000xM5-Knu-R 16.000 0.94 2.82
3 (EA) SCM050x00200CP-SKT-H M5x0.80 (5mm) 0.94 2.82

Total for primary knobs = $5.64
Total for all knobs = $10.74. Postage was nearly that much again.

If any of you do this, it's quite difficult to get the knobs on the screw heads. The best way to do it appears to be by pressing them in with a vice or clamp rather than bashing them in with a hammer.

There isn't much clearance between the secondary knobs and the mirror holder. You might consider slightly longer screws. I actually ordered longer ones as well, but only one set of knobs. There is plenty of clearance on the primary knobs, you could probably use shorter screws there. The primary knobs are red because Small Parts only sold the black ones in boxes of 100 (for ~$20).

Knobs were delivered within a couple of business days after placing order through their website. I wish I'd known about this shop years ago!

I don't understand why these would not be standard features on a scope.

Cheers,
CL

[JethroB76 (Jeff)]

Good work.

Nice saving

[stephenb (Stephen)]

Nice work. I agree if you can find a cheaper solution and you have the ability to do it, it certainly works out to be a cheaper option. I am looking at this supplier also for primary mirror collimation screws and truss clamp connector knobs. I would by the Bob's knobs but they are too short for my Dob project.

[Astrobserver99 (Rob)]

I bought a few 5/32" x 1/2" socket head cap screws and caps from the local Thomas Warburton. They replace the existing philips head screws in the SCT secondary holder. The same as Bob's Knobs, all for a few dollars. At the same time, I added a few o-rings. Makes collimation adjustment even easier.

Oops, that should be allen head screws, not phillips head.

Cheers,

[mozzie (Peter)]

great stuff cl i bought bobs for the secondary didnt like the thought of dropping the allen key onto the primary. your primary locking knob is a beauty its ashame the adjusting screw is right next to the locking one
mozzie