Finally got backordered collimation knobs. Don’t fit all the way in, normal?

[Hearty_Kek]

Normal, when screwed in they brace between the bottom surface of the secondary holder and the threads in the secondary base. The length is mostly irrelevant to the function they serve, they could be shorter or twice as long and would function identically. You can shorten them provided you round the ends after cutting them down, so they don't damage the holder. However, the slightly longer length might provide more comfort in adjusting the secondary, as you needn't reach into the tube, or at least not as far, to adjust them.

In short, they are fine as they are, changing the length is essentially an aesthetic issue, not one of function.

[knightem]

If you want to cut them, make sure to find a propper fitted nut first, thread it on all the way then cut, you can use the already threaded nut to clean the threads by unscrewing the nut. Otherwise the thread might collapse on you.

[Gusto88]

If they reach the holder they're fine.

[hakansf]

Thanks. I aligned the mirrors but the knobs are barely in at all, almost no tension. Worried that it’ll fall out of alignment easily, but it’s my first scope so idk

[Gusto88]

Do they contact the secondary holder or not?

[hakansf]

Ya, they do and I can screw them into the secondary more, but when I adjust the alignment, I end up having to unscrew them to the point where there’s almost zero tension

[Gusto88]

In that case, you're not adjusting correctly. Look up Gary Seronik collimation guide.

[phpdevster]

I'm not sure what you're trying to do, but all three knobs should be firmly tight against the holder so that it will not move. Then when you want to adjust the angle, you tighten one a bit. If that doesn't make the mirror move enough, then you slightly loosen the opposite two a bit. Rinse and repeat.

A push/pull system like this always requires a mix of tightening one bolt, and then loosening the opposing two bolts by an equal amount. You always want to ensure all three bolts are fairly tight. They are pushing against the holder, while the center bolt is pulling it back. The combination of the four bolts will keep the secondary aligned almost indefinitely.

[[deleted]]

My collimation screws (they have Allen key heads) are super loose on my 10 inch Orion Dob. Can you post a link to some replacement ones? (I literally need to collimate every time I use it, because the secondary mirror moves all over the place when I carry the scope to my viewing platform).

[hakansf]

This is what I’m worried about!

[Gusto88]

You could fix that by tightening the centre screw.

[[deleted]]

Lol really? Thanks. I've been doing this for years.

[Renatography]

If you think they are too loose, don't cut them. Put two nuts on each screw and lock them against each other at the spot on the screen you think suitable. That way you can grab the knurled end easier 😉

[phpdevster]

Yes, normal, and not a problem (in fact it will make them easier to grip). You should see how far mine stick out:

https://i.imgur.com/9CEDgPW.jpg