Hideous and needless situation to find oneself in.
I hope you can get it sorted and it turns out they are not cross threaded and are the correct kind.
If they have been cross threaded IN it really does beggar belief.
Bob Knobs 101
" Also, since telescope manufacturers often re-design their hardware during production, check that the knob
threads match the factory screw threads before attempting to install the knobs.
The center tang in the housing fits into the corresponding central depression on the backing plate, forming a pivot point.
When the three collimation screws are tightened at the factory, the secondary housing flexes outward
slightly, thus maintaining tension between the housing and the backing plate and keeping the
secondary mirror assembly firmly in place.
If a factory screw is removed without releasing this tension, the backing plate can pivot away from the
housing at that screw location, preventing the knob threads from reaching it. Furthermore, the factory screw that was
just removed may no longer reach the backing plate either, and even if it does reach, the risk of cross-threading is increased from misalignment."
"If the knob threads won’t reach the secondary backing plate, first pivot the telescope on its mount so that its
secondary end is pointing downward at about a 45 degree angle with the hole at the lower (close to six o’clock)
Loosen each remaining screw a maximum of one turn. Do not remove either of the remaining screws. The
goal is to allow the secondary backing plate to pivot slightly toward the hole so you can install the knob. By placing
the hole below the other two factory screws, gravity will assist you.
Pushing on the other two factory screws will
pivot the backing plate further, if necessary.
Now thread the knob into the hole two to three full turns. Remove the
second factory screw, push on the knob and remaining factory screw if necessary, and thread a knob two to three
turns into the backing plate.
Now remove the third factory screw, push on the other two knobs if necessary, and
thread the third knob two to three turns into the backing plate.
In stubborn cases you may need to adjust the telescope on its mount for additional gravity assistance.
If you cannot get a knob to reach the backing plate after loosening each remaining factory screw one turn, do not
loosen these screws further or you risk releasing the secondary mirror assembly. Instead, obtain a screw at least one
inch (25 mm) long with the same threads as the factory screws.
You can find this at your local hardware store, or
contact us and we will send you such a screw without charge.
Insert the long screw into the hole and screw it two to three turns into the secondary backing plate.
This will hold the secondary in place while you remove a second factory screw and install a knob.
You can manipulate the long screw and remaining factory screw until the knob
threads reach the backing plate.
Install the second knob in place of the remaining factory screw, then install the third knob in place of the long screw.
Now the knobs will probably be very loose.
Tighten each knob one-half turn at a time, moving from knob to knob,
until each knob is finger tight and the entire assembly is secure. Proceed with coarse collimation, followed by star
collimation, as outlined in our instructions."
As always experience is gained the second after you needed it.
Edited by Old Speckled Hen, 08 May 2022 - 12:59 PM.