Celestron CG-5⁴, CGEM², C6-N, C6, C8, Nexstar 8SE, 6SE, ONYX 80 EDF, Orion ST 80 A Vixen R130SF w/Porta II mount William Optics ZS110 ED APO, FLT 132 Triplet APO, SV70 ED SV115T20 Wicháhpih'a
Quote:Last night I noticed a slight shift or rocking in my dec axis. It is locked down tight but I am able to rock the axis back and forth a slight, very slight, amount. I noticed this when looking at the moon last night. As I was focusing, the scope would the slight distance with the pressure from my fingers. The moon moved 1/2-way across the eyepiece before the slop was gone.Any idea on how to fix this. I check all the allen heads and they were tight.
Uncle Rod Uncle Rod's Astroblog: http://uncle-rods.blogspot.com/
CGEM, C8, C11, AT72ED, NexStar 5SE
Orion Starshoot Pro V2 Color NexImage 5 / ASI120MC Planetary imagers
My photos: http://astrobin.com/users/Steve/
Quote:I installed Heli-Coil inserts in all of the worm gear housing bolts on both axis, for both the motor mounting bolts, and Keensert repair sleeves in the ALT adjusting screw threads. This was a much more proper fix to the problem than the use of longer bolts that would only strip out the already damaged and weakened threads at a later time. I found the casting of the CGEM main body to be very brittle. I found the use of a specifically for aluminium cutting fluid was required to do the job properly. I no longer have to handle the threads with kid gloves or worry about further thread damage.Stan
Quote:So for a 5mm existing hole that is damaged, if you wanted the new hole to also be 5mm, then you have drill out to 5.5mm? 6mm? 6.5mm? 7mm? Just trying to figure out if there is enough room to do this. I guess I could go to a smaller bolt.What I need to fix is a part on my lawnmower's aluminum deck.
Ed Thomas Deep Space Products www.deepspaceproducts.com
Quote:I have installed a lot of thread repair inserts. They all require drilling out the original threaded hole oversize. Some applications do not have enough material to permit this. I do not know if this is a problem in this specific instance. It sounds like it is variable among samples.
Quote:I've have installed the inserts on the worm gear housing mounting threads for 8 mounts so far. All have turn out perfectly well. The use of SS thread inserts in aluminum castings is a very common practice. From an engineering standpoint it makes much more sense than just drilling and tapping the aluminum to a larger size. Although drilling and tapping to a larger size is a much more simple procedure, in my opinion it just isn't the right way to solve the problem of weak aluminum threads.Stan
Quote:orlyandico,I suppose you are right about that. I only charged $15 ea to install Heli-coil inserts in my shop. Not a prohibitive amount. I see some shops that charge as much as $25 per insert. That would be $200 to do all the inserts for the worm gear housings for both axis. I'm sure Ed could come in somewhere in that price range. The problem with using a larger bolt is that it requires a larger bolt head. In the case of the worm gear housings you now have created more labor time to accommodate for the larger bolt head. This weakens the casting of the worm gear housing. Maybe that's a trade off, but I would prefer to go with the original factory engineered fixture size. I don't like having to alter the design of the housing and I was never a guy that was comfortable with a mechanical 'good enough'. I have found that when you alter something in such a way, it leaves you open to more customer dis-satisfaction that satisfaction. In my opinion it's just not being professional, but that's how I ran my business.Stan
Quote:Hmmm, I think one alen bolt for the dec head (just below where the dovetail is) is already stuck, A mayhave over tightened it, as you Gus said might happen. Anyway, though that was lose before i don't think that's where the current wobble is coming from. I do think that using the mothers to rotate thendec , then releasing the clutch and rotating the opposite way might get me back onto a tighter part of the gear, so ill try that next.I'm planning on going to NEAF, I wonder if there's a celestron rep there that can tune up the mount and save me the cost of shipping?
Docent at the Rose Center for Earth and Space at the American Museum of Natural History