Help! Broken SXD Latitude adjustment knob

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cloud_cover
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Help! Broken SXD Latitude adjustment knob

Post by cloud_cover »

I was trying to adjust the latitude knob SXD for proper lignment when it broke off!
Its already adjusted for Singapore latitude and uses a brass worm screw to adjust the latitude.
The screw itself is attached to the handle that allows the user to turn the knob and is secured down via a set screw.
Apparently the set screw has been coring into the softer brass latutide worm screw with the result that its eaten enough into the screw that the whole thing has now failed and the knob broke off!
What do I do now? Local dealer generally will not support resale products so other only option is to ship back to Vixen in USA (not under warranty), pay big bucks for repair and ship it back again ($300USD shipping cost each way). Ouch.
Unless someone knows how to replace the latitude adjustment bolt? All I really need is tools and the worm screw.
Hopefully the local reseller will be willing to help me fix (at my cost, of course)

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orly_andico
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Post by orly_andico »

this is Vixen's fault. Why did they have to deviate from the tried-and-true "two opposing bolts" design, I can't see. PMed you on possible work-around.
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timatworksg
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Post by timatworksg »

WOW! Is that the Azimuth Adjustment bolt?

Brass is soft! And it seems, looking at the break, that knob has been overtightened with no more travel along the lattitude. Forcing the knob further would think that there are more threads for travel to adjust, but in fact it just made the set screw eat into the brass bolt. Looking at the spindle shaft bit that travels on the bolt, it is at it's end which stops when it hits the mounts side. Hence no more travel. And being brass...it just grinds away far easier then any other metal.

If it was me here's what I'd do.

- Remove that brass bolt and use it as a sample to machine a new Brass bolt with similar threads. Brass isn't cheap, but something small like this shouldn't cost much.

- If it's the Azimuth, I would remove the bolt, tap the holes both sides and replace with 2 short bolts and use a DIY or another mounts Puck which has the Azimuth peg for resistance. This puck can be DIY'd.

- Remove and replace with similar diameter bolt. But may be hard to find similar thread pitch. Alternatives are possible though.

Sorry to see and hear of this. You got this mount 2nd hand did you? Somehow that bolt looks badly taken care of and seems overtightened to the point of no travel causing the grinding and wear which broke off the soft brass. Not blaming anyone or anything but such a waste.

If you need help, PM me and perhaps we can meet up to see what we can do. I can't promise you anything, but there are possibilities available. I know a few machinist so if we can get that bolt out, I could use it as a sample for quotes. Maybe even machine one out of Stainless Steel instead!

In the end, it will be a modded SXD but it works the same. Lemme know!
My wife never complained about how much time, effort & money I spent on my Astronomy hobby!................suddenly I met her!!!
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orly_andico
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Post by orly_andico »

Tim, I'm also in need of a machinist. :-P

I need to fabricate a low-latitude wedge for my CGEM, something like this one on an Astro-Physics AP900

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(the AP900 can't go down to low latitudes either)
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timatworksg
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Post by timatworksg »

Ah...hmmm. Interesting project Orly. One of the biggest probs here in SG when it comes to machining is the cost to fabricate and the metal used.
It can be done...as it's a case of IF the machinist wishes to do so.
Lemme go talk to my suppliers and get their feel on the various machinist that can do such projects. As it boils down to cost...I can also check on various metals. Cheapest is Mild Steel. Stainless costs!! Aluminum is expensive and mostly sold in large pieces...unless scraps are around with a usable size. Lemme snoop. Perhaps we can meet up and discuss the wedge idea! Cloud Cover...you could also meet up and we can discuss more on the bolt. As I often get High Pressure manifolds custom made for our Breathing Air Equipment, I don't see why they can't fabricate something outta a chunk of metal...it's the same process really.
I can't promise anything...but no harm trying. Won't know till you know!

Anyway, found a Lead Metal supplier recently and need to pay him a visit! He has Lead in various shapes, flat thin pieces and rods! I'm interested in the rods as they can make nice small counterweights! Hope for the best!
My wife never complained about how much time, effort & money I spent on my Astronomy hobby!................suddenly I met her!!!
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rlow
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Post by rlow »

Kelvin, as discussed earlier, let me know if you would like my help with the suggested repair. I hope you resolve this issue soon (:
rlow
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wucheeyiun
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Post by wucheeyiun »

Hi bro, it is a very good mount, and the problem is quite solveble , don't worry over it :)
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cloud_cover
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Post by cloud_cover »

Thanks guys for the support! :)
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