74 replies to this topic

[Michael Covington]

Right.  I don't normally remove my counterweight bar.  And even if I did, that would be only a few rotations against the washer every month. 

Is the same part available from Pep Boys or other auto parts chains?

[fgraus]

Did you use any adhesive to hold the washer in place so it isn't lost if you remove the counterweight bar?

[AstroNikko]

Right.  I don't normally remove my counterweight bar.  And even if I did, that would be only a few rotations against the washer every month. 

Is the same part available from Pep Boys or other auto parts chains?

Possibly. It is a fairly common part, but I think the size may be somewhat uncommon. There was an abundance of M12 and M14 drain plug gaskets at O'Reilly Auto Parts, but no M16 gaskets. At least not exactly M16, or the aluminum variety. The one that I purchased from NAPA was the last one in stock in my area.

 

I think the more common term for this part is a sealing washer. They tend to have a narrower flange, and therefore smaller outer diameter, than a standard fastener washer. Thus allowing it to fit into the recess of the lock nut.

 

My goal here was to find a source that was easy to purchase from, so that others following along with this thread could easily pick one up. Unfortunately, I haven't found anything definitive, yet. A quick Google search turns up a bunch of options, though.

 

If you find a reliable online outlet, please do share the link here.

 

Did you use any adhesive to hold the washer in place so it isn't lost if you remove the counterweight bar?

I didn't, but I didn't really see the need to use an adhesive in this case. At least not at the time. When you loosen the lock nut and remove the counterweight bar from the mount head, the washer doesn't easily fall out since the lock nut serves as a fairly deep cup with the threaded counterweight rod protruding from the center. You have to turn the bar completely on end for the washer to fall out.

 

I guess an adhesive could be helpful in case you forget that it's in there. Although if you don't want to apply an adhesive, some of these drain plug gaskets do come with a rubber inner lip that would prevent it from sliding off the threads of the counterweight bar if it were inverted.

 

Good point. Thanks!

[WadeH237]

If you find a reliable online outlet, please do share the link here.

I found a package of drain plug washers for Honda/Acura on Amazon that appears to be very close to your measurements.  I ordered it and it should be here today or tomorrow.

 

If they are a good fit, I will post a link to the specific parts.

[AstroNikko]

Thanks, Wade! Much appreciated.

[17.5Dob]

Isn't it a bit ludicrous that so many people have experienced this problem and responded here ?

If only it were that easy to install an actual roller bearing on the Dec axle while you were at it, so that you could actually get a reasonably performing mount for all of that effort and additional costs....

[Michael Covington]

Installing this washer doesn't involve taking the axis out.  But if there are published instructions on how to install roller bearings on both axes, I'd like to see them.

[WadeH237]

Isn't it a bit ludicrous that so many people have experienced this problem and responded here ?

If only it were that easy to install an actual roller bearing on the Dec axle while you were at it, so that you could actually get a reasonably performing mount for all of that effort and additional costs....

I'm not sure what you mean by "all of that effort and additional costs".

 

I fixed the problem by installing a hose gasket in the lock nut.  It took literally two minutes, and most of that time was grabbing a hose gasket out of my garage.  If I had to buy a hose gasket, it would have probably cost less than a dollar at the local hardware store.

 

And as for decently performing mount, I am completely satisfied with how both of my AVX mounts perform.

[WadeH237]

Following up:

 

The drain plug washers did not work out.  They were oh, so close, but the inner diameter would need to be about half a mm larger in order to fit on the counterweight shaft.

 

For now, I'm happy with the hose gasket.  I don't need to get the lock nut gorilla tight.  And if I need to replace it every now and then, they are dirt cheap and readily available.

 

-Wade

[AstroNikko]

The drain plug washers did not work out.  They were oh, so close, but the inner diameter would need to be about half a mm larger in order to fit on the counterweight shaft.

I'll keep looking to see if I can find some on Amazon with the right dimensions. Thanks for trying! I appreciate it.

 

I've got a drawer full of washers now that didn't make the cut. Keeping them since they may come in handy for something else later on.

 

Thanks again!

[Michael Covington]

Your solution is better than mine, so I did it to my mount and photographed it (below).  I found washers at Pep Boys (in an assortment) but this seems to be the right Amazon product: https://www.amazon.com/dp/B078RFCHVH/ 

They need to total 3 mm in thickness (on my mount), which would be 2 or 3 washers stacked.  That may depend on the particular mount.  They are in a fixed position (with nothing rotating against them) in use and suffer no wear.   A 5/8-inch lockwasher might even do the job.

So here's a summary:

PROBLEM: Tightening the counterweight bar lock (the big round black nut) applies torque to the dec axis retaining ring and can tighten it.  Over time, the dec axis becomes stiffer and stiffer.   OR the counterweight bar lock makes contact with the outer housing itself and binds when the telescope moves in declination.

SOLUTION: Washers on the counterweight bar, inside the big black nut.

 

 

Edited by Michael Covington, 12 February 2019 - 06:03 PM.

[AstroNikko]

Excellent! Thank you posting this followup, and including the Amazon link for these M16 washers!

 

Glad this worked for you  Thanks again!

[Michael Covington]

Even better, there is a 5/8"x1" spacer bushing available at Home Depot that is the perfect size.  Here it is, and also a picture that more accurately explains the problems we're solving.

 

Edited by Michael Covington, 13 February 2019 - 03:12 PM.

[AstroNikko]

Thanks! Here's the link to the spacer bushing on the Home Depot website. The link can be used to check availability, and request to ship to a local store for pick up if need be. Unfortunately, none of the stores in my area have this one in stock.

[chakel]

+1 for an ordinary garden water hose washer.

 

Once fully seated in the well formed with the threads of the counterweight bar/black plastic cover assembly, it simply needs to be hand tightened and you're good to go. It will remain in place even when removed.

[makeitso]

I’m not sure if I need to do this or not, how can I tell? I’m not having any issues but I have noticed a few times that counter weight bar has been loose when I disassembled the mount after use.

 

 

Thanks, Jack

[AstroNikko]

Hi Jack,

If you take a look at the counter weight bar locking nut, inspect the flat surfaces for signs of abrasion which could indicate that it has come in contact with, and may be binding with, another surface. See the photos in this thread for examples.

If you see similar abrasion marks, adding this washer or spacer bushing should offset it enough to prevent any further rubbing, which can cause the lock nut to tighten or loosen depending on the direction the dec axis is rotated.

Hope this helps,

Nikko

[Michael Covington]

Yes.  Another way to check for contact is to put a tiny dab of grease on one surface, put the lock nut on, and see if the grease transfers.

Edited by Michael Covington, 14 February 2019 - 08:16 PM.

[makeitso]

Thanks Nikko, I do see where some of the black is worn in a similar manner to the photos in this thread. Maybe I’ve been lucky so far. I’m going to order a washer now.

 

Thanks, Jack

[kel123]

What is the implication of not using the nut at all? That is removing the nut and threading the CW bar directly?

[AstroNikko]

The nut is what keeps the counterweight bar securely in place. It's liable to come loose otherwise.

[kel123]

When I encountered this problem I removed the nut and it has not come loose, so I was wondering what the trade-off is.

I have not imaged or polar aligned with it that way, hence I don't know if it will affect alignment or goto if the CW shaft itself does not loosen.

I noticed in this case at least that when I rotate the declination axis the CW shaft does not rotate in a perfect circle. This is what lets the nut make contact with the body and tighten or loosen.

Part of the problem could probably be threading issues that make the shaft inclined at a little angle.

Edited by kel123, 25 June 2019 - 10:03 PM.

[Dynan]

Not having an AVX, I'm just following the thread and experiential testimony. From what my small mind gathers is that the 'large nut' needs to provide compression and still rotate. Is this the case? If so, would a properly sized thrust bearing do the job?

 

[Michael Covington]

If you mean the big nut that holds the counterweight bar on (black and conical), it's not really a bearing -- when installed correctly, rotating surfaces do not contact each other.  Sometimes a washer has to be added to make it sit at the right height so this is so.

[mrkhagol]

Based on the solution mentioned here...what is supposed to happen exactly?

Meaning...after washer is put in place and the dec axes would start moving again?

I am having the problem of dec axis is not moving at all with the direction buttons on the hand controller but does turn manually fine.

So how would you have the dec axis turn again with hand controller (or computer whichever) if the motor doesn't turn it. 

Wondering if my problem has something to do with dec motor itself than not having the washer. My AVX mount is brand new and can't tell if it got damaged somehow in shipping or what? I couldn't even test the hand controller before because didn't have power plug but now I got one. And after turning on, only the RA motor moved and not the dec motor...

 

So please (anyone) give me your suggestion as to if this is strictly motor problem or something else..this thing is hard to figure out.