Jump to content


Photo

Fix for 25x100 wobbly center bar

  • Please log in to reply
45 replies to this topic

#1 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 09 February 2013 - 03:01 PM

Regarding the wobbly center bar on the BA3 (and BA10?) binoculars....

I spent some time examining my Zhumell Tachyon 25x100 today and was able to find the culprit with the wobbly tripod mount. There was some "play" in the center bar that allowed the binocular to rock back and forth by a couple mm after locking the vertical tripod mount to it. This made focusing less convenient than it could have been.

It turns out that the center bar that the tripod mounting post rides on is simply held in place at the eyepiece end with a couple of set screws. These set screws are located under the threaded collar down by the eye piece end. If you unscrew this collar, you'll see something like this:

Posted Image

On the Zhumell-branded BA3s, there are three tapped holes intended for set screws, located 120* apart. But only two of them actually have a screw installed on mine, and they were not tight. I snugged them up carefully (I think this bar is aluminum - if so, it's soft so be careful!) and the wobble is gone. If I knew the size/threads of these set screws I'd find a third one and install it as well, for good measure. If the problem returns I will make the effort to do that. For now I'm happy. I thought I should share this, as I've seen others here complain about this issue on big binos.

#2 Rich V.

Rich V.

    Skylab

  • *****
  • Posts: 4015
  • Joined: 02 Jan 2005
  • Loc: Lake Tahoe area, Nevada, USA

Posted 09 February 2013 - 03:47 PM

This is a common problem with the design of these giant binoculars. Small set screws gouging into soft aluminum is not a great solution. The "premium" BA8 binos rely the set screw solution as well.

On my WO BA8s, there are three set screws on the eyepiece end pictured; the more the merrier. The objective end also has a round "nut" with one set screw under the threaded end cap. On the eyepiece end the cylindrical "pipe coupling" you have screwed back in the photo can be tightened against the hinge like a jam nut to firm things up after tightening the three set screws.

Still a poor design... :p

Rich

#3 KennyJ

KennyJ

    The British Flash

  • *****
  • Posts: 34239
  • Joined: 27 Apr 2003
  • Loc: Lancashire UK

Posted 09 February 2013 - 06:23 PM

I rarely apply my engineering background to matters discussed in this forum,but some of the problems I see reported make me wonder what kind of people are paid to design and build such third rate monstrosity apologies for what would have been very basic metalwork principles understood by 12 year olds in the UK half a century ago.

The mind boggles as to the mentality of these people!

Kenny

#4 StarStuff1

StarStuff1

    Soyuz

  • *****
  • Posts: 3847
  • Joined: 01 Apr 2007
  • Loc: South of the Mason-Dixon Line

Posted 10 February 2013 - 03:40 AM

Those set screws are almost certainly metric. Your profile doesn't list your location but if in the USA there might be an Ace Hardware store nearby that could possible stock them. One with a little longer thread length could be cut/filed down to size. Check "Nuts, Bolts and Hardware" in the phone book for possibly other sources.

Another idea is to put ThreadLocker or even nail polish on the threads and re-install them. That should keep them from working loose...at least for a pretty good while.

#5 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 12 February 2013 - 03:14 PM

Called the "Zhumell" warranty 800 number (It's actually hayneedle's customer service number) about the missing set screw. The gentleman who answered the phone was very sympathetic but told me unfortunately they don' t have replacement parts. He offered for me to return the binocular at their cost (not going to do it - this pair is collimated nearly perfectly as far as I can tell), or for me to find a set screw locally and they would reimburse me for the cost. Of course the cost is mostly going to be gas driving to/from the hardware store, but still I thought it was a nice gesture on their part.

So I'm off to find a set screw.

#6 Mxplx2

Mxplx2

    Mariner 2

  • -----
  • Posts: 236
  • Joined: 12 Sep 2012
  • Loc: PA USA

Posted 12 February 2013 - 04:04 PM

I assume the set screw in question uses an Allen wrench, but any screw of the right thread would do the job.

#7 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 12 February 2013 - 04:43 PM

I assume the set screw in question uses an Allen wrench, but any screw of the right thread would do the job.


It's not - just a slot. Whatever I use has to countersink far enough to allow the aluminum collar to screw back into place.

Home Depot had 4mm as the smallest. Lowe's only has SAE sizes. This looks like a 3mm to me. I'll have to put calipers on it later to make sure because it looks like I may have to mail order it.

#8 tag1260

tag1260

    Apollo

  • *****
  • Posts: 1028
  • Joined: 07 Oct 2012
  • Loc: Ohio, USA

Posted 12 February 2013 - 06:00 PM

Try your local model airplane shop. They'll have them. OR if you can't find them, send me your address and I'll get one out to you.
Tag

#9 hallelujah

hallelujah

    Fly Me to the Moon

  • *****
  • Posts: 5025
  • Joined: 14 Jul 2006
  • Loc: North Star over Colorado

Posted 12 February 2013 - 07:51 PM

So I'm off to find a set screw.


Make sure that you take one with you. ;)

Stan

#10 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 02 March 2013 - 10:53 AM

These set screws are size M3 (3mm x 3mm). I never located them locally, but was able to order some through ebay (amazon also has them) for a couple dollars. A simple phone call to Hayneedle and they graciously reimbursed $10 for my troubles.

#11 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 02 March 2013 - 07:51 PM

Try your local model airplane shop. They'll have them. OR if you can't find them, send me your address and I'll get one out to you.
Tag


You know, I just saw this. Thanks for the offer! I now have 5 extra screws so can make a similar offer to the next member who experiences this issue...

#12 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 12:12 AM

These set screws are size M3 (3mm x 3mm). I never located them locally, but was able to order some through ebay (amazon also has them) for a couple dollars. A simple phone call to Hayneedle and they graciously reimbursed $10 for my troubles.


My brand new Oberwerk 25x100mm I.F. Binocular have this same cheap wobbly design. Its been driving me nuts (no pun intended) for a week. Thanks for the screw size, I'll be ordering me some of these also from amazon. would 4mm long screws be too long? the slotted head set screw I see with mine now seem very short and they are difficult to tighten

I was thinking it could use a nut in the front also, instead of that cheap screw and cap design it currently has maybe with a large nylon washer.



What do you think?

..thanks.. Ralph

#13 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 12:16 AM

I considered drilling a hole straight through the bar and tapping the entire hole with a 4-40 screw and just run one longer 4-40 set screw through the entire thing.
My brand new Oberwerk 25x100mm I.F. Binocular have that same cheap design, and even with the slotted scews tightened, it still wobbles a little.

...Ralph

#14 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 03:53 AM

I think by the nature of that sliding mounting shaft and the way these binoculars get their innerpupil distance adjusted, this drsign has to rock back and fourth a little. If the two optics were so tight that it didnt do that, it would be nearly impossible to adjust the innerpupil distance because they would be too stiff to adjust. Thats definately something we just have to accept in this binocular design.

..Ralph

#15 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 15 March 2013 - 08:06 AM

Hmmm, my Zhumell tripod mount is tight and still easy to adjust IPD after this procedure. I don't have insight into how the tripod mount interacts with the IPD mechanism so am having trouble visualizing what you are saying.

There is a little clearance between the top of the set screw and the top of the hole, so 4mm long screws might fit but it would be close. If they do, you'd have a couple extra threads grabbing the hole. That would be a good thing in terms of applying more torque with less risk of stripping.

I hope you will find a way to get it adjusted it to your liking.

#16 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 10:09 AM

Hmmm, my Zhumell tripod mount is tight and still easy to adjust IPD after this procedure. I don't have insight into how the tripod mount interacts with the IPD mechanism so am having trouble visualizing what you are saying.

There is a little clearance between the top of the set screw and the top of the hole, so 4mm long screws might fit but it would be close. If they do, you'd have a couple extra threads grabbing the hole. That would be a good thing in terms of applying more torque with less risk of stripping.

I hope you will find a way to get it adjusted it to your liking.


Doing the same thing you did, I really closely looked at my binoculars last night and found the round aluminum screw "nut" on the front of the binoculars that holds the front steady has holes for 4 set screws and there are non installed.
This is the poorly machined aluminum screw that has the shinny end cap which screws over it. This is why mine is always rocking back and forth.

One of the reasons I purchased Oberwerks binocular from the Big Binoculars. com was because I thought they inspected everything before they sent out their products. Apparently like most others that get imported products, they also probably open up each package, drop in their own documentation, make sure everything is in place, and send it on its way and let the customers deal with problems.

Too bad I guess. I ordered some M3 screws from Amazon last night. This front set "nut" takes four of them.

We'll see how this works when they arrive.

...Ralph

#17 hallelujah

hallelujah

    Fly Me to the Moon

  • *****
  • Posts: 5025
  • Joined: 14 Jul 2006
  • Loc: North Star over Colorado

Posted 15 March 2013 - 10:39 AM

Ralph or Jarrod,

Would you please post a link, to eBay, for the 3mm screws.

Thanks,

Stan

#18 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 11:47 AM

Ralph or Jarrod,

Would you please post a link, to eBay, for the 3mm screws.

Thanks,

Stan


Hi Stan, went through Amazon and bought a set of 6 of them for a few dollars, this is what I ordered last night.

http://www.amazon.co...x_ya_os_product

I think for this size binoculars, 25x100mm. the mounting method is just way too light. It works, and is acceptable, and I guess to get something more substantial, it would cost more, but I don't think at the weight of these units, and larger ones, I think there should be a more robust method.

...Ralph

#19 SMark

SMark

    Apollo

  • *****
  • Posts: 1034
  • Joined: 29 Aug 2011
  • Loc: Atlanta, GA USA

Posted 15 March 2013 - 01:23 PM

Thanks to this thread, I also made this adjustment on my Zhumell Tachyon 25x100. And just as Jarrod found on his, only two of the three adjustment holes actually had set screws.

I just received a Celestron Skymaster 25x100 and there is only one adjustment hole on it, and there is a replacement screw in it that really doesn't do the job very well. It looks like the Zhumell set screws should fit the Celestron, but they don't screw in. My fear is that this replacement screw wasn't the correct size and so it stripped the original threads. Since there is only the one hole (rather than three on the Zhumell) and it seems to be stripped, how would you go about fixing this problem?

#20 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1115
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 15 March 2013 - 01:35 PM

SMark,

Glad it worked for you on the Tachyon.

The Celestron has just one ??? That is truly disappointing. How handy are you? If you are good with tools, I'd seriously consider giving this a go:

http://www.harborfre...-set-95529.html

Or something like it. M3 is the size, but if you're doing it from scratch I guess it could be whatever size you deem necessary - maybe M4 would be good since I found those setscrews to be available locally at Home Depot and Ace.

And I'd practice on some scrap aluminum before taking a drill/tap to your nice binoculars :grin:

#21 OBERWERK

OBERWERK

    Vendor

  • *****
  • Vendors
  • Posts: 191
  • Joined: 24 Jun 2003
  • Loc: OH

Posted 15 March 2013 - 03:59 PM

...Doing the same thing you did, I really closely looked at my binoculars last night and found the round aluminum screw "nut" on the front of the binoculars that holds the front steady has holes for 4 set screws and there are non installed.
This is the poorly machined aluminum screw that has the shinny end cap which screws over it. This is why mine is always rocking back and forth.
One of the reasons I purchased Oberwerks binocular from the Big Binoculars. com was because I thought they inspected everything before they sent out their products. Apparently like most others that get imported products, they also probably open up each package, drop in their own documentation, make sure everything is in place, and send it on its way and let the customers deal with problems.
...Ralph

Hold on guys. The round nut at the end of the shaft only requires one setscrew. The setscrew does not lock the shaft- it only prevents the round nut from unscrewing. There are 4 holes because you don't know where the nut will stop when it is tightened. You put the one setscrew in the hole that is most-easily accessible (it's a very tight space between the two objectives). If you put a setscrew in each of the 4 holes, at best you'd only be able to get to 2 of them. And again, one setscrew is plenty since the purpose is only to prevent the nut from turning. The setscrews in the round nut have nothing to do with the center bar being loose or rotating.
Kevin Busarow
Oberwerk Corp.

#22 hallelujah

hallelujah

    Fly Me to the Moon

  • *****
  • Posts: 5025
  • Joined: 14 Jul 2006
  • Loc: North Star over Colorado

Posted 15 March 2013 - 04:14 PM

Ralph & others,

Fortunately for me, when I unscrew the end cap off of my Burgess Series II 20x90 binoculars,
the minuscule screws (2) are intact.

The screwdriver size, for the slotted screw heads, is 1.2mm. :( (extremely tiny)

Unscrewing the end cap off of my Barska 30x80 X-Trail exposes a brass end piece/slotted brass nut?
which is also secured by a single minuscule screw, similar to the ones that came with the Burgess.

Everything on the Barska is tight as well.

The end cap on my Orion 30x80 MEGAView won't budge, and I have never experienced any looseness with the center bar,
so I see no reason to investigate further.

Thanks

Stan

#23 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 923
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 15 March 2013 - 04:40 PM

...Doing the same thing you did, I really closely looked at my binoculars last night and found the round aluminum screw "nut" on the front of the binoculars that holds the front steady has holes for 4 set screws and there are non installed.
This is the poorly machined aluminum screw that has the shinny end cap which screws over it. This is why mine is always rocking back and forth.
One of the reasons I purchased Oberwerks binocular from the Big Binoculars. com was because I thought they inspected everything before they sent out their products. Apparently like most others that get imported products, they also probably open up each package, drop in their own documentation, make sure everything is in place, and send it on its way and let the customers deal with problems.
...Ralph

Hold on guys. The round nut at the end of the shaft only requires one setscrew. The setscrew does not lock the shaft- it only prevents the round nut from unscrewing. There are 4 holes because you don't know where the nut will stop when it is tightened. You put the one setscrew in the hole that is most-easily accessible (it's a very tight space between the two objectives). If you put a setscrew in each of the 4 holes, at best you'd only be able to get to 2 of them. And again, one setscrew is plenty since the purpose is only to prevent the nut from turning. The setscrews in the round nut have nothing to do with the center bar being loose or rotating.
Kevin Busarow
Oberwerk Corp.


The round nut in the front has everything to do with whether the binoculars rock back and forth (wobble) on the center shaft. Mine came without a set screw and is just part of the problem. That round nut cant be screwed in tight enough even if it did have a set screw in place without a special tool because before the set screw can lock down the round nut has to be tighten down first, which mine wasn't. The back set screw was in place but it wasn't tightened down, also. Im looking for an M8 x 1.0 nut with a nylon insert to keep the front of the binoculars secure because I don't have a special tool to secure down that round nut.
Thats the delema I'm in right now, which is a real shame because I'm not sending these back to get repaired and miss comet PannStarr's show thats going on right now.

...Ralph

#24 OBERWERK

OBERWERK

    Vendor

  • *****
  • Vendors
  • Posts: 191
  • Joined: 24 Jun 2003
  • Loc: OH

Posted 15 March 2013 - 05:03 PM

The round nut in the front has everything to do with whether the binoculars rock back and forth (wobble) on the center shaft. Mine came without a set screw and is just part of the problem. That round nut cant be screwed in tight enough even if it did have a set screw in place without a special tool because before the set screw can lock down the round nut has to be tighten down first, which mine wasn't. The back set screw was in place but it wasn't tightened down, also. Im looking for an M8 x 1.0 nut with a nylon insert to keep the front of the binoculars secure because I don't have a special tool to secure down that round nut.
Thats the delema I'm in right now, which is a real shame because I'm not sending these back to get repaired and miss comet PannStarr's show thats going on right now.
...Ralph

Hi Ralph,
The round nut on the end is supposed to be a bit beyond finger-tight. You don't want it too tight or it will bind up the objective hinge rings and cause the objectives to toe in/out when adjusting IPD. There is supposed to be a slight amount of play at the end, as the hinge rings have slightly-elongated holes. Wobble is taken care of at the body-end of the shaft- there are 3 setscrews there, I always tighten these but sometimes they work loose.
Regards,
Kevin

#25 hallelujah

hallelujah

    Fly Me to the Moon

  • *****
  • Posts: 5025
  • Joined: 14 Jul 2006
  • Loc: North Star over Colorado

Posted 15 March 2013 - 05:20 PM

Wobble is taken care of at the body-end of the shaft- there are 3 setscrews there, I always tighten these but sometimes they work loose.

Kevin


So, perhaps a little bit of Loctite would solve the problem?

http://www.loctitepr...e-Threadlock...

Stan






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics