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DaveL59

Swift Audubon HR/5 - repairing the eyepiece arm

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Not sure if this should be in DIY or here under binos, mods feel free to move if you feel the need :) 

So I recently bought a pair of Swift Audubon HR/5 which from the description had the dioptre eyepiece cup detached. Figuring it may just be loose grub screws I figure take a punt. They arrived yesterday and initial look were a bit grubby but intact.

917307678_AudubonHR5.JPG.1da044f91502bf0b4ab08791a10be56e.JPG

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Eyecup was definately off and sorting the grub screws it refitted ok, tho I note the plastic body has a split so this will need attention. Dioptre was smooth and sticking, closer inspection shows why that was

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The carrier arm has broken at the hinge loop. Oh dear.

Further inspection then revealed:

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oh no! A lemon then 😢

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Cleaned the lenses in and out then put it back together while I decide what to do and gave them a test. Out of alignment before I opened them up, but having teased the chipped prism up a touch that seems to have sorted the alignment - well when you get the eyepiece in the correct plane. Image is nice and sharp but of course awkward to get the RH eyepiece to sit right as you focus. Luckily the chip doesn't seem to interfere with the view, possibly just outside the FoV but I'll try masking that with some matt black later on just in case it affects the contrast. Almost tempted to try windscreen chip-repair to flatten it out but it'll be the wrong optical index so maybe a bad idea, other that it might stop the chip worsening.

Having had a look around for ideas on the arm, came across this thread and in particular this post
https://www.cloudynights.com/topic/700039-celestron-30x80-giant-brokenrepair/?p=10066320

Interesting, a bit of metal plate shaped to suit and spliced in, sounds like something I could do, tho no milling machine so it'll be files and drills to achieve it. Definitely worth a go, since none of the junk spare pairs I have suit then as a cut-n-n-shut donor to splice in for that part of the arm. I'd seem a previous effort using fibreglass board but I think metal will be easier to work.

 

 

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so thinking a bit on the arm repair, and not having aluminium plate laying around at the moment (might find a bit at my dads tho), what other options...

Well I've some thick penny washers, looks to be M11 hole needed. Found a couple but they're 12.6mm, too loose on the shaft, but might it work I wonder?

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hmmm it might actually be an option. Just needs to be re-worked to the right shape

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In fact like this it'd reinforce the broken part and could be fixed above the arm with epoxy, perhaps. Downside is that'd reduce the amount of thread holding the centre screw in place so perhaps not.

So cut it into the arm sounds like maybe a better plan, so I'll need a thicker washer (2.7-3.0mm ish)

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Just ordered M10 2.5mm thick penny washers in stainless, when they arrive I'll see if this is viable. Plan will be to grind back the broken hinge overlap down to half the arm thickness or just under. Then once a washer has been shaped to suit the job, secure together with epoxy and once set, drill and tap and use a couple 2.5-3mm grub screws to give some torsional relief to the joint.

Will update as I go...

 

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thought I'd test the idea a little by placing a penny washer I do have and see:

test1.JPG.1f19144a593a46eabbdc49e2051e3704.JPGtest1a.JPG.0278387d1c6c1f39f3a42fc667796b7e.JPG

yep it's under the bottom arm and the break is in the top one, the hole in this washer is large enough to allow the hinge locator pin to pass through and engage too with the washer offset for this. Tightened down the centre screw and now the focus action is smooth and the arms both stay aligned level with each other, allowing the occulars to move easily in their tubes. Of course this does limit the focal range toward infinity since the occulars can now not travel in by 1.5mm ish. But it does support the idea that a solution with a thick washer is possible.

Now I'd guess that working a metal plate isn't going to be that much less work if I actually had one laying around that is. But I'm thinking stainless steel at 2.5mm would have more durability than aluminium in this use case.

Am now so tempted to glue a washer to the top of that arm and fit it as a temp fix just to see how it does. Will do my best to resist, since the new washers should be here in a week-ish. Meantime it can live as it is with the washer under the arms and at least be usable for quick looks around the garden :) Collimation is a tiny bit I think off but not so much as it feels like eyes being ripped out, not really going to get much real use till I've done a "proper" bodge repair on them tho ;) 

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Interesting thread.  I also read the CN topic facing the same issue, I'm pretty sure the washer reinforcement option is the best way forward.  I would certainly use steel rather than aluminium as I don't think the latter would offer enough stiffness.  The Swift "Audubon" 8.5x44 is a well regarded binocular and well worth repairing.  I look forward to hearing how it all works out as I have a binocular with the same problem that I have been meaning to repair for years.  It is a 60 year old Kershaw "Monarch" 12x40 which not only belonged, from new, to my late father but was the very instrument that started me on my astronomical career, so of immense sentimental value.    🙂

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thanks Peter, that bodge with the washer under, I added some double-sided tape now too to hold the broken arm steady and was just out testing, working quite well just like this and can focus on distant clouds. Was hoping to get a peek of Venus but lots of cloud that way so no luck there.

Am hoping that a reshaped washer will do it, similar to what the CN thread did with a plate he made. Am now also thinking some M3 or M4 countersunk screws as I could chamfer the steel and thread the ally under so there's no sideways motion. Not sure brass grubscrews would have the strength in use, tho if I epoxy the 2 parts together then they'd just be a bit of reinforcing rather than taking the full load.

Nice that you still have the monarch's esp since they are sentimental to you. Hopefully you'll also be able to fix them up and get them back to fully functional :) 

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Well Venus is now peeking out of the blue sky between clouds and guess what?

The HR/5 with that 1.5mm washer under the arms actually hits focus on her right at the stop! Lovely sharp image to boot so I think these HR/5's are definitely worth trying to get repaired. In fact they're a better fit to my hand that the older MK2's which are the bulkier body format. Both give really nice views though so likely will stay in the collection.

Will need to sort a case for these once I get done but if I needed inspiring to get it done that view of venus sure did it for me. Earlier I was seeking the birdies in the oak tree out back and I could make out small insects and spiderwebs at the very top of the tree so resolution on these is excellent.

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Thanks for that, interesting read because over many years I’ve fixed things up with all sorts of DIY solutions.  Some of these worked well and others needed a second or third attempt.  A few turned into a disaster however. My shed is full of bits and bobs that may come in handy.  Problem with that is sometimes I know I have something but cannot locate it.....it’s in here somewhere 😀

Ed.

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Posted (edited)

I so know what you mean Ed, took me ages to locate those washers and I'm sure I've a thicker one somewhere but didn't find it. Was hoping one of the junk bino's would have an arm that fitted over the centre pin as I could've sacrificed the part to do a splice onto this, but Swift seem to use a larger pin and wider arms, hence deciding another route would be best.

Definitely worth saving these if I can, they're pin sharp and bright, lightweight and for my hands much easier to use than the older wide bodied 804's. Handy to have another project to work on too while I wait for the paint to cure and some flocking to arrive before I pick up the TAL-M refurb again ;) 

Edited by DaveL59
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Good luck, sounds like for the JB Weld, rough up all the surfaces to get a good bond. I’d leave the chip, unless you’re playing tennis with them it shouldn’t get any worse... shouldn’t be and internal strain to change it... or the glass would be all birefringence.

good luck 

peter

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