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Improved Pentax dust caps


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Pentax make lovely eyepieces. But their dust caps suck! The ones supplied with the XLs are just plain wrong- parallel sided things that are somehow meant to stay put on a tapered rubber cup- what were they thinking 🤔 (were they thinking? 😉) The XW caps are a much better design but still not right- the bit that fits inside the rubber eye cup is just a bit too short and though it can be made to stick, it takes a conscious effort to make them- either excessive pressure to deform the rubber downwards or a twisting action to replace them. Too often they just fall off. Crazy 🤦‍♂️

So I made some improved ones :) The bit that fits inside the rubber cup is just a few mm longer- now they just push in and stay there. I made a full set and added individual identifiers recessed into the print. They’re SLS black dyed nylon- it looks a bit rough close up like this but in reality it’s quite a pleasing texture.

Ive just filled the inlay with some glow in the dark paint- it works sort of but I think it needs a few more applications as it’s quite faint and fades too quickly.

I made a set for the XLs too as I’ve started a little collection of them 🙄 (i obviously don’t have enough eyepieces yet...) They have a smaller eyecup aperture and different focal lengths.

Mark

improved Pentax eyecup caps:

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Edited by markse68
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Pentax make lovely eyepieces. But their dust caps suck! The ones supplied with the XLs are just plain wrong- parallel sided things that are somehow meant to stay put on a tapered rubber cup- what were

TeleVue is switching over to a new single-sided cap that fits very well and stays on.  It's a running change, though. The Apollo, Delites, and a few others now come with the new cap. Baader,

What time did you test the cap, John?   🙂  

Posted Images

Great idea - nicely executed :icon_biggrin:

The best names in eyepieces do seem to have difficulty with dust caps don't they ?

The Tele Vue dual-fit 2 inch ones are not the best either :dontknow:

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4 minutes ago, John said:

Great idea - nicely executed :icon_biggrin:

The best names in eyepieces do seem to have difficulty with dust caps don't they ?

The Tele Vue dual-fit 2 inch ones are not the best either :dontknow:

Thanks John- odd isn’t it!  Since I managed to chip an ep that i’d not bothered capping whilst fumbling in the dark putting another away, I think protective caps are super important and the manufacturers should take them much more seriously!

Mark

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5 minutes ago, Captain Magenta said:

... if you could knock up a Televue set I'd be your first customer. Actually second after @John. The supplied TV ones I agree are not very good.

M

Hi Magnus, I could probably do that but I don’t have any modern TV eps so I don’t know the dimensions- are they common across the ranges? If you like I could have a go if you provided some dimensions :) 

Mark

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28 minutes ago, globular said:

Mark, I'm eyeing up your case too now.... what are the EP's sitting on/in?  Another custom insert?

 

Hi Glob- it’s an insert i made using 3mm hdpe sheet laser cut and in a spaced sandwich that just sits inside the case on standoffs. I’ll try to find where I posted some images

Mark

Edit: found it :)

 

 

Edited by markse68
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Thanks Mark.  You filled your holes very nicely since then :thumbright:

I notice your design exploits the fact that all the eyepieces are roughly the same height above the shoulder and so are kept snug against the foam in the lid when it's closed up.

Can you think of a way of achieving something similar with eyepieces of varying lengths? 
I guess varying depths of foam in the lid might do it? 
I think I'd prefer an insert that had different shoulder heights so that all the eyepieces were held with their tops flush with the top of the case - but can't think how to achieve this while retaining strength and stability.

Edited by globular
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14 minutes ago, globular said:

Thanks Mark.  You filled your holes very nicely since then :thumbright:

I notice your design exploits the fact that all the eyepieces are roughly the same height above the shoulder and so are kept snug against the foam in the lid when it's closed up.

Can you think of a way of achieving something similar with eyepieces of varying lengths? 
I guess varying depths of foam in the lid might do it? 
I think I'd prefer an insert that had different shoulder heights so that all the eyepieces were held with their tops flush with the top of the case - but can't think how to achieve this while retaining strength and stability.

Hi Glob, figured i might get hit by a bus tomorrow so better hurry up! And yes exactly- they’re all the same height (and same optical design i think!) at the top end so that makes it easy! 

I sort of did that with my first ep case for smaller eps- it used 3 layers but could be extended to 4 or more but there’s almost an inch of foam so it accommodates quite a range of heights. I’ll see if i can find where I posted about it...;)

Mark

edit: found it :)

 

 

Edited by markse68
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Yeah multi layers with varying sizes holes customised to each EP would do it :thumbright:   [edit: just seen your added link... looks amazing!]

Now if only I had the materials and skills to make it I'd be laughing 🤔

I could follow the herd and go with foam in the base and the lid - but I much prefer your solid holes idea; it feels like the EPs will be more grabable in use as well as more durable.

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5 minutes ago, globular said:

I could follow the herd and go with foam in the base and the lid - but I much prefer your solid holes idea; it feels like the EPs will be more grabable in use as well as more durable.

Thanks Glob- you can certainly fit a lot into a small space this way and yes they are very convenient to swap between- that was the plan- I don’t bother with barrel caps so it’s very quick to swap eps. I did have one concern though about shocks from accidentally dropping a case- particularly the Pentax case- not sure if it’s really a concern but foam gives you that shock absorption should accidents happen. They’d probably be ok though- the plastic is soft and quite forgiving hopefully 🤞

Mark

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Maybe some foam under the bottom plastic layer; so the EPs stand on foam when the case is open and are sandwiched between foam when it's shut? But are still held by the plastic holes with all their aesthetic and practical advantages.

Anyway, thanks for your help and ideas and sorry for distracting your Pentax Caps thread. 
(Which, as you know from another thread, I love; and that I am, despite Magnus's false claim, your real 1st customer 🤣)  

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You’re more than welcome Glob- good luck with your case design! Look forward to seeing it :)

I’m not concerned  so much with up and down shocks- the eps are floating in that axis and the plastic plates can give, but side to side it’s quite rigid- maybe some rubber buffers or a peripheral foam bumper strip but i’m probably overthinking it- i’m unlikely to post them anywhere or put them in the hold on a plane, and i’ll just try my best not to chuck them at anyone 😉

Mark

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6 minutes ago, markse68 said:

i’m probably overthinking it

My doing.  I agree the design as is is more than fine.  I used to be very careful and never dropped anything. Then I turned 50 and my previously regressive clumsy gene seemed to get activated; so I now think soft and cushioned in everything I do 🤐

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I keep my eyepieces stored upright in the case with only the top above the foam.  I've never had trouble with the XL caps in this orientation over the last 22 years because gravity keeps them in place for the most part.  Sure, they don't lock on, but short of a gale wind, they don't come off of their own accord between uses.  I just toss the cap down the empty hole when I go to use the eyepiece and then grab it back out of the hole and put it back on when I'm done.

The annoying caps are those packaged with the AstroTech AF70 and similar lines.  The cap fits so snugly on the rigid eye cup that you have to work your finger around the edge of the cup to push it all up into the cap.  It's such a pain that I just unscrew the eye cup and use it sans-cup with eyeglasses.  That way, the cap stays on the cup between uses.  I just place the cup/cap combo loosely over the top of the eyepiece between uses.

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Really good solution, intrigued as to how you made them. I do like the glow in the dark number paint, really useful when swapping and trying to identify between similar focal lengths. Currently just use TeleVue eyepieces, I have had a 'rogue' slightly ill fitted (non TeleVue) cap from a used one, which has had to be rectified. I do like the quality of TeleVue caps though, particularly the newer ones on the DeLite range. 

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20 minutes ago, scarp15 said:

Really good solution, intrigued as to how you made them. I do like the glow in the dark number paint, really useful when swapping and trying to identify between similar focal lengths. Currently just use TeleVue eyepieces, I have had a 'rogue' slightly ill fitted (non TeleVue) cap from a used one, which has had to be rectified. I do like the quality of TeleVue caps though, particularly the newer ones on the DeLite range. 

Thanks Scarp :) well i say i made them but that’s not really true- i virtually made them in a cad program then emailed them to a company who loaded them into a machine that actually made them 😉

Mark

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I need to get a new larger dust cap for the ES 17mm 92 degree. The one supplied fits fine with the eye cup in the rolled down position but I use it in the rolled up position and that means a larger diameter dust cap. I'd prefer not to fiddle with rolling the eye cup up and down as I re-cap the eyepiece. I've been looking out for a suitably sized dust cap but so far not found one. The size is around 64-55mm I think.

 

 

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+1 for that John.  A cap that fits in the rolled up position as well as one that fits in the rolled down position should be standard issue. (For all EPs like this, not just ES).

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4 hours ago, John said:

I need to get a new larger dust cap for the ES 17mm 92 degree. The one supplied fits fine with the eye cup in the rolled down position but I use it in the rolled up position and that means a larger diameter dust cap. I'd prefer not to fiddle with rolling the eye cup up and down as I re-cap the eyepiece. I've been looking out for a suitably sized dust cap but so far not found one. The size is around 64-55mm I think.

 

 

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I could get one made for you John next time we do a print run- I’ve been making caps in odd sizes for my other eps that didn’t have them like my CZJ orthos . I make them slightly oversize but with 4 little dimples that grip the ep so they stay on but are easily removed (like the black polythene ones you sometimes get)- just let me know a more precise diameter and depth and I’ll see what i can do :)

Mark

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1 hour ago, markse68 said:

I could get one made for you John next time we do a print run- I’ve been making caps in odd sizes for my other eps that didn’t have them like my CZJ orthos . I make them slightly oversize but with 4 little dimples that grip the ep so they stay on but are easily removed (like the black polythene ones you sometimes get)- just let me know a more precise diameter and depth and I’ll see what i can do :)

Mark

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Thanks Mark - that's a nice offer :smiley:

I'll do a more careful measurement as soon as I get a chance.

 

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On 08/11/2020 at 17:10, markse68 said:

Thanks Scarp :) well i say i made them but that’s not really true- i virtually made them in a cad program then emailed them to a company who loaded them into a machine that actually made them 😉

Mark

How much did that cost you? Having used my XWs during the day and exposed them to the sun, there is no correlation between the size of the cap and the eye guard. 

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5 hours ago, Ricochet said:

Having used my XWs during the day and exposed them to the sun, there is no correlation between the size of the cap and the eye guard. 

Hi Ricochet, trying to parse your sentence but I can't work out what it means? Did they shrink?

Didn't cost me anything as it goes- I managed to squeeze them in with a large print order of work parts and they calculate the cost on the bounding cube volume- which is very handy ;) But if i were to order them normally i think they’d be c£2-3 each

Mark

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