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Focus knob grip material

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16 replies to this topic

#1 SoCalPaul

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Posted 28 June 2022 - 10:24 AM

Please share your recommendations for a replacement item or material for the rubber cover on a metal focus knob.

 

This is for a Tak CN212, which has a moving-mirror focus mechanism. The knob is similar to a Celestron SCT, only a bit larger in diameter.

 

Clear skies,

Paul



#2 Jon Isaacs

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Posted 28 June 2022 - 10:58 AM

Paul:

 

What I've used is the prickly side of black Velcro. 

 

Jon


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#3 havasman

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Posted 28 June 2022 - 11:41 AM

Those small but wide blue rubber bands that sometimes wrap produce stalks at the grocery store work great. But I'm a committed utilitarian.


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#4 Felix OJ

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Posted 28 June 2022 - 02:11 PM

Paul,

 

I noticed your roadie cycling kit your photo. I keep old road and mtn bike tubes of various thickness for just this type of situation. A small road tube should be just right. Snip the width to fit the knob and slip it on. Using car or bike tubes like this is called Ranger bands, I believe after the Army Rangers.  They can even be chained together if the inside diameter is not large enough for your purpose.  On another thread on CN, a member described how Don Pensack told him how to use the band to put on the eye piece instead of a tall eye cup - pretty ingenious.  

 

Good luck,

 

Felix

 

P.S.  I am registered to do the Ventura Cool Breeze in August, do you do any of these types of rides?


Edited by Felix OJ, 28 June 2022 - 02:41 PM.

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#5 SoCalPaul

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Posted 28 June 2022 - 03:33 PM

Paul,

 

I noticed your roadie cycling kit your photo. I keep old road and mtn bike tubes of various thickness for just this type of situation. A small road tube should be just right. Snip the width to fit the knob and slip it on. Using car or bike tubes like this is called Ranger bands, I believe after the Army Rangers.  They can even be chained together if the inside diameter is not large enough for your purpose.  On another thread on CN, a member described how Don Pensack told him how to use the band to put on the eye piece instead of a tall eye cup - pretty ingenious.  

 

Good luck,

 

Felix

 

P.S.  I am registered to do the Ventura Cool Breeze in August, do you do any of these types of rides?

Hey Felix,

 

This is a great suggestion! Unfortunately, I recently threw out a bunch of my holey tubes and will now have to wait for a new flat, LOL. Or maybe check with some of my roadie friends.

 

I ride with the Conejo Valley Cyclists out of Westlake Village but have stopped doing Gran Fondos and other organized events, other than club rides.

 

I rode the Cool Breeze back on 2018 but no plans to ride it this year.

 

Enjoy, have fun, hydrate and stay safe! Rubber side down!

 

Clear skies,

Paul


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#6 tag1260

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Posted 18 July 2022 - 12:38 AM

Three or four rubber o-rings work very well to fill in the space between the risers on the knob.


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#7 lphilpot

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Posted 18 July 2022 - 09:42 AM

Dunk it in Dip-n-Grip repeatedly until the coating it thick enough?



#8 kfiscus

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Posted 18 July 2022 - 02:23 PM

Short sections of large shrink tubing.

Rubber tires from small R/C cars.


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#9 Felix OJ

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Posted 18 July 2022 - 02:45 PM

Wow, so many great ideas and different ways to solve a problem.

Felix



#10 Pauls72

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Posted 18 July 2022 - 02:51 PM

Plastic dip used on tool handles.

https://plastidip.com/



#11 Xeroid

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Posted 18 July 2022 - 02:59 PM

From El Cheapo:

 

Reduces focus wiggle by 97%

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  • IMG_20211107_132104768_HDR.jpg

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#12 SteveG

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Posted 19 July 2022 - 04:59 PM

As mentioned, fat o-rings of the appropriate diameter.


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#13 izar187

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Posted 20 July 2022 - 02:16 AM

Paul:

 

What I've used is the prickly side of black Velcro. 

 

Jon

But perhaps skip the fuzzy gloves in the cold weather. : )



#14 SoCalPaul

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Posted 02 August 2022 - 01:26 PM

From El Cheapo:

 

Reduces focus wiggle by 97%

Wow, this looks crazy simple but effective! Can't wait to give it a try!

 

Thanks for posting it.

 

Paul



#15 SoCalPaul

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Posted 02 August 2022 - 01:28 PM

Three or four rubber o-rings work very well to fill in the space between the risers on the knob.

This also sounds like a good solution, as the uneven surface might improve grip. Will also give this a try.

 

Thanks all for the great ideas!

 

Paul



#16 lphilpot

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Posted 02 August 2022 - 04:06 PM

Also Olefin heat-shrink tubing might be a decent grip



#17 clearwaterdave

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Posted 02 August 2022 - 05:03 PM

I put a thin strip of rubber shelf liner around it with just a tiny bit of super glue to hold it on.I glued the rubber to itself and not the knob.,works all good.,Good luck.,




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