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Add adjustable drag to TS UNC focuser / Baader Steeltrack

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#1 luxo II

luxo II

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Posted 24 May 2019 - 06:44 AM

A while back I replaced the focuser on my mak with a TS Optics UNC low-profile unit:

https://www.teleskop...0mm-height.html

 

This is essentially the Baader Steeltrack focuser, and I am guessing some readers may have added similar to their SCT or Newtonians.

 

This is beautifully smooth and free-running, however like many Crayford focusers it tends to roll out under the weight of a heavy eyepiece. While it has a locking screw, that seems to be all-or-nothing, ie achieving smooth drag is almost impossible. 

 

However there is a simple modification, as follows.

 

On the underside of the focuser are two 5mm threaded holes which originally had 5mm grub screws fitted. These are for the motor drive - but I'm not using that.

 

Remove these grub screws and insert two 5mm nylon screws long enough to press against the shaft inside. It only requires modest finger-force to apply drag to the shaft - enough to hold heavy eyepieces - without compromising the ability to focus. This works much, much better than the lock screw.

 

The two nylon screws I used are part no. SFTR-M5-20-N  from ACCU in the UK:

https://www.accu.co....ry=SFTR-M5-20-N, these are visible in the attached photo.

Attached Thumbnails

  • IMG_3895.jpg

Edited by luxo II, 24 May 2019 - 06:55 AM.



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