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ed80 slipping focus adjustment


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If I understand you correctly, the silver focusser tube is sliding out under the weight of the DSLR?

There are adjustment screws on the focusser to increase and decrease pressure of the roller that drives the tube in and out, but at the end of the day, it is a thin metal rod, pressing on a flat on the silver tube, and relying on friction to stop it moving. I stripped mine, and put some adhesive tape along the flat of the silver tube to increase friction. Sellotape, electricians tape etc. This should help as the slightly rubbery surface of the plastic tape should provide more friction than metal on metal.

Edited by ArmyAirForce
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Do you mean the tightening the draw-tube in the focuser so that it does not slip (with the weight of the DSLR)?  or as in the reply above do you mean tightening further a connection from the DSLR t-adapter to the focuser?

If it's the focuser draw-tube that is slipping with the weight if you've got it pointed near the zenith so all the weight is acting with gravity and the focuser is the weak link with the 80ED however it can be tightened to function better (not 100% - but better...).  I found with time this loosens up anyway -I noticed my 80ED needs re-tightening again - One day I'll get round to fitting a much stronger focuser!

Here's the guide for tightening / adjusting the focuser:

http://www.teleskop-austria.at/information/serv-just-hu/pdf/Adjusting_Crayford_focuser.pdf

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9 minutes ago, ArmyAirForce said:

If I understand you correctly, the silver focusser tube is sliding out under the weight of the DSLR?

There are adjustment screws on the focusser to increase and decrease pressure of the roller that drives the tube in and out, but at the end of the day, it is a thin metal rod, pressing on a flat on the silver tube, and relying on friction to stop is moving. I stripped mine, and put some adhesive tape along the flat of the silver tube to increase friction. Sellotape, electricians tape etc. This should help as the slightly rubbery surface of the plastic tape should provide more friction than metal on metal.

yes its this cheers

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I believe ArmyAirForce has struck the nail square on the head. Many slippage problems with focusers, clutches, so forth - can be solved with a low-tech application of tape that gives something to grab onto. Like masking-tape. I've used glue & sandpaper to fix a mount that was so poorly designed, the outfit selling them dropped the price by 2/3rds. just to get rid of 'em. For 5p. they worked better than originally advertised to work.

Mechanical-Engineering For Dummies 101,

Dave

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  • 3 weeks later...
On 5/5/2016 at 10:16, Davesellars said:

Do you mean the tightening the draw-tube in the focuser so that it does not slip (with the weight of the DSLR)?  or as in the reply above do you mean tightening further a connection from the DSLR t-adapter to the focuser?

If it's the focuser draw-tube that is slipping with the weight if you've got it pointed near the zenith so all the weight is acting with gravity and the focuser is the weak link with the 80ED however it can be tightened to function better (not 100% - but better...).  I found with time this loosens up anyway -I noticed my 80ED needs re-tightening again - One day I'll get round to fitting a much stronger focuser!

Here's the guide for tightening / adjusting the focuser:

http://www.teleskop-austria.at/information/serv-just-hu/pdf/Adjusting_Crayford_focuser.pdf

cant get this link to work anymore does anyone know of a similar guide cheers

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