Probably not real necessary. You can get really close manually already or you wouldn't be able to see anything so just get it close manually tighten the centre bolt and gently adjust with the turnbuckle, shouldn't take more than a turn or two at the most. The knob does look good though
I think the main use would be when changing eyepeices or observing near the horizon or zenith.
ive got the problem of my BFG over balancing (quite a lot actually)
when ive got the solar filter on it plus the 2 inch barlow with the 2 inch 32mm GSO, it has a definite tendency to drop to the ground.
i managed to find some speaker magnets havent had a chance to use them yet
though.
so i reckon it seems to be an other good alternative.
might have to invest in a turn buckle and a drawer knobbie i wonder how he attached it (drilling a dirty big hole thru it ?)
Similar principal to what I fitted. Though I used a triangular shaped plate backed with rubber which sits on top of the brace I fitted to strengthen the base. The original bolt I fitted with a compression spring a washer and a 25mm circular super slider.The rubber side of the plate sits against the alt bearing. The slider sits against the plate and stops the bolt from turning as you change alt.A simple arrangement which only means fitting the tensioning bolt (if needed) during setup.
Not much tension is needed to change the feel.
I only use it when theres heavy dew or when the kids are using it. Sticking a 600ml coke in the focuser and movement is still very very acceptable.
When you unscrew the hook/s, the centre piece is just a flat/rectangular section. Simply drill 2 suitably sized holes thru the knob & chisel out the bit in between, or drill one BIG hole & silastic it. L.
i had a go at the mod
however when i turn the turnbuckle the short arm just turns on the centre altitude bearing bolt and it doesnt matter how thight you turn the bolt in
so it looks like you are gonna need that clutch knob or if anyone has an other idea ? on how to solve that little prob ?
Vin if your scope is nosediving I'd recommend using weights to balance the scope rather than using a friction clutch setup to cover up the problem. For the eps and barlows I use my scope balances perfectly. My alt motion I stiffened a slight touch with felt strips and have never found a need to use the springs. But I've fitted a Telrad and removed the finderscope which lightened the front nicely. The clutch setup I made is for extreme conditions...kids..heavy dew.
Starkler has weights fitted for using his hand grenade and has mentioned he's removed his springs so he must have worked through this and for him they aren't necessary any more. He might be able to shed more light on the balancing issues with the use of heavy gear up front.
Hey guys, the disk type clutch is a good idea, but the locker and adjuster sucks. Why not modify a pushbike type locking cam to do the same thing, i.e. the cam goes in the centre of the disk and tightens. I'm sure you could buy one for a couple of dollars. Here's a pic of one.
I don't think the original idea was to cover the effect of an unbalanced scope, the speaker magnet trick is the best here. The shackle adjuster is great to allow changes in eyepieces followed by re-balancing with the magnets, or to allow fine tracking adjustments.
As for the problem Vindictive has, the material used in the bearings on GS dobs is very smooth. When I make mine I will have a layer of wood between the bearing and the metal to increase the friction levels. Hopefully, this will make the problem go away.
The guy who made our scopes and taught us stuff in the beginning long ago uses aquarium cleaning paired magnets - so we do to - they arent exactly cheap - but more conveniently weighted/shaped and smaller for finer increments than the free old speaker magnets i reckon - i also wrap them with one layer of duct tape to stop them scratching tube.
Kearn
L.
or if anyone has an other idea ? on how to solve that little prob ? 
