Orion Optics dobsonian friction brake

[NGC 1502]

Hi all, anyone have a friction brake on their O.O. dob like this :-

Dobsonian Mount

Its at the bottom of the page. I'm wondering how well the friction

brake works, I may make a DIY version. Looks like a thick teflon

pad, plus ally bar & handwheel ( all in my shed )

Any feedback appreciated, before I attack that nice aluminium

mount

Best Regards, Ed.

[johninderby]

Yes I have one, although I don't use it as it's not needed with the StellarCAT system.

It does work very well though. There are actually two arms on it, one inside the frame and one outside. On one end of each arm there is an adjustable grub screw with a pointed end that fits into a hole in the frame. On the other end of each arm there is a Teflon disk. About in the middle of the arms is a threaded bolt that fits right through the frame. Tightening this bolt clamps the Teflon disks on the rings.

Simple concept but it works. One thing to note though is that this type is used on the medium to large dobs only. On the small dobs a different type is used but you'll be able to check by looking at the pics for each size dob on the OO website.

John

[NGC 1502]

Thanks John for that detailed reply. So there's more to it than the pic shows,

with an inner arm too.

I may stay with a removable counterweight that I've made. I know you can slide

the OTA within the tube rings, but that's a hassle when swapping between

EPs that are very different in weight. And that doesn't work when viewing at a high

elevation, when with a heavy EP the tube is unbalanced radially, not along its length,

& the tube tries to drift higher. The counterweight sorts that issue.

Thanks again John, regards, Ed.

[johninderby]

If you ever do decide to make your own I can send some deatil pics and measurements.

Cheers

John

[NGC 1502]

Thanks v much John. Would be after Kelling if I do that, too much to get done !

Cheers, Ed.

[BinocularSky]

We made a simple DIY one (half a clothes peg) for this telescope; worked perfectly.

[Moonshane]

I agree this works well. I have one on my 12" dob but have also created a simple counterweight system as this is easier and prevents the slight stickiness I sometimes get with the brake - this might be solved though with some furniture polish on the teflon disks - not been bothered to do this yet