Dob mount and a milk bottle

[Craig.a.c]

I came into the same problem that others have with stiff dob mounts.
After doing some searching on this site and reading how others have
corrected the problem, I decided to have a crack at it myself.
I cut up a milk bottle and made some, very crude, washers out of it (8 in total).
Now I can rotate it sideways with some, but very little friction. There is
enough friction to keep it from moving freely but easy enough make very
slight movements without having to push to hard and overshooting what I
want to look at.
Who would have thought that a plastic milk bottle would do the trick.

[Kevnool]

If it works craigs go with it, thats called recycling at least all the bottle aint going to landfill......cheers Kev.

[erick]

Yes, don't let those milk bottle go to waste. Made great friction bearings in my binocular mount:-

http://www.iceinspace.com.au/forum/attachment.php?attachmentid=21250&d=1167558541

Well done!

[RB]

Good work Craig, yes I've heard of the milk bottle trick too and imagine it works a treat !

[Starkler]

The trick is get to spacing just right to support enough weight at the centre to reduce the friction at the outer pads. One too many washers will lift the centre too high and make the base wobble.

[Craig.a.c]

While I was doing it I thought it would just be a temporary fix to the problem, seems to be working a treat so I might leave it. I put 8 washers down first and put the OTA tube on the mount, to little friction and a slight wobble because of the spacing as Starkler (Geoff) said, took 2 out (down to 6 now) and seem to have found that sweet spot.

[Starkler]

Dont throw the spares away. They seem to compress down a little over time.

[pjphilli]

Hi Craig
In my previous DOB (now sold) I used a ball bearing of about 40mm diameter that I had in the junk box. I laid it on its side and arranged for the centre ring to be attached to the DOB base and the outer ring attached to
the rotating section. It was then a matter of spacing up the outer teflon pads to optimise friction vs wobble. The friction from the rotating ball bearing which took the bulk of the weight was near to zero.
Cheers Peter