ATM balance point in a dob

[CharlesMitchard@aol.com]

Greetings all,
I've just completed renovating a 6" f8 dob.
I built a bearing box to clamp to the ota with what I thought was the bearing 
axis aligned with the ota centre axis.
It balances with the heaviest eyepiece in but only between 20' from 
horizontal to within 15' of vertical, ie outside of these elavations it 
either continues to vertical or drops to horizontal.
I've overcome this with an adjustable  friction type of device that does not 
impede the smooth movement so there is not a problem but as this is the first 
telescope I've built I wondered what I've done wrong.
The bearings are teflon and ebony star.
tia
Charles