CNC Precision Manufactured

Clearance Specials
Two solid Dobsonian mounts.
Azimuth bearing laminate rings
Dobsonian Mounts
Current lead time: 6 weeks.
Overview Of Mount Choices

Standard Solid Mounts.
Custom Solid Mounts
Custom Collapsible Mounts
All offer setting circle board.
Dobsonian Mount Accessories
Height Adjustment Stands.
Digital Setting Circles
Nexus II
Sky Commander
Amateur Telescope Making
Cells & Image Sharpening
Current lead time: 1 week.
Mirror Cells.
Mirror Masks.
Aperture Masks
Sharpening Double Stars!
Altitude Bearings
Current lead time: 1 week.
Standard 12" And 18" Bearings
Fix For 5" Small Bearings.
Altitude Bearing Guides.
Altitude Bearing Supports.
Clamshell Rings For Tubes
Upcoming Items
Contact us to inquire.
Mirror Box Integrated Cells.
Rotating Tube Rings.

Upper Tube Assembly Rings.
Anonymous Survey
How did you find us?
Zip / Postal Code
Altitude Bearings 

12" Big Bearings.

5" factory bearings.

Substitute small factory bearings with
12" Big Bearings drop in replacements.

Small factory bearings standard on many mass produced Dobsonian telescopes use clamps and springs to fix an inherent design flaw causing balance problems. 12" Big Bearings solve this issue, while improving balance, motion and adding finer control.

We customize every order individually designing hub hole size and spacing that fit onto your existing bearings. Attach the Big Bearings to the existing small ones, install the side board supports under them, and remove the factory"Teflon" pads to complete the upgrade; a five minute job. Bearing Fine Tuning Guides are now included with Big Bearings to allow friction adjustment and keep bearings centered on the mount.

All parts included: bearings, supports, support screws, teflon, bearings laminate, fine tuning assembly. Requires glue for laminate (contact cement), Philips screwdriver and 3/4" longer bearings bolts.


Standard 12" bearings with carrying handle cutouts, supports and guides.

Standard 12" and 18" Bearings.

Standard 12" and standard 18" altitude bearings with incised channels for fine tuning guides and sideboard supports. Both 12" and 18" designs incorporate cutouts to allow easy lifting and carrying of your telescope. Inside braces (shown on left bearing) are individually cut to precisely match your telescope tube outside diameter. Choose among these options:

  • With 3/8" center hole for bolting to you tube.
  • Holes to mount to your existing tube ring set.
  • No mounting holes (drill your own).
  • Curved bearing braces with matching bearing holes.
  • Fine tuning guides, channels and sideboard supports.
  • Other custom sizes upon request.

Carry handles are built in.

Standard 18" bearings

Bearing Guides (fine tuning)

Bearing Braces

Bearing Supports

Assorted Bearing Parts

Bearing Braces

Bearing braces attach to inside facing surface of your altitude bearings. Custom cut to your tube diameter. Kits only.

Bearing Supports

Bearing Supports are for 8" to over 23" diameter bearings, includes Teflon pads and screws. Specify diameter. Kits only.

Bearing Guides

Inside bearing facing side recessed 1/8" to not rub, and curved to match your sideboard cutout. 1/4-20 nylon screw tightens within inset threaded insert to desired friction in corresponding bearing channel. Kits only.

Assorted bearing parts come as unfinished kits. You fine sand and paint/finish. All holes in wooden parts and Teflon are predrilled and countersunk. #12 wood screws, #4 screws for Teflon, bearing laminate, nylon 1/4-20 screw and threaded wood inserts included. Wooden parts arrive rough sanded with 80 grit sandpaper.