Gear dimensions and meade eq2 mount

齒輪模數 gear modules

estimation of 144 tooth gear in eq1/2 series mount: using evolvent spur generator

 

generated image:

 

actual photo of the RA gear:

Always check the worm gear is meshing properly, and aligned with the RA gear, 

this angle can be slightly adjusted by the two screws sideways:

 

 

this direction below can be adjusted: 

However, this tooth to tooth gap distance below cannot be adjusted (this is major handicap of this series of eq mounts), allowable tolerance of H7 to H8 means 20 to 30 microns:

In case the RA gear is worn, backlash will increase, and periodic error will be larger.

Wild guess of damage: 1 worm is screwed in/out too much that it's actually grinding the RA gear. 2 The counterweight is missing or highly un-balanced, and actually metal to metal grinding by the worm gear.

3 poor gear material is the least suspect, as there are so many such mounts in the market, and this is not so common

Another case, DEC gear clutch not locked properly:

Vibrationschool

lubrication blog

In the worst case, the telescope will shake or even slip. So far it is impossible to find the replacement gear and worm set ( as a pair), and you will need to buy a new mount

Next step forward for upgrade:

Look for a equatorial mount that houses both the worm and RA gear in one single metal enclosure, eg bresser EQ3, skywatcher EQ3-2

The metal enclosure is designed and manufactured in such a way that the two gears are not allowed to rotate too far off to damage the threads, esp the RA gear.

bearing to upgrade AXK1024 AXK2035 AXK2542 AXK3047和AXK3552

EQ3  hypertune

Next is to look for RA gear made of strong durable material, eg annealed steel, or stronger. The worm made of phosphor bronze or similar.

Similar to those used in skywatcher sky adventurer

Overall, the tracking accuracy depends on polar alignment, and also the RA shaft axis ( and bearing) tolerance, which is seldom talked about in forums

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