Touptek AAF on ES-Bresser hexafoc focuser

intro
The hexafoc is an underrated 2-1/2" rack and pinion focuser. The pinion is housed in an enclosure secured by one pair of push and one pair of pull bolts. Both pairs are located centrally to either side of the locking screw. The push-pull system is used to control the pinion to rack backlash.

Adaption to the AAF is easy.

materials
m4 bolts, 2 off, 25mm long with associated washers.

method

1. Set tension and backlash correctly.
2. Remove the large central locking screw.
3. Remove the coarse adjustment focuser knob.
4. Remove the two diagonally opposed pull screws, leaving the push screws intact.
5. Fit the focuser bracket using the longer bolts (see photo for best slots) until the slack is just taken by the bolts but still adjustable longitudinally.
6. Locate the motor and coupling ensuring the flats on both the focuser spindle and the AAF spindle coincide with a grub screw.
7. Slide the bracket so that it is receives the AAF without distortion of the coupler.
8. Torque each of the long bolts alternately in small -say 1/8th.- turns evenly until the bracket is held firmly.
9. Finally, rotate the focuser until the two motor housing sockets align with the bracket slots and secure with the bolts and washers supplied with the AAF.

notes
You may wish to set the approximate focus position of the focuser and the absolute focus position of the AAF before tightening the coupling grub screws. Under INDI, we used an absolute start position of 10000.

AAF fitted to a hexafoc
ES-pn208 f3.9