Heritage 130P telescope secondary redesign

My take on SkyWatcher Heritage 130P improvements. 

This is definitely not the first redesign of this affordable but capable telescope. Depending on your goals it may not be your best option, see lordzurp's award-winning effort if you want to use a helical focuser and possibly motorize the existing mount. In any case visit his page to take a look and also to download at least the wrench that he modelled for removing the two bolts that hold the secondary assembly to the extending rods. The ideas are the same and I would not have bought this telescope before seeing his design. 

My design constraints were these:

• to use existing front cover. I needed to slightly increase the width of an existing slot on the front cover (using a pair of side cutters) but it fits like the original.
• to use a Skywatcher AZ-GTI mount, so no need to motorize.
• to use my Crayford focuser design so a 4-bolt mounting is provided
• to add (an optional) light shield that remains permanently attached

This is the result. I printed it with Prusament PETG Matte Black and it is strong while being a pleasing low-sheen black.

Instead of heat-insert brass threads here I have used hexagonal recesses for conventional nuts. This is because the inserts sometimes do not go straight in, being able to melt their own path unless you insert them perfectly straight. Nothing worse than finding a thread is not aligned on a print that took many hours… Nuts always go straight. Maybe I need to invest in better heat-insert equipment and better brass inserts? I used M2 hardware to attach the dust shroud, M3 on the secondary bolts and focuser. Also in the focuser mount there are two holes for metal rods to be inserted, I used 2mm rods sold for nylon gear axles. You don't have to if you have good layer adhesion but they add a lot of strength and the focuser mount will break at the widest part of the circle if bent. On the sides of the focuser mount are holes for brass inserts which I may use with future focuser developments but you can ignore them.

I think this is complete now. As you see in the pictures I am still messing around with my Crayford focuser design, I may add a gear reduction in the form of a belt drive or a planetary drive, possibly motor drive, and I have a new drawtube with a quick tightening ring in progress.

Results with a Baader Zoom IV eyepiece have been pretty amazing! I'd like to do the same for a 150P, the larger version of this telescope, but don't have one.

Edit 16 August 2023 - added .SLDPRT and .STEP files for the front assembly piece, if you would like to modify this should help.