UPDATE: I posted a new version of my shifters! Make sure to go check it out!

I designed 3 different shifters for my logitech g27;

1- Custom size;
-The G27 long shifter part 1 will connect the g27 shifter shaft to a 11 mm steel rebar.
-You can make the rebar the length you want.
-I don't know if it is normal but my rebar was slightly oval (by a 1mm difference) so I had to make the holes oval, so if you have issues inserting it maybe try rotating it as it
may be oval too.
-The G27 long shifter part 2 will connect the 11 mm steel rebar to the G27 shifter grip.

2-Short shifter;
-The G27 short shifter will connect the g27 shifter shaft to the G27 shifter grip.
-Shorter and more casual looking shifter then the Custom sized ones (also because not everyone has 11 mm rebar laying around :) ).

3-Ball shifter;
-It is slightly bigger then the normal g27 ball shifter.
-It has the gear patern on the top (1-5 + reverse).

PRINTING SETTINGS;

1-Custom size;
-G27 long shifter part 1 needs to be printed flat with 15% infill and supports (BP only), I used pla+ but regular pla should be strong enough.
-G27 long shifter part 2 needs to be printed flat with 15% infill and supports (BP only), I used pla+ but regular pla should be strong enough.
-G27 shifter grip needs to be printed standing up with 10% infill (I printed mines in 5% with giroid infill, and it is REALLY squishy, maybe too much) . The grip should be printed in TPU for better comfort altought if you don't have some, pla should work fine too.

2-Short shifter;
-G27 short shifter should be printed flat with 15% infill and supports (BP only), I used pla+ but regular pla should be strong enough.
-The grip is the same as the custom size one.

3-Ball shifter;
-G27 ball shifter should be printed side ways with 15% infill and supports (BP only), I used pla+ but regular pla should be strong enough.

ALL of the holes that fit in the g27 shifter shaft are going to be very tight in the begining but with a bit of deburring and putting it on and off it should loosen up to a point where it won't come out on its own but it is easy to remove.