IKEA Markus armrest mount cap & fabric clamp

I love the IKEA Markus office chair. Unfortunately, because of the not adjustable armrests and my sitting style, I never mount the armrests and that leads to a very annoying situation: the armrests mounting points remain uncovered and the fabric of the seat tends to stretch over in a very messy way.

Those simple caps double as covers and clamps to hold the fabric tight.
They not protrude so much and the soft shape is comfortable, even if you sometimes sit in “creative” ways like me.

I have two Markus chairs and the “mounting cylinders” are sligtly different, ones protruding 7 mm while the others 8 mm. I've included both versions. If your chair is different, feel free to modify the files.

I've bought some bolts with smaller head and shorter than the original. The bolt head measures 13.5 mm diameter x 3.5 mm height. The bolts are M8 x 16 mm.
I've included two versions of the caps compatible with the original bolts (IKEA 122134), although they are too long in my opinion (you can always cut them down, of course).

If you don't want to buy new bolts or your original bolts are missing, here's a link to an M8 bolt model gently shared by Qbi (thank you).

The caps need a little support for the central hole.
I've printed mine with 0.16 LH, 3 perimeters and 20% infill.

BONUS FEATURE: you can use those caps to “color tag” personal chairs in a shared office or just add a touch of color. Enjoy!