The glass tensioner can be used with a 300x300mm or a 12x12 inches glass plate.
If you have a 310x310mm glass plate, then you can use this link: https://www.thingiverse.com/thing:3434223

Because of the tensioners low design, you will not lose any printing area when printing.
This glass tensioner uses a M4 nut as a thread.
This is a complete solution for printing on a glass plate with glass tensioners.

Previously there has been a problem with the bottom x-axis wheel colliding with the tensioner. That is not an issue anymore since I have changed the design.

This solution makes it very easy to mount and remove the glass plate. (Please see the video below)
The tensioners have to be placed at the rear part of the bed, to prevent them from colliding with the print head. I have also added a strain relief to this solution.

You need: (Please see the picture in post printing)

• 2 pcs of M4 20-30mm hexagon head bolt (DIN 933).
• 2 pcs of M4 nuts (DIN 934).
• A tiny screw for the strain relief.

The strain relief shall be printed in a vertical position with the flat side down.
The other parts shall be printed with the long flat side down.

When you place the nut into the slider mount, it is important that one corner of the nut is pointing upwards. (Please see the picture in post printing below.)
Then you have to apply a little force to press it in place.

Do not tighten the tensioners too much, as they create tension in the corner holes on the heat bed glass plate.

08.12.2018 Picture update.
15.02.2019 New upgraded tensioner released. The tensioner is much lower to avoid collision with the x-axis wheel.
09.03.2019 Tensioner modified. Height decreased by 1mm lower. The position of the nut is changed.