About this 3D model

I have been tried a lot of Sand Paper Holder but I have difficulty to stretch well the sandpaper. This is my design witch include it's own stretcher. The stretch mechanism is detachable and is interchangeable. Loaded Profile is for 100*40mm. You will need: 1 M3 Threaded insert 1 M3*20mm Bolt 1 M3 Bolt - length need to be same size of the width of Holder 1 M3 Nut You will need to sand the “Riser” surfaces and other surfaces witch come in contact with. You need to apply a little grease to surfaces witch slide one above other (check red Marks). For other dimensions you can write a comment and i will upload then asap.