Recently I built a scissor-style laptop raiser and book lectern. It works fine, but the weighty laptop requires much tightening of the wingnuts, making me fear that over time the wood will crack (they're some simple pine scraps and I already remember hearing some cracking, although not much). The logical way forward seems to be increasing the friction between the arms at the contact points by gluing some material (or something like Nordlock nuts) to both parts, thus increasing the friction coefficient between the surfaces. That would enable me to get more force of friction per unit of normal (~tightening) force, reducing sliding and the need for drastic tightening.

I have researched about the best materials for increasing friction, and thought that the best options would be either two pieces of rubber on both sides or something like anti-slip tape, or perhaps the aforementioned expensive Nord-lock type nuts.

I also want to avoid wood abrasion.

What is the simplest, quickest and least expensive way to increase the overall strength and/or decrease the need for tightening per unit of "strength"?

Recently I built a scissor-style laptop raiser and book lectern. It works fine, but the weighty laptop requires much tightening of the wingnuts, making me fear that over time the wood will crack (they're some simple pine scraps and I already remember hearing some cracking, although not much). 

The logical way forward seems to be increasing the friction between the arms at the contact points by gluing some material (or something like Nordlock nuts) to both parts, thus increasing the friction coefficient between the surfaces. That would enable me to get more force of friction per unit of normal (~tightening) force, reducing sliding and the need for drastic tightening.

I have researched about the best materials for increasing friction, and thought that the best options would be either two pieces of rubber on both sides or something like anti-slip tape, or perhaps the aforementioned expensive Nord-lock type nuts.

I also want to avoid wood abrasion.

What is the simplest, quickest and least expensive way to increase the overall strength and/or decrease the need for tightening per unit of "strength"?