Technique to Minimize Backlash by Gérard C.

Gérard C. has an interesting technique in solving this problem using two special nuts, one on either side of the MDF, to minimize the backlash (and is adjustable). I've said the word a few times, but you are saying to yourself, what is backlash? Backlash isn't the character located above your enter button, that's the back-slash, nor is it the post experience from a fight with your wife. Backlash is caused by the space between the threads of a screw, and the threads in the nut. If space exists where the two mate, then there will be a loss of movement in the linear motion when the screw is turned, or worse, vibration can transmit through this space make for undesirable accuracy or precision in the cut. Software can eliminate backlash for the short term, but calibration in needed constantly. Totally eliminating the space in the mating of the screw and nut can also cause binding problems, so it is a good idea to lubricate the screw and nuts before use, or use ballscrews. From Gérard C: Backlash occurs when the screw changes direction of rotation because the driving strength is reversed and then applied to the opposite wall of the threading. Interchangeability and machining allowances make compulsory a functional gap between nut threading and screw threading, so it exist a dead time while nut is not driven when screw rotation has just reversed because rubbing against the opposite wall is not immediate and screw must turn some degrees before it occurs. Principle : Backlash is lowered if functional gap is reduced, a simple way to do this is to use two opposing nuts, one is permanently rubbing against the left wall of threading while the other rubs against the right one. Opposing nuts are here threaded inserts for hard wood, they are both screwed inside the same hole bored through a MDF part. First insert is locked while second is firmly held in the opposite hole entry, it can nevertheless be rotated for adjusting.