What is the difference between tolerance and clearance? And most importantly, why do these things matter when it comes to premium bolt actions?
How words are used can create confusion. When people use “precision” and “accuracy” to mean the same thing, they can get their message across generally but that is because people have to use the context of the rest of the discussion to understand what they actually mean.
When “precision” and “accuracy” are used to say the same thing, which is usually “good performance”, it is a clear indicator that the source of the information does not have a strong understanding of the actual difference between these terms since they regard them as interchangeable. Which they are not.
What does this have to do with actions and using “clearance” and “tolerance”? Most importantly, it can help customers understand which brands really knows what they are talking about compared to those who use these terms interchangeably as buzzwords for affect.
“Tolerance” in action making is the amount a dimension can vary from a target dimension. If a thread depth target dimension is 1.403”, the “tolerance” is what that dimension can be other than 1.403”. Defiance has a “tolerance” of +/- (plus or minus) 0.0005 on thread depth. This allows the thread depth dimension to be 1.4025” to 1.4035”. This is a very tight tolerance.
“Tolerance” is what we use to create the geometric dimensions of all the parts used on our actions. When you combine these dimensions with their tolerances into a finished product, the spaces between these physical dimensions is the “clearance”.
“Clearance” is a space around and between the physical dimensions that comes from the target dimensions and their stacked tolerances. Clearance, in some areas will be tight because the function of that specific area needs to guide or position something. Clearance in other areas may be wider so that a different area can have room for smoothness and motion.
If someone describes their product’s quality by saying, “Our products have tight clearance.” Not only is that the wrong way to use the word but it also offers that, if correct, their product may not be well designed since more clearance is needed in certain areas than others.
Quality is measurable by how consistent the clearance is based on hitting the target dimensions within their tolerances. If the target dimensions reached are within the appropriate tolerance, a larger clearance can be high quality.
“Tolerance” can be used incorrectly by saying things like, “The tight tolerances of our product creates smooth function.” Smoothness can result from manufacturing within tolerances; however, the clearance is what makes an action function smoothly.
Some might say, “Why does this matter? I know what he is trying to say.” It matters when you are deciding whether you want a genuinely premium action made by highly knowledgeable specialists instead of an action touted as having “Tight Clearance” or that its “Tolerances make it Smooth.”
When it comes to spending money on premium products made by qualified professionals, is their knowing what these words mean important or not? Consider sitting in a doctor’s office talking about your upcoming procedure. If you heard the doctor struggle over using the right words, would your confidence in their ability to succeed go up or down?