Nut and a method of use of the nut in a fastener system for crane mats

1. A method for producing crane mats without countersunk holes for nuts comprising:

(a) providing structural pieces having substantially the same length to provide the length of the crane mat that need to be held together to form the crane mate, to stabilize a working surface for heavy equipment moving over rather soft or environmentally sensitive ground, each structural piece having a plus minus variable in the width and thereby creating a variable in the width of each crane mat being assembled;

(b) providing bolts having a fixed length,

(c) providing bores within the crane mat having substantially the same diameter at each end of the bores, the diameter of the bores being large enough for each bolt to fit into a piece of structural pieces;

(d) providing nuts that can thread with the bolts and secure the structural pieces together to form the crane mat, the nut having a pass through;

(e) fastening the structural pieces together to form the crane mat by inserting the bolts into the bores and fastening the nuts and bolts together, wherein part of the nuts are within the bores, the fixed length of the bolts do not substantially extend past an outside edges of each nut.

2. The method as recited in claim 1 wherein:

(a) the bolts have a length that is at least 1 inch shorter than the width of the crane mat;

(b) each nut has a stud and the stud is of a length so that the stud is the part of the nut within the bore and can thread with the bolt to accommodate the amount of length each bolt is short.

3. The method as recited in claim 1 wherein the bolts have a flat head.

4. The method as recited in claim 1 wherein each bolt has a surface that assists it through the bore and aligns the bolt with the nut.

5. The method as recited in claim 1 wherein each bolt has a chamfered leading edge so that it can easily be inserted into the nut.

6. The method as recited in claim 5 wherein one of the nuts is used to drive and attach one of the bolts and that nut together.

7. A method of making a construction mat, comprising:

providing a plurality of planks arranged to form a mat with a first surface serving as a ground-engaging surface and an opposite surface serving as a load-bearing surface;

further providing the planks with a plurality of through bores that are each of generally uniform diameter and which extend through the mat;

providing a plurality of bolts each having an elongate shank of predetermined diameter with an enlarged head at one end and a screw threaded section at an opposite end; wherein the length of the bolt from the head to the end of the screw threaded section is less than the length of a respective one of the through bores in which it is to be installed, and further wherein the diameter of the through bore is equal to or greater than the diameter of the shank of the bolt;

providing a plurality of nuts each having an enlarged head portion and a sleeve portion extending from the head portion and including a threaded passage in the sleeve portion and a through passage extending completely through the head portion and communicating with the threaded passage and being of a size to accommodate passage of the threaded portion of an associated one of the bolts through the head portion of the nut;

extending the bolts into one end of corresponding ones of the through bores of the planks until the head of each bolt engages the portion of the mat at the edge of the respective through bore;

extending the sleeve portion of the nuts into the opposite end of the corresponding ones of the through bores of the planks and rotating the nuts to thread the sleeves into engagement with the threaded section of the bolts and to tighten the head of the nut against the portion of the mat at the edge of the respective through bore on the opposite side.