Plastic spacer stock, plastic spacer frame and multi-sheet unit, and method of making same

A spacer frame for making a multi-sheet insulating unit comprising:

• a spacer stock member having a first end and a second end, and
• a corner key comprising:
• a bendable elongated body having a first end in the first end of the spacer stock member, an opposite second end in the second end of the spacer stock member:
• a first upright leg and a second upright leg joined to a base and spaced from one another to provide the body of the corner key with a generally U-shaped cross section, wherein the base has an inner surface facing a space between the first and second upright legs of the body of the corner key and the first end of the body of the corner key comprises a first end of the first upright leg, a first end of the second upright leg and a first end of the base;
• the opposite second end of the body of the corner key comprises an opposite second end of the first upright leg, an opposite second end of the second upright leg and an opposite second end of the base;
• a first V-shaped cut out and a second V-shaped cut out in the first upright leg and a third V-shaped cut out and a fourth V-shaped cut out in the second upright leg, wherein each of the first and the second cut outs comprises a first sloping side extending from edge of the first leg to the base and a second sloping side facing the first sloping side and extending from the edge of the first leg to the base, and the first and second sides meeting at a vertex adjacent the base, and a section of the first upright leg between the first and the second V-shaped cut outs, wherein one of the sloping sides of the first cut out and one of the sloping sides of the second cut out provide sides of the section of the first leg extending from the edge of the first leg to the base, and wherein each of the third and the fourth V-shaped cut outs comprises a third sloping side extending from edge of the second leg to the base and a fourth sloping side facing the third sloping side and extending from the edge of the second leg to the base, and the third and fourth sloping sides meeting at a vertex adjacent the base, and a section of the second upright leg between the third and the fourth V-shaped cut outs, wherein one of the sloping sides of the third cut out and one of the sloping sides of the fourth cut out provide sides of the section of the second leg extending from the edge of the second leg to the base, and bending the first end and the second end of the corner key toward one another in a direction over the inner surface of the base decreases the spacing of the first, second, third and fourth V-shaped cut outs to move the first and second sloping sides of the first cut out against one another, to move the first and second sloping sides of the second cut out against one another, to move the third and fourth sloping sides of the third cut out against one another, and to move the third and fourth sloping sides of the fourth cut out against one another to form a corner of the spacer frame wherein, there are no more than 2 V-shaped cut outs in each of the first and second legs.