One of our primary product lines, Slotted Steel Shims, just got bigger. We’ve added 10” long and 12” long to our inventory.
Interestingly all of our customers can make their own shims. In very slow seasons they sometimes do. But any analysis of the cost per piece shows without the right equipment it is too expensive and time consuming for most Steel Fabricators to produce in house. As well, when the need arises it is frequently for large quantities. The larger the quantity the more the important the cost and time lost differential is.
That’s why The Steel Supply Company keeps an ample supply of each shim part number. Many are also stocked Hot Dip Galvanized. Typical stock sizes went from 3” long to 8” long.
Occasionally a request would come in for 10” and 12” long shims. As usual we would make them to order and typically the 3 day turn around time was sufficient for delivery time and cost. These longer shims might be used on Moment Connections, Under Base Plates, to fill gaps between Columns and Beams, etc.
One of the locations that usually requires a large quantity of shims is the Relieving Angle, also known as a Lintel Angle. These angles usually require 4”, 5” or 6” long shims and as yet we haven’t seen a Relieving Angle that required 10” or 12” long shims.
These 10” and 12” slotted steel shims were added to stock at the request of several customers who felt immediate delivery would make it easier to keep jobs moving forward. As well, some erectors were using 5” and 6” long shims on Moment Connections that were 10” or 12” wide. By shimming from both sides they were able to make up the full distance. (See Drawing)
In the example shown above 12 shims are required to properly shim the Moment Connection. This assumes the thickness of one shim is sufficient to fill the gap. From a cost per shim standpoint it doesn’t much matter if the erector uses 6” shims or 12”. Two 6” shims are approximately the same cost as one 12”. Where the difference occurs is on installation. The 6” shim is installed 6 times on one side, the erector has to then re-position himself and repeat the process. The more locations that require shimming, the greater the time difference becomes.
The 12” shim is installed from one side 6 times.
This saves installation time, hence labor cost. It is important to note using 12” shims on a 12” wide Moment Connection will leave one edge with visible gaps where the slot is exposed.
In terms of actual surface area the difference is very little. Roughly calculated the surface area of each is shown below.
3” x 6” Steel Shim with 1-1/16” wide slot provides approximately 12-1/4 sq. in. of surface area.
12-1/4 sq. in. x 12 shims = 147 sq. inches total surface area
3” x 12” Steel Shim with 1-1/16” wide slot provides approximately 24-1/4 sq. in. of surface area.
24-1/4 sq. in. x 6 shims = 145-1/2 sq. inches total surface area
Note: Despite the minor difference in surface area the Project Engineer, Architect or Supervisor should approve the method of shimming.