Slotted Holes are elongated holes with round or square ends. They are available from stock in either a side staggered or a straight line pattern in plain steel. Others gauges, hole sizes, patterns and materials are available by special order. You may narrow your selection choices by using the left navigation pane or browse our stock list below.
When you request a quote, if you do not specify a tolerance for quantity, McNICHOLS provides the ’exact’ quantity you requested. On large orders, you can lower cost by specifying ’standard’ tolerances. ’Standard’ tolerance is +/- 10% (plus or minus 10 percent). On an order of 50 sheets with a ’Standard’ tolerance, you would receive at least 45 sheets and no more than 55 sheets.
Slotted perforated is a sheet or coil of material made from metal that contains holes punched by a die. The shape of the hole is determined by the shape of the die. For perforated with a slot hole pattern, the die is shaped like a slot. The die can vary in the width, length and the ends of the slot can be round or square. Common, in-stock sheet sizes for perforated slot hole products include:
Hole pattern is the arrangement of the slots on a sheet—either straight row or end or side staggered. The long dimension of the slots can be punched parallel to the width or to the length of the sheet (see slot direction).
As a rule of thumb, the slot width should be at least the same size as the thickness of the perforated material or larger. Preferably, the width should be at least twice the size of the material thickness. As the slot width approaches the material thickness, the higher probability of tool failure. Modifications can be made in certain instances at additional costs. For stainless steel and similar higher-strength materials, it is preferable to specify a slot width at least three times the thickness of the material.
Side Center is the distance between adjacent slots measured parallel to the slot’s length. Centers is one of two measures of perforation spacing. The other is open area. Because side centers and open area measure essentially the same attribute (perforation spacing), you only need to specify one or the other, not both. End centers
Perforated sheets contain holes and material. Open area is the total area of the holes divided by the total area of the sheet and is expressed as a percent. In other words, open area describes how much of a sheet is occupied by holes. If a perforated sheet has 60 percent open area, then 60 percent of the sheet is holes and 40 percent is material.
Thickness is the measurement from the top surface to bottom surface of the material. Gauge is the most common measurement, but thickness can also be measured in fractional inches or millimeters. This gauges and weights chart can provide additional information.
End pattern is the pattern of the perforations at the beginning and the end of the sheet. End patterns are either finished or unfinished. An unfinished end pattern is standard. A finished end pattern requires special tooling and is typically more expensive.
Bar width is the distance between the edge of one slot to the edge of the nearest slot. Because slots are asymmetrical, there are two bar width measurements: end bar and side bar. When you specify bar widths, make sure your specifications meet the guidelines for minimum bar width.
As a rule of thumb, the bar width should larger than the thickness or gauge of the material. Preferably, the bar will be at least twice the material’s thickness. For stainless steel and similar higher-strength materials, specify a bar width at least three times the material thickness.
Length is the overall measurement of the long side of the piece; width is the overall measurement of the short side of the piece. Note that mill tolerances for length and width apply to stock sheets unless otherwise specified. If you have a stock sheet cut-to-size, cut tolerances apply. If you want to specify other than standard tolerances, you must use the Quote Form (see link in left column) to specify the exact tolerances you desire.
Quantity is the number of full sheets or cut pieces you need. Unless otherwise specified, the standard tolerance on quantity is Exact Quantity. In other words, McNICHOLS will deliver the exact quantity you specify.
Margins are the blank (unperforated) area along the edges of the sheet. For stock sheets, the standard is minimum margins along the length and no margins along the width.
To specify other than standard margins, use the perforated Slot hole pattern quote form. Provide the width of each margin on all four sides (measured from the edge of the sheet to the edge of the first hole) and the direction to which the margin is parallel (side or length dimension). Manufacturing considerations may affect margins. If the margins requested are not possible, the quote you receive will specify the new margins.
Below is an example of a margin specification based on the illustration to the right:
· 0.25 inch margins parallel to both 25 inch dimensions
· 0.50 inch margins parallel to both 48 inch dimensions