Combination Square
Considerations
- Pre-Operation Checklist is a prerequisite for ANY operation.
- Applies to standard metal, movable head squares commonly found in the shop. Imperial, Metric, and Dual System squares are all used approximately in the same way.
- Tools are in working condition, capable of being properly verified for accuracy.
- Test examples are of appropriate size to be measured using the available tools.
Pre-Operation Checklist
Performance Standard –
Level 1
- Verifies head and rule are free of debris and defects.
- Releases pressure on head when making adjustments.
- Handles square with care to maintain accuracy.
Level 2
- Verifies head is square to rule and slides freely.
- Ensures square is clean and lubricated and rust free.
- Meets Level 1 performance standard.
Verify Material Squareness
Level 1
Given 3 pieces of material 3/4″ thick, 6″ wide, and at least 12″ long, with the end of one piece cut slightly out of square (about 1/2º) to the long edge, and tool set up and ready to measure and/or calibrate, check the end of each piece of material for squareness; or, given one piece of 12″ panel stock, verify if it is square or out of square.
- Correctly identifies which piece of material is out of square.
Level 2 – N/A
Layout Material For Perpendicular Cuts
Level 1
Given material of uniform width and thickness and tool set up and ready to layout, make marks around a 3/4” x 4″ S4S(Surfaced 4 Sides) board (all 4 faces) for a 90º cut.
- Marks are crisp and easily read.
- No measurable deviation from 90º is apparent.
- No measurable deviation occurs where lines meet at adjacent planes
Level 2 – N/A
Layout Material For Angled Cuts
Level 1
Given material and tool set up and ready to measure and/or calibrate, mark 3/4” x 4″ by any length stock for a 45º cut across the wide face of stock.
- Mark is crisp and easily read.
- No measurable deviation from 45º is apparent.
Level 2
Given material, tool and a protractor head, mark 3/4” x 4″ x any length stock for a specified angle cut across the wide face of stock.
- Installs Protractor Head.
- Adjusts head to within ± 0.5º.
Layout Mortises
Level 1
Given material and a combination square, lay out a 3/8″x 2″ mortise, centered on the edge of a piece of milled stock, 1/2″ from the end of the stock.
- Marks are crisp and easily read.
- Layout is centered on the stock (side to side).
- Lines are accurate to within 0.4 mm (1/64″) [0.015″].