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In use, the body is aligned against the one edge of the object and the blade is presented to the end or body of the object. If the end is being checked, then a strong light source behind the square will show any mismatch between the blade of the square and the end of the object. The purpose of this
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The simplest method of checking a low grade square for accuracy is to draw a line across a board with a flat face and straight edge (illustrated). Then flip the square over 180 degrees and check if the blade aligns with the line just drawn. Any error is multiplied by two and appears as a wedge or
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Under both these standards there are basic dimensions set out for blade/body length ratio, and cross sections of both, as well as different types of squares such as those with a solid body and an inserted blade, or those with a single piece blade and body being precision ground with another plate
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Typically there are A or B grade squares made and sold, B grade being perfectly serviceable for most general use where accuracy is required in a workshop situation. A grade squares are typically used in applications where a higher grade of accuracy is required, in a toolroom for example, or for
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Also under these standards there are different grades of accuracy to which a square can be made. It usually relates to a deviation of 'X' amount of blade lean vs. height of measurement usually done at the top of the blade. This also assumes that the blade and body widths are both perfectly
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Machinist squares can have a linear error of no greater than 0.0002 mm/mm. Squares must be occasionally checked for accuracy. The four disk method is one way to verify overall squareness. However, it cannot detect bent blades.
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into a heavier body at an angle of 90°. Usually a small notch is present at the inside corner of the square. This prevents small particles from accumulating at the juncture and affecting the square's reading.
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that is flat. By nature of their construction a cylindrical master square cannot help but sit at a perfect 90-degree angle to the flat surface. A square to be tested can be presented to the master and
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used with a source of light behind the gap to get a reading of deviation. If done cleanly and correctly, this method can find errors down to 0,01 mm, which is the limit of practical accuracy since
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There are several different
International or National standards that Engineer's Squares are manufactured to, two main ones being: - BS 939. (British Standards). - DIN 875-1 (German/Euro standards).
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Other methods of calibration utilise modern technology by using a CMM (Coordinate
Measuring Machine) for example, or a vertical machining center fitted with a
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Essential Guide to the Steel Square: Facts, Short-Cuts, and
Problem-Solving Secrets for Carpenters, Woodworkers & Builders
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parallel, making for a true reading along the blade length and inside and outside the square.
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for square, or for making jigs and fixtures where high levels of accuracy are needed.
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The ultimate method of mechanically calibrating a try square or similar is with a
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from contact with the fingers will distort the blade by approximately that much.
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attached to the base of this to provide a square 'butt' to refer to.
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Simple method for checking a low grade square against itself.
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138:. It consists of a steel blade inserted and either
54:. Unsourced material may be challenged and removed.
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114:Learn how and when to remove this message
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15:
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274:, Fox Chapel Publishing, p. 31,
134:is the metalworkers' equivalent of a
52:adding citations to reliable sources
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13:
986:Metalworking measuring instruments
230:sitting on a granite or cast iron
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14:
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210:Accuracy checking and calibration
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39:needs additional citations for
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20:Two typical engineer's squares
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185:Accuracy grades and standards
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164:the body of the workpiece.
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697:Magnetic switchable device
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228:cylindrical master square
981:Metalworking hand tools
755:Engineer's spirit level
156:action is to check for
470:Oxy-fuel cutting torch
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955:Tools and terminology
722:Measuring instruments
217:
175:
19:
268:Horner, Ken (2007),
48:improve this article
845:Thread pitch gauge
810:Optical comparator
564:Combination square
361:Metalworking tools
220:
178:
63:"Machinist square"
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281:978-1-56523-342-3
242:thermal expansion
132:engineer's square
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785:Machinist square
594:Needlegun scaler
589:Machinist square
402:Water jet cutter
369:Cutting machines
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860:Smithing tools
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526:Machine press
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204:other squares
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65: –
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59:Find sources:
53:
49:
43:
42:
37:This article
35:
31:
26:
25:
18:
893:Steam hammer
840:Tape measure
830:Straightedge
815:Radius gauge
790:Marking blue
784:
780:Height gauge
760:Feeler gauge
740:Center gauge
707:Rotary table
687:Lathe center
599:Piercing saw
588:
584:Hand scraper
455:Hand scraper
323:Metalworking
270:
263:
246:
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131:
127:
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104:October 2009
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84:
77:
70:
58:
46:Please help
41:verification
38:
925:Fabrication
903:Trip hammer
898:Swage block
883:Hardy tools
800:Marking out
770:Gauge block
657:Angle plate
619:Tap and die
536:Screw press
531:Punch press
485:Tipped tool
440:Countersink
435:Counterbore
975:Categories
945:Metallurgy
805:Micrometer
730:Bore gauge
551:Hand tools
255:References
158:squareness
136:try square
74:newspapers
940:Machining
935:Jewellery
634:Workbench
569:Drift pin
392:Miter saw
202:checking
950:Smithing
888:Pritchel
825:Sine bar
490:Tool bit
445:End mill
382:Cold saw
168:Accuracy
162:mark out
960:Welding
930:Forming
920:Casting
735:Caliper
712:Wiggler
702:Mandrel
672:Fixture
614:Scriber
574:Hacksaw
465:Nibbler
377:Bandsaw
223:taper.
88:scholar
878:Fuller
667:Collet
639:Wrench
604:Pliers
579:Hammer
480:Shears
475:Reamer
430:Chisel
420:Broach
397:Plasma
278:
160:or to
144:pinned
140:welded
90:
83:
76:
69:
61:
873:Forge
868:Anvil
820:Ruler
765:Gauge
662:Chuck
624:Tongs
609:Punch
559:Clamp
506:Brake
387:Laser
176:float
95:JSTOR
81:books
629:Vise
450:File
425:Burr
276:ISBN
67:news
682:Jig
511:Die
151:Use
142:or
130:or
50:by
977::
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126:A
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339:v
315:e
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111:(
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102:(
92:·
85:·
78:·
71:·
44:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
