Sheet Metal: Notes and Descriptions MachinesProceduresTools

LAYOUT Sheet metal – Ranges from.004” to 3/16”. Plate steel is anything 3/16” and over. Sheet metal – Ranges from.004” to 3/16”. Plate steel is anything 3/16” and over. There are different types of layout procedure with sheet metal. Find the best process for your purpose. There are different types of layout procedure with sheet metal. Find the best process for your purpose.

LAYOUT CONT. Pattern- one dimensional object which can be folded into a 3 dimensional product. Often drawn on paper and transferred to the metal. Carbon paper and a scribe are used to transfer. Pattern- one dimensional object which can be folded into a 3 dimensional product. Often drawn on paper and transferred to the metal. Carbon paper and a scribe are used to transfer. Stretch Out- When layed out directly on the metal. Stretch Out- When layed out directly on the metal. Template- a permanent pattern. Usually made out of metal or something hard enough to be traced around. Slightly smaller than the finished project. Template- a permanent pattern. Usually made out of metal or something hard enough to be traced around. Slightly smaller than the finished project.

HEMS There are three types of hems as follows: There are three types of hems as follows: Single hem – To improve strength, appearance and eliminate sharp edges. Always use at least a single hem when working with sheet metal. Single hem – To improve strength, appearance and eliminate sharp edges. Always use at least a single hem when working with sheet metal.

HEMS Double Hem – When extra strength is needed. Add 1/16” extra metal to allow for the double bend. Ex. ¼” double hem = ¼” + ¼” + 1/16” = 9/16” Double Hem – When extra strength is needed. Add 1/16” extra metal to allow for the double bend. Ex. ¼” double hem = ¼” + ¼” + 1/16” = 9/16”

HEMS Wire Edge – For additional strength or appearance. Add 2 ½ times the diameter of the wire used. Ex. 1/8” wire hem = 2 1/2 x 1/8” = 5/16” Wire Edge – For additional strength or appearance. Add 2 ½ times the diameter of the wire used. Ex. 1/8” wire hem = 2 1/2 x 1/8” = 5/16”

HAND TOOLS Scratch awl or Scribe – Hard steel tip used to mark on sheet metal. Scratch awl or Scribe – Hard steel tip used to mark on sheet metal.

HAND TOOLS CONT. Gage – Used for determining the thickness of sheet metal in gage size and in thousandths of an inch. Gage – Used for determining the thickness of sheet metal in gage size and in thousandths of an inch.

Hand tools Snips – Used for cutting light gage sheet metal. To prevent over cutting, place the end of the snips at the end of the line to be cut. An over cut is called a crows foot. Types of snips include, Curved (right, left and straight), Seamers and Aviation. Snips – Used for cutting light gage sheet metal. To prevent over cutting, place the end of the snips at the end of the line to be cut. An over cut is called a crows foot. Types of snips include, Curved (right, left and straight), Seamers and Aviation.

Hand tools Whitney Punch – Punches holes in sheet metal for use with rivets. Light gage metal only. Whitney Punch – Punches holes in sheet metal for use with rivets. Light gage metal only.

Combination Square: Used for general layout. Do not loose the gold tightening screw! Used for general layout. Do not loose the gold tightening screw! Three heads/attachments: Three heads/attachments: –Combination 90° - 45° –Center Finding –Protractor

Hammers –Used to form or shape sheet metal. –Two types: –Hard Faced – ball peen or sledge –Soft Faced – rubber or wooden mallet.

Punches Center punch 90° point used to mark centers for drilling holes. Center punch 90° point used to mark centers for drilling holes. Pin punch flat face for driving out bolts or pins. Pin punch flat face for driving out bolts or pins.

Measuring devices Steel Scale – found on combination squares, usually grades in 1/8ths, 1/16ths, and 1/32nds. 1/64th is the smallest division of the inch on a steel scale. Steel Scale – found on combination squares, usually grades in 1/8ths, 1/16ths, and 1/32nds. 1/64th is the smallest division of the inch on a steel scale. Circumference rule, large like a yard stick, has conversions for diameters to circumference Circumference rule, large like a yard stick, has conversions for diameters to circumference

MACHINES Square Shear – Used for cutting long straight lines up to 52 inches in length, also cuts to a square 90° corner. Square Shear – Used for cutting long straight lines up to 52 inches in length, also cuts to a square 90° corner.

MACHINES CONT. Bar Folder – Used to fold hems on projects. 18 gage flat stock capacity max. Bar Folder – Used to fold hems on projects. 18 gage flat stock capacity max. Depth of the fold is adjustable. Use a steel scale to set the depth. Depth of the fold is adjustable. Use a steel scale to set the depth.

MACHINES CONT. Box and Pan Break For folding sides and ends of your project. Adjustable fingers – can be set at different widths. Box and Pan Break For folding sides and ends of your project. Adjustable fingers – can be set at different widths.

The Pittsburgh Machine This machine folds a type of lock seam that fastens pieces of sheet metal to each other. This machine folds a type of lock seam that fastens pieces of sheet metal to each other. Watch hand placement and do not use without instructor approval. Watch hand placement and do not use without instructor approval.

METAL FASTENING METHODS There are several ways to fasten metal together. Three of these are: There are several ways to fasten metal together. Three of these are: Cold rivets – set with ball peen hammer and rivet set. Not commonly use today. Cold rivets – set with ball peen hammer and rivet set. Not commonly use today. Pop Rivets – as with cold rivets, should extend 1 ½ times the diameter of the rivet. Aluminum or steel rivets. Pop Rivets – as with cold rivets, should extend 1 ½ times the diameter of the rivet. Aluminum or steel rivets. Spot Welding – fusion welding using a resistance welder. Spot Welding – fusion welding using a resistance welder.

SAFETY Edges of sheet metal are very sharp. Take care to prevent cutting yourself. Edges of sheet metal are very sharp. Take care to prevent cutting yourself. Do not use scribe for anything but drawing lines on sheet metal. Do not use scribe for anything but drawing lines on sheet metal. Watch fingers and toes when using the square shear. Watch fingers and toes when using the square shear. Always wear eye protection. Always wear eye protection. Do not weld on Galvanized metal. Metal that has a galvanized coating will melt and form toxic fumes. The coating is there to protect the metal from rusting. Do not weld on Galvanized metal. Metal that has a galvanized coating will melt and form toxic fumes. The coating is there to protect the metal from rusting.