Transcription

Conduit Bender GuideConduit Bending Basics:The line of Klein Tools conduit benders have been designed for performance and durability exceedingthe expectations of today’s professional. It is recommended to familiarize yourself with bendingconcepts, techniques and learn the bender’s functionality to provide you a positive experience whilegreatly improving the overall outcome of your project.Conduit come in two types, EMT and Rigid conduits and can be found in various sizes. Klein Toolsprovides conduit benders for EMT in ½”, ¾”, 1” and 1-¼” conduit and ½”, ¾”, and 1” Rigid conduit.To aid bending when performing a ground or air bend, the benders are marked with different alignmentsymbols to help the operator create the bends necessary to accomplish any project. The symbols foundon the Klein Tools benders are the arrow, the teardrop, the star point and angle markings. Thesemarkings are found on various sides of the bender head.Center of Bend Rim NotchesUses: Locates the center of asaddle bend.Klein ToolsDuctile Iron Series:½” EMT: #56203¾” EMT: #562041” EMT: #562051-¼” EMT: #56211Klein ToolsAluminum Series:½” EMT: #56206¾” EMT: #56207Star PointUses: Back bends.Angle MarksUses: Offset, saddle bendsand various installationsituationsArrowUses: Stub-up, Offsetand outer marking ofsaddle bends.Stub HeightUses: Number to usefor bender take-up.The 4 most common bends to know how to make are the 90 Stub-Up, Back to Back, Offset and the 3Point Saddle bends. It is common to use a combination of the bender markings when making certaintube profiles. Knowing the proper technique and method of making the bends will allow you toaccomplish most projects efficiently.Things to remember while bending:1. A proper bend is made by rolling the conduit about the bender in the conduit’s cradle using all foot pressure.2. Use the correct size bender for the conduit size being bent.3. Some over bending may be required to allow for spring back of the conduit. The resting condition of the conduit is to be atthe final angle desired.4. Measure and properly mark your conduit using the tables and information provided.5. Floor bending: Make sure conduit is secure so it does not slide prior to bending. Apply ample foot pressure to the bendersheel while minimizing the use of the handle as a lever but more of a guide.6. Air Bending: Make sure handle’s hilt is secure on ground and is reinforced by your foot so it does not slide out. Make sureyou are balanced and apply force close to the tool and your body controlling the tubing as you bend it around the bender’scradle making sure the conduit does not slide in the bender head.7. To prevent injury, always wear protective gear and do not over exert.1

90 Stub-Up Bend:The stub bend is made by bending a piece of conduit into an L shape or 90 bend by placing the free end(short end) of the tube to a predetermined length as indicated in the diagram below. This is the mostcommon bend and is a building block for other bends. Common uses for this bend are: Running conduitinto electrical boxes, running conduit up or down walls, running conduit into walls through floors andceilings and making inner and outer corner turns.Bender Take Up Table90 Stub-Up BendConduitSizeStubHeightAmount to subtractfrom Measurement½” EMT¾” EMTand ½” Rigid1” EMTand ¾” Rigid1-¼” EMTand 1” Rigid5”6”8”11”1.Determine the overall free end height of the conduit you want after the bend.From the overall free height, subtract the stub height listed in the Bender Take-Up Table for theconduit size you are bending. Klein Tools has provided the correct stub height on each bender head.3. On the conduit, measure from the free end to be bent up the calculated number and mark theconduit.2.As an example, to bend 3/4” EMT conduit have a free end heightof 8.5”, the table indicates to subtract 6” from the 8.5” whichleave 2.5” from the end to bend up to make the mark. Tip:Advanced benders can lay a tape measure next to the conduit and perform thebending operations if the bend does not call for high degree of accuracy.4. Always use the proper size conduit bender for the conduit size beingbent. The conduit will not bend properly and/or will be damaged if amismatch of bender and conduit size is used. Place the bender onto thetubing with the hook pointed towards the free end to be bent upwards.Make sure the conduit is resting properly in the bender’s hook andlineup the arrow symbol with the mark you placed on the tubing.2

5. Keeping the conduit flat, apply ample foot pressure to the bender’s heel minimizing the use ofthe handle as a lever, rolling up the free end into the 90 position checking the degree with alevel. When done properly the free end will be at the desired height and the arrow will be atthe stub height as indicated.In some installations there will be a need to cut down theunbent side of the conduit to another desired length to fitthe installation. Use a tube cutter for smooth precisecutting and burr removal to ensure the safety of theelectrical wiring when pulled through. A hacksaw can besubstituted as long as the tubing’s cut edge is preparedproperly.Klein Tools Tube Cutter: #88975 & 88977Klein Tools Hacksaw: #701-10, 701 -12 &701 -SKlein Tools Level: #931-6RE & 931-7RE3

Back to Back Bends:The back to back bend is the next style of bend that is needed while running electrical conduit. In realitythe concept is formulated by the need to know the distance from the back edge of a 90 bend to a fixedpoint down the conduit to mark for other bend operations to meet the installation requirement. As youwill see it builds on the 90 stub bend and when done the most common use of this bend will look likean elongated U.You will need to know this bend method when you want to fit conduit between two parallel surfacessuch as two walls or joists while keeping the U’s outer edges of the legs touching the two surfaces. Thisallows for proper anchoring and a nice clean appearance.1. Determine the distance betweenthe two parallel surfaces to get thedimension for back to back bend.2. The first bend for the back to back bend is the 90 stub-up bend. Follow the steps from the 90 StubUp section to create the ideal bend for theconnection on the first side.3. From the back edge of the 90 stub-up bend,measure the distance found in step 1 and makeyour mark on the conduit.4. Place the bender on the conduit with the bender’s hook facing the free end of the tube to bebent opposite the original bend side. Make sure the conduit is resting properly in the bender’scradle and lineup the Star Point Symbol with the mark you placed on the tubing.4

5.Keeping the conduit flat, apply ample foot pressure to the bender’s heel, with minimal use ofthe handle as a lever, rolling up the free end into the 90 position checking the degree with alevel. It is very important to keep the first 90 bend in the same plane as the new bend. If notthe two legs of the U will be skewed and will not produce the desired shape. If this happens,some correcting can be done to properly align the legs depending on how out of shape they are.When the bend is done properly the conduit will lay flat and will fit inside the two surfacesmeasured.In some installations there will be a need to cut down the unbent side of the conduit to another desired length to fit the installation. Use a tubecutter for smooth precise cutting and burr removal to ensure the safety of the electrical wiring when pulled through. A hacksaw can besubstituted as long as the tubing’s cut edge is prepared properly.Klein Tools Tube Cutter: #88975 & 88977Klein Tools Hacksaw: #701-10, 701 -12 &701 -SKlein Tools Level: #931-6RE & 931-7REIf the back to back distance is short (a tight U) so the bender has problems fitting to make thesecond bend, you may compensate by subtracting the stub height from the measured distance to fitthe gap then follow step 3 to mark the calculated number on the conduit. But this time you wouldput the bender on the conduit with the hook facing the first bend and line up the Arrow Symbol asdemonstrated in the Stub-Up section, step 5, with the conduit mark and proceed to make the bendas in step 5 rolling up the previously bent end up into the 90 position giving you the desireddimension. Caution should be taken when creating the second bend. With this technique the first bend will be coming atthe operator as the second bend is made.5

Offset Bends:An offset bend is a style of bend that is built independently of the 90 stub and the Back to Backbend and is an important bend to know when running conduit. It is common to shift the conduit acertain distance while continuing to run parallel in the same direction as the pre-shift portion of theconduit. There are many situations that call for an offset bend. The most common uses of this bendare: staggered joists, running tight on a wall and offset into an electrical box and changes inelevation.Offset Formula TableAngle ofBend10 X 10 22½ X22½ 30 X 30 45 X 45 60 X 60 ConstantMultiplier62.6Shrink PerInch of Offset1/16 .0633/16 .1882.01.41.21/4 .2503/8 .3751/2 .5001. Determine/measure the offset distance necessary to clear the obstacle and how far away theoffset will need to be bent from the end of the conduit.2.Decide what angle you wish to make the offset bend and determine the proper values from theOffset Formula Table. Calculate the proper values to mark on the conduit to clear the obstacleand fit in the gap measured.Offset Formula TableAngle ofBend45 X 45 ConstantMultiplier1.4Shrink PerInch of Offset3/8 .375As an example, the offset distance of the obstacle is 6” andthe distance to obstacle is 20”. The installation allows fora 45 X 45 offset bend. Note: The choice of degree isusually the installer’s choice and most of the time theinstallation location will determine what degree will fit.6

3. From the table use the 45 X 45 offset row for the values to calculate the series of markingsnecessary to make the proper bend. To find out where to place the first mark on the conduit,multiply the measured Offset Distance to clear the obstacle by the tables Shrink/Inch that willoccur to the conduit after all the bends are made due to that offset distance or:(Offset Distance) X (Shrink/Inch) Total Shrink.Example: 6” X .375 2.25” of total shrink.This value is then added to the measured Distance to Obstacle number or:(Distance to Obstacle) (Total Shrink) First Mark Distance.Example: 20” 2.25” 22.25” to make first mark.To calculate the second mark needed on the conduit, multiply the measured Offset Distance bythe Constant Multiplier of the table or:(Offset Distance) X (Constant Multiplier) Second Mark Distance (Distance between Marks).stndExample: 6” X 1.4 8.4” between 1 & 2 mark.This calculated value is how far apart to make your marks from each other on the conduit andwhere to make your 45 bends.4.Using the technique to align thebender on the conduit asdescribed under the Stub-UpSection 5, Place the bender onthe conduit with the hookfacing away from the secondmark and line up the ArrowSymbol up with the first mark.7

Keeping the conduit flat, apply ample footpressure to the bender’s heel minimizing the useof the handle as a lever, smoothly rolling up thefree end until the 45 mark is reached. Whendone properly the free end will be at a 45 anglefrom the original plane.5.Note: Some over bending may be required to allow forspring back of the conduit. The resting condition of theconduit is to be at the final angle desired.6. Keeping the bender and conduit together flip thetwo parts upside down and put the bender’s handlehilt on the floor, balancing the conduit in the air,allow the conduit to rotate 180 in the cradle. Slidethe conduit down so the first bend is moving awayfrom the bender head, aligning the second mark asoutlined before using the Arrow Symbols (See StubUp section, note 5).7.The second bend of the offset isaccomplished by performing an air-bend. Makesure the handle hilt is secure on ground and isreinforced by your foot so it does not slide out.Make sure you are balanced and apply force closeto the tool and your body controlling the tubing asyou bend it around the bender’s cradle. Bend thefree end until the 45 mark is reached.It is very important to keep the first 45 bend in the same plane as the new bend will be. If not, the twolegs of the offset will be skewed and will not produce the desired shape. If this happens, somecorrecting can be done to properly align the legs depending on how out of shape they are. When thebend is done properly the conduit will lay flat and fit inside the measured distance to and clear theobstacle.In some installations there will be a need to cut downthe unbent side of the conduit to another desiredlength to fit the installation. Use a tube cutter forsmooth precise cutting and burr removal to ensure thesafety of the electrical wiring when pulled through. Ahacksaw can be substituted as long as the tubing’s cutedge is prepared properly.Klein Tools Tube Cutter: #88975 & 88977Klein Tools Hacksaw: #701-10, 701 -12 &701 -S8

Three Point Saddle Bend:The three point saddle bend is a variant of the offset bend since it is an offset bend that returns to theoriginal in-line run after clearing an obstacle. This bend is intended to bridge over obstacles such asexisting conduit or plumbing running perpendicular to the intended conduit installation.1.Determine/measure the offset distance necessary to clear the obstacle and how far away thesaddle bend will need to be from the edge of the conduit. Unlike the offset bend you mustmeasure to the center of the obstacle to bridge over.2. Choose the angle that will be used for the center bend. The other two return bends will be 1/2the center angle chosen. If the center angle is 45 , the two return bends will be 22.5 . Use thetable to calculate the distance between bends and how much shrink is to occur to the conduitdue to the bends.Degree ofBend:3 Point Saddle Bend Table45 Ce