FabricateaTrivet

Description

Metalfabrication involves basicskills such as cutting,bending, and assemblingto createsomethingfrom raw material. Inthis activityplan,students will layout, cut,bendandassembleatrivetaccordingto theblue prints. Trivetsarea functional lowplatform usedto keep hotobjects offsurfaces that cannot tolerate high heat. Teachers will lead equipment and processdemonstrations andthe students will followup by building atrivet.

LessonObjectives

The student willbeableto:

•Identifycommonmetals

•Identifycommon fasteners

•Demonstrateappropriateshop behaviour

•Demonstratesafe andappropriate useofhandtoolsand equipment

•Useappropriate layout toolsand scales

Assumptions

Thestudent:

•Knowsbasic metallurgy

•Knows howto usehand tools safely

•Knowsbasic measurement

•Understands basic layouttechniques

EstimatedTime

5–10 hours

Thetimeforthis activity willdepend onthefamiliarityof studentswithtoolsandthescope oftheproject(how much teachers prepare for studentsahead of time, or how far theytake thefinishingportionofthe project, based on theavailabilityoftools/equipment).

RecommendedNumberofStudents

20, basedonBCTechnologyEducators’Best PracticeGuide

Facilities

Secondaryschool metal shop orequivalentlyequipped technology educationshop

Equipment/Machinery

•Benchgrinder

•Box and pan brakeor bar folder

•Di-Acrobender

•Drill press

•Foot shear

•Handdrill

Tools

•Aviationsnips

•Beverly shear orhacksaw

•Centre punch

•Poprivet gun

•Scribe

•Sharpie

•Square

•Steelscale

•Emerycloth

Materials

Item / #ofpieces / Material / Thickness / Width / Length
Trivetlegs / 4 / ½" flat bar / 1⁄8" / ½" / 6"
Trivet body / 1 / 22ga sheet metal / 22ga / 7" / 7"

8–1⁄8"steel rivets

Resources

Howto useaBeverly shear

Howto usea footshear

Howto use apoprivet gun

Howto use aboxand pan brake

Teacher-ledActivity

Leadthe class throughthefollowingstepstofabricate a trivet.Refertotheplansprovidedbelow.

Legs

1.Obtain½"flatbar.

2.Teacher demonstrates safe andcorrect useofBeverly shear orhacksaw.

3.Layoutlinesat6"andcutbarstock on Beverlyshear(4 pieces required).(IfBeverlyshearisnotavailable,havestudentsuse a hacksaw.)

4.File endsof 6"barstock round and remove anysharp edges.

5.Using layouttools:

a.Draw a centrelinedownthelengthoftheflatstock.

b.From one end, measure ½" and mark with centrepunch.

c.Then measure ½" fromprevious mark.

d.Centre-punch both marks.

6.Teacher demonstratessafeand correct use of drill press.

7.Drill ⅛" holes atcentrepunchmarks.

8.Fileexcess metalfrom drilling.

9.Teacher demonstrates safeand correct useoftheDi-Acrobender.

10.UseDi-Acro bender to bend a1"radiusbendon all four barsofmetal, atopposite ends tothedrilledholes.

Di-Acrobender

If no benderisavailable,a simple jig canbe made forstudentsusinga1"diameterpipeheldina bench viseto create radius.

Base

1.Get7"stripofsheetstock(22gaugemildsteel).

2.Teacher demonstrates safe andcorrect useofthefootshear.

3.Cutone piece at7" (perfectly square).

4.Using layouttoolson oneside:

a.Scribelines fromcorner tocorner diagonally onone sideofsheet metal.

b.Measureand centre-punchholes1"from theintersection.

5.Using layouttoolson reverseside:

a.Scribea line4 mm from edge of all four corners.

b.Scribe a second line 8 mmparalleltothefirst.

c.At 24 mm from each corneron the outsideedge, mark apoint,drawaline on eachcorner tojoin thesepoints.

6.Cutoffcorners withfoot shear.

7.Drill ⅛" holes on centrepunchmarksalongthediagonallines.

8.Teacherdemonstratessafeand correct useofbarfolder(orboxandpanbrake).

9.Foldalong scribed linesusingbarfolder(orboxandpanbrake).

a.First fold, alltheway.

b.Secondfold, 90 degrees.

Assembly

Teacher demonstratessafe andcorrect use of popriveter.

1.Using a pop riveter,rivetthefirstholeinthesheetmetaltothelegs.

2.Usethe second hole inthe legsto lineup the second holeon the base.

3.Drill second ⅛"holewithhanddrill.

4.Rivet second ⅛"hole.

Finishing

1.Clean anygrease,dirt,or scratches offmetalusing emery cloth.

2.Chooseanappropriatemethodoffinishing(painting,powdercoating,etc.).

Evaluation

Consider co-creating theevaluationcriteriawithyourstudentsatthebeginningoftheactivity/project. You maywanttoincludethe following:

•Allfour corners aresquare

•Allfoursides are the sameheightandall sidesareparallel tobottom

•Rivetsaresecureandfiledflatandsmooth

•Allfourlegs are of uniformsize andbend

•Finish: All files markedareremoved,andsandingisuniform

TrivetBodydrawings

Trivetbodydrawings

TrivetLeg specifications

Trivet leg specifications