Manufacturing Workmanship Standards
ManufacturingWorkmanship StandardsYHF-WS Rev 2Approved by & date:02/25/16Approved by & date:02/25/16
York Haven Fabricators, Inc.Workmanship StandardsThis document is a statement to the quality and workmanship of York HavenFabricators, Inc., henceforth referred to as YHF.The definitions, procedures, and responsibilities contained in this WorkmanshipStandard are fully supported by:PresidentMichael ShefetGeneral ManagerRichard WashkoSenior ProgrammerJim SaubleProduction ManagerMichael GoodlingMaterial Review Board:General ManagerRichard WashkoQuality ManagerJon SobkowiakQuality TechnicianPaul NashProduction ManagerMichael Goodling 2
York Haven Fabricators, Inc.Workmanship Standards1) PurposeThe purpose of this specification is to define standard quality workmanshiprequirements for sheet metal fabricated by YHF.2) ScopeThe intent of this specification is to supplement all engineering drawings,blueprints, and customer specifications. If a conflict exists between this specificationand the requirements outlined in the engineering documents or customerspecifications, engineering documents and customer specifications shall takeprecedence. This workmanship standard shall be invoked when aforementioneddocuments do not clearly define requirements.3) ResponsibilityIt shall be the responsibility of all YHF personnel to conform to requirementscalled out in this workmanship standard.4) General Sheet Metal RequirementsA) The tolerances in this specification shall not override those provided onengineering documents, blueprints, and specifications. In all cases, blueprinttolerance or work order instructions shall override this standard.B) All blueprint dimensions will be interpreted as prior to organic finish unlessspecified otherwise.C) When grain direction is not specified, raw material will be nested to maximizeusage.D) Variation from flatness shall not exceed 0.005” per inch of material.E) Angles not specified on engineering documents which appear to be 90 will beinterpreted as 90 . Angular tolerances will be interpreted as /- 1 if notspecified on the documents.F) Nibble marks as a result of multiple punching sequences are not considered aburr. Nibble marks are acceptable and will be minimized whenever practical. 3
York Haven Fabricators, Inc.Workmanship StandardsG) Mismatches or steps on a punched edge or cutout may not exceed 0.010”.H) When bend radii are not specifically called out on the blueprint or specification,a sharp radius shall be manufactured.I) Radii on ground surfaces shall be blended smoothly, consistent with the externalsurface radii. No flat areas are acceptable.J) Large bend radii will cause grain to stretch and distort or smooth out. This is tobe expected and considered acceptable.K) Weld spatter is not desired and shall not appear on cosmetic surfaces. Minorweld spatter is acceptable on non-cosmetic surfaces. All hardware, thru holes,and threads must be free of weld spatter.L) All features which are dimensioned from a formed edge shall be measured at thebend line. Angular, squareness and flatness call-outs will govern the remainderof the profile.M) Hardware shall be installed per manufacturer’s specification. When drawingrequirements conflict with manufacturer’s specifications, YHF shall not beresponsible for resulting limitations.N) Slight imperfections in diameter and edges related to the start of a laser cut or“Lead-In” are typical in laser operations and not considered a defect. 4
York Haven Fabricators, Inc.Workmanship Standards5) General Dimensions and TolerancesA) The following chart depicts general manufacturing tolerances, which can beaccomplished with standard manufacturing techniques. Stud or standofflocations shall be taken from the base of the hardware. Specifications whichrequire closer tolerances than those listed below will typically require specialprocessing or fixturing to obtain compliance.Dimensioned TolerancesHole to HoleHole to EdgeEdge to EdgeHardware to HoleHardware to EdgeHardware to HardwareHole to BendBend to HardwareBend to BendBend to EdgeTolerance /- 0.010” /- 0.010” /- 0.010” /- 0.015” /- 0.015” /- 0.020” /- 0.015” /- 0.020” /- 0.030” /- 0.015”B) The following chart indicates standard hole diameter tolerances which are to beheld during fabrication at YHF. The tolerance for any size diameter requiringhardware is .003”/-.000”.Hole DiameterLess than 0.250”0.251” to 0.500”0.501” to 1.000”1.001” to 2.000”2.001” to AboveTolerance 0.003”/-0.002” 0.005”/-0.002” 0.008”/-0.002” 0.010”/-0.003” 0.015”/-0.005”C) Shapes other than circular are defined as cutouts. Unless otherwise specified,the tolerance for cutouts shall be /- 0.015”. 5
York Haven Fabricators, Inc.Workmanship StandardsD) Countersink diameters have standard tolerances independent of the above listedstandard diameter tolerances. These tolerances are listed as follows:Countersink DimensionLess than 0.250”0.251” to 0.500”0.501” and AboveStandard Tolerance 0.012”/-0.003” 0.016”/-0.003” 0.020”/-0.005”E) Sheet metal will be purchased with a nominal requirement. Nominal dimensionswill have a tolerance as listed below. Material thickness shall be measured noless than 1.00” from any coil width �.3125”.375”.500"Cold ”.090”.105”.120”.135”- /-.003 /-.003 /-.003 /-.004 /-.005 /-.005 /-.005 /-.006 /-.006 /-.007-Hot RolledPickle & ��.187”.250”.3125”.375”.500” /-.005 /-.005 /-.005 /-.006 /-.006 /-.007 /-.007 /-.010 /-.012 /-.015 /-.015 /-.015Stainless 5”.375”.500” /-.002 /-.002 /-.002 /-.003 /-.003 /-.004 /-.004 /-.005 /-.005 /-.006 /-.007 /-.009 /-.012 /-.015 /-.015 �.079”.094”.108”.124”.138”- /-.003 /-.004 /-.004 /-.005 /-.006 /-.008 /-.008 /-.009 /-.009 .063”.080”.090”.125”.190”.250”.375”- /-.002 /-.003 /-.003 /-.004 /-.004 /-.004 /-.005 /-.005 /-.006 /-.009 /-.012 /-.015-F) When tolerances are not specifically called out on blueprints, YHF willmanufacture sheet metal products to the following tolerances.XXX”.XX”.X”Fractions /- 0.030” /- 0.030” /- 0.030” /- 1/16” 6
York Haven Fabricators, Inc.Workmanship Standards6) Sharp Edge and Burr StandardsA) Unfinished End ProductI) Unfinished material being punched or laser-cut will be dressed at theblanking operation to remove laser slag or burrs. A burr is defined asraised or displaced metal.II) When a specific callout for safe handling edges are identified on thedrawing, specified edges must pass the requirements of UL 1439sharpness specification. Safe handling edges are typically limited tocustomer or end user interface or maintenance areas.III) When edges on material require as edge which exceeds the requirementsof UL test, drawings must call out specific edge break, radius or chamferdimension.B) Pre-Coated MaterialI) Coated raw material (Tri-Clear, galvanized, etc.) is material whichgenerally in not timesaved or dressed-up after punching or laseroperations.II) When a specific call-out for safe handling edges are indentified on thedrawing, specified edges shall be deburred by hand to a level which canmeet the requirements of UL 1439 sharpness specification.III) When the drawing does not specify burr size or safe handlingrequirements, product may be supplied with a maximum burr of up to 5%of the material thickness. 7
York Haven Fabricators, Inc.Workmanship Standards7) FinishesA) All rust, stains, manufacturer’s ink stampings, and other blemishes shall beremoved.B) Class A Criteria – Highly CosmeticI) Surface Preparation Class A surfaces are either the industry standard #4 finish,polished, or other processing performed without coating material(shotpeen, tumbling, etc.). The grain will, unless otherwisespecified, run parallel to the longest dimension on the part.Graining or processing shall remove all scratches or imperfectionswhich exist in the material. Class A finishes shall be free of any burrs, and surfaces shall beprepared per Section 6.A, subsection I. Class A surfaces shall be restored after processing. Slightmismatches may be observed when blending grain on large radii(ref. Section 4.I) or when matching a supplied grain.II) Acceptance Criteria Class A bare metal finishes shall be free of the following defects ata viewing distance of three feet for an unlimited time period: Scratches Pitting Weld Burns or Spatter Dents or Depressions StainsC) Class B Criteria – SpecificI) Bare metal finishes are typically highly cosmetic or have no specialrequirements. If requirements do not fall under Class A or Class C, specificcriteria must be called out on the drawing.D) Class C Criteria – Non-CosmeticI) Class C finishes shall be free of any burrs and surfaces shall be preparedper Section 6.A, subsection I. 8
York Haven Fabricators, Inc.Workmanship Standards8) Packaging and Shipping RequirementsA) Finished product shall be packaged to protect product from damage caused byshifting of material within the container and from possible abuse duringshipment. Particular attention and care must be given to parts having protrudingdetails or hardware.B) Packaging containers shall be full as a result of filling with product and packingmaterial to prevent shifting of product during shipment.Approved by & date:Approved by & date: 9
York Haven Fabricators, Inc. Workmanship Standards 2 This document is a statement to the quality and workmanship of York Haven Fabricators, Inc., henceforth referred to as YHF. The definitions, procedures, and responsibilities contained in this Workmanship
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York Haven Fabricators, Inc. Workmanship Standards 4 G) Mismatches or steps on a punched edge or cutout may not exceed 0.010". H) When bend radii are not specifically called out on the blueprint or specification, a sharp radius shall be manufactured. I) Radii on ground surfaces shall be blended smoothly, consistent with the external
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