C11000 ETP Copper CNC Turned Parts, C11000 Copper Components Screw Machine Parts
Rate: US$19.50 per kg
Electrolytic tough pitch copper is a useful starting point when a machined part must carry current through a substantial copper cross section. Typical requests are threaded adapters with wrench flats, terminal bodies with a blind or through bore, stepped conductive posts and contact discs with a defined seating face. Conex Screws reviews the relationship between the intended current path and the mechanical interfaces before selecting a machining route. A part can pass ordinary diameter checks yet seat on a thread runout instead of its conductive shoulder. That distinction matters when heat must leave the joint through the same faces that carry current.
The UNS designation C11000 identifies the material composition. It leaves the bar form, temper, final geometry and acceptance tests to the drawing or purchase order. Copper Development Association lists a minimum of 100% IACS for this grade in the annealed condition. Use the material certificate and the applicable product specification for the ordered form and condition. An IACS value is a material property, while joint resistance includes the contact interfaces, clamping arrangement and surface condition of the finished assembly. Equipment designers establish current, temperature rise and electrical life in the intended assembly.
Component families and their critical features
| Part or characteristic | Drawing and application details | Inspection and quoting considerations |
|---|---|---|
| Terminal bodies with axial tapping | Identify the shoulder or pad that carries current and the threaded hole that supplies clamp force. | Confirm full-form thread depth before tool runout and verify the bearing face against the primary axis. |
| Stepped contact posts | Control the locating pilot and the transition into the contact shoulder. Keep the corner radius compatible with the mating part. | Check step length from the seating datum and measure runout at the indicated diameter. |
| Wrench-flat adapters | Put the flats on a sufficiently robust section and show where a wrench may contact the part. | Inspect across flats, root clearance and wall remaining under the flats, particularly near a blind tap. |
| Contact discs and pads | Define which face touches the mating conductor, the contact diameter and any recess used for location. | Separate flatness, finish and face runout. A disk can meet one of those requirements while failing another. |
| Through-bored terminals | Show whether a bore locates a conductor, provides clearance or accepts a threaded member. | Control the bore and end faces from a common reference. Check the exit for raised edges that prevent seating. |
What to specify for C11000
| Part or characteristic | Drawing and application details | Inspection and quoting considerations |
|---|---|---|
| Bar stock and temper | Order the UNS grade, form and temper together. When calling up a rod or bar specification, check the edition and product scope. | For temperature-sensitive assemblies identify whether the part is brazed, soldered or subsequently heated. Process heat can affect the resulting condition. |
| Thread fit at delivery | Define Unified or metric designation, class, usable engagement and the end that accepts the mating component. | Check the finished thread with the agreed gauge where plating is specified. A standard thread designation alone leaves usable depth open. |
| Stud interface | Share the stud drawing or a dimensioned sketch of the mating shoulder, thread end and washer stack. | A top thread that engages freely can still bottom out against a blind hole or shoulder before the pad makes contact. |
| Bolted contact face | Define flatness, roughness and an inspection area. Include the intended direction of clamp force and any finish boundaries. | Take resistance or temperature measurements in the assembled joint if the equipment acceptance plan calls for them. |
| Clearances at pads | Mark any conductor envelope, tool access and insulating clearances that constrain the machined profile. | Verify against the equipment layout. The cutter clearance and the assembly clearance solve different problems. |
Engineering questions for the first article
What changes when the contact face is a datum?
Using the actual bearing face as a datum connects the inspection setup to the functional assembly. Establish the reference cleanly and specify face runout or perpendicularity to the relevant turned diameter as required. Measuring everything from the opposite cutoff end can hide a short shoulder or a tilted pad.
Can the certificate replace a resistance measurement?
A lot certificate identifies the stock properties requested by the purchase order. It provides one input to electrical design. For a resistance limit on a connector assembly, define the mating parts, applied force, surface preparation, measurement points and temperature. A four-wire method can separate lead resistance when the method is appropriate.
How should silver or tin plating be specified?
Identify the coated surfaces, coating thickness basis and any masking on a print. Specify whether dimensions apply after coating and how to inspect coverage in recessed areas. For deep internal threads ask which surfaces are measurable and which agreed method will support acceptance.
How do we protect a flat contact pad in transit?
Use clean separation between parts and keep other components from rubbing on the working face. List any packaging material restrictions and identify the face on an illustration so both production and receiving inspection see the same requirement.
Example of a C11000 terminal drawing review
Consider a drawing for a threaded terminal with a turned pilot, a flat annular pad and a blind tapped hole. The customer’s insulating housing locates on the pilot. The mating conductor sits on the annular pad and is secured with a screw. Three separate checks matter. The screw must enter without striking the drill bottom, the bearing face must engage across the intended pad and the pilot must fit in the housing without forcing the part off axis. Sending the three drawings together helps establish where the useful thread and true bearing area begin.
Suppose the mating screw projects 9 mm below the conductor stack at nominal conditions. A tapped hole labelled 10 mm deep may appear adequate. If 10 mm describes the drill depth including the point, and the tap requires clearance for runout, the full-form thread can be shorter than the screw projection. Calculate the projection using the longest screw and thinnest permitted stack and specify both usable thread depth and minimum end clearance. The chosen dimensions must also allow a sufficient copper section behind the hole. This is a drawing-review example with illustrative dimensions.
Separate resistance in the copper from resistance at the interface
Bulk resistance depends on resistivity, effective cross section and length. For a simple straight cylindrical segment, its cross-sectional area is proportional to the square of its diameter. A local reduction in diameter therefore has a larger effect on area than the same percentage change in length. A threaded region, radial hole or deep counterbore can introduce a reduced section that a simple overall diameter calculation misses. Evaluate the narrowest part of the current path and the way current spreads into the contact pad before selecting dimensions.
Contact resistance is also influenced by the actual points of metal contact, clamp force and the surface condition. If current passes from an adapter into a bus connection, establish where the assembly draws heat away and where temperature will be recorded. Submit the mating bus or terminal detail when the conductor is much wider than the turned pad. Give the inspection team clear separation between dimensional acceptance of the turned part and any electrical test on the complete connection.
Review bearing stress and threaded assembly
A large outside diameter can leave a small annulus when a bore or relief removes central material. For illustration, a circular seat with outside diameter 16 mm and inside diameter 10 mm has nominal annular area of about 123 square millimetres before any chamfer, flat or groove is deducted. Actual pressure distribution depends on the mating faces and the applied force. Use the design review to check that the washer, screw head and shoulder load the region intended for support. Specifying the outer diameter alone leaves the real bearing area ambiguous.
Where copper parts are clamped between harder members, identify which surface must retain shape through assembly and service. For a thin shoulder consider the supported region and the local relief at the thread start. Give the design torque and temperature requirements with the assembly test plan when a torque trial is requested. Conex Screws can quote dimensional and agreed sample checks from the submitted assembly detail.
Suggested references for ETP terminals
Consult the Copper Development Association C11000 data sheet for material-property references and the applicable ASTM stock specification for the ordered bar. Use the drawing’s thread and geometric dimensioning standard to define finished acceptance. Specify those documents by revision when they govern a purchase order. If a stock note and a component note differ, flag the difference before releasing the part for production.
How to prepare a drawing for quotation
Send a dimensioned PDF for acceptance and a STEP model for geometry review when available. Identify the current revision on both files. The PDF should distinguish basic, reference and toleranced dimensions, specify units and define precedence when the model and drawing disagree. Share the assembly context if the finished part seats against an insulator, mates with another copper piece or passes through an enclosure. The most valuable information is usually a section through the working axis and a note identifying the features that govern acceptance at receiving.
Mark the expected order quantity, lot size and annual demand separately. Production tooling, inspection and stock planning depend on how the demand is released. A batch of samples can qualify geometry before the full release. If the drawing changes between a sample and production order, state whether the earlier inspection report still applies and list the features affected by the change. Include any quality clauses that carry over to later releases.
Choose the stock specification and condition
A copper grade is a material designation. It does not specify all of the attributes of the starting stock. State the form, temper, material specification and revision required by the contract. Where the drawing cites ASTM B187/B187M for copper rod, bar or shapes, confirm that the grade and stock form are covered by the selected edition and scope. If stock is approved to a different standard, request engineering disposition before material is ordered. Separately identify the requirements for the finished component, including dimensional checks, coating and packaging.
A material test report is most useful when the receiving team can map it to the parts in a container. If traceability is contractual, define whether it must be maintained by heat, manufacturing lot or individual piece, and how identification will be applied. A bag or carton label can protect working surfaces from marking. A permanent stamp needs an approved location away from mating faces, thin walls and tight diameters.
Set up the turning sequence around the working interface
Turned features that share an axis may benefit from production in one setup. A long bore, slot or radial hole can still require an additional operation. Establish which relationships drive the setup before the machining plan is frozen. If a part must transfer to another chuck or a separate fixture, identify the gripping zone and the surface that re-establishes the location. Check whether a previously finished section must be protected against fixture marks.
A part drawing can leave the machining sequence to the supplier while preserving requirements for the result. For qualification, ask the supplier to explain how the operation sequence protects critical faces and how it will respond when tools wear or stock changes. Where sequence is contractual because of an approved special process, put that requirement on the purchase order and identify the conditions under which a change needs customer approval.
Specify bore geometry and tool access
On a blind hole, distinguish total drilled depth from the depth of full cylindrical diameter. If the hole contains a thread, specify full-form thread depth separately from the depth of drill point and thread runout. A counterbore or spotface should have its own dimension from the reference face. Deep narrow passages need sufficient access for measurement as well as for machining. If the application accepts the natural drill point, that allowance can help simplify inspection and production.
For a through bore, give the edge requirement at both ends. A raised burr on the exit face can prevent the part from seating and skew an assembly. If a radial passage intersects the axial bore, establish where the edges may be broken and which intersection surfaces must remain clear. Inspection may combine measurement of the passage with a visual or functional check for blocked flow or snagging, depending on the application.
Use thread callouts a buyer and inspector can verify
Use the thread series, nominal size, pitch and class from the drawing. Unified inch callouts can refer to ASME B1.1 as applicable. A metric M-profile callout uses a metric diameter and pitch and its own tolerance designation. State left-hand thread explicitly when required. For an unusual thread, supply the mating drawing or master and the acceptance method. A drawing that shows only nominal diameter may leave incompatible threads looking interchangeable to a buyer.
Define usable engagement, the clearance at the end and the entry edge. On a blind tapped part, specify how much full-form thread is needed ahead of the runout. On an external stud-like feature, verify that a relief groove does not remove a length needed for engagement. Standard thread gauges check the aspects of the thread covered by their design. Where an installed shoulder or a mating member with its own runout limits travel, add a functional fit check to the inspection plan.
Compare turned surfaces, finish and edge treatment
The surface roughness requirement should identify the parameter, units and working area. When traces can run in more than one direction, specify the direction relevant to the function and the method if it is important for repeatability. Compare the desired finish with what the actual bearing surface or bore can accommodate. A small annular contact pad may leave limited space for an instrument trace, so agree the method before production.
Define where burrs are unacceptable and where edge rounding is constrained. A blanket edge break may be inappropriate on small grooves or edges that establish a working length. Show these as exceptions and identify safe handling edges where a normal chamfer is acceptable. Agree whether small surface marks are cosmetic or restricted by a functional requirement. A photographic limit sample can help clarify a finish specification when visual acceptance matters.
Plan coating around the finished part
Tin, silver and nickel can serve different functions. Specify the coating and any underlayer, thickness and areas to cover on the drawing. Call out surfaces that need masking, any limits on buildup or bridging, and areas used for rack contact if a witness mark matters. Report material and coating requirements separately so the ordering team can distinguish the base copper from the final surface. When the intended process is still being selected, describe the application and ask for an engineering review.
In a simple concentric bore with a uniform deposit on both opposing walls, a coating of thickness t on each wall reduces the diameter by approximately 2t. A corresponding outside diameter increases by about 2t. This geometric estimate assumes uniform coverage and simple cylindrical surfaces. A deep blind hole can plate unevenly, and threads require separate treatment of flank geometry and gauge fit. Verify the finished fit using the inspection method agreed for the drawing.
Agree how critical dimensions will be measured
The inspector needs the same functional datums as the design and assembly teams. Specify what establishes the axis, the face from which axial distances are measured and any feature that clocks a slot or hole. A datum setup should support the part without distorting it. For short or slender features, identify a practical checking method before committing to a tight dimensional tolerance. A dimension that can be machined reliably still needs a method that can distinguish conforming parts.
External diameters can be measured at selected planes, while bores may require plug gauges, internal measuring instruments or coordinate measurements. A go gauge confirms an acceptance condition within its design. It does not report the full bore profile. If taper, ovality, position or axial variation matters, put that geometric requirement on the drawing and agree how to check it. Document the inspection condition when temperature, measuring force or fixturing can change the readings.
First article and ongoing inspection
A first article is most useful when it comes from the intended production material and process route. Ask for a marked-up drawing with numbered characteristics and a report showing actual values for the agreed dimensional features. Give a separate row to any functional test, material verification or coating acceptance criterion. Review the lot certificate and finished inspection together so the identified sample can be tied to its stock and operation history.
Agree sampling and records before production. Identify any features subject to complete inspection, any dimensions to record at process intervals and the method for addressing a suspect batch. If process capability is requested, define the study conditions and the minimum data set. A first article shows an inspected sample at a point in time. Ongoing records and change control show whether the agreed process continues to deliver the same features during repeat orders.
Receiving and handling of machined copper parts
Decide how parts are cleaned after machining and after any coating. Bores, slots, blind recesses and intersecting holes can retain chips or processing fluid. Give a cleanliness test or an acceptance sample when the allowable condition is important. Define whether the supplier may use corrosion protection or whether the component will go directly into a customer cleaning, soldering or assembly step. Incompatible protective products can create additional preparation work at receiving.
Protect dimensions that are easy to mark or distort. Separate sharp projections from thin walls and keep the working faces from rubbing against one another. Discuss trays, dividers, individual sleeves or simple bulk packaging in light of the size, surface condition and handling route. Identify the lot, drawing revision, order number and quantity on the outer label when requested. Where the parts are supplied in groups for a matched assembly, give each group a distinct identifier.
Common RFQ questions
Can Conex Screws quote from a sample?
A physical sample can help identify the machining route, mating conditions and finish. Supply a drawing or approve a controlled drawing before production. Surface measurements on the sample may include wear, distortion or coating, so identify the accepted nominal values and state whether a replacement part must mate with legacy hardware.
Can I request both metric and inch information?
Yes. Use one unit system as the controlling dimension set and mark the other as reference where appropriate. An exact unit conversion can produce a precision that the original tolerance did not intend. Keep the thread family in its native designation. If the product goes into a mixed-unit assembly, share the mating drawing with the enquiry.
How are tolerances and lead time confirmed?
Review is based on grade, part geometry, tolerances, inspection, lot size and the stock or tooling needed for the order. Highlight the dimensions tied to assembly or electrical performance. Conex Screws can then review measurable acceptance methods, production sequence and lead time with the buyer at quotation.
How does the per-kilogram rate relate to ordering?
The listed rate for this product family is US$19.50 per kilogram. Send the drawing and requested quantity for a written quote that identifies the order basis, finish, inspection and shipping terms. If your purchasing system orders individual pieces, request the agreed piece-weight basis and price presentation for the quotation.
Can I specify a material grade different from the examples?
State the UNS designation, specification and temper and provide the target application. Quote review can check grade and stock availability, cutting access and inspection. Procurement should approve the exact designation against the drawing before any material is released.
Which checks apply before and after plating?
Use before-coating checks where they control machining or establish a baseline. Set finished-part acceptance against the agreed drawing and functional gauges. Where access is limited, agree coating measurement locations and test frequency at quote stage. Provide an approved mate for assembly-sensitive interfaces when useful.
What should a quote package include?
Provide the product drawing, revision, part quantity, target delivery, material grade and temper, critical tolerances, finish, packaging and any required reports. Include the mating drawing or assembly section if available. Attach any first article forms and identify requirements that have to be agreed before materials are procured.
Turn an assembly requirement into an inspection characteristic
Start with a sentence describing the risk. A part that stops short at assembly, rocks under a clamp or loses engagement during handling needs a different check in each case. Identify the feature in the drawing section that controls the outcome. Write its acceptance as a measurement with a datum or as a test with a controlled mating condition. Avoid a note that relies only on interpretation, such as asking for a good fit, when the requirement can be described in a drawing or test plan.
Create a short list of characteristics that govern release. Review them with the receiving team so the supplier knows which actual values and documents to include. A first article can document the relationship between related features, and ongoing checks can focus on the measurements likely to change during production. If a tolerance is changed in the drawing, record which master sample or gauge revision applies. When the fit depends on a downstream operation, agree whether the receiving inspection verifies an intermediate condition or the finished assembly.
Manufacturing and purchasing checklist
Before ordering, confirm that the drawing names the component and clearly identifies the part revision. Verify that the quotation records the same material and the same delivery condition. Ask for an approved sample or dimensional report if the geometry is new, if a new stock size must be sourced or if the same part number was previously ordered with a different finish. Include an approved deviation on the order when engineering has accepted an exception. Identify the point at which approval expires if the deviation applies only to samples.
Set the information required for future reorders. Preserve the drawing number, revision, material requirement and the inspection or packing conditions that define the part. Where samples use a process different from the intended production route, agree what evidence the production process needs before release. Where a surface has multiple requirements, identify their order of precedence and the areas to which they apply. This gives purchasing a repeatable order description and gives the incoming inspector a set of clear checks.
Define the finish and limits for visual acceptance
A finished machined surface may have normal turning marks visible under directional lighting. When appearance affects assembly or end customer acceptance, state the lighting, viewing area and permissible marks, or reference approved samples. On a concealed body, machining marks outside the working area may matter only where they create a burr or change the dimension. On a mating diameter or face, the same marks can affect seating or friction. Set the acceptance area on the drawing and identify any surfaces where contact from packing material is restricted.
Agree how witness marks are handled. A rack contact can leave a small mark after plating, and a fixture can mark a part during transfer. Restrict marks on the functional zone and establish any agreed acceptable areas before the process is approved. Keep the visual limits separate from quantitative checks for dimensions, roughness and coating thickness. When a part is intended to be further machined, specify which surfaces remain on the completed assembly and which are left as extra stock.
Material, thread and product references
- Copper Development Association C11000 data
- Copper transformer studs
- ASTM copper rod, bar and shapes specification
- ASME Unified inch screw thread standard
Send your drawing to Conex Screws
For a quotation, provide your drawing revision, material designation, finish, order quantity and any inspection documents. Include the mating geometry where fit matters. Conex Screws will review the manufacturing and acceptance requirements with your engineering or purchasing team.
Email your drawing for a quote at sales@conexscrews.com
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