Define success by the passage geometry, not depth alone
A manifold drilling has to reach the intended connection while preserving nearby cavities, threads and wall sections. The manufacturing task includes where the hole starts, where it ends and how it intersects other features. Those relationships matter alongside the hole diameter and depth.
Long internal passages
Plan the route against the material and condition, diameter, required depth, entry surface and available access. Tool reach and chip-removal requirements are assessed for the actual component before process suitability is confirmed.
Cross holes and branch passages
Connect the specified drillings in the approved locations. The sequence must account for interrupted cutting, internal edges and access for later deburring, including intersections near valve cavities.
Passages from different faces
Keep the locations and drilling depths related to the drawing datums. For opposed or intersecting drillings, define the required connection and applicable positional requirements before setting up the part.
We confirm achievable depth, diameter, geometry and inspection scope from your drawing. No single maximum depth, length-to-diameter ratio or accuracy figure describes every material and manifold. Layout changes are resolved with the design owner before they become machining instructions.
Review passage layout and manufacturing accessUse the drawing datums to connect every setup
A correctly located entrance does not prove the full drilling follows the intended path. Setup and tooling need to support the specified geometry through the depth of the feature and across any change of machining face.
Locate and support the component
Plan workholding around the drawing datum system, tool access and the surfaces that must remain undamaged. Keep features machined in different setups tied to the same part definition.
Control entry and reach
Consider entry geometry, tool alignment, support and the reach needed for the operation. A sloping or interrupted entry can change the cutting conditions; the process route must account for it rather than treating every start as a flat face.
Define the end of the drilling
Keep the drawing’s depth convention clear, including drill-tip and full-diameter depth where relevant. Increasing depth to reach a junction requires checking the effect on neighboring features and obtaining approval for any design change.
Keep the cutting process stable as the passage develops
Hole quality depends on the interaction of the tool, material, setup and chip removal. We connect those process choices to the approved feature requirements, rather than treating the drilling cycle as an isolated operation.
| Control point | Why it matters | Manufacturing response |
|---|---|---|
| Tool geometry and condition | A worn or unsuitable edge can affect hole size, surface condition and burr formation. | Match the tool to the material, geometry and operation; manage its condition alongside the relevant feature checks. |
| Chip formation and evacuation | Retained or poorly evacuated chips can damage the hole surface and disrupt cutting. | Select the drilling strategy and cutting-fluid provision for the operation. Address chip-removal problems before continuing with the same process. |
| Crossing an existing hole | Cutting support and chip evacuation change as the drill enters and leaves the intersection. | Plan the crossing as part of the operation, considering the tool, material, intersecting geometry and drilling sequence. |
| Repeat production | A conforming first part does not establish that later parts remain conforming as tools and conditions change. | Keep the released setup and tooling requirements connected to the specified inspection checkpoints and revision control. |
Cutting conditions are selected for the actual material state and tool. A process used on an aluminum block is not automatically transferred unchanged to stainless steel or heat-treated steel. Tool preparation and checks remain part of the manufacturing plan.
Technical context: Sandvik Coromant guidance on chip formation and cross-hole drilling considerations. Tool-specific recommendations are applied to the relevant operation; they are not universal manifold cutting parameters.
Tooling preparation and custom tool developmentProtect valve cavities when passages intersect them
Cross-drilling and cavity finishing need a coordinated sequence. A later drilling can leave an edge or burr inside a previously finished feature; removing it carelessly can alter a sealing transition. We consider these operations together so access and final geometry remain part of the same plan.
Before the intersection is cut
Identify the intended junction, neighboring sealing areas and the tool path. Establish the order of drilling and finishing for the actual geometry, with access for the subsequent work.
After the intersection is formed
Address the resulting edge and any burr using an appropriate method. Preserve the specified cavity steps, chamfers and sealing surfaces; a broadly rounded edge is not a substitute for the drawing requirement.
Before the feature is accepted
Check the applicable final dimensions, surface requirements and edge condition. Any required process change or rework must retain the approved part definition and its inspection requirements.
The selected route may differ between parts. We do not present one drilling order or a fixed feed reduction as suitable for every intersection.
Connect the passage to its valve cavity requirementsFinish the internal work before protecting the delivery condition
Drilling completion is followed by the relevant deburring and cleaning work. Cross-hole junctions, cavity edges, thread exits and blind regions need attention based on their geometry and access. Experienced manual deburring is an important part of complex, small-batch manifold manufacture.
Remove burrs without changing the feature
Use the agreed access and operation sequence to address critical junctions while protecting sealing surfaces and the specified edge geometry. If access is inadequate, resolve the process or design question before accepting the part.
Remove residues and preserve the result
Cleaning addresses chips and residues after the relevant machining and deburring stages. Include drying, subsequent operations, any agreed closure work and protection of openings during handling and packaging.
Cleaning does not, by itself, establish that an attached burr has been removed. If a measured particle-cleanliness result is required, agree the method, sample, acceptance limits and report separately from routine process control.
Deburring, cleaning and packaging Project-specific third-party cleanliness verificationMatch the inspection method to the feature being accepted
Dimensions and relationships
Inspect the required diameters, accessible depths, locations and specified geometric tolerances using appropriate methods. An entrance diameter or position measurement alone does not establish full-depth straightness or the condition of a hidden junction.
Agree access and evidence early
Where a critical internal feature cannot be verified by the proposed method, resolve the inspection approach before production. Material certificates and dimensional reports can be provided; first-article and CMM coverage are agreed for the actual project.
Normal manifold acceptance verifies the specified material and drawing conformity, including threads, required bore geometry, sealing-surface roughness and burr removal. Pressure and functional testing are not routine checks for the machined block.
Wall thickness, material selection and pressure design are determined by the responsible design engineer. Machining to the drawing does not independently establish the hydraulic performance of the assembled system.
Inspection methods and their scope Records linked to the supplied partQuestions about deep-hole and cross-hole machining
What maximum drilling depth or length-to-diameter ratio can you offer?
It must be confirmed from the actual material, hole diameter, required geometry, entry conditions, intersections, access and inspection needs. Send the drawing for a project-specific assessment; a single depth figure does not define all manifold work.
Can passages be drilled from opposite sides?
The manufacturing route can be reviewed for that approach where the design and access allow it. Specify the required connection and geometric relationship. Any change from the approved route or geometry needs review and authorization.
How do you address drilling near a finished valve cavity?
Plan passage cutting, cavity finishing and deburring together. Identify the intersection and sensitive sealing features, then preserve their specified geometry through the later operations and applicable checks.
Does a CMM report prove every internal passage is correct?
No. The report covers the features measured by the stated method. Some internal features may be inaccessible or require a different approach. Agree how critical requirements will be verified before manufacture.
Will you use the same process for aluminum and steel manifolds?
The material grade and condition affect tool choice, chip behavior and cutting conditions. We plan the process for the specified material and geometry, while keeping the final drawing requirements unchanged.
What information is needed to quote the passage machining?
Provide the manifold drawing and model, material and condition, hole diameters and depths, datums, intersections, critical sealing areas, final finish, inspection requirements and quantities. Highlight difficult internal features or known problems with an existing part.
Send the drawing with the critical internal features identified
Include the current revision, 3D model if available, exact material and condition, passage dimensions, cavity references and any specified geometric or surface requirements. Add sample and production quantities, finish, cleanliness needs and requested inspection records.
Complete manifold drawings are preferred; a schematic can start a review. Send DWG, DXF, PDF or JPG drawings and STEP, X_T, IGS or SLDPRT models by email or WhatsApp.
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