Start with the deepest functional feature
Hydraulic fitting boring deserves a separate review when a threaded connector contains a stepped bore, a recess or an internal shoulder. For a machining shop comparing CNC turning proposals, the useful starting point is a section drawing showing how the cutting edge reaches each feature. Put the entry diameter, finished bore, shoulder position and permitted gripping area on the same view. This makes it possible to discuss access before committing to a tool list. The scope here is a connector with a mainly axial bore, with any intersecting passage identified separately.
The tool guide connects overhang, bar size and clearance
Sandvik Coromant’s turning application guide connects internal-turning stability with boring-bar diameter, overhang and clamping. It also explains that space between the bar and bore is needed for chips. Its thread-turning guidance separately discusses chip direction and coolant access in internal threads, particularly near a hole bottom. GEDEMA’s editorial application of those points is to request a tool-access sketch alongside the part drawing. Review the bore entrance and the supported tool position together, then ask the supplier to explain how the proposed tool reaches the working surface.
Separate part length from the proposed tool overhang
On the setup sketch, label the tool-support boundary, the cutting edge at its deepest working position and any clearance needed at the component face. Ask the supplier to identify the overhang convention used for that holder. Keep the workpiece datum and holder reference clearly named so two proposals can be compared. A quotation that gives only the connector’s overall length leaves this setup question open. Also show the largest envelope of the cutting head along the entry and withdrawal path. A small shank alone does not establish that the complete tool can pass the entrance.
Compare the bore features before comparing configurations
Use the following hydraulic fitting boring checklist during the drawing review. Each row asks for a concrete explanation in the quotation or process proposal. Give the proposed tool a reference number and connect it to the relevant drawing feature. Where access is uncertain, request a section sketch showing the tool at entry, at the cut and during withdrawal. Keep these sketches with the quotation so later revisions of the bore or gripping arrangement can be reviewed against the same assumptions.
| Bore feature | Mark on the drawing | Request in the proposal |
|---|---|---|
| Through bore | Smallest entry, steps and exit | Tool envelope and chip exit along the complete path |
| Blind bore or internal shoulder | Depth from the locating face and bottom geometry | Deepest tool position, approach and withdrawal space |
| Internal thread | Thread specification, useful length and runout space | Pre-bore, tool clearance, chip direction and gauging access |
| Intersecting passage | Intersection location and adjacent functional surfaces | Separate edge-treatment and inspection steps |
Ask where the chips and coolant can travel
Sandvik’s boring-bar guide describes chip clearance, coolant delivery and insert geometry as connected considerations. Its internal-thread guidance also treats chip direction as a setup decision. Apply those observations by asking the supplier to mark the expected chip exit and coolant delivery point on the setup sketch. For a blind feature, identify the bottom region where evacuation needs review. Record the proposed holder and coolant connection in the scope of supply. During the part trial, ask how the operator will observe chip behaviour with the machine’s guarding and approved procedure in place.
Give bore finishing and thread cutting their own review
List bore finishing and internal threading as separate operations in the process sheet. Ask which tool handles each surface, where it starts and ends, and what inspection follows. Include the thread specification and any designer-approved relief in the RFQ. If the connector has a cross hole, give its intersection a separate edge-treatment requirement. This creates a place for the supplier to explain sequencing, access and verification. The same operation list should appear in the proposed trial plan and in the final quotation scope.
Make the part trial answer the open setup questions
Create one trial record with fields for drawing revision, material condition, stock form, gripping length, tool reference, holder, measured overhang, coolant arrangement and operation order. Add a photograph or sketch reference for the assembled setup. Agree in advance which bore locations, shoulder dimensions and thread features will be measured and how the results will be recorded. Include operator observations of chips, tool access and any interruption. Recording these conditions allows the buyer and supplier to connect a trial result to the actual setup being quoted.
Compare quotations with the same access assumptions
Check that every proposal names the same drawing revision and material condition. Request an itemised scope for holders, cutting tools, coolant connections, workholding and any separate edge-treatment operation. Identify what the supplier has reviewed on a sketch, what has been demonstrated and what still needs a part trial. These categories help the buyer decide which uncertainty matters before ordering. Preserve the proposed tool layout with the quotation, especially when changing an entrance diameter or internal shoulder could affect the selected tooling.
Bring the bore sketch into the machine discussion
After defining the bore and access requirements, use GEDEMA’s published GDM-T40-360D page as a starting point for a configuration discussion. Ask the team to review the drawing, holder arrangement, workholding and trial scope together. For a useful first enquiry, Send Us Your Drawing. Include the material, quantity, critical dimensions and a section view. Share a drawing link through the enquiry form or use the contact details provided. Mark the entry bore, deepest feature and surfaces that may be gripped so the response can address the proposed process.
Technical references
Sandvik Coromant · Publication date not stated · Accessed
Sandvik Coromant · Publication date not stated · Accessed