Blind Hole Broaching Services for Keyways, Splines and Internal Profiles
Broaching Technologies provides blind hole broaching for keyways, splines, internal grooves and special profiles that must stop inside the part. Our Menomonee Falls, Wisconsin shop operates C.A.M.S. vertical slotting machines, the equipment we also supply to manufacturers.
Send your drawing or CAD file, material, quantity and tolerances. We review the required cutting length, clearance near the closed end and chip removal before selecting tooling and confirming the machining approach, price and lead time.
Blind-Hole Machining for Closed-End Internal Features
A blind hole is closed at one end, requiring any internal keyway, spline, or groove to terminate before reaching the opposite face. That changes the machining problem. A conventional through-broach normally needs an open path through the workpiece, while a blind feature requires controlled cutting depth, room for the tool to enter and retract, and a plan for managing chips inside the bore.
For many blind features, Broaching Technologies uses vertical slotting rather than forcing a conventional pull broach into an application it was not designed to handle. A reciprocating cutting tool removes material in controlled increments and stops at the required depth. The method can also support indexed cuts for multiple keyways or spline teeth when the part geometry, tooling and machine configuration are suitable.
The best process cannot be selected from the feature name alone. Bore diameter, feature length, bottom geometry, material condition, tolerance, production quantity and tool clearance all influence feasibility. Our engineering review addresses those factors before tooling or production begins.
When Blind Hole Broaching Is the Right Fit
- An internal keyway must stop before the end of a hub, gear, pulley or coupling.
- An internal spline requires a controlled length inside a closed or partially enclosed bore.
- A groove, radial slot or indexed internal profile cannot be reached effectively with ordinary through-broaching equipment.
- The part requires repeatable feature depth across a prototype, short run or recurring production order.
- The outside geometry or opposite face must remain intact.
- The manufacturer needs an outsourced process instead of purchasing dedicated slotting equipment and developing the tooling in-house.
Blind-hole machining is not automatically the best choice for every internal feature. If the bore is open and the same fixed profile will be produced in substantial repeat volume, through-hole or conventional contract broaching may offer a more efficient production path. A feature with insufficient tool clearance, chip space or bottom relief may require a design adjustment or another process, such as shaping, EDM or a CNC-based broaching approach. Material hardness, heat-treatment condition and feature depth can also change the recommendation.
Blind Keyways, Splines and Custom Internal Profiles
Blind Keyway Machining
A blind keyway is a single internal slot that stops inside the bore. It provides a seat for a key used to transfer torque between a shaft and a mating hub, gear, pulley, sprocket or coupling. The width, depth, straightness, location and end condition of the slot must work together with the mating key and assembly requirements.
Our keyway broaching and keyseating capabilities support standard and application-specific internal keyways. For blind work, we evaluate how the tool will approach the feature, where the cut must stop, how chips will be removed and whether the drawing provides adequate runout or relief.
Blind Spline Machining
A blind internal spline uses multiple teeth or grooves to distribute torque and maintain alignment, but the profile terminates before the opposite end of the bore. Producing that geometry requires controlled depth as well as consistent indexing and tooth form around the bore.
Broaching Technologies reviews the spline type, tooth count, fit, pitch, usable length, entry condition, bottom geometry and inspection requirement before selecting a method. Our internal spline broaching services page covers the broader spline capability; this page owns the additional access and depth-control requirements created by a blind bore.
Internal Grooves and Custom Profiles
Some projects do not fit a standard keyway or spline definition. Internal grooves, multiple indexed keyways, radial slots, squares, hexagons and other non-standard forms may be possible when the part provides a workable tool path and the profile can be supported by the available machine, tooling and inspection method.
Our broached-parts and application gallery shows the range of internal forms associated with Broaching Technologies. Gallery examples demonstrate capability categories; they do not mean every size, material or geometry can use the same setup. Each new profile still requires a drawing review.
How Vertical Slotting Addresses Blind-Hole Challenges
Broaching Technologies is the exclusive North American distributor of C.A.M.S. vertical slotting machines, and we also use this equipment in contract production. That combination matters because our recommendations come from both machine knowledge and practical application experience.
C.A.M.S. offers machine configurations with NC-controlled axes, programmable movement, tool-lift functions and indexing options. For an appropriate blind-hole application, the selected configuration can help the process control:
- Cutting stroke and stopping depth
- Tool position relative to the bore and part datum
- Incremental material removal
- Return motion and tool clearance
- Indexed positions for multiple slots or spline features
- Repeatable setup for additional parts or future orders
The machine is only one part of the solution. Tool geometry, workholding, part rigidity, cutting conditions and chip management must be planned around the actual material and feature. We evaluate the complete setup rather than treating CNC control by itself as a guarantee of part quality.
Blind-Hole Versus Through-Hole Broaching
The correct method depends first on feature access and then on volume, geometry and tooling economics.
Decision factor | Blind-hole machining with vertical slotting | Conventional through-hole broaching |
|---|---|---|
Bore condition | Closed at one end or feature must stop inside the bore | Open path through the workpiece |
Tool movement | Controlled reciprocating cuts stop at a specified depth | Broach travels through the complete feature |
Material removal | Incremental passes with application-specific tooling | Progressive broach teeth form the profile during tool travel |
Chip planning | Chips must be managed within or removed from the blind feature | Chips can leave through the open side |
Typical strength | Flexible depth and profile control for blind, enclosed or specialized work | Efficient repetition of a fixed profile when part access and volume support the tooling |
Main review questions | Entry, stopping point, bottom relief, tool lift, chip space and indexing | Pull or push path, broach length, part support, tooling and production quantity |
Neither method is universally better. Broach when the profile is fixed, the tool has a complete path and production economics support dedicated tooling. Slot when the feature is blind, the profile or depth requires more flexibility, or the production requirement does not justify a conventional through-broach. We confirm the decision after reviewing the part.
What Determines Feasibility, Cost and Lead Time
Blind-hole broaching is quoted from the application because two parts with similar-looking keyways can require different machines, tools, fixtures and inspection plans. The main project factors include:
- Bore and part geometry
Bore diameter, bore depth, wall thickness, overall part size, feature location and clamping surfaces affect access and rigidity.
- Feature requirements
Width, depth, length, tooth count, profile, corner condition, runout, bottom relief and relationship to the datum influence the cutting strategy.
- Material and condition
Material grade, hardness, heat-treatment stage, coating and prior machining can change tool design and cutting conditions.
- Tolerance and finish
Dimensional tolerances, position, concentricity, tooth-form requirements, surface finish and inspection documentation affect setup and verification.
- Quantity and repeat demand
Prototype quantity, current lot size, annual usage and expected repeat orders influence tooling and process economics.
- Tooling and fixturing
Existing usable tooling may reduce setup requirements; a new profile may need custom tooling, workholding or inspection fixtures.
- Schedule and coordination
Material availability, upstream machining, first-article approval, outside processes and requested delivery date all affect timing.
We do not confirm price, lead time or final process suitability until the required project information has been reviewed.
How Our Blind-Hole Broaching Process Works
Our goal is to make the next step clear before you submit an RFQ.
1
Drawing and requirement review
We review the part print or CAD file, material, quantity, feature geometry, tolerances, heat-treatment condition and required delivery or inspection documentation.
2
Process and manufacturability review
Our team evaluates access, tool travel, chip removal, bottom condition, part rigidity and the relationship between the blind feature and its functional datums. We then identify the appropriate slotting, broaching or alternative path.
3
Tooling and workholding plan
We determine whether suitable tooling exists or whether the project requires an application-specific tool, fixture or setup. Tooling decisions are based on the profile, material and production requirement.
4
Setup and first-part verification
The machining setup is established and the initial part is checked against the agreed drawing requirements. Any required first-article or customer approval step should be defined during quoting.
5
Production, inspection and repeat support
Approved parts move through the planned production and inspection sequence. For repeat work, the documented project requirements provide a controlled starting point for future orders, subject to drawing, material or scope changes.
Serving Precision Driven Industries
Our blind hole broaching services support manufacturers across multiple industries where precision internal features are critical.
Oil and Gas Equipment
Pump & Fluid Handling
Electric Motors & Power Transmission
Agricultural & Construction Equipment
Aerospace & Defense Components
Medical Device Manufacturing
Materials We Review for Blind-Hole Broaching
Blind-hole broaching projects often involve industrial materials selected for strength, durability, wear resistance, corrosion resistance, or operating conditions. Broaching Technologies evaluates projects involving material groups commonly used for precision mechanical components, including:
- Carbon and alloy steels
- Stainless steels
- Aluminum alloys
- Bronze and brass
- Inconel and other high-strength alloys
Material suitability depends on the specific grade, hardness, heat-treatment condition, feature geometry, and tooling requirements. Providing the complete material specification helps determine the appropriate machining approach and avoids assumptions during project review.
Components That May Require Blind Internal Features
Blind-hole broaching is commonly considered for components where internal features such as keyways, slots, or profiles are required within a limited-depth bore or enclosed area. Typical component applications include:
- Gears, hubs, pulleys, and sprockets
- Shaft couplings and power-transmission components
- Gearbox housings and drive components
- Pump, valve, and fluid-handling components
- Hydraulic manifolds and actuator components
- Oilfield, mining, and boring equipment components
- Industrial machinery and custom mechanical assemblies
The component type alone does not determine manufacturability. Broaching Technologies reviews the part drawing, operating requirements, feature location, material condition, and production needs to determine whether blind-hole broaching is the right process or whether another internal machining method may be more suitable.
What to Send for a Blind-Hole Broaching Quote
Providing complete information at the beginning helps us evaluate the project without building assumptions into the quote. Start with the current part drawing and, when available, a CAD model. Identify the material grade, condition, hardness and heat-treatment sequence. The drawing should define the bore diameter and depth; the feature width, depth, length and location; and all relevant tolerances, datums, surface-finish and inspection requirements.
Also provide the prototype quantity or lot size, estimated annual usage and repeat-order expectations. Note any upstream or downstream operations that could affect the feature, along with the requested delivery date and required documentation.
Broaching Technologies uses this information to evaluate whether the feature fits the available process and machine envelope. We also review the machining method and sequence, tool access, stopping point, chip clearance, relief, workholding, tooling, fixturing, measurement and first-part verification requirements. Once those conditions are understood, we can define the appropriate production path and confirm feasible scope, price, lead time and the next approval step. If the design is still being developed, mark the drawing as preliminary. We can identify the information that must be finalized before tooling and production are released.
Why Manufacturers Work With Broaching Technologies
Agricultural and gear applications are central to the Illinois market, but broaching is also relevant to pump, valve, electric-motor, and industrial-equipment manufacturers.
Machine Knowledge Connected to Production Work
We do not evaluate C.A.M.S. equipment only from product specifications. Broaching Technologies sells the machines in North America and operates them for contract machining. For the buyer, that creates a more practical conversation about part access, tooling, setup and production fit.
Specialized Broaching and Slotting Focus
Our team brings more than 30 years of hands-on experience in broaching, slotting and tooling design. That specialization helps us compare methods instead of defaulting every internal feature to the same process.
Tooling and Engineering Support
Blind features depend heavily on the cutting tool and the way the part is held. We review the profile, material, clearance and volume together, with access to slotting-machine tooling and accessories for standard and custom applications.
Support From Prototype Through Repeat Orders
We review one-off and prototype requirements as well as recurring production work. The selected method, tooling investment and approval process are matched to the project rather than assumed from volume alone.
The combination of contract machining, C.A.M.S. machine distribution and tooling support gives customers one technical path from part review through production planning.
How to Evaluate a Blind-Hole Broaching Supplier
A useful supplier review should do more than repeat the feature dimensions. Before awarding the work, ask whether the provider can explain:
- Why the proposed method fits a closed-end feature and what alternatives were considered
- How the tool will enter, stop and retract without damaging the required bottom condition
- How chip clearance, part rigidity and workholding affect the setup
- Whether new tooling, fixtures or inspection equipment are required
- How material grade, hardness and heat-treatment sequence influence the plan
- Which drawing assumptions, exclusions and schedule dependencies will appear in the quote
- How drawing revisions, first-part approval and repeat orders will be controlled
A provider should not commit to a final tolerance, delivery date or price without reviewing the conditions that drive those commitments. For Broaching Technologies, that review begins with the current drawing and production requirements.
Start a Blind-Hole Project Review
If your component needs an internal keyway, spline, groove or special profile that must stop inside the bore, start a project review through our contact page. You can also email the drawing to sales@broachingtech.com or call (262) 820-1200. Include the material, quantity, feature dimensions, tolerances and requested timing so our team can evaluate process fit, tooling, fixturing, inspection requirements and the information needed to prepare a responsible quote.