7mm Expansion diamond reamers (Single Pass / Stroke Honing) with straight shank

Expansion Diamond Reamers (Single Pass / Stroke Honing) with Straight Shank

Expansion diamond reamers for single-pass / stroke honing operations are precision finishing tools designed for final sizing and surface finishing of valve guides and precision through-holes in hardened, wear-resistant and difficult-to-machine materials.

These tools are used after pre-machining or rough reaming operations to achieve stable bore geometry, controlled sizing accuracy and fine surface finish with minimal stock removal.

Application:

• Valve guide finishing and sizing
• Cylinder head repair and rebuilding
• Precision honing of hardened and coated bores
• Fine finishing of precision through-holes
• Automotive, motorcycle and industrial engine applications

The expandable honing system allows precise diameter correction during operation while maintaining low cutting forces and stable bore geometry.

What the tool actually does:

This is a precision finishing tool intended for light stock removal only.

During operation the diamond abrasive:

• improves surface finish,
• stabilizes final bore size,
• reduces bore waviness,
• improves cylindricity and dimensional consistency.

Because the tool removes only a very small allowance, it is not intended for correcting major taper, bellmouth or bore misalignment.

Expansion adjustment system:

The expansion mechanism allows controlled adjustment of the working diameter during operation.

• Compensates for abrasive wear
• Allows precise final sizing
• Improves dimensional repeatability

Important technical clarification:

A new diamond honing tool may initially measure slightly oversized relative to its nominal diameter.
This is a normal characteristic of all diamond honing tools because the abrasive layer has not yet been fully broken in or dressed.

Before precision use, the tool should:

• be properly broken in,
• run through several test passes,
• or be dressed before final sizing operations.

Only after this process does the diamond layer stabilize and begin operating within its normal working range.

Operating principle:

• Designed only for final sizing and finishing
• Requires pre-machined bores close to final dimension
• Not intended for rough machining or heavy stock removal
• Does not correct major bore geometry errors

Tool life:

Typical tool life ranges from approximately 500 to 10,000 holes depending on:

• workpiece material,
• bore geometry,
• coolant quality,
• machine rigidity,
• operating parameters and honing allowance.

Recommended machining sequence:

Drilling → rough machining → pre-sizing → diamond honing finish

Best results are achieved when only a small and uniform finishing allowance remains before honing.

Available sizes and recommended operating parameters:

Specification:

• Tool type: Expansion diamond reamer / stroke honing tool
• Shank type: Straight shank
• Operation type: Single-pass honing / finishing
• Diamond type: AC32
• Diamond grit: 80/63 (ANSI 170/200)
• Diamond layer thickness: ~0.23 mm
• Surface finish: Ra 1.25-0.63 µm
• Application: Precision finishing / sizing
• Material compatibility: Hardened and wear-resistant materials

Cutting performance:

• Very low stock removal
• High dimensional stability
• Fine surface finish
• Low cutting forces
• Long diamond service life

Recommended operating parameters:

• Spindle speed: 200-400 rpm for diameters 6-10 mm
• Feed motion: Uniform reciprocating stroke
• Operation: Single-pass / stroke honing
• Coolant: Honing oil or cutting oil required

Operating recommendations:

• Excessive RPM causes overheating and rapid diamond wear
• Reciprocating feed motion should remain stable to produce proper honing crosshatch
• Do not stop spindle rotation while the tool is inside the bore
• Stopping rotation inside the hole may produce longitudinal scratches
• Use light and even honing allowance
• Maintain accurate spindle alignment
• Break in new tools before precision sizing

Use for:

• Valve guide finishing
• Cylinder head rebuilding
• Precision honing operations
• Automotive engine repair
• Industrial bore finishing

Limitations:

• Not for drilling
• Not for rough boring
• Not intended for heavy stock removal
• Cannot correct major bore misalignment
• Requires pre-machined bore close to final size

Maximum Recommended Material Removal per Pass*

• Manganese Bronze: 0.0005"–0.0010" (13–25 µm)
• Cast Iron: 0.0003"–0.0008" (8–20 µm)
• Powder Metal (PM): 0.0002"–0.0005" (5–13 µm)
• Sintered Bronze: 0.0002"–0.0005" (5–13 µm)

*Actual stock removal depends on guide material, machine rigidity, lubrication conditions and the condition of the diamond abrasive layer.