Teams match the allowance chart, still scrap on finish marks or lobing—then open the PCD reamer drawing as if stock millimeters were the whole story.
Size the stock with PCD Reamer Allowance & Pre-Hole Size (mm / stock method). Qualify the hole here—roundness, taper, wall damage, inherited runout, dirty or work-affected walls—before you change the reamer. This page does not reprint the allowance seven-step size path.
Size-OK / quality-bad: shop-floor scrap patterns
Dial says the create hole is “in stock,” but the finish still fails. Typical shop patterns:
- Finish streaks that follow the create tool’s scratch path
- Lobing the reamer cannot fully erase
- Local oversize bands from wall damage or leftover BUE smear
- Offset fights that reset every batch though diameter stock looks fine
Undersize / cast-Al create confusion: PCD Reamer Undersize Hole (ADC12). Handoff routing: Al drill→ream process.
Pre-hole quality checklist (beyond mm)
| Check | Why it matters | Fail signal |
|---|---|---|
| Roundness / lobing | Reamer follows the path | Periodic size/finish variation |
| Taper / bellmouth | Uneven stock | Entry≠exit behavior |
| Wall damage / scratch | Recut damage into finish | Longitudinal marks |
| Cleanliness / residue | Rubbing, built-up restart | Sticky walls, stain |
| Entry ding / chamfer damage | Lead engagement chaos | First-mm scrap |
Create-process inheritance (do not rewrite D4 here)
Bad create setup lands in the reamer cell:
- Assembled runout / stickout — Stickout & Runout Before Geometry
- Chip packing that scratches walls — Carbide Drill Chip Packing Checklist
- Oversize/taper mis-read as “reamer diameter” — Oversized Holes with a New Carbide Drill
Fix the create inheritance first; then ask whether the PCD reamer geometry is wrong.
What to measure before blaming the reamer drawing
- Confirm allowance band with the allowance article method
- Measure roundness/taper/wall condition on the create hole
- Record holder runout at production stickout
- Freeze gauge + temperature practice
- Only then open a reamer revision discussion
Cost per Good Part → RFQ fields
Log create-tool changes, reamer offsets, and scrap against accepted holes (Cost per Accepted Hole). RFQ packet: drawing, material, measured pre-hole (size + quality notes), create tool, scrap mode → Custom Cutting Tool RFQ · Custom PCD Reamer.
Frequently Asked Questions
We matched allowance—why still scrap?
Quality defects (roundness, damage, dirt, inherited runout) can fail the bore even when stock mm is in band.
Does this replace the allowance article?
No. Allowance sizes stock; this page qualifies the hole.
What photos help?
Create-hole wall, entry, and chip/packing evidence beat adjectives.
What to send XRZ?
Drawing, material, measured pre-hole size+quality, create tool/setup, scrap mode → RFQ.