Specification
Where to buy| Item | Value |
|---|---|
| Type | Countersink cutter, integral pilot |
| Material | High speed steel; cobalt and carbide tips available upon request |
| Maker | Martin Aircraft Tool, Zephyr Tool Group |
| Angles stocked | 82° and 100° |
| Flutes | MM-305: 2 flutes. MM-305A: 3 flutes |
| Item | Value |
|---|---|
| Two flutes for | Aluminum and dural |
| Three flutes for | Stainless steel and titanium |
| When ordering | Specify the angle and pilot diameter, and MM-305 for 2-flute or MM-305A for 3-flute |
| Status | Maker's catalogue, read 30 Oct 2026. Check the current catalogue before you order. |
Part numbers
| Part no. | Size | Shank | Pilots carried in stock |
|---|---|---|---|
| MM-305-0 | 5/16" | 1/4"-28 | 3/32, #40, 1/8, #30, 5/32, #21 |
| MM-305-1 | 3/8" | 1/4"-28 | 3/32, #40, 1/8, #30, 5/32, #21, 3/16, #10 |
| MM-305-2 | 7/16" | 1/4"-28 | 3/32, #40, 1/8, #30, 5/32, #21, 3/16, #10 |
| MM-305-3 | 1/2" | 1/4"-28 | 3/32, #40, 1/8, #30, 5/32, #21, 3/16, #10, 7/32, 1/4, F |
| MM-305-4 | 5/8" | 1/4"-28 | 1/8, #30, 5/32, #21, 3/16, #10, 7/32, 1/4, F, 5/16 |
| MM-305-5 | 3/4" | 3/8"-24 | 3/16, #10, 7/32, 1/4, F, 5/16, 3/8 |
| MM-305-6 | 7/8" | 3/8"-24 | 7/32, 1/4, F, 5/16, 3/8, 7/16 |
| MM-305-7 | 1" | 3/8"-24 | 7/32, 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| MM-305-8 | 1-1/8" | 3/8"-24 | 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| Part no. | Size | Shank | Pilots carried in stock |
|---|---|---|---|
| MM-305-9 | 1-1/4" | 3/8"-24 | 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| MM-305-10 | 3/4" | 7/16"-20 | — |
| MM-305-11 | 7/8" | 7/16"-20 | 7/32, 1/4, F, 5/16, 3/8, 7/16 |
| MM-305-12 | 1" | 7/16"-20 | 7/32, 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| MM-305-13 | 1-1/8" | 7/16"-20 | 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| MM-305-14 | 1-1/4" | 7/16"-20 | 1/4, F, 5/16, 3/8, 7/16, 1/2 |
| MM-305-15 | 1-3/8" | 7/16"-20 | 5/16, 3/8, 7/16, 1/2 |
| MM-305-16 | 1-1/2" | 7/16"-20 | 5/16, 3/8, 7/16, 1/2 |
Every tool number in the catalogue. D is the cutter diameter. Pilot sizes are the maker's stock list for that body and thread; other pilot diameters are quoted.
Notes
- Catalogue items linked to this sheet match it by type: the seller's listing does not name this maker, so check the listing before you take a value from here.
- The catalogue's stock pilot list has no row for 3/4" × 7/16"-20, so MM-305-10 stays blank there.
- That list also shows bodies with no MM-305 number: 1/4" × 1/4"-28 (pilots 3/32 to #30) and 1-3/8" × 3/8"-24 (pilots 1/4 to 1/2).
- 6, 8 and 10 millimeter threaded shank cutters and special millimeter pilot diameters on request.
Where to buy
AmericaDistributor coming soonOur partner for this region is on its way
EuropeDistributor coming soonOur partner for this region is on its way
OceaniaDistributor coming soonOur partner for this region is on its way
Distributors coming soon.
Sources
- Martin Aircraft Tool Catalog — Zephyr Tool Group, pages 5, 6 and 24 — tool numbers, diameters, shanks, stock pilot sizes and cutter styles, from the maker's catalogue.
Educational reference only. not approved data. Always consult the applicable SRM, AMM, or AC 43.13-1B and your certifying authority.