TL-303-12
3 Flute Extra Length Tuffy Grade Carbide End Mill
0.375-in Dia 3-Flute End Mill, 1.5-in LOC, 0.375-in Shank, 3.5-in OAL with Weldon Flats


3-flute extra-length Tuffy grade square end mills — long flutes for deep side milling, with shank flats on the larger inch sizes.
- 3 flute square end extra-length Tuffy grade carbide with 30° helix
- Long flute lengths for deep walls — up to 3" of flute on the 3/4" tool (5" OAL); metric MTL runs up to 75 mm flute on the 20 mm tool (130 mm OAL)
- Inch sizes 1/8"–3/4" (TL-303); metric sizes 3–20 mm (MTL-303)
- Shank flats on the 3/8", 1/2", 5/8", and 3/4" inch sizes for secure holding; 1/8"–5/16" and 7/16" sizes and all metric tools do not have flats
- Rated for side milling, semi-finishing, and finishing — wet, cold air, or spray mist
- Broad material range: aluminum, copper, magnesium, cast iron, steel, stainless steel, plastics, brass, and wood
- Tolerances: cutting dia −.001/−.002 at 1/8" and +.001/−.000 from 3/16"–3/4"; shank −.0001/−.0002; flute length +.060/−.000 (MTL cutting dia +.025/−.000 mm from 4–20 mm)
- Guide cross-reference for chatter on long reaches: consider the FM Series or add Mirror Edge treatment
From the RobbJack Applications Guide.

About this series
TL / MTL Extra Length Tuffy Grade Carbide End Mills
3 flute extra-length square-end mills for deep-reach work
The TL-303 is a 3 flute, extra-length, square-end Tuffy Grade carbide end mill with a 30 degree helix. MTL-303 is the metric extra-length version (metric tools do not have flats). Available in inch sizes 1/8" to 3/4" and metric sizes 3 mm to 20 mm.
- Extra length, 3 flute square end, 30 degree helix
- Inch (TL) and metric (MTL) versions
- Metric tools do not have flats
Aluminum, copper, magnesium, cast iron, steel, stainless steel, plastics, brass, wood
Headline spec
Extra length, 3 flute, 30 degree helix
Best for
- Side milling
- Semi-finishing and finishing
Specifications
US machining terms with ISO 13399 codes.
- Cutting DiameterDC
- 0.375″
- Diameter ToleranceDC tol
- 0.0010/0.0000
- Max Cutting DiameterDCX
- 0.376″
- Shank DiameterDMM
- 0.375″
- Length of Cut (LOC)APMX
- 1.5″
- Overall Length (OAL)OAL
- 3.5″
- Number of FlutesNOF
- 3
- Helix AngleFHA
- 30°
- Helix HandFHH
- Right-hand
- Cut Direction
- Right-hand cut
- End Type
- Square End
- Center Cutting
- Yes — plunges
- Series
- TL-303 — 3 Flute Extra Length Tuffy Grade Carbide End Mill
Cuts these materials
Applications
See it run
Tolerances
| Type | Min | Max |
|---|---|---|
| Cutting Diameter | +0.001 | 0 |
| Length of Cut | +0.06 | 0 |
| Overall Length | +0.06 | -0.06 |
| Shank Diameter | -0.0001 | -0.0002 |
Made & shipped in the USA · lead time confirmed at order. Buy at retail or through your distributor.
Performance guaranteed. Run it against the tool you use today — if it doesn't beat it, we'll make it right.
Adds Uncoated · $155.50 — our pick for your material. Choose another finish below.
Proven in the field
- $548,290saved per year drilling carbon-fiber aircraft
- $216,000saved per year trimming aircraft skins
- 1,000%metal-removal increase in Inconel 718 (SPS)
Finishes (1)
Uncoated
TL-303-12
$155.50
Available to order
Starting at
$155.50
Performance guaranteed
More in the TL-303 series
Same series, different size — what changes from this tool is shown in red.
- TL-303-04$98.90Ø 0.125″LOC 1″OAL 3″3 FL
- TL-303-06$102.65Ø 0.1875″LOC 1.125″OAL 3″3 FL
- TL-303-08$116.85Ø 0.25″LOC 1.25″OAL 3″3 FL
- TL-303-10$125.60Ø 0.3125″LOC 1.375″OAL 3″3 FL
- TL-303-14$207.35Ø 0.4375″LOC 1.75″OAL 3.75″3 FL
- TL-303-16$250.00Ø 0.5″LOC 2″OAL 4″3 FL
- TL-303-20$345.45Ø 0.625″LOC 2.5″OAL 4.625″3 FL
- TL-303-24$507.65Ø 0.75″LOC 3″OAL 5″3 FL