Mitsubishi SPMW120304 UTI20T | Carbide Milling Insert for Steel
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SPMW120304 UTI20T
Mitsubishi Materials | Uncoated Carbide for Extreme Edge Toughness
The Mitsubishi SPMW120304 UTI20T is a workhorse indexable carbide insert designed for general-purpose milling. Utilizing the legendary UTI20T grade, this insert is the go-to choice for workshops requiring a long-tail tool solution that balances cost-effectiveness with high fracture resistance. It is exceptionally stable for machining stainless steel, alloy steels, and gray cast iron in both manual and CNC operations.
ISO Code Breakdown
Square Shape
11° Relief Angle
M-Class Tolerance
With Fixing Hole
12.7mm IC Size
3.18mm Thick
0.4mm Radius
Global Standard Comparison
| Specification | Metric (ISO) | Inch (ANSI) Equivalent |
|---|---|---|
| Part Number | SPMW120304 | SPMW 421 |
| Inscribed Circle ($IC$) | 12.7 mm | 0.500" |
| Thickness ($S$) | 3.18 mm | 0.125" |
| Corner Radius ($RE$) | 0.4 mm | 0.016" |
Grade: UTI20T Tough Carbide
The UTI20T grade is an uncoated micro-grain carbide specifically designed for interrupted cutting and unstable machining conditions. While coated grades may peel under extreme pressure, the UTI20T maintains a consistent cutting edge. It is highly recommended for machining austenitic stainless steels and cast iron where thermal shock resistance is required.
Geometry: W-Type General Purpose
The W-Type geometry features a flat top face with a countersunk hole for secure clamping. It provides a sharp shearing action that reduces cutting torque and vibration. This makes it ideal for older machines or lighter CNC setups where spindle rigidity may be an issue.
Recommended Cutting Parameters
| Workpiece Material | Cutting Speed ($v_c$) | Feed per Tooth ($f_z$) |
|---|---|---|
| Mild Steel (1018/1045) | 100 - 180 m/min | 0.10 - 0.25 mm/t |
| Stainless Steel (304/316) | 60 - 120 m/min | 0.08 - 0.20 mm/t |
| Cast Iron (Gray/Ductile) | 80 - 160 m/min | 0.15 - 0.35 mm/t |
Universal Holder Compatibility
This insert fits all standard SPM 42x series tool holders and Mitsubishi screw-on milling cutters.
View Compatible Milling Holders →
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This Mitsubishi insert is in stock. 24-hour quote response. ISO 9001 certified. Ships from Hangzhou in 3–7 days.
Technical FAQ & Buying Guide
When choosing CNC cutting tools, check the full model code, dimensions, grade and selected variant before ordering. Do not rely on the product image alone.
For carbide inserts, tool holders, drills and end mills, compare the mounting dimensions, connection type and manufacturer's specifications with your holder or machine. If you are unsure, share your existing part number and machining application with us before ordering.
Check the product listing for the selling unit, pack quantity and included components. If it is unclear whether the price is per piece or per pack, or whether a tool body and inserts are sold separately, contact us before purchasing.
Select cutting speed, feed rate and depth of cut using the relevant manufacturer's recommendations for your tool model, workpiece material, machine conditions and coolant method. The same settings are not suitable for every product or application.
Our automatic quantity discount is 6% off for 2–9 items and 12% off for 10 or more items, based on the total product quantity in the cart. Other offers may not combine with this discount; check the applicable offer conditions.
According to our shipping policy, orders are typically processed and shipped within 1–3 business days after confirmation. Delivery generally takes 5–20 business days, depending on your destination and shipping method. Customs clearance or unforeseen delays may affect delivery times. A tracking number is sent by email after shipment.