🔧 Surface Finish Calculator
Estimate Ra, Rz, scallop height, spindle speed, and finish-safe feed settings for turning, milling, routing, and planing.
📌 Presets
📊 Calculator
🧮 Material Properties
📋 Speed and Feed Reference
| Material | SFM | RPM Range | Chip Load |
|---|---|---|---|
| Softwood | 3000 | 12000-24000 | 0.012 in/tooth |
| Hardwood | 2200 | 10000-22000 | 0.008 in/tooth |
| Plywood | 2600 | 12000-24000 | 0.010 in/tooth |
| MDF | 2400 | 12000-24000 | 0.009 in/tooth |
| Aluminum | 500 | 3000-12000 | 0.003 in/tooth |
| Mild Steel | 120 | 500-3000 | 0.0015 in/tooth |
| Stainless | 70 | 400-1800 | 0.0010 in/tooth |
| Acrylic | 600 | 6000-18000 | 0.0025 in/tooth |
🔧 Blade and Bit Selection
| Tool Size | Teeth / Flutes | Kerf Width | Best For | Max RPM |
|---|---|---|---|---|
| 1/4 in carbide end mill | 2 flutes | 0.250 in | Hardwood, MDF, aluminum | 24000 |
| 3/8 in ball nose | 2 flutes | 0.375 in | Contour finishing and 3D relief | 18000 |
| 1/2 in spiral router bit | 2 flutes | 0.500 in | Plywood and clean edge work | 22000 |
| 5/8 in insert cutterhead | 4 knives | 0.625 in | Planing and surfacing passes | 10000 |
| 3/8 in turning tool | 1 edge | 0.375 in | Aluminum and brass finish cuts | 3000 |
| 1/2 in insert turning tool | 1 edge | 0.500 in | Steel and stainless light passes | 2000 |
📆 Common Project Sizes
| Project | Typical Size | Recommended Settings | Estimated Time |
|---|---|---|---|
| Lathe spindle | 1.5 x 18 in | 0.002-0.004 ipr, 32 Ra | 12-18 min |
| Aluminum shaft | 1.0 x 8 in | 0.0015 ipr, 16-32 Ra | 8-12 min |
| Edge-milled board | 3/4 x 36 in | 0.003 ipt, small step | 4-8 min |
| Router contour | 1/4 x 48 in | 0.004 ipt, light climb | 5-10 min |
| Planed panel | 12 x 24 in | 4 knives, shallow cut | 3-6 min |
| Stainless finish | 50 x 120 mm | 0.02 mm/rev, slow RPM | 10-16 min |
💡 Tips
Surface roughness estimates the final irregularities in the texture of surface. It includes three main elements: roughness, waviness and form. Estimate the roughness of surface finish matters for production and quality control.
Like this one ensures that the product accomplishes the involved standards and is good for its intended use. You commonly describe roughness by means of values Ra, where it grows from Rz 50 until Rz 800.
Surface roughness and how to measure it
You commonly measure that by means of Ra, the arithmetical average of roughness. Ra shows the middle value of absolute deviations of the surface profile regarding the centerline during certain length. It well points the general surface quality and commonly used for specifications.
The theory of Ra assume ideal conditions without tool wear, with little vibration and stable material attributes. Ra rank between the two most common units. Except that is Rz, the so-called deep roughness.
Rz you count estimating the vertical distance between the highest peak and the deepest valley in scanned profile. Also it is possible to estimate surface finish by means of entering arithmetical roughness and maximum depth in calculator.
Calculator for surface finish is useful for metal cutting or machining projects. Many tools estimate surface finish, inches for revolutions and corner radius values. Some calculators intend to help about finish of ball endmill or about altered radius of endmill with corner on slope.
Exist also tools for ball nose endmills. During turning you can estimate the surface roughness (Ra) according to tool nose radius and feed per revolutions. They help to accomplish demands, balance production with final quality or remove bad finish.
From feed per revolutions and radius you receive Ra, or rather. Results you can show in metric or imperial units.
Knives with one spot for finishing operations have rounded front corner or nose. That nose creates little peaks and valleys in the material according to the feeds of the tool. During turning the stepover depend of the feedrate, what gives ripples alike to the turning form.
Deeper edges cause rougher finish. The feedrate matter for surface finish and breaking a chip. For good milling surface finish care that feed per revolutions be under 80% of BS.
Calculators also convert finish of Ra to Rz either vice versa.
