How much approach and overtravel should I add?

Usually 2 to 5 mm (0.197 inch) in turning and milling. For drilling, add about 0.3 × the drill diameter for the drill point as well.

Why does my real time come out longer?

The calculation counts cutting only. Tool changes, measuring, rapid moves and chip clearing add time; many workshops add 10 to 20% on top.

How do I turn machining time into a price?

Multiply the hours by your machine hour rate, then add material, setup and margin. The part cost calculator does this step by step.

Machining time calculator: turning, milling and drilling

OperationLength of cut (mm)(3.94 inch)Approach and overtravel (mm)Drilling: add about 0.3 × drill diameter for the point.Spindle speed (rpm)From the Cutting speed & RPM calculator.Feed (mm per revolution)Number of passesQuantity (parts)Setup time for the batch (min)Loading and unloading per part (min)

Cutting time per part: 0.53 min
Per pass: 0.53 min
Feed rate: 200 mm/min
Whole batch (1 part): 0.5 min

How it is worked out

Time per pass (min) = (length of cut + approach and overtravel) ÷ feed rate (mm/min).
Feed rate = feed per revolution × rpm (turning, drilling), or the table feed (milling).
Per part = time per pass × passes + loading time. Batch = per part × quantity + setup.

Questions

How much approach and overtravel should I add?: Usually 2 to 5 mm (0.197 inch) in turning and milling. For drilling, add about 0.3 × the drill diameter for the drill point as well.
Why does my real time come out longer?: The calculation counts cutting only. Tool changes, measuring, rapid moves and chip clearing add time; many workshops add 10 to 20% on top.
How do I turn machining time into a price?: Multiply the hours by your machine hour rate, then add material, setup and margin. The part cost calculator does this step by step.

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Results use standard formulas and typical values. Use them for estimating and planning; check critical figures against the drawing, the material certificate or the maker's data.