CNC Machining Blog
Material comparisons, process selection, tolerances and cost — written for the person who has to put a drawing on a machine and place the order. Every article ends with the callout that actually belongs on the drawing.
25 articles · latest October 30, 2026
Comparison
Which material, which process, and when the answer changes. These articles compare two options on the properties that decide a machined part — not on a spec sheet.
- Wire EDM vs CNC Milling: Corners, Slots and Hardened SteelMilling leaves a radius at every internal corner. Wire EDM does not, and it cuts hardened steel as easily as soft. Where each process actually wins.Read →
- Cold Heading vs CNC Turning for FastenersCold heading moves metal into shape; turning cuts it away. That difference decides grain flow, fatigue strength, material waste and the volume at which each wins.Read →
- CNC Machining vs Die Casting: Volume Is the Whole ArgumentDie casting needs an expensive die and gives a cheap part. Machining needs almost no tooling and gives an expensive part. Where the two routes actually meet.Read →
- 3-Axis vs 4-Axis vs 5-Axis Machining: What You Are Paying ForAdding an axis rarely makes the cut faster. It removes setups — and setups are where cost and position error come from. What each axis actually buys.Read →
- CNC Turning vs Swiss Screw Machining: Where the Line SitsA fixed-head lathe holds the bar and turns it. A Swiss machine feeds the bar through a guide bushing and cuts at the support. That changes what is possible.Read →
- CNC Turning vs Milling: How the Part DecidesTurning rotates the work, milling rotates the tool. The part's shape decides which one — and the setup count decides what it costs.Read →
- Acetal vs Nylon for CNC Machining: POM, PA and WaterAcetal holds its size and machines beautifully. Nylon is tougher and absorbs moisture, which moves machined parts. How to choose between POM and PA.Read →
- Brass vs Bronze vs Copper: Picking a Copper AlloyBrass, bronze and copper are one base metal with three different jobs. Machinability, dezincification, bearings, conductivity and the lead question, compared.Read →
- 5052 vs 6061 Aluminum: Formability Against Machinability5052 cannot be heat treated and 6061 can. That one difference decides welding, forming, machining and which of the two belongs on your part.Read →
- Hot Rolled vs Cold Rolled Steel for Machined PartsThey are not two steels — they are two conditions. What hot rolling and cold drawing change about tolerance, surface, residual stress and the price of a machined part.Read →
- 12L14 vs 1215: Which Free-Cutting Steel to Specify12L14 is the fastest-cutting steel available and contains lead. 1215 is lead-free. That single difference decides most specifications — including RoHS.Read →
- 1045 vs 4140 Steel: Choosing a Medium-Carbon or Alloy Grade1045 and 4140 are both hardened and tempered. The real difference is hardenability — how deep the hardness goes — and that is decided by section size.Read →
- 4140 vs 4130 Steel: Strength, Weldability and What It Costs4140 and 4130 are both chromoly, one carbon step apart. Why 4130 is a welded-tube grade and 4140 is a machined-part grade — and where the comparison misleads.Read →
- 17-4PH vs 304 Stainless Steel: When Strength Beats Corrosion17-4PH is roughly five times the yield strength of 304. What that costs in corrosion, machinability and price — and why the hardest condition is the least corrosion resistant.Read →
- 316 vs 316L Stainless Steel: What the L Actually Changes316 and 316L differ by carbon content alone. What that does to welding, sensitisation, specified strength and cost — and when the L is not the safe default.Read →
- 303 vs 304 Stainless Steel: Machinability Against Corrosion303 is 304 with sulphur added for free machining. What that buys on the machine, what it costs in corrosion and welding, and how to choose.Read →
- 304 vs 316 Stainless Steel for Machined Parts304 and 316 stainless compared on corrosion, chlorides, machining, welding and cost — and the environments where choosing 304 is a mistake.Read →
- 6061 vs 7075 Aluminum: Which Grade for CNC Machined Parts6061-T6 and 7075-T6 compared on strength, machinability, anodizing, corrosion and cost — with the callout that belongs on your drawing.Read →
Cost & Pricing
What actually moves the price of a machined part, and where a design change saves money without changing the function.
- How Tolerances Drive CNC Cost: The Tolerance You Do Not NeedTolerance cost is a curve, not a line. Why the last increment of precision costs far more than the first, and how to find the tolerances worth paying for.Read →
- The Most Cost-Effective Metals to CNC MachinePrice per kilo is the wrong ranking. Machinability, stock form and finishing decide finished part cost — and the answer often reverses the price list.Read →
- What Actually Drives the Cost of a CNC Machined PartMaterial, setups, cycle time, tolerances and quantity — how each one moves the price, which levers actually work, and the changes that save nothing at all.Read →
Design & DFM
Design rules for parts that have to be machined: tolerances, threads, features and callouts that survive the shop floor.
- Drill Size Chart: Metric, Number and Letter DrillsEvery drill size in one place — metric 1 to 20 mm, number drills #1 to #80, letter drills A to Z — and why the hole a drill makes is not the size on its shank.Read →
- Types of Thread Taps and When Each One Is UsedTaper, plug, bottoming; straight flute, spiral point, spiral flute; and form taps that make no chips at all. How the tap is chosen, and why chip direction decides it.Read →
- Threaded Holes: Depth, Drill Size and How to Call Them OutThe tap drill is not the thread diameter, and thread depth is not drill depth. The rules behind both, and how deep a thread actually needs to be.Read →
- ISO 2768-m Explained: The Tolerance Chart on Your DrawingThe ISO 2768-m tolerance table, what the four classes mean, and the four things general tolerances do not cover — threads, reference dimensions, radii and geometry.Read →
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