Published · 3 minute read
Negotiating price on a metal part is a weak lever. The cost is largely fixed by the design, and by the time the RFQ goes out most of that cost is locked in. These are the five decisions that move the number most, and all of them can be changed before you send anything.
The single most common cost driver is a drawing covered in ±0.05 mm tolerances on features that have no functional requirement. A tolerance costs money in proportion to how hard it is to hold: it forces slower feeds, more inspection, and more scrap. Mark only the features that matter as critical, and let everything else sit under a general tolerance block. On a typical turned part this change alone moves the price by 10–25%.
Ra 0.4 is roughly ten times the cost of Ra 3.2 to produce and inspect. If a surface is not a sealing face, a bearing seat or a sliding interface, Ra 3.2 is almost certainly fine. Specify finish only where a function depends on it — and say what that function is, so the manufacturer can suggest an alternative if one exists.
A cross-hole, an undercut or a slot on the opposite face of a turned part can force a second fixturing, and a second fixturing is often a second machine and a second setup charge. If the feature can be moved to the same face, or replaced with a drilled feature from the same direction, the part can often be completed in one operation.
If a drawing names a specific mill's trade name, you have limited the supply to one source and removed the manufacturer's ability to buy steel competitively. Specifying the grade and the mechanical properties gives you the same part and a lower material cost.
This is not a design decision, but it has the largest single effect on the quote. A part quoted at 500 pieces and the same part quoted at 50,000 pieces are different manufacturing routes — one is machined from bar, the other is forged and finish-machined. If you do not state volume, you will be quoted the expensive route by default. Always state annual volume and expected order frequency.
A STEP file, a PDF drawing with a clearly marked general tolerance block, the critical-to-function dimensions called out, annual volume, and any standard the part must meet. Five items. Suppliers who receive all five quote faster and lower than suppliers who receive a drawing and a question mark.
Send the drawing and the annual volume — we will tell you whether the process route in your head is the cheap one. Request a quote
Questions about a specific part are usually faster by email than by form.
quotes@vertex-industrial.example
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Read articleSend a STEP file or a PDF drawing with your annual volume. Technical review within one business day, indicative pricing within three.