How to Get a Custom Metal Part Made

To get a custom metal part made, send a machine shop the following: a drawing or 3D CAD file, the material your part will be made in, and how many you need. Specify the dimensions that are most critical and ask for a quote. Finished engineering drawings are not always required. A dimensioned sketch is usually enough to begin.

This guide covers what to send, how to specify the part, what determines the price, and what to expect on lead time.

1. What to send the shop

Machine shops work with various file types and inputs, in roughly this order of preference:

A 3D CAD file (STEP or IGES). The preferred format. Every shop can open a STEP file, and it removes any ambiguity about geometry.
A 2D drawing (PDF or DXF). Required for tolerances, threads, finishes, and surface callouts. A 3D model conveys shape; a drawing conveys requirements.
Both. The professional standard: STEP for geometry, a PDF drawing for the specifications that matter.
A dimensioned sketch. This can be enough for a simple part. Measured dimensions on a paper drawing are more useful than a written description.
The actual part. If you are replacing a component that is broken or worn out and there is no drawing available, send the actual part. It can be reverse engineered and reproduced to the original spec.

A common misconception

You do not need to be an engineer or own CAD software to have a part made. A significant share of shop work begins with a sketch, a measurement, and a phone call. If you can describe what the part does and what it has to fit, a capable shop can take it from there.

2. How to specify material

Material selection is important, and usually one of the first considerations when quoting a part. Guessing a specific alloy could be a costly mistake. Instead, describe the function of the part. Note what it touches, whether it will live outside, and what kind of load it will see. A shop can help select a material that is suitable and readily available.

The most common choices in general job-shop work:

Material	Typical use	Notes
Aluminum (6061)	Brackets, housings, fixtures	Light, machines fast, corrosion resistant. Usually the cheapest to cut.
Steel (1018, A36)	Structural parts, brackets	Strong, inexpensive material. Will rust without coating.
Stainless (303, 304, 316)	Food, medical, marine, outdoor	Corrosion resistant, harder to machine, higher cost.
Tool steel	Dies, punches, wear parts	Hard and durable. Often requires heat treat.
Brass / bronze	Bushings, fittings, marine	Machines cleanly, good bearing properties.

3. Tolerances, and why they drive cost

A tolerance is how much a dimension is permitted to vary. It is the single largest factor in the price of a machined part, and the most common source of unnecessary cost.

Standard machine shop tolerance is around ±0.005" on most features. Specifying a tolerance of ±0.001" can drive the cost up significantly, as holding these tight tolerance features can require specialized tooling, additional cutting time, and more stringent inspection procedures.

Specify the dimensions that matter. Most parts carry two or three critical features that determine if it functions correctly. A bore that holds a bearing or a sealing face for example. The rest of the part can vary within the standard tolerance and still be perfectly functional. Applying tight tolerances where unnecessary can be the difference between a reasonable quote and something that will have you reconsidering if you need the part at all.

If you are unsure what tolerance is required, say so. Describe the fit instead. A shaft that rides in a bearing, or a plate that bolts to existing hardware. That lets the shop set the right tolerances for you.

4. Quantity and minimum order

Most machine shops have no minimum order quantity. Quantity does not determine whether a shop will accept the job. It determines the price per piece.

Machining costs are divided into setup time and run time. Setup covers fixturing, design work, programming, and first article inspection. It only occurs once regardless of quantity. Run time is incurred per part. On a single piece you are largely paying for setup, which is why the price seems so high. Across a 50 part run, the same setup cost is distributed and the per part price drops significantly.

For this reason, it is worth stating your anticipated quantity rather than only your immediate one. One now and about 40 a year is a different job. It changes how the part is fixtured and programmed. It can also change the price of the first one.

5. What actually determines the price

Machining time. How long the part is in the machine. Complex geometry, deep pockets, and hard materials all take longer.
Setups. Every time a part has to be re-fixtured to reach another face, cost goes up. Parts that can be machined from fewer directions are cheaper.
Tolerances and finish. Tight tolerances and fine surface finishes demand slower feeds and more inspection.
Material. Both the raw stock price and how readily it cuts. Stainless costs more than aluminum twice over.
Quantity. Setup amortization, as above.
Secondary operations. Heat treat, anodizing, plating, powder coat, and passivation each add cost and days.
Lead time. Expedited work displaces other jobs and is priced accordingly.

Because these factors interact, no shop can quote a custom part from a description alone. A firm price offered without reviewing the geometry is an estimate at best.

The math behind a machining price is much the same everywhere. The setup, tooling, and machine time behind it belong to the shop quoting it. Our How we work page describes how we quote our custom parts and what we need to price it out.

6. Lead times

Lead time depends more on shop backlog and secondary operations than on machining itself. As general expectations:

Simple parts with material in stock: six to twelve days.
Typical machined parts: two to three weeks.
Parts requiring outside processing such as heat treat, plating, or anodize: add two to three weeks. The part leaves the shop and joins another vendor’s queue.

State a required date up front if you have one. A shop can often sequence work around a firm deadline, but not one it was never given.

7. Finishes

Machined parts will come off of the machine with no protection against the environment and in whatever color the material happens to be. If your part will be exposed to the elements, or is an aesthetic component, there are some finishing options available:

Anodizing (aluminum): hard, corrosion resistant, can be colored.
Powder coat: durable colored finish, good for steel brackets and housings.
Zinc or nickel plating (steel): corrosion protection.
Passivation (stainless): restores corrosion resistance after machining.
Bead blast or brushed: cosmetic surface texture.

8. What to include in your quote request

A complete request for quote produces a faster and more accurate response. Include:

Drawing, CAD file, sketch, or photo with dimensions
Material, or a description of the operating environment
Quantity now, and likely annual quantity
Which tolerances are critical, and which dimensions are not
Finish requirements, if any
Required delivery date
Whether this is a prototype or a production part

Our CNC machining page lists the machine we run and the size of part it takes. How we work describes the order of work and what gets checked before a part is cut.

Frequently asked questions

How much do custom metal parts cost?

There is no list price for custom work. Cost is driven by machining time, number of setups, tolerances, material, quantity, and finish. A small aluminum bracket is inexpensive. A tight-tolerance stainless part requiring several setups and plating is not. Send the geometry to a shop for a quote.

Can I get one part made, or do I need to order a batch?

One part is acceptable at most job shops. Replacements and prototypes are routine work. Expect a higher unit price than at volume, as setup cost is carried by a single piece.

What file format should I send?

STEP for geometry and a PDF drawing for specifications is the ideal combination. IGES and DXF are also widely accepted. If you have none of these, a dimensioned sketch or the physical part is sufficient.

What if I do not have a drawing at all?

Send a photograph with measurements, or send the part itself. Shops reverse-engineer existing components regularly, particularly for obsolete or discontinued equipment.

How long does it take to get a custom part made?

Two to three weeks for standard machined parts. Less for simple work in stocked material. Longer if the part needs heat treat, plating, or another outside process. Quotes are typically returned within a business day or two.

Do I need to be local to the machine shop?

No. Files are sent by email and finished parts ship anywhere in the country. Proximity helps only when a job benefits from reviewing a fixture or assembly in person.

Have a part you need made?

Schwantek is a precision machine shop in Colorado Springs, Colorado, producing custom metal parts to order and shipping nationwide. Send a drawing, a dimensioned sketch, or a photograph with measurements, and we will return pricing and a lead time.

Request a quote