Machining Services

CNC Machining Capabilities

Sinclair & Sons Custom Welding & Machine Service is an AS9100D and ISO9001:2015 Registered manufacturer of custom metal components. Our skilled machinists use the latest equipment and manufacturing techniques to create precision components of unsurpassed quality.

Our specific machining capabilities include:

  • Conventional milling
  • CNC milling
  • CNC lathe
  • Big blocks
  • Small blocks


Computer numerical control, or CNC, has made it fast, efficient, and affordable to machine complex parts. The term refers to any manufacturing process in which a computer guides automated cutting tools to machine stock. Typically, this type of automation is used with mills and lathes, allowing the material to be removed rapidly and precisely.

CNC stations differ depending on the number, type, and position of the machining parts. For instance, in some machines, the workpiece is held stationary while the tool moves along 2 or 3 axes. In others, the tool remains in place while the workpiece rotates and moves. More complex stations allow both the workpiece and the tool to move in tandem, facilitating more complex cuts and features.

As a full-service provider of metal parts, Sinclair & Sons combines CNC with conventional machining to create the most precise components possible.


CNC Milling

Milling is one of the most common and versatile CNC processes. In CNC milling, one or more cutting tools progressively remove material from a workpiece to yield the final geometry. Because the cutting tools are controlled by a computer, their movements are extremely precise, allowing CNC mills to achieve extremely tight tolerances regardless of complexity.

CNC mills typically perform 3 millings. In 3-axis milling, the workpiece is stationary while the cutting tool moves along the X, Y, and Z axes. This process is most appropriate for machining features on a single plane of the workpiece.

Both types of CNC mills can handle workpieces of different sizes and materials, including a full range of wood, metal, and plastic workpieces. Some common materials include:

CNC Machining Services Infographic


  • Aluminum
  • Stainless steel
  • Steel
  • Copper/Brass

This versatility means that CNC milling can be useful wherever tight tolerances are required. This includes applications such as:

  • Rapid prototyping and modeling
  • Screws, bolts, fasteners, and fittings
  • Pistons and rods
  • Precision instruments
  • Furniture
  • Electronics housings
  • Panels

In general, CNC milling is an effective choice for precision components at all production volumes.

CNC Lathe

Lathing is common application of CNC technology. CNC lathes move cutting tools back and forth across a rotating workpiece, which is clamped in place. As with CNC milling, different numbers and types of cutting tools may be used, and the lathing stations may feature different axes of motions.

CNC lathing is the best choice for creating precision components with radial symmetry. Working from bar stock, CNC lathes allow manufacturers to create shafts, barrels, fasteners, and other components with defined outer and inner diameters.


Conventional Milling

In addition to CNC milling, our machining services also include conventional milling, another subtractive manufacturing technique used to create custom metal components.

Conventional milling uses a rotary tool with an upward cutting pattern to chip metal off of a workpiece. The cutting tool rotates in the opposite direction of the feed and removes the narrow end of the chip first, progressing upward toward the widest part of the chip. This method eliminates backlash between the machine’s table and its lead screw.

Although CNC milling is ideal for complex components or high volumes, manual, conventional milling can be the faster and more affordable option for simple components at low production volumes. Conventional milling also allows our skilled technicians to manually add features when necessary.


Big and Small Blocks

One of the primary advantages of CNC machining is that it can be applied to workpieces of all shapes and sizes. Whether working from a tiny blank or a large block of material, CNC machining services ensure consistent results with tight tolerances.

At Sinclair & Sons, we create large and small components from both blocks and round bar stock, depending on our clients’ needs. Our team can answer questions about specific dimensions and tolerances, as well as regulatory compliance. All of our components, large and small, can be manufactured in compliance with MIL-I-24768 and similar specifications according to client needs.