An edge finder is an essential tool in precision machining, helping machinists accurately locate the edges and center points of a workpiece on a manual milling machine. While not commonly used on CNC machines, edge finders remain indispensable in traditional machining setups for layout accuracy and setup repeatability.
At Travers Tool Company, we offer a wide selection of high-quality edge finders designed to meet the needs of both professional machinists and hobbyists. This guide explains how to choose the right edge finder and provides step-by-step instructions on for using it effectively.
Selecting the right edge finder for your milling setup depends on your specific application. Travers Tool carries various types to suit different precision tasks:
The most widely used and traditional type of edge finder
Features a spring-loaded body with a cylindrical or pointed tip
Turns in the spindle and visually offsets (or “jumps”) upon contact with the edge of the workpiece edge
Uses electrical conductivity to detect the edge of a conductive workpiece
Typically includes LED indicators, audible signals, or both for clear edge detection
Edge finders come in various sizes and tip designs to accommodate different workpiece shapes. At Travers Tool Co., we offer the following options:
Ideal for smaller and more precise setups
The 1/2” body provides more tip offset
A common choice for general machining
Suitable for finding the center of a round tube or solid rod
Provides more contact area for larger workpieces
Offers more tip offset than the 3/8” body size
Suitable for finding the center of a round tube or solid rod
Often used for finding the center of a round tube or solid rod
The 1/2” body provides more tip offset
Here’s a step-by-step guide to help you use a mechanical edge finder effectively and avoid common mistakes:
Ensure the workpiece is properly clamped in the milling machine.
Mount it in the spindle and set it to an appropriate speed (approximately 1,000 RPM for mechanical types).
Slowly move the tool toward the workpiece, allowing the tip to contact the surface.
For mechanical edge finders, the tip will “kick” or offset when contact is made.
At the moment of deflection, set the machine’s DRO (digital readout) or dial reading to zero.
Move the Edge Finder away from the workpiece, then slowly back in, to confirm your zero setting.
Add (or subtract) half the tip diameter (e.g., 0.100” for a .200” tip) to set the DRO or dial to the true zero.
To locate the center of a symmetrical or round feature:
Repeat the edge-finding process on the opposite side without resetting the zero.
Subtract the first reading from the second and divide by two.
Move the machine table to the midpoint value and reset your DRO or dial to zero.
Use the same process described in the “How to Find the Center…” section above.
To properly position the edge finder along the side of a round workpiece, use either a cylindrical edge finder with a tip diameter equal to its body diameter or one with a cone-shaped tip.
While edge finders are a go-to solution for many machinists, other tools and methods are also available, each with its own process:
Ideal for high-precision setups but require careful positioning
Excellent for centering on bores
Digital touch probes for fast X, Y, and Z detection
Suitable for general alignment tasks
Use a method similar to that described in “How to Find the Center…”
Specifically designed for locating the center of round stock
An edge finder is a crucial tool for machinists seeking precision, accuracy, and repeatability in their work. At Travers Tool Co., we provide a variety of high-quality edge finders in different styles, sizes, and configurations to suit your machining needs. By selecting the right tool and following proper techniques, you can ensure accurate positioning and enhance overall machining efficiency.
Explore our complete selection of edge finders, indicators, and other precision tools: