The mechanical characteristics of many materials can make them difficult to thread using traditional cutting technologies. Chip control and work hardening can be an obstacle to efficient machining. Cold thread forming (thread rolling) often can be used to efficiently improve machinability.
Thread rolling is especially efficient in many Nickel, Monel, Inconel, Titanium, Silicon Bronze, Copper, Brass, Copper alloys and Aluminum alloys. Typically, these materials can be threaded faster and at lower cost through rolling. The chip-less cold formed method adds strength and improves thread performance and is amendable to today’s modern production equipment. Identifying a material grade can quickly determine if rolling is a benefit both in thread cost and thread quality.
Most common thread forms UNC, UNF, UNEF, M, MF, MEF, Acme, Stub Acme and Whitworth are several thread types that are good candidates for rolling. Other forms are also capable. We can quickly identify your specific need and determine capability.
The long-term performance of a thread rolling tool is
directly related to wear of the spindles, bearings, backing plate and face
plate of the rolling head. Wear of any or all these components will manifest
initially in pronounced taper of the finished thread. Older style heads were
equipped with needle bearings while newer style heads utilized carbide
bushings. The carbide helped to maintain parallel form for longer life cycle
than the needles. Correcting taper generally requires replacing one or more of
the contributing components. In a pinch, the straightness is achieved through
preparation of a counter tapered part prep. This can squeeze additional life
out of the tool without the time and cost of immediate repair or part
We inspect, evaluate and quote repair cost and time when
tool performance becomes suspect and the inspection is scheduled regarding
Roll threading with a threading head on a Hydromat transfer machine required modification of the operating station of the machine to include an operating trigger mechanism to trip the threading attachment once it was in the correct position to thread.
The latest offering from LMT Fette is a unique EW style tool that uses the part as the trip mechanism. A rotating mandril inside the head is engaged by the part and collapses the tool on itself through a 4 millimeter air gap. This compression trips the tool activates the thread rolls and resets itself once the toll retracts. The mandril accurately positions the thread location and prevents any unwanted forward movement of the part from its gripping jaws. No special mechanism is required of the machine operating station. This eliminates the need for station modifications that typically add $20,000 to the machine cost. If no part is in position to thread no compression takes place and the head is not tripped removing potential for false tripping.
What you want/need to know
Sintered carbide was discovered in the early 1920’s in Essen Germany as a resultant of a furnace explosion at the Krupp Iron and Steel Works. It was developed and played an important role in German military production during WW2. The Allied nations acquired carbide knowledge following the fall of the Hitler regime. While all carbide products offered today are sourced from the limited suppliers of the carbide powders. The recipe, tool design and coatings vary from manufacturer to manufacturer and have improved dramatically since 1950. Modern carbide products have been designed to run at speeds and feeds that will shorten cycle times and improve tool life. The biggest mistake made with carbide application is ignoring the information provided by the manufacturer. Adhering to the suggested feeds and speeds provided by each manufacturer guarantees maximum tool performance. Surface speed is the most important followed by feed rate. Depth of cut has the least impact on tool life. Ignoring the manufacturers recommendations will seriously degrade tool life and product output.