Tag Archives: mounting flanges

Threaded Bars in Heat Exchangers

Keystone Threaded Products

At Keystone Threaded Products, we manufacture quality roll threaded products, and we use our threaded bars in heat exchangers. We specialize in the production of roll threaded products including acme threaded bars, precision acme components such as acme round nuts, acme cylinder nuts and mounting flanges. We work with a variety of metals, including various grades of carbon steel, alloy steel, heat treated metals and stainless steel. We also work with bronze, aluminum brass, titanium, alloys and exotics.

When it comes to selecting the right heat exchanger, the process consists of a trade-off between the overall heat transfer measurements, which affect the pump head on the HVAC system. It also influences other factors including the pressure drop and surface area.

Generally, low pressure drop increases the surface area of the heat exchanger, which will then increase the unit’s initial cost. The key to choosing the proper heat exchanger is to find the smallest model with the same type of plate corrugation capable of handling the flow during both the summer and winter.

The next step in choosing the right heat exchanger is to simulate it with the largest surface area and plate corrugation type. This can be done by selecting the unit with the temperatures and flow profiles of the other season to obtain the duty value required for the season. The best solution is achieved when temperature, flow and pressure drop are all within the acceptable limits. Be sure to keep all of this in mind when looking for a heat exchanger so that it’ll last in the long run.


Your applications deserve the best. And We lead the pack when it comes to precision and custom roll threaded products like acme threaded bars and acme precision components such as round nuts, cylinder nuts, and mounting flanges… plus our complete line of standard threaded products.

As you’ve come to expect, a good roll threading process produces a uniform, precise surface without tears, chatters or cutter marks.

How is it done? In roll threading, steel is extruded to form the threaded portion, instead of being removed as in done in cut threading. The product is fed or “rolled” through threading dies to form the threads. To help make this process even more clear, here are some roll threading terms and their definitions.

Class of Thread: alphanumerical designation indicating the standard grade of tolerance and allowance specified.

Crest: top surface joining two sides of thread.

Depth of Thread Engagement: radial distance, crest to crest, by which thread forms overlap between two assembled mating threads.

Helix Angle: The angle made by conical spiral, or helix.

Major Diameter: distance across the crests of thread of the major cylinder.

Minor Diameter: root diameter of thread of minor cylinder.

Nominal Size: designation for general identification based on the major diameter.

Pitch: axial distance from a point on one screw thread to the corresponding point on the next screw thread. Pitch is equal to the lead divided by number of thread starts.

Pitch Diameter: On a straight screw thread, diameter of an imaginary cylinder surface that passes through the threads at such points to make thread width and the width of the spaces cut by the surface of the cylinder equal. On a taper screw thread, diameter at a given distance from a reference plane perpendicular to the axis of an imaginary cone, the surface of which would pass through the threads at such points as to make thread width and the width of the spaces cut by the surface of the cone equal.

Profile of Thread: contour of a screw thread ridge and groove delineated by a cutting plane passing through thread axis. (Also called form of thread)

Root: bottom surface joining two sides of thread.

Root Diameter: diameter of an imaginary cylinder bounding the bottom of the roots of a screw thread. (minor diameter of thread)

Thread Series: Groups of diameter/pitch combinations distinguished from each other by the number of threads per unit of measurement.