Every manufacturing operation we perform revolves around a specific control processing technique called Geometric Dimensioning and Tolerancing (GD&T)

It ensures consistency through three separate datum surfaces, ultimately leading to tighter pieces and extremely precise parts. Six degrees of freedom are considered along a 3D coordinate system through datum surfaces A, B and C. With A controlling three degrees, B controlling two degrees and C controlling one degree along the different axis’. This triangulation method is instrumental in pinpointing exact locations on both the parts and the fixtures. Using the six degrees of freedom established by the datum surfaces, GD&T is a means of continually attaining and measuring consistency.

Through the implementation of this technique, our machinists and engineers are able to refer back to a controlled feature on each part at any point during the manufacturing process. First, GD&T is essential to maintaining and controlling the part’s weight, balance and dimensional accuracy. Next, the inspection process remains consistent from part-to-part and batch-to-batch, allowing for materials to flow smoothly on the production line. Lastly, by constantly referencing back to the datum surfaces we are able to make finite adjustments and improvements without abandoning even the smallest detail. Not only do our strategies determine a strict standard for all individual products, but they serve as a built-in auditing system active in maintaining that standard day-to-day and for years to come.

A typical V8 racing engine running at 10,000 rpm equates to the rotating assembly spinning at over 166 times per second with virtually all of the force then being transferred through the connecting rod. For every revolution, the piston and connecting rod must go through one full compression cycle and one full tension cycle. Under these extreme conditions, connecting rods manufactured with a wider tolerance margin are at risk of causing oscillations and stress concentrations in the rotating assembly. In turn, the friction of the reciprocating assembly is compromised. GD&T works to eliminate these risks by enabling Oliver to reach the highest possible degrees of concentricity, circularity, parallelism, perpendicularity and a number of other factors that govern the relationship between the crank and pin bores of our connecting rods.

Concentricity of the bores is critical to ensure friction free runout relative to the piston pin and crank journal.

Concentricity of the bores is critical to ensure friction free runout relative to the piston pin and crank journal. Twist and bend in the automotive world is often associated with the quality of connecting rods. Oliver goes well beyond these simple concepts and fully defines the relationship between the pin and crank bores.

As one of the most challenging measurements in GD&T, concentricity is obtained through in-process air gauging, verifying that Oliver rods adhere to the highest accuracy standards. Air gauging, described in detail below, is an extremely precise measurement device for this particular feature. Even better than the most accurate coordinate measuring machine (CMM), air-gauging effectively monitors concentricity of every Oliver rod. Since World War I machinists have used jig borers to ensure accuracy of bores. Through Oliver’s multi-step GD&T governed process, we have developed a modern day systemic version of the jig borer specific to connecting rods. This confirms that every Oliver rod has met our strict tolerances.

It seems like this would be a common practice for all connecting rod manufacturers. However, modern machining practices allow some manufacturers to cut corners and create concentricity of the bores through the honing operation, a function and tolerance never intended for any hone machine.

At Oliver concentricity is built into the part throughout our multi-step process, ensuring that the hone operation is correctly utilized to impart the final surface finish optimized for lubrication. Because extremely small tolerances, reaching beyond visibility, are often taken for granted, it is what we cannot see through conventional measurement techniques, that makes Oliver rods stand above the rest.

Ultimately, our commitment to achieving exact measurements between the pin bores and intangible axis surfaces of our connecting rods is only possible through GD&T. We are confident in our rods’ ability to reduce frictional loss to the absolute minimum amount, directly improving engine durability, performance and longevity. Most importantly, it allows the entire reciprocating assembly to be more efficient and ultimately generate more power.

GD&T protocol requires that all measurements be taken at 20 degrees Celsius...

GD&T protocol requires that all measurements be taken at 20 degrees Celsius to achieve the desired tolerance. However, in a continuous effort to perfect the repeatability of our rods, Oliver takes this concept even further.

We apply temperature control to our entire manufacturing process. Our state-of-the-art climate controlled facility, based in Michigan, is maintained through four HVAC systems, automatically preserving a targeted temperature range within four degrees. In a pressing effort to remove any human or mechanical error during production, we’ve implemented this system to eliminate any expansion or contraction that may otherwise occur. Additionally, the positive pressure atmosphere keeps air particles reduced to minimum amounts and allows us to keep our coordinate measuring machine (CMM) on the actual shop floor. This means that our parts are measured in the same atmospheric and temperate conditions as they are machined.

The consistency in temperature carries throughout all of our measuring activities, in addition to our machines, fixtures and parts, leaving absolutely no room for variability. Once received into our facility, Oliver connecting rods are held within the same temperature window from raw material to finished product. Temperature control is just one additional example of how GD&T results in unmatched accuracy during production, placing the quality of Oliver connecting rods in a category above the rest.

ZEISS CMM – Coordinate Measuring Machine (CMM)

The ZEISS CMM provides ultimate dimensional information directly on the production line. The temperature control on our shop floor makes it possible for the ZEISS CMM to perform within the actual production line through the facility’s tightly controlled atmospheric pressure and climate. This elite machine offers maximum efficiency when it comes to in-production waiting times, but quality control remains our top priority. Most importantly, the ZEISS CMM establishes reliable reproducibility through top-of-the-line software and technology, erasing any uncertainty or fluctuations as a result of outdated manual measuring techniques.

Sunnen Hone

Air Gauge

Working with the tightest of tolerances, air gauging as a measurement method is critical to Oliver’s accurate high volume manufacturing process. Parallelism and concentricity implemented prior to the hone operation opens up the potential for extremely consistent bores for the gauging of the part. With only .002 travel and a measurement tolerance of .00002, our gauges offer the ability to control the part and therefore, give us authority over the entire gauging process. Lastly, we run the air through a dryer and two micron filters to generate consistent dry air for every single measurement. When measuring rod diameters down to the most extremely precise points, air gauges are not only one of the most elite choices, but they also take out any chance of a flawed or limited mechanical instrument entirely.