Throughout my more than thirty years in the smelters, mills, and mines in the Sudbury area, my company has always sought out the best people, the best communications equipment, and the best measurement equipment. There has, however, been a long and recurrent theme of deficiencies with finding high quality targets. To solve this problem, Bull Corp, in business for 40 years, designed and had machined, targets which do not exist for sale anywhere else in the world. Ourseven specialized scales/targets and/or their corresponding design drawings are available for sale on this website, as well as their accessories and adapters. In the following paragraphs, you will read about the development of these instruments over the years.

To begin, most conventional measurements still require two components, that being firstly the optical/electronic total station and secondly the optical reflective target. It is the optical reflective target which has consistently come up short in my company’s expectations for a reliable, accurate and fast measurement. To address this problem, standard off-the-shelf tripod targets, which my company received direct from the manufacturer, were disassembled, stripped of parts, and new machined parts were added to them. Hand-held targets required years to improve upon. The practice of suspending a glass reflector (commonly known as a prism) on a plumb line, usually with oddball target heights which were constantly varying, was neither dependable nor accurate nor fast.

Twenty years ago, my company began developing scales with multiple sheet targets. In 2020, after many years of improvements, our development of multi-target scales reached its apex with the introduction of the 400 mm Universal Block Scale, followed by the introduction of the 1100 mm Universal Block Scale in 2021. These beautifully designed scales, which are of lasting worth, timeless, and of the highest quality, quickly became classics. Multiple targets with preset target heights and multiple circular level vials provide certainty with target heights, and the redundant level vials enable the integrity of the scale to be checked for every measurement. Although most of my company’s work has been QA/QC (sometimes referred to as back checking), we occasionally provided layout, and my personal favorite for this is the 185 mm Block Scale introduced in 2012. It is compact, self-supporting and carpenters enjoy working with it as it is easy to use as it slides about on deck plate, plywood, or 2×6 boards. If more height is required, the 600 mm Plastic Block Scale is the next choice for carpenters as it is light weight and machined from a stock carpenters’ level. An experienced and careful carpenter can layout points and lines with the 600 mm Plastic Block Scale to an accuracy of 0.8 mm (1/32”) four times out of ten and to an accuracy of 0.4 mm (1/16”) eight times out of ten. The 50/220 mm Universal Block Target was introduced in 2017 when we were setting large diameter anchor bolts which were well above the hoist house floor. The hoist, which we were working on, had three anchor bolt diameters and the 50/220 mm Universal Target was useful in providing an anchor bolt adapter which we could leave attached to the target thus avoiding constantly switching between the other two anchor bolt diameters. The 650 mm Forward/Reverse Up/Down Universal Scale, introduced in 2010, was intended to be so flexible that after the scale had been machined no other scales would be required. The handle of the 650 mm Forward/Reverse Up/Down Universal Scale is held in place by a pair of Brunson parallel jaws. By releasing the jaws with the thumb screws, the handle could be removed, and then the scale could be used upside down. The scale was subsequently used upside down when we made a model of a counterweight conveyance in a mine shaft. The underside of the conveyance was observed using the 650 mm Forward/Reverse Up/Down Universal Scale with an outside corner adapter attached and by standing on the safety doors below the conveyance. However, the scale is relatively heavy when assembled and has moving parts, which introduces the potential for misassembly in the field. The scale was subsequently replaced by later and improved designs, but it is still useful, reliable, and accurate. In 2012, the 1900 mm Aluminum Scale was designed and machined for observing points which are very difficult to access. This lightweight, precision-machined scale may be used with a variety of specially machined attachments at both ends, such as a coupling for a 2-inch diameter furnace rod. The scale is not necessarily used in the horizontal plane but may be used in the vertical plane or any skew plane.

Our seven specialized scales/targets have been given descriptive names which represent the length of their scales as well as their functionality. These composite, descriptive names are derived from three categories of scales/targets: Block Scales/Targets, Universal Scales/Targets, and Universal Block Scales/Targets.

The first category, Block Scales/Targets, includes the 50/220 mm Universal Block Target, 185 mm Block Scale, 400 mm Universal Block Scale, 600 mm Plastic Block Scale, and 1100 mm Universal Block Scale. All block scales/targets have a 316 stainless steel block. The 316 stainless steel block in the 185 mm Block Scale is not detachable while the 316 stainless steel blocks in the other block scales/targets are detachable. The detachable stainless-steel blocks are ordinarily used to check, set, and adjust the circular level vials on the instrument. The block scales/targets may also be used with the stainless-steel blocks attached and supporting the scale in the vertical.

The second category, Universal Scales/Targets, includes the 50/220 mm Universal Block Target, 400 mm Universal Block Scale, 650 mm Forward/Reverse Up/Down Universal Scale, and the 1100 mm Universal Block Scale. Universal scales/targets are designed to accept various attachments and adapters which may be needed for measuring in an industrial environment, depending on the conditions present. Universal scales/targets are ordinarily used in one of four configurations:

1. With a 316 stainless steel point.
2. With a 316 stainless steel, gently curved bottom adapter.
3. With a 316 stainless steel anchor bolt adapter which accepts various anchor bolt diameters.
4. With a specially machined attachment such as a saddle which can sit on top of a motor pinion shaft.

Finally, the third category, Universal Block Scales/Targets are both universal scales/targets and block scales/targets. This group includes the 50/220 mm Universal Block Target, 400 mm Universal Block Scale, and 1100 mm Universal Block Scale. Universal block scales/targets are the most versatile of the scales/targets. These scales are capable of multiple configurations and will provide reliable horizontal and vertical observation data in difficult to access points. These scales are also the most recent scale designs and are based upon many years of earlier designs and design modifications.