Custom-Made Tool for Cutting Large Quantities of Standard Size Padding - Bristol Dinosaur Project

CUSTOM-MADE TOOL FOR CUTTING LARGE QUANTITIES OF STANDARD SIZE PADDING BRISTOL DINOSAUR PROJECT by Pedro A. Viegas and Charles Clapham
Pedro A Viegas and Charles Clapham 2012. Custom-made tool for cutting large quantities of standard size padding - Bristol Dinosaur Project. The Geological Curator 9 (8): 429 - 432. At the Bristol Dinosaur Project, the processing of thousands of microfossils makes it essential to have good methods and materials for protecting such an immense number of specimens. We present a simple tool for cutting thousands of standardsize Plastazote® foam pads which saves time and minimises repetitive strain injury to those that have to do the job. Pedro A Viegas and Charles Clapham - University of Bristol, Dep. of Earth Sciences, Wills Memorial Building, Queen´s Road, BS8 1RJ, UK email: [e-mail] Received 16 August 2012.

Introduction
Efficient conservation methods are essential in fossil preparation. At the Bristol Dinosaur Project (BDP), good conservation methods are vital to preserve the prepared minute microfossil specimens. Protecting them for future use by researchers is no easy task, because of their delicate nature and quantity. As Smith (2007) stated, "microfossils can be very numerous ...... curation costs per unit add up quickly for time and materials ...… a poor storage system can take up a disproportionate amount of space in a cramped collection". At the BDP new methods of specimen storage were developed in order to protect the specimens, to maximize the available space and to facilitate access to specimens. One of these new methods is the custommade lining of all specimen housings with Plastazote®, a closed cell cross-linked polyethylene foam, protecting these extremely fragile specimens from being destroyed by being loose in card or plastic boxes. The standardization of box sizes and the need to create thousands of pads for them involved a painstaking task that even the most willing volunteer eventually refused to do. The repetitive job of cutting round pieces of Plastazote® with a cutting punch gave the operator very sore hands. In this paper the authors describe the materials and methods used to create a simple and very effective tool to cut thousands of standard-size pieces of padding material.

brate fossils on a scale that virtually requires the use of a microscope (Madsen 2009). Even though this is not the case for all fossils recovered from the BDP´s acid processing, we generally tend to call them microfossils. With an average size between 250µm to 15 mm, the fossils handled at the BDP are very fragile, not only because of their size and taphonomic history, but also the outcomes of acid preparation methods; all this makes them very friable and therefore in need of proper conservation treatment. Specimens are picked and placed individually into clear round Polystyrene containers with an external diameter of 20 mm and internal diameter of 16 mm (Figure 1).

Figure 1. Clear Polystyrene receptacles used for microfossil storage at the BDP.

Materials overview
Micropreparation is any manual preparation of verte-

Round Plastazote® pads were cut using a hand-held mild-steel punch (Figure 2), which is simply a piece of 20 mm-diameter solid mild-steel pipe that has been partially hollowed and sharpened. This punch, even though very effective for producing a couple of

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something similar, but for cutting thick padding materials. A small Clarke® Arbor press was ideal for this, as it has a long central post that can be adapted with almost any kind of bit/tool and it operates by a simple and smooth lever action that multiplies the force and therefore reduces the amount of force exerted by the operator. By creating a punch bit with the exact dimensions of the standard size boxes used at the laboratory and fitting it to the Arbor press post, all padding making problems would vanish. We present a step-by-step description of the manufacture of this tool.

Figure 2. Hand punch originally used - a piece of sharpened mild steel tube.

pads at a time, gives a very sore hand when handled hundreds of times, because of the natural position the user adopts while making the downward-circular movements necessary to cut a round object with such tool. After several complaints from our volunteers and a very sore hand from one of the authors a new method had to be created. A custom-made PEEK knob adapted to the existing punch was fabricated by one of the authors (C.C.) in an attempt to increase the area upon which the hand would exert pressure and thus reduce the hand stamping and painful after effect (Figure 3). This did not achieve the expected outcome and the adapted punch still gave the operators sore hands. The hand-held type of punch was discarded and a new, completely user-friendly tool had to be made.

The Cutting Bit
1. An easily available and cheap 1-ton Arbor press was bought (Figure 4); there are numerous online sites that sell these for very cheap prices, and they come in a variety of tonnage.

Figure 4. Clarke® 1Ton Arbor press.

2. The press was dismantled and an 8 mm thread was machined into the base of the central post (Figure 5).
Figure 3. PEEK knob adapted for the hand punch, to protect the operator 's hands.

Construction of the custom cutting machine
The solution to our problem was to construct a tool that would cut thousands of standard size padding material with no painful after effects to the operators. The eureka moment came considering how a holepunch bladed cylinder works and trying to make

Figure 5. Machining the 8 mm thread into the Arbor press ram.

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3. A piece, 75 mm long, of 20 mm-diameter mild steel was cut and a thread 20 mm long was machined in to it (Figure 6); this is the blank cutting bit.

The Support Plate
In order to get a perfect circle the cutting bit has to go through a plate with the same exact dimensions. 1. We cut a piece of Trespa®, a high pressure compact laminate (HPL), 130 mm long x 85 mm wide x 16 mm deep (Figure 9), that fits perfectly into the base of the Arbor press. The choice of Trespa® has to do with its impact and chemical resistance properties, and also because it is a readily available material at the University´s workshop, but other materials such as steel or aluminium could be used. 2. A hole with 16 mm in diameter was drilled into the centre of the plate. 3. The plate was glued using medium strength epoxy (5 min. Epoxy) in order to be strong, but easily removable if necessary.

Figure 6. The 8 mm thread, machined into the mild steel blank.

4. A concave hole-punch shape was machined into the cutting bit (Figure 7), 5 mm deep.

Figure 7. Concave hole-punch shape machined into steel blank.

5. Finally a hole, 7 mm in diameter, was drilled into the cutting bit about 30 mm from the cutting tip, which will serve to tighten or un-tighten the cutting bit in the press (Figure 8).

Figure 9. Trespa® plate drilled and glued into the base of the Arbor press. Perfect alignment with the cutting bit is fundamental.

Conclusions
By using 2 mm thick mild-steel tube, shaping the tip into a concave hole-punch-like shape and adapting it to an easily available and cheap Arbor press, the cutting process is now not only pain-free but also fast and fun. It is now easy to produce thousands of standard size padding material in less than an hour, ˜ 3000 p/h. Another advantage of this system is the almost limitless possibilities that threaded tools bring; one can easily remove the cutting tip by unscrewing it and attach any other custom made cutting tip with any different size or shape. For this the Trespa® base plate would be screwed to the Arbor press using countersunk or butterfly screws instead of glue. Another improvement could be the use of higher quality stainless steel instead of mild steel, this could keep the cutting bit sharper for longer.

Figure 8. A 7 mm tightening hole drilled into the finished cutting bit.

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Notice that the presented production numbers are ideal for the project this tool was designed for, the BDP, where the needs for this padding material is about 3000 every month and a half. Other projects with higher production demands might need to resort to numerous operators or to a specialist cutter with hydraulic or similar cutting equipment to cut in bulk without the risk of causing repetitive strain injuries to the operator.

References
MADSEN, S.K. 2009. Wax On, Wax Off: A Guide to Fossil Vertebrate Micropreparation, http://preparation.paleo.amnh.org/assets/MadsenWaxonfinal2.pdf SMITH, M. 2007. Vertebrate Microfossil Storage, the Basics and a New Technique. John Day Fossil Beds National Monument, http://vertpaleotest.sherwoodgroup.com/AM/documents/Smith_2007.pdf

Acknowledgments
We thank the Heritage Lottery Fund for funding the BDP for 4 years. Also a big thanks to Ed Drewitt for his comments and a special thanks to Mike Benton for his encouragement and valuable comments during the writing of the manuscript.

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References: MADSEN, S.K. 2009. Wax On, Wax Off: A Guide to Fossil Vertebrate Micropreparation, http://preparation.paleo.amnh.org/assets/MadsenWaxonfinal2.pdf SMITH, M. 2007. Vertebrate Microfossil Storage, the Basics and a New Technique. John Day Fossil Beds National Monument, http://vertpaleotest.sherwoodgroup.com/AM/documents/Smith_2007.pdf Acknowledgments We thank the Heritage Lottery Fund for funding the BDP for 4 years. Also a big thanks to Ed Drewitt for his comments and a special thanks to Mike Benton for his encouragement and valuable comments during the writing of the manuscript. 432