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Starrett Core Ejector addresses an age-old problem

Following comprehensive product testing and evaluation at its facility in Jedburgh, the LS Starrett Company is launching a cost-effective and simple solution to an age-old problem. Its new Core Ejector for bi-metal hole saws has been designed and developed to effectively remove the slug of material that usually ends up inside the cup of the hole saw once it passes through the sheet material being cut.

Comprising of a precision-tapered spring and an aluminium pressure plate, the Core Ejector has been created to improve productivity and efficiency as well as operator health and safety.

Marketing manager John Cove said: “Safely removing the annular disc of sheet material that often becomes jammed inside the hole during normal operating conditions is a problem that many customers have faced. Usually the operator will stop the saw, remove the entrapped material by sliding a drift, or even a screwdriver, into the slots in the side of the hole saw. As well as the lost time required to perform this task, there is an obvious danger to the operator as the teeth of the saw are naturally sharp and will be at an elevated temperature.”

The Core Ejector addresses these problems in a simple and reliable way. As the saw cuts into the sheet material, the aluminium pressure plate compresses the spring inside the cup of the saw. When the saw breaks through the spring will act on the pressure plate as it returns to its natural open state, effectively ejecting the disc of raw material before it becomes trapped. 

Fitting the Core Ejector is very straightforward, as the saw’s pilot drill slides through the internal diameter of the nickel-plated spring. The narrowest wrap of the spring is precisely sized to sit on the shank of the drill, holding the Core Ejector in position so it rotates with the hole saw when it is in use and keeping it correctly located when it is not running.

Available in six sizes to cover a range of hole saw diameters, the Core Ejector works best for sheet material below 7mm thick with optimum performance achieved with material between 2mm and 5mm thick. The range starts with the KA8-1 Core Ejector for saws between 20mm and 24mm in diameter, stepping in increments up to the largest: KA8-6 for saws between 133mm and 210mm in diameter.

“There is a lot of flexibility in the size ranges and customers do not need to stick to the sizes too rigidly,” said Mr Cove. “During our tests, we have taken the KA8-1 and used it perfectly with a 38mm diameter saw. So, even though the purchase cost is very reasonable, at just a few pounds, the number of units required to cover a vast range of hole sizes is very low.”

As well as ferrous and non-ferrous sheet metal, the Core Ejector also works effectively when applied to holes generated in sheet GRP and composite materials, as well as ceramics and tiles when fitted to diamond hole saws.

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