Cutting paving slabs, especially natural stone, which tends to be much denser and harder that man made products, is one of the basic work skills we have to master as Landscapers – certainly hard landscapers or paving specialists.
Cutting internal curves has always been the greatest challenge that we face. Therefore first time accuracy is paramount, and is greatly mitigated if the line scribed or drawn on the slab to be cut is correct, not just for the radius, but also the juxtaposition of the cut slab to its’ neighbour.
Around 1990, I started to produce a hand made ‘tool’ or piece of equipment, robust enough to be used more than once, and also serve as a template system that could be appreciated by my clients. (The first customer I showed my prototype – but did not tell him that he was first! -was a German engineer – Herr Verry Fussi if I recall his name correctly!) He was really impressed, left me alone and went off to annoy a plumber working on site.
So, taking a piece of 25mm shuttering plywood, 600 x 600mm (to replicate a slab size), fix two lengths of timber 25mm x 50mm x 600mm as cross members and bolt these timbers across the length of the square, approximately 150mm in from either end, with a 300mm gap between the pieces. These timbers are fixed with threaded bolts with wing nuts on the top, large enough to tighten by hand.
In between these side timbers, formed by the threads of the bolts and running the full length/height of the square, install a row of 18mm dowels.
If you find that you have not accurately gauged the distance between the bolts, and the dowels are not secure enough, add a sheet of rubber under the dowels – one of the bath bottom non slip mats is ideal – to add more friction.
The tool may be offered up to the edge/curved wall to be cut against, using the tool as though it were a paving slab being placed ready to mark for cutting, orientating it to match the existing slabs. Unscrew the wing nuts gently, to release the dowels sufficiently to extrude them to fit the desired curve, then simply tighten the nuts and secure the shape. Transfer the unit over the slab to be cut, mark with chalk, and cut to shape.
I used a roof ladder rack fixing to provide the bolts and wing nuts, although anything similar would suffice. Total cost of materials c. £40.00 (the wing nut/bolts cost £30.00).
I fully appreciate that you may have alternative methods which you use very successfully. There may be other tools on the market that are similar, although I have not found one (except of course, the metal version used by carpenters).
This particular tool looks the part, and certainly intrigues the customers!
