An RT Blanking Saw.
The Roger Taylor Blanking System, otherwise known as the RT Blanking System, is a very useful kit for the creation of your own, inexpensive steel cutting and pressing stamps. You can cut sheet silver, copper, gold, gilding metal, brass and other materials such as papers and cards, creating infinite identical cuts of your design, in just a few moments each time. However, the creation of the stamp involves sawing through carbon tool steel on an angled table through a sawing process that is not as easy as straightforward sawing with a jewellers saw. It costs a couple of hundred pounds to buy the kit which includes the saw and materials and takes a fair bit of time and practice to get the hang of using the RT blanking saw. The process of cutting through the tool steel is slow and arduous, but well worth the initial outlay if you are needing to produce many dozens or hundreds of a particular shape, over and over again. Here, I outline the procedure in its most basic form....
Above you can see a sheet of 0.7mm copper with jelly bean blanks stamped out of it, there's just a little tidying up of the shape to do, but even this is unnecessary if the stamp had a shape cut out of it in two parts (which is explained in detail in the instruction book that come with the saw purchase). Notice one jelly bean has been created as a depressed 'emboss' instead of being stamped out, this is because the metal was inserted incorrectly into the steel stamp, I'll come to that later.
Here is the basic jelly bean steel stamp with a piece of un-annealed copper in it, ready to be cut out. If the copper was annealed, then it wouldn't cut cleanly every time, instead it would stretch in places.
Here is the copper ready to be cut, inserted in the blanking stamp. It is on a steel block and another piece of steel is about to be placed ontop, so the die (stamp) is sandwiched between steel...
...before being given a few firm blows with a hammer. The cutting die is pressed down into the copper and the jelly bean shape is blanked out.
To make the hardened tool steel cutting stamp, the design is drawn onto the surface with a starting drill hole (on the right-hand side) and an end point hole. There is no less than 1cm of steel surface area around the shape, between the holes and the edge of the steel. There are more detailed instructions about design placement in the instructions that come in the kit. There is a cleverer way of cutting out the 'splat' shape above so that there is no need to finish off the last section but for this article I won't go into that. Note the angle of the sawing table in relation to the saw blade.
When the design has been sawn, you push it up slightly so that the smaller surface area-side is the top. You can just see here the angled cut. This would blank out your shape. If you pushed it through the other way so that the larger surface area is on top, then you would create an embossed depression as shown in an earlier picture. It is this precisely worked-out angle, which is so important for creating an effective cutting tool.
The handle is lost on this saw, but here you can see a student having a go at sawing by sliding the saw up and down on its fixed post. The blade runs through the steel and a slot in the table. The steel is gradually pushed into the teeth of the blade rather than pushing the sawblade forward into the metal as you would do traditionally.
To insert the blade into the saw, you slacken the tension on the saw frame (compress it) by turning the threaded bar around.
The blade is inserted into the pads and tightened into place with the allen-key. Same applies at the top of the frame before tightening the blade tension by opening up the frame with turns of the threaded bar again.
The next thing we need to do is to adjust the sawing table to the correct tilt and that's what this chart is for. In this example, I have a piece of tool steel which is 1.00mm thick. I find 1.0 in the top of the chart and read down that column to find that there are letters in 2 white squares and a letter in 1 partially shaded square. Those 3 squares align to blade sizes in the lefthand column of 6/0, 4/0 and 2/0. The clear white squares have the letters P and T in them, the partial shaded square says letter Z. This tells me that for 1mm tool steel I should choose to saw my design out with either 6/0 or 4/0 blades. I could get away with using a 2/0 blade but results might not be ideal as the cut would be a little too wide in relation to the thickness of the steel. I chose 4/0 as this is what I usually saw with for most jobs anyway, if I cross reference 4/0 blade choice with 1mm steel then I am given the letter "T"...what does this mean?
Using a second chart, I find a specific line which has a "T" labelled to it, and I line up my blade exactly with the "T" line on the chart by loosening the sawing table and adjusting the angle of it. The table loosens with another allen-key screw at an obvious pivot point.
There are many more uses for these steel blanks which are explained here by a company who actually make the blanks for you, if you can't face making them yourself or do not wish to purchase an RT Blanking system kit yourself. In todays era of lasercutting technology, I think there is still a place for tools like this in the small workshop.