Ferry, if you go into a hardware store, or motor mechanics supply store and ask for a "skrap", they will show you a scraper that mechanics use to fit engine bearings. This is the large, commercially produced scraper you can see in the photos. This is a useful size to work the length of the blade and to rough out the kruwingan.
The other smaller scrapers have been made from three corner files. You can buy second hand ones from the junk markets. You just use a grinder to grind a radius onto the end of the file, and then sharpen it on a whetstone.
The funny looking bent tools are riffle files. You need these for refining the various contours. These files here are Dick files from Germany, which probably cost a king's ransom these days---I haven't bought any for maybe 10 years or more and the last one I bought cost me more than $50. However, you can buy Chinese ones in Indonesia. They're not as good, they do not last as long, but they can do the job, and they are much, much cheaper.
The chisels and gouges are made from old files and other tools, and a few are made from 01 tool steel. You use these to begin the shape of a feature and to remove big quantities of metal. They are not used for fine work.
The other tools I have use to make keris, and that are not shown here are normal small jewellers files, a 6" file, and big heavy 15" file, a hacksaw, and a small hammer. The hacksaw and big file are only used in the initial shaping stage.
Using only these tools, this is what can be produced:-