AS ARMS deals go, it was not the slickest. On an industrial street near the kasbah in the West Bank city of Nablus, a balding middle-aged man described his services. He couldn’t supply an AK-47 or a Tavor, the standard-issue Israeli assault rifle—those are too hard to find. In fact, he had no guns at all. But he insisted that he had the next-best thing: a friend with a lathe.

Palestinians have carried out near-daily attacks against Israelis since October, killing 34 people and wounding hundreds more. At first, the knife was the weapon of choice: only 10% of last year’s attacks involved guns. Since January, though, that percentage has steadily risen, and they are now used in 25-30% of cases.

Yet guns are actually quite hard to find in the occupied West Bank. Palestinian civilians are not allowed to own them, and the Israeli army carries out regular raids, seizing everything from shotguns to antiquated hunting rifles. The American-trained Palestinian security forces keep tight control of their own arsenals. Israeli officers say there is no evidence of their guns being diverted to militants, a common problem during the second intifada, which lasted from 2000 to 2005.

Modern firearms are beyond the reach of most Palestinians, especially the unorganised young people who are involved in what many call the third intifada. An M-16 assault rifle can cost $15,000 in the occupied territories, twice the average annual salary. One man from the Hebron area, who used to run guns for a militia linked to the ruling Fatah party, left the business a few years ago and now works in tourism. “I need to make a living,” he shrugs.

So the attackers are buying home-made guns. Many of these are based on the Carl Gustav—the “Carlo,” as it is known locally—a simple submachinegun developed in Sweden in the 1940s. The makeshift variety first appeared in Israel about 15 years ago, as a common fixture in the criminal underworld. They are assembled in garages and workshops using car parts, broken bits of other weapons and scrap metal. A simple “Carlo” costs as little as $500. One version, used in February to kill an Israeli policewoman outside Jerusalem’s old city, had a barrel made from a water pipe.

The rise of homemade guns suggests something good: that co-ordination between Israeli and Palestinian security forces is still working well, despite the unrest. Well-armed militias like the Fatah-linked Tanzim have stayed out of the violence, under orders from the Palestinian leadership. But it also means that the attackers are getting better organised. The first stabbings were carried out by individuals who acted on impulse, grabbing a knife or even a screwdriver from the kitchen drawer. Today they increasingly work in pairs or small groups, motivated by revenge: more than 120 Palestinian attackers have been killed in the act, and their deaths fuel further violence. Israel’s generals believe that boosting the West Bank’s stagnant economy is the best way to curb the violence. But this is one growth industry they’d rather snuff out.