Roger Bisby takes Bosch’s GDX impact driver for a spin.
The Bosch GDX 18 V EC impact driver is an unusual tool that gives you the best of both worlds. If you need an impact wrench for use with sockets then the ½ in. square drive will do this and if you need a ¼ in. hex impact driver for your impact bits then this machine does that as well. The unique feature is that it does it without the need for adaptors. The middle of the ½ in. square drive has a hex bit holder built in. The red rubber collar is the release for the hex bits and it can still be operated with gloves on.
This is an ideal tool for plumbers and electricians who have to fit cable trays and pipe brackets on hangers because it switches quickly and easily between the socket drives and the impact bits. What it lacks, however, is the out and out grunt that you get with dedicated impact wrenches. In fact the 185Nm, whilst being respectable, is not even as powerful as some of the top of the range impact drivers. That said, I often wonder if all that power delivered through a ¼ in. drive is not pushing the envelope. For high torque applications the ½ in. drive wins hands down.
The run time of this machine on an 18 V Bosch Cool Pack battery is phenomenal, and it would certainly suit somebody fitting sheet metal roofing. This is partly due to the battery technology but also due to the EC brushless motor that gives you more power for the same power input. There is electronic protection on the motor and battery so if you do happen to put it on a rusty nut that won’t budge you won’t burn anything out from trying. The other thing I would recommend is lubrication. It is amazing how a little oil on the bolt thread helps this machine punch well above its weight.
The EC motor also means that the length of the body is shorter than a brushed motor and that helps in tight spaces. Although most people tend to use impact drivers for doing up screws and bolts they are also very good at drilling holes for pipes and cables. A flat bit with a hex shaft is ideal for this but make sure the flat bit is suitable for impact drivers or you will turn it into a corkscrew.
This impact driver is certainly the most versatile in its 18 class and, although I mentioned the lack of top end torque I would not be put off by it because there aren’t that many applications where you need that much torque. If you are a scaffolder or steel erector this is not the tool for you but for general builders, carpenters and mechanical services trades this is a very useful tool.