Have you ever tried a chipping hammer from another brand and realized that your chisels don’t fit in the hammer? Even though the datasheet states that your chisel shank is the correct one? Well, you are not alone.
Most manufacturers of chipping hammers don’t manufacture chisels. Chisels are typically produced by specialized companies, that can adapt the chisel shanks to the specifications of any chipping hammer. There’s no common standard on how to design the shank - therefore, even the smallest change in dimensions can make the chisels impossible to fit in the hammer.
The three most important dimensions for the fit
- the length of the shank
- the shank size (hex – width across flats, round – diameter)
- the guide diameter
If the shank is too long, the piston will strike the chisel early, which leads to reduced performance. On the other side, if the shank is too short, the piston may hit the inside of the cylinder instead of the chisel, thus damaging the tool and creating a lot of unnecessary vibrations. Further, if the shank size is too large, the chisel won’t fit in the hammer. And if the shank size too small, the shank will wear out the nozzle faster, which may damage the tool. A guided shank may also become non-guided due to the wear. Finally, if the guide diameter is too large, the chisel won’t fit in the hammer. And if it is too small, the tool will lose power because air will leak out.
Example: three Hex 14.8 shanks from different manufacturers
The table below shows three Hex 14.8 shanks from three different manufacturers. One will fit Atlas Copco tools perfectly, while the other two won’t.
| Width across flats | Guide diameter | Shank length | |
| Atlas Copco | 14,8 | 17,3 | 60 |
| Brand 1 | 14,7 | 17,2 | 63,5 |
| Brand 2 | 14,8 | 17,5 | 60 |
- “Atlas Copco” shank is designed to fit all our chipping hammers.
- “Brand 1” shank will fit our tools, but it will leak air due to the smaller guide diameter. Also, the shank is longer so the piston will strike the chisel early, which will reduce the performance. Plus, due to the slightly smaller hex size, there is an increased risk of unnecessary wear of the nozzle.
- “Brand 2” won’t fit at all because the guide diameter is too large.