Archived from the Tools In Action forum (Power Tools). This thread is read-only.
Looking inside the drill on the net doesn’t explain what causes the hammer action or how it’s turned on and off. Can anyone tell me, please?
From what I understand, your average hammerdrill/driver drill use a type of marry-go-round hammering. Where the top of the merry-go-round is the chuck and the mechanical toy model horses that go up and down are attached to chuck. i.e. every time a horse goes up, the chuck is pushed up…that energy is transferred to the bit and from the bit to the material.
here a pic i found on the webs hammer drill/driver…
[External image (2.bp.blogspot.com), not copied]
On SDS drills, I believe it does not work this way…i could be wrong though, but I believe is more of a piston action hit.. that goes up and down. Think of a piston in a car rotated by the crank.
here is a pics a found on the webs SDS drill..
[External image (www.its.co.uk), not copied]
[External image (www.freepatentsonline.com), not copied]
A marry-go-round action, although while doing thousands of blows a minute, is is not as direct of an impact as a piston moving up and down.
Tool joe is pretty much right. A “hammer drill” or percussion hammer is essentially two ribbed “gears” hitting against each other (one stationary, the other spinning and connected to the bit)., whereas an sds+ or sds max rotary hammer uses an actual beat piece (heavy piece of metal pushed forward to interact with the bit). An sds+ bit is pneumaticly pushed by the beat piece being driven forward by the piston driven off of the motor, and an sds max hammer is driven by a beat piece actually striking the bit. The sds+ and max hammers function in a very similar manner, while the percussion style is completely different.