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> Bosch 6.9 amp 7/8" chuck sds plus rotary hammer drill
Bosch 6.9 amp 7/8" chuck sds plus rotary hammer drill
NEW BOSCH 6.9 AMP 7/8" SDS-PLUS ROTARY HAMMER DRILL
* SDS-plus bit system - tool-free bit changes with automatic bit locking, dust protection and maximum impact energy transfer rate
* Multi-function selector - 3 modes of operation, rotation only, rotary hammer and hammer only mode
* Variable-speed reversing trigger - for accurate bit starting, as well as removing fasteners or bound bits
* Vario-LockTM positioning - rotates and locks chisel into 36 different positions to optimize working angle
* D-handle design - for extra control, ideal for overhead and downward drilling applications
The first thing you'll notice about Bosch's rotary hammer is its great ergonomics, which clearly were a major consideration in the design of the hammer. The grip and trigger mechanism are well integrated, especially the front grip, and long enough to accommodate different body styles (I've got long arms; my buddy is the opposite: we both liked the tool's feel). For a rotary hammer, design is especially critical during overhead and down-drilling operations, where fatigue can quickly rear its ugly head. The tool's vario-lock positioning is great; it gives you 36 different working angles to choose from so you can modify the tool to fit the application. Likewise, the hammer offers three operational modes: hammer only, rotation only, and hammer with rotation. Are there drawbacks? Not many. The bit-changing mechanism is a little stiff and a little cumbersome, perhaps-but that's a pretty minor negative in a tool that otherwise provides such pleasant operation. The people at Bosch really know what they're doing, and it shows in this tool. -Michael Shilling
Variable speed reversing trigger control. 0 1100 RPM and 0 6150 BPM. Hammer lock off mode. Electro pneumatic impact mechanism for reduced vibration. Fully enclosed tool holder. Slip clutch. 360 auxiliary assist handle. Depth gauge and metal case.
* Impact Energy: 1.6 ft. lbs.
* Maximum Capacities: Concrete: 7/8", Steel: 1/2", Wood: 1"
* Thin Wall Core Bit: 2 1/2"
* Optimal Concrete Capacity Range: 1/2"-5/8"
The SDS shank has the advantage of a simple spring-loaded chuck, so that bits can be chucked with a simple and quick hand action. Further, the shank and chuck are uniquely suited to hammer drilling in stone and concrete. The drill bit is not held solidly in the chuck, but can slide back and forth like a piston. The hammer of the drill acts to accelerate only the drill bit itself, and not the large mass of the chuck, which makes hammer drilling with an SDS shank drill bit much more productive than with other types of shank. So, SDS shanks are most often seen on masonry drills, for which hammer drilling action is most helpful.
Rotational drive uses the sliding keyways that open to the end of the shank, which mate with keys in the chuck. The smaller indentations that do not open to the end are grasped by the chuck to prevent the drill bit falling out. The hammer of the drill hits the flat end of the shank. To allow the bit shank to slide in the chuck, the shank must be lubricated with grease.
SDS is available in four sizes, SDS, SDSplus (or SDS-plus or SDS+), SDS-Top and SDS-max. SDS-plus is the most common by count of tools manufactured, with masonry drills from 5 mm diameter to 30 mm diameter ordinarily available. The shortest SDS-plus masonry drill bits are about 110 mm overall length, and the longest 1000 mm. This long drill bit is entirely practical for use in a portable power drill, provided a 400 mm long bit is first used to start the bore off. It's very useful for installing wiring and plumbing in existing brick and stone buildings.
The SDS bit was developed by Bosch in 1975 and the name comes from the German "Steck Dreh Sitz" (Insert Twist Stay). German-speaking countries may use "Spannen durch System" (Clamping System), though Bosch uses "Special Direct System" for international purposes.[1][2]
* Relatively complex to manufacture
* Superb hammer drilling performance
* Drills with a "rotation-stop" mode can use chiselling bits
* One-handed quick chucking operation
* Can only be held in an SDS chuck
* Not very accurate centering
* High torque transmission
