Dewalt just announced their new Impact Clutch (DWHJHLD) accessory holder that they say will help alleviate some of the frustrations encountered in heavy-duty impact driver applications. Common high-torque issues include bit tip breakage, fastener stripping and fastener breakage.
The new Impact Clutch is designed to activate in high torque applications to reduce the stress and damage on bits and fasteners. A Dewalt product manager remarked that in high torque situations, bits often break before they wear. This leads to increased costs over time, not to mention the frustration of having to stop what you’re doing just to replace a bit.
The clutch accessory will be ideal for framers, glaziers, electricians and other tradesmen tasked with heavy-duty fastening. A sleeve on the clutch can be moved forward and backward to engage and disengage the clutch as needed.
The Impact Clutch will be bundled with two Impact Ready screwdriving bits, and is expected to be priced at $17-20 when it’s released next March.
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I wonder how long it will be before something like this moves on board the tool. A step closer to a drill/driver/impact all-in-one tool?
Good question. The thing, many impact drivers are touted for how compact they are. Slap in a built-in clutch, and that’s going to change.
Plus, this is a one-setting clutch. I don’t think that manufacturers will extend the length of their drivers unless they can implement an adjustable clutch, which wont be an easily accomplished feat (if it’s even possible).
The variable speed feature of all the different impact drivers is the principal means of controlling the driver torque. The faster the tool is run, the harder the rotating hammer hits, and the more torque is generated. Running the tool slowly reduces the torque applied to the fastener, and with practice, you can “finesse” the trigger to get the desired torque. These little cordless impact drivers are quite easy to control compared to pneumatic heavy duty tools.
I picked up a set of Milwaukee “impact rated” driver bits, the ones with the black finish and the reduced cross-section meant to prevent breaking the bit tips. Compared to all the other bits I had been using (Vermont “Ice Bits”, DeWalt, Makita, Bosch, standard Milwaukee, etc), the “Impact Duty” bits broke sooner and more often. This is with either the 12 or 18volt Bosch impact drivers I have.
Phil, that sounds like a pretty valid point, and it will certainly give me much thought.
I often think of impact drivers’ variable speed trigger as useful for driving smaller fasteners using rotary-only mode. Once impact mode engages, each impact should deliver the same amount of instantaneous torque regardless of motor speed. At least given my current understanding of impact drivers – I may need to reevaluate this stance after additional research.
Stuart, you have a more accurate model in your mind of how an impact driver works. Once the impact mechanism engages, the delivered torque is “roughly” the same regardless of rotational speed. This is because of the way the hammer and anvil mechanism work together inside the driver. When there is back pressure (resistance), the hammer slips and makes a full rotation, where it strikes the anvil again with about the same force every time.
This, in fact, is one of the stated down sides of impact drivers. Because the torque is always the same, and there is no torque-limiting clutch, you can damage your fasteners/materials in lighter duty applications.
I think what Phil is referring to is the fact that by controlling the variable speed trigger, you can engage the impact mechanism without having the bit spin at a high rate. You get that high torque impact even though the bit is hardly moving. This allows you to control better the depth at which you ultimately drive the fastener. You’re not really “finessing” the torque, you’re simply controlling the amount of rotation, and thus how deep the fastener goes.
This is illustrated by the fact that when you engage the impact mechanism even at very little rotation, the sound and rate of the impacts are steady.
This makes absolutely perfect sense, thanks for the insight! I can now see exactly what Phil was getting at.
I’ll give this a try later this week when I’m reunited with my power tools.