Understanding torque -- impact guns and high torque drills

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Discussion Overview

The discussion revolves around understanding torque in the context of impact guns and high torque drills, comparing their specifications and performance metrics. Participants explore the relationship between torque, RPM, and horsepower, while questioning how these tools can achieve high torque ratings compared to traditional engines.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions how an impact gun rated at 1000 Nm at 2200 RPM can compare to a car engine producing only 400 Nm at 2500 RPM.
  • Another participant suggests that the torque rating might not be matched to the RPM and highlights that impact guns generate torque through impacts rather than continuous application.
  • Links to specific models of impact guns and drills are provided for reference, prompting further discussion about their specifications.
  • Clarifications are made regarding the RPM of the impact gun, noting that it operates at 2200 impacts per minute and 1800 RPM under no load.
  • Participants discuss the implications of torque ratings under load conditions, with one participant questioning if maximum torque occurs at higher RPMs.
  • There is a calculation attempt to relate torque and RPM to horsepower, with some participants expressing confusion about the resulting values.
  • One participant asserts that the maximum torque is the peak torque during an impact, not a continuous output, and provides a reference for a similar drill's power rating.
  • Another participant states that with no load, a drill produces no output power, contributing to the complexity of the discussion.

Areas of Agreement / Disagreement

Participants express differing views on how torque ratings relate to RPM and horsepower, with no consensus reached on the calculations or the implications of torque under load versus no load. The discussion remains unresolved regarding the accurate interpretation of the specifications of the tools.

Contextual Notes

Participants note limitations in understanding the relationship between torque, RPM, and horsepower, as well as the conditions under which torque ratings apply. There is an acknowledgment that maximum torque may not be sustained continuously and that the impact mechanism of the tools complicates direct comparisons.

Sonic
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Hi i have a question regarding torque with impact guns and high torque drills.

So i just bought a impact gun which is rated at 1000nm at 2200 rpm how can this have such high torque were my cars engine makes only 400nm at 2500rpm

So i guess my question is how can we compare these torques to each other?

To my understanding horsepower is a function of torque and rpm

So for the torque wrench if we convert 1000nm to ftlbs we get around 737 ftlbs

So rpmxtorque/5252

2200 x 737/5252

We get 308hp which is obviously incorrect so what am i missing here?

Thanks hope i made sense in my question
 
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I see two possibilities:

1. The torque isn't matched to that RPM. Do you have the exact wording of the specs (a link?)?

2. Being an *impact* gun means the torque is generated by a series of impacts and is not continuously applied.
 
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Ok so with no load i will still be making 115nm in the drill correct spinning at 2100rpm?

Even if the drill spins at 300rpm underload with 115nm torque i get close to 5hp

Thats that's quite a large petrol engine in comparioson (briggs and stratton etc)
 
Ok so i think i messed that up because if we assume 300rpm then by lowering the rpm would mean we no longer are making 115nm so our hp level would be lower.But i still question the max torque of 115nm can we assume that's happening at 2200rpm?

If so no load were making close to 35hp?
 
I had a think about it greatest torque would be in low gear so that's rated at 550rpm much lower than the 2200.

So my calcs show at 550rpm and 84ftlbs of torque we make 8.8hp with no load does this sound reasonable for a small drill?
 
No 8hp is way too high. 1hp = 750w. I think most drills are probably sub 500w.

The max torque will be the peak torque that occurs during an impact not continuously.

Edit: similar drill here is rated at 640w continuous.

http://www.powertoolworld.co.uk/makita-dlx2040tj-18v-brushless-impact-driver-combi-drill-kit-inc-2x-5-0ah-batts#gref
 
Last edited:
PS: with no load a drill produces no output power.
 

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