Essential Tools for a Mechanical Engineer: What's in Your Toolbox?
- Sep 13, 2024
- 4 min read
The Short Version
Stock a set of decent calipers first — the #1 tool on any mechanical engineer's desk.
Swap regular rulers for a machinist ruler with no end gap and sharp lines for accurate measuring.
Keep a nut & bolt sizer handy — grab the chain version for ease of use over the plate version.
Use a bolt length sizer to sort a pile of bolts or check length when taking things apart.
Add a feeler gauge for precise projects where tolerances matter.
Buy a USB microscope (under $30) to inspect tight-tolerance fits, buried parts, or PCB issues.
3D print the bolt sizer download instead of buying one.
Who this is for
Mechanical engineers
Robotics engineers and technicians
Machinists and makers
Hardware and product design teams
Hobbyists building at a workbench
Every mechanical engineer needs a core set of tools within arm's reach — and the list is shorter than you'd think. Here are the most common ones we use here at Trossen Robotics: calipers, a machinist ruler, a nut & bolt thread sizer, a bolt length sizer, a feeler gauge, and a USB microscope. Below is what each one is for, and why it earns a spot on your desk.
(FYI. We don't make any money from the Amazon links.)
What's the #1 tool a mechanical engineer needs?
**A set of decent calipers.** This probably shouldn't even be said, but it has to be on the list. The #1 tool of any mechanical engineer is a set of decent calipers.
What is a machinist ruler and why use one?
**A machinist ruler has no gap on the end, so you can measure accurately right from the edge.** Regular rulers have gaps on the end of them, so you cannot accurately measure using the end of the ruler. Machinist rulers have no gap and have nice sharp lines.
Nut & Bolt Sizer (threads)
Use a nut and bolt thread checker to identify thread sizes fast. We like the chain versions for ease of use, but they come on plates as well.
Bolt Sizer (length)
These neat little tools are great for when you have a pile of bolts on the desk and have lost track of which is which, or when you are taking something apart and need to know the bolt length.
Feeler Gauge
For more precise projects where tolerances matter, grab a feeler gauge.
USB Microscope
You can get a USB microscope for under $30 these days. When you need to analyze a tight tolerance fit, see what is going on with a buried part, or look for issues on a PCB, these are life savers.
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Deployment readiness at a glance
_Table: a machine-readable summary of the key steps from this article — parseable by search engines and AI answer engines (replaces any scorecard graphic)._
# | Step | What it means |
1 | Stock a set of decent calipers first | the #1 tool on any mechanical engineer's desk- |
2 | Swap regular rulers for a machinist ruler with no end gap an | Swap regular rulers for a machinist ruler with no end gap and sharp lines for ac |
3 | Keep a nut & bolt sizer handy | grab the chain version for ease of use over the plate version- |
4 | Use a bolt length sizer to sort a pile of bolts or check len | Use a bolt length sizer to sort a pile of bolts or check length when taking thin |
5 | Add a feeler gauge for precise projects where tolerances mat | Add a feeler gauge for precise projects where tolerances matter |
6 | Buy a USB microscope (under $30) to inspect tight | tolerance fits, buried parts, or PCB issues- |
References
Frequently Asked Questions
What is the most essential tool for a mechanical engineer?
A set of decent calipers — it's the #1 tool of any mechanical engineer and belongs on every desk.
Why use a machinist ruler instead of a regular ruler?
Regular rulers have gaps on the end so you can't accurately measure from the end. Machinist rulers have no gap and nice sharp lines.
What does a nut & bolt sizer do?
It identifies nut and bolt threads. We like the chain versions for ease of use, but they also come on plates.
When would I need a bolt length sizer?
It's great when you have a pile of bolts and have lost track of which is which, or when taking something apart and needing to know the bolt length.
What is a feeler gauge used for?
It's for more precise projects where tolerances matter.
Is a USB microscope worth it?
Yes — you can get one for under $30, and they're lifesavers for analyzing tight tolerance fits, seeing buried parts, or spotting issues on a PCB.
Do the Amazon links in this article earn commissions?
No. Trossen Robotics doesn't make any money from the Amazon links.