Caliper From Wire Nails




About: I make and create anything that comes to my mind from skateboard hooks to garden rooms. And I footle around with electronics and instruments at night....and I have a passion for reducing waste packaging by m...

Need a tool...Make it!

I had a great little project for a client, to repair the timber base to a chair of theirs... of the tapered chair legs had split leaving the chair unusable.

I found a piece of timber that was a close match and roughed out on the wood lathe.

Now to make it exactly the same size as the original...

...I needed a set of external calipers...

...and I don't own any!

Come with me as we make a super easy + quick external calipers from a couple of wire nails...

Step 1: Get Your Bits Together

x2 Wire nails - I used 125mm long nails [steel not galvanised]

A small nut + bolt from my glass jar of old ones.

A few tools

Butane gas torch


Anvil or heavy metal object

Drill + drill bits


Plumbers solder + flux

Vice [vise]

Metal bending tool - not essential though makes a lovely curved bend

Optional - for thumbturn

Brazing kit

Brazing flux + filler

Step 2: Get Bending

Take the two wire nails and bend the pointy ends around... the nail heads overlap and the sharp ends touch.

I used a little metal bender tool though could be easily achieved by hammering around a pipe or clamping in a vice and hammering around into shape

Step 3: Hot Hammering

Flatten the nail heads so that they can be bolted together.

I find that heating them up with a blow torch helps by softening the metal...

...hammer the head...heat some more...and hammer again...

...until the heads are flat.

Step 4: The Pivot

Find a suitable nut + bolt...

...and punch a central mark for the pivot hole on both flattened nail heads...

...drill out both nails + clean up with your sander

Step 5: Solder

The bolt needs to be fixed to one of the nails.

I used plumbers solder to achieve this, plenty strong enough for what we need.

Apply plumbers flux to the nail head + bolt...

...cut a thin strip of plumbers solder and wrap around the nut...

...heat with a blow torch and push down firmly as the solder flows.

Leave to cool.

Probably not the most sensible to solder onto timber, it burns! It looks good in the video though could be a fire hazard, take care when using a flaming torch.

Step 6: Thumb Turn

I wanted to make a little thumb turn nut for the caliper for ease of use...

...though I didn't have one... why not make one!

I carefully cut out a section of a washer so it would fit snugly onto the nut

I am fortunate to have inherited a little brazing kit and used this as my first experience of brazing

Add a little brazing flux powder...

...light up the torch and braze either side of the washer with some bronze filler rod.

It worked well allowing the calipers to be tightened by hand.

Due to my inexperience of brazing one side came loose after some time and I ran out of oxygen when re-brazing, so for the time being I am using a standard nut and pliers to tighten, which also works well.

Step 7: Now to Finish the Chair Leg

Bolt the calipers together...

...pop into a vice and with a hammer knock the pointy ends until they come together.

All done and ready to make sure the chair leg was finish to perfection.

I am entering this project into the Build a Tool Competition. If you have enjoyed this project, I would really appreciate your vote. Many thanks.

This project is part of my YouTube series where I try to make cool and interesting projects.

Please check out my channel if you want to see more of the projects, if not there will be more coming to Instructables soon.

Why not check out what I am up to with

And also catch me on Facebook + Twitter and now on Instagram!



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13 Discussions


2 years ago

I need a set of dividers for dovetail work. If I don't bend them inwards, should this do the job?


2 years ago

This looks great. But perhaps a nylock/self-locking nut might help.

Thank you for sharing

1 reply

Reply 2 years ago

Hi Rehmatullah, unfortunately I didn't have a wide g nut so tried to make one from a nut + washer, would have worked well if not for my inexperience of brazing. Fun to try though.


2 years ago

Fantastic! I love your resourcefulness.

1 reply

Reply 2 years ago

Thanks Rush, it's a surprisingly easy little tool to make and worked perfectly.