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I've always enjoyed making custom knife handles, and have used a few I found on Instructables as a guide (shown here, e.g. LINK). However, many are crafted in wood, and almost all are solid. I was curious to not only create a custom profile - but a custom hardness also. This required me to work in a polymer, Sugru to get the desired result. I think this is quite an unconventional REMIX, and hope you'll vote if you are inspired to do other personalised projects out of polymers!

What if products were designed for everyone - but had tailored elements to fit you personally?


Many consumer products are designed for the '95th percentile' - i.e. the majority of people, but although this works pretty well for things like toothbrushes, which are unlikely to justify bespoke design/manufacture, (being disposable and cheap), but for tools and other items which become personal possessions for many years, perhaps there is an exception to be made?

One option would be to to make a 100% bespoke knife, but few of us have the cash or even ability to design an entire knife from scratch. So I wanted to make a bespoke grip to my hand.


This project is aimed at people who like custom gear and materials. It's a bit niche, so not for everyone, but I've shared a lot of these tips and for those who need to sculpt and shape things, so thought it might be useful to share here at Instructables, perhaps as an exercise in learning how to prototype in different grades of rubber/polymeric materials. If you take a company such as JosephJoseph, (who uses silicone rubbers extensively) one can quickly appreciate that being able to prototype - and specify technical design details like this, is effective in terms of cost and time, and of course allows for more user testing without having to produce expensive moulding tools.


To be clear, I did work for Sugru, but I did this sort of exploratory work in my free time, examples include (Oyster Card Hacks (LINK), Wireless Charging SatNavs, etc. in my other Instructables). My views are my own, and you attempt anything here at your own risk.

Step 1: Tools

Picture of Tools

Handle-less Knives

I was lucky to be able to source an 'un-finished' knife from knife makers TOG*, which had a tiny defect (they are perfectionists - love it!). However, as this was luck on my part and TOG does not commonly do this, the suggested alternative, would be to:

a. Buy a blade from a company such as F.Dick

b. Buy a finished knife and remove the handle by inserting a saw blade between the 'Tang' (see diagram) and the wooden/plastic handle, and saw it from the surface, before grinding the adhesive away. Then you'd start from the same point as myself.

*Blade kindly supplied by TOG Knives.

Safe Working

The "Swivel-Vice" is a valuable item if you have it (typically around $15-$20), as it will allow you to work at a multitude of angles - while keeping the blade not pointing towards you (or in the direction you are working). Please cover the blade with a cover at all times when working, it is all too easy to injure oneself when focused on a detail of the handle, and then absent-mindedly knock into the blade. You have been warned.

Variable Shore-A Hardness of Handles

Sugru Softener is an additive which reduces the Shore-A Hardness of Sugru from 70 (bike type) as low as 45 (elastic band). It is not widely available, as is in beta-testing. Similar results can be achieved by either using different modelling putties, (Green Stuff, Fimo, etc) or by adding Blu-Tac to Sugru. Some experimentation is required here, but it's interesting if you are into material science.

BUY: Sugru Family Safe and Sugru Original are now available and have different softnesses, and can be blended.

Tools/Items not shown:
Dremel/Proxxon Rotary tool., IPA, Wire Wood,