In The Shop – Elna Friction Wheel Tools

In my past life I worked as a Rehabilitation Practitioner, Machinist, and bicycle frame builder / technician and now I rehabilitate sewing machines and fabricate small parts, and am looking to expand my workshop capabilities to offer even more shop services.

The Elna Supermatic came out in 1951 and is among my favourite machines of all time, and rather than using a belt drive, Elna used a friction wheel. These wheels were available for many years, and were produced to a fairly high standard.

Over time Elna stopped offering OEM friction wheels and we have been less than pleased with the aftermarket ones, as they have a high failure rate and often run poorly, so with the advent of 3D printing we now have some high quality replacements.

The replacement wheels use replaceable friction elements and are dimensionally different than the originals so setting the sprung pin required a different tool.

The tool on the left is a prototype for extracting the old friction wheels while the tool on the right was made in out shop to set the pin for the new friction wheel.

Although it looks simple there were a lot of machining steps required to cut, mill, drill, and thread the inside to fit and retain the new pin, and I had to make a custom screw by turning down an existing 4mm stainless bolt.

I will be making a few more extractors now…