# Ghetto knurling

This is related to the restoration of the bug key but maybe
worth a mention of its own.

Due to having to replace one of the pivot bars, I ran into an issue.
I can replace the bar, the bar is 1/8" diameter and can be found
fairly easily in a number of materials. But, the original is straight
knurled, which expands the rod diameter slightly so that it will
sit tightly in the hole and not move.

It's a process usually performed on a lathe by applying a toothed
tool under pressure to the piece while it is being rotated.

I don't own or have access to a lathe...

So, as any good researcher does, I spent an hour or watching
youtube videos on knurling and the various methods people had
employed.

The distillation of what I saw is that, you need to apply pressure
and have a hardened tool to press into the rod.


## The plan

Based on all I'd seen up to that point, I hatched a plan.

My first choice for applying mechanical pressure, in my limited
workshop, is a vice. As you may remember, I recently used it to
press out a pivot rod from the McElroy key.

In one of the videos I'd seen someone use a file, please don't
follow their example and start hammering your files. Tools should
be respected and used for their intended purpose. Screwdrivers are
not chisels, files are not knurling tools... or are they?

Picture this. You can't rotate a file under pressure, it's flat.
However, if you can turn the round work piece while maintaining
pressure then you can use the bite into the steel to drive it along
like a rack and pinion. I just needed a bearing, of sorts, either
side of the rod.

I went searching and found a couple of old skateboard bearing
spacers.  It would probably have been better if I could have found
the bearings but, these would do for a proof of concept.

I got myself a 6" nail and put the spacers over it, I put a flat
file edge on between the spacers up against the nail. On the file
side I put a fibre jaw cover so as to not damage the jaw teeth or
the file. I tightened it down by feel and found a tap tool that
would fit over and clamp onto the shaft of the nail and tightened
it up to give a good grip.

I then proceeded to turn the shaft and try as best I could to keep
the rod at 90 degrees to the file. Once I'd turned it back and forth
a few times and was certain I'd gone 360 I removed the ![piece][1]
from the vice.

I love it when a plan comes together...

[1]: gopher://gopher.icu/I/images/ghetto-knurl.jpg