Making a Custom Tap on the Proxxon PD 250/e Lathe

Making a tap is well within the reach of a home machinist, and I needed a very unusual tap to try and repair my G Boley watchmakers lathe. After watching a few other YouTubers' videos on the subject, I jumped in and made a tool which successfully cuts a thread.

The thread in question is a left hand 4mm by 0.6mm pitch with a 55 degree angle. It predates most modern thread standards, and is not compatible with any older standards I can find. This video contains my first attempts at a number of skills, including precise thread measurement, heat treating steel, and grinding.

This is my entry for Emmas Spareroom Machineshop Toolmaking Competition. Check out her channel here:
   / @emmaritson  

#toolmakingcompetition2019 #whenhellfreezesover

The links below will financially support this channel if you use them to buy stuff:

Machines:
Proxxon PD 250/e Lathe (24002) - https://ebay.us/5wRMlb
Proxxon FF 230 Milling Machine - https://ebay.us/Ikfxh1
Chronos PP-U3 Tool and Cutter Grinder - https://ebay.us/rIQJVy

Tools:
Universal Bevel Protractor - http://bit.ly/3YDGgUH
External Threading Tool - http://bit.ly/32sOked
Thread Gauge - http://bit.ly/2p28ywK
55 degree Threading Inserts - http://bit.ly/33NS6za
Triangular Needle File (part of a set) - http://bit.ly/2BrXlZ7
DCMT External Lathe Tool - http://bit.ly/2oOVwD2
ER32 Hex Collet Block - http://bit.ly/2BvET1U
ER32 Metric Collets - http://bit.ly/2J6XTI9
1.5mm Solid Carbide Ball Nose End Mill - http://bit.ly/2P4kh8N
10mm Solid Carbide Square Nose End Mill - http://bit.ly/2MXGIK9
MAP/Pro Gas Cylinder - https://ebay.to/2VV90ZY
Pizza Oven Bricks - https://ebay.to/2BpDb1Y

Materials:
BS1407 Silver Steel, 5mm precision ground round bar - https://ebay.to/2LnNJFA
Brass, 4mm round bar - https://ebay.to/32vHc1d

Music:
Easy Lemon by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/...)
Source: http://incompetech.com/music/royalty-...
Artist: http://incompetech.com/