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For a long while I've wanted to be able to use a boring head with the Proxxon FF 230 milling machine, but it hasn't been easy to sort out. Most commercially available boring heads use an arbor to fit into a standard taper such as NMTB, R8, or Morse, but the Proxxon just has a short collet taper machined directly into the spindle.
The most obvious solution was to make an arbor with a straight shank to fit into a collet, but the largest collet is 10mm, which is quite a narrow shank for something as heavy as the smallest boring head I could find for a reasonable price. Instead I decided to make an arbor which would screw onto the outside of the spindle using the collet clamping thread.
This project has been a major lesson in difficult machining. To start with it's a large part for a lathe as small as the Proxxon PD 250/e, but I also made life harder by choosing difficult material. EN24T is similar to pre-heat-treated 4340, and can be very hard work to machine. In this video I try and show all the problems I had, do my best to explain how I got around them, and show where the project nearly failed.
It's a lot of content, and I had to squeeze it into 20 minutes to be eligible for Emma's Spareroom Machineshop toolmaking competition, which can make the pace rather fast. Keep up, it's gonna be a wild ride.
Check out this playlist of all the competition entries:
00:00 Introduction 01:38 Cutting and cleaning up the stock 03:39 Drilling and boring the internal thread 08:55 Single pointing the internal thread 11:58 Turning the external thread 15:03 Single pointing the external thread 18:02 Testing out the arbor
Edited with: kdenlive 20.11.70 audacity 2.3.3
Music: Easy Lemon by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/) Source: https://incompetech.com/music/royalty-free/index.html?isrc=USUAN1200078 Artist: http://incompetech.com/