Making A Tandem ACME Tap - Its A Bit Weird

G'day everyone,

I need a tap again. Or two. I need some acme taps for tapping some deep holes for an oncoming project. I will be remaking the lathes top slide and parts of the cross slide to better suit my needs and the first part of that will be to make a new ACME/metric trapezoidal nut.

Given the smaller diameter that I need it for, and relatively long length, I doubt that I would be able to single point cut them with the lathe without it chattering.

So I decided to make a tap, which you have probably seen me do before on the channel. I would have skipped over this, however I came upon a small guide on how to make tandem taps for cutting acme threads, and I thought that it might be interesting to give it a go.

Never used one of these before but they are designed in two stages to allow for a roughing pass to be done, before being followed by the full ACME profile. I think the final tap looks pretty funky but it does seem to work.

I hope you enjoy the video, cheers.

Lathe - Hafco Al250g
Mill - Sieg x2.7l

ACME Tap build
Trapezoidal Tap Builld
Tandem Tap build

#diy #machining

Timestamps
0:00 - Intro
2:24 - HSS Cutter
5:06 - Cutting The Tap Profile
9:45 - Milling The Flutes
13:29 - Final Part, Hardening and Testing