Duncans Metal Pages
VDH - Micro attachment
Last updated: 30 Nov 2016

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This is the last section in building the head - the micro attachment.  Using the micro attachment allows any division to be made up, the attachment being calibrated in steps of one thousandth of a degree.

Micrometer drum

Drum1 18-May-2005: To make the micrometer drum requires the basic dividing head in order to get the 100 graduations.  In this instance, the drum is being engraved using the Hemingway graduating tool and the headstock dividing attachment shown in the accessories section.
Drum2 Stamping the numbers onto the drum - the dividing head is helping out with alignment of the numbers.  This is arguably a bizarre way to use the Universal Pillar Tool, but it works.
Drum3 The results don't look too bad.  Now for the remaining bits and pieces...

Body

Body1 22-May-2005: All through the project, there have been quite a number of components which vary in diameter necessitating a substantial amount of turning.  The bearing sleeve has been glued up from two bar sections to save on machining time.
Body2 Drilling through the locking pads - a dodgy operation which runs the risk of ruining the bore in the bearing sleeve.
Body3 That's it, the last part of the dividing head.  The nut on the end hasn't been made to fit a pin spanner (I don't posess any), so a couple of flats have been machined to allow a 7/16" spanner to tighten it up.  The lockscrew is actually on the wrong side giving the wrong orientation for the micro adjuster; something which came back to haunt me when drilling the plates...

Making the remaining plates

All we have right now is a single plate with 60 holes in.  However, this in conjunction with the micro-adjuster will allow all the plates to be completed.

Plate1 Disaster has struck on plate 1.  This is supposed to be 78 holes around the outside but looks more like 79 and two thirds.  The micro-adjuster is on the wrong way round and is spinning the main plate backwards instead of forwards with each increment.  Rather than throw the plate away it will be drilled 37/41/43/47/60/78ish and will become plate number 3.
Plate2 Plate 3 is done.  The 78.something circle is where the 60 hole circle would have gone, the 60 circle has been move in a row and the 53 hole circle that should have been there is now lost.
 

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Warning: These pages consist of images and descriptions of equipment which can reach high temperatures creating hazardous and potentially dangerous situations.  These pages should not be taken as a step by step guide on how to construct any items or carry out any particular procedure, nor should any references to safety contained herein be taken to guarantee safety in all situations.