About 10 years ago a fellow volunteer at a heritage railway who worked in the pattern shop said that he was planning to make patterns for the George Thomas design Versatile Dividing Head, and would I like a set. I said yes, and agreed to make the pattern for the milling machine adaptor plates. The castings soon arrived and I did some work on them before setting them aside to carry on with projects already in hand. One problem was that in his usual haste he had not actually looked at the drawings for the tailstock and had made its pattern much like the headstock one, so the casting was not really much use. I have recently bought a replacement from Reeves/Hemingway.
Not long after that purchase, and starting to prepare for work on the Quorn spindle, it seemed to me that the trickiest job would be those deep trepanned grooves in the end covers. Trepanning is not a job I enjoy. In this case it is important that the diameters are accurate. It seemed to be a good idea to make a proper cutter for the job, as Prof Chaddock suggests. It would need to be held firmly and dead on centre. I let this question mature for a while before it struck me that I already had the answer to hand. By using the redundant casting I could have a massively rigid dedicated toolpost for heavy boring jobs.
I made the cutter from O1 oil hardening steel. While I was at it, I also made the ball handles for the VDH proper. GHT mentions not arriving at a satisfactory design for a stop for the ball handle in the slack position. I could not resist, and had to try out an idea on this job. Although it does the job, I am not sure it is worth the extra work. Another addition that probably will make its way the VDH is the pair of locating buttons on the lower front edge. (In the retracted position these appear to give the front view of the tool the headcode for an express.)
By comparison with the Gibraltar Toolpost, I need a suitable name for this thing. I wondered about Uluru.
