Maybe start by looking on the Hemingway site?

It's a George Thomas versatile dividing head but the maker has fabricated the body. Do you have any plates or the rest of the micrometer adjust worm ?

regards Martin

The worm assembly is certainly GHT. I made the Headstock Dividing Attachment which uses the same dividing plates, sector arm and micro adjustment as the Versatile Dividing Head.

In a similar way to the original maker of your DH, I adapted a base, in this case the Timmins, to take the GHT stuff.

Your base looks very nicely made, possibly milled out of a solid lump. You will see that I have also made it possible to do direct indexing in the holes as well as via the worm and wheel. GHT's Dividing and Graduating is available second hand **LINK** somewhat cheaper than buying the compendium Workshop Techniques.

Hope this helps,

Rod

Maybe yours was castings supplied by another company? An earlier one, before minor modification/improvement by Hemingway? Car models retain the same basic design but bodywork and engineering details change with later versions. One must accept what your eyes see, taking into account possible alternative sources.

Some kits are now metric instead of imperial or modified to accommodate both system details. The Hemingway site at the very least should have provided you with all the missing parts and details of where to locate build. It was all there for you if you simply used that as a starting point.

What is the centre height?

Looks to me like a hybridised Geo. H Thomas VDH / Tom Senior design re-worked for home construction by carving from solid and sized to match a Boxford or SouthBend 9" clone.

Basic layout follows the Tom Senior design, which also used a Boxford compatible spindle nose, but the worm drive and carrier arrangement is GHT.

Way back I looked into fitting a GHT drive set up onto a Tom Senior head that had lost its original worm drive and plates. From memory the size and relative dimensions from your pictures look similar to my concept sketches. Objectively the over the top arrangement of the GTH worm drive isn't completely ideal but made necessary by size constraints. With a slightly bigger device the Senior arrangement is preferable.

Nice unit but I'm surprised that the builder used a simple split body and closing screws to clamp the spindle rather than the GHT floating collet system.

Clive

Edited By Clive Foster on 17/08/2020 08:08:29

Yeah he was a bit of an old bodger.

As already mentioned at least twice, the body looks like it is milled from solid rather than a casting which would suggest that it is a one off shop made item. In the days before cnc, it was much more cost affective to buy in batches of castings for finish machining than milling from solid.

When I was in aircraft engineering making parts for Airbus amongst others, we made lightweight brackets which were part of the undercarriage, they carried hydraulic and electrical lines. They were castings, and did not require much machining. However, it turned out to be cheaper to mill them out of solid rather than pay for the castings and £100 each for the mandatory X ray when the solid ones could be NDT tested in house. Only using CNC machinery could the saving be made, plus a lot of swarf, (about 90%, I would estimate).

That's the reference I was thinking of. Does sound though like only the OD was punched out of flat plate and not the myriad holes. That would have been quite the die to do that when you think about it.