DSG screwcutting dial

[DC31kParticipant @dc31k]

In this thread:

DSG lathe – Matrix 5 1/2 dry plate clutch

there is a link to a DSG manual:

http://vintagemachinery.org/pubs/4080/25469.pdf

On page 48 of the pdf file, there is a description of a ‘patent applied for’ screwcutting dial that can be used for both imperial and metric threads on a 4tpi leadscrew.

The dial is also shown at the bottom of page 9 here:

http://vintagemachinery.org/pubs/4080/28742.pdf

Is there any way to locate ‘applied for’ patents so we might learn more of how this operated?

The manual refers to a 1963 British Standard and the brochure is pre-1976 so that gives a first pass at a date range.

[Graham MeekParticipant @grahammeek88282]

I would say the outer dial or Metric engagement dial rotates at about 1/9th of a turn to everyone of the Imperial engagement dial. (There is an inaccuracy with this simplified ratio). A simple Epicyclic gear arrangement can be used to achieve this. By driving the Metric dial off the Imperial dial.

Using a similar arrangement it could be made to fit the Myford Super 7 or any 8 TPI leadscrew lathe.

Regards

Gray,

[John HaineParticipant @johnhaine32865]

https://worldwide.espacenet.com/patent/search?q=pa%20any%20%22dean%2C%20smith%20%26%20grace%22

The espacenet site is excellent for patents searching.  Applications as well as granted patents are all archived, since disclosures in applications count as prior art against new applications.  A quick scan of the linked page didn’t have any obvious matches to the subject matter here so you’ll need to look at each citation.

Aha!  I just tried searching using Google Patents and found this:

https://patents.google.com/patent/GB1217060A/en?assignee=Dean+Smith+%26+Grace&oq=Dean+Smith+%26+Grace

So the application number was GB1217060, and it has expired.  Searching with this number on either Espacenet or the UK IP Agency site should yield a copy.

[Robert Atkinson 2Participant @robertatkinson2]

https://worldwide.espacenet.com/patent/search/family/010486908/publication/GB1217060A?q=pn%3DGB1217060A

[DC31kParticipant @dc31k]

Thankyou for the replies. 1217060 is indeed the correct one. “Lathe attachment device” is not a very illuminating title.

Would the Alan Binns noted as the inventor have any connection with Binns & Berry, the lathe makers?

The device works by having an inner dial and an outer dial. The inner dial is geared directly to the 4tpi leadscrew with a standard 16t gear (so it is a 4″ indicator in Cleeve’s terminology). The outer dial is geared to move at 1/63 of the outer dial (16:21 and 12:36) so it is a 15 3/4″ indicator in the same terminology. It so happens that 15 3/4″ is 0.002″ (0.05mm) longer than 400mm, which is an error of 1 part in 8000, and deemed acceptable.

The dial has a second mode of operation for ‘awkward’ metric threads (like 1.75mm), where it interacts with the inner dial. I have not yet thought that one through…

[John HaineParticipant @johnhaine32865]

Neat!

[John HaineParticipant @johnhaine32865]

Patent titles are not intended to illuminate but to put off the searcher!

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