What am I doing wrong.

[AjohnwParticipant @ajohnw51620]

The problem with the GTH one will be the quality of the worm wheels. Industrial units may well have been ground however in real terms it works out and error using 0.001 degree intervals for a vernier scale which he probably intended that for wouldn't be significant in use. On the other hand people have made 127 and other prime tooth gears on them. I don't need one now – came with my Boxford. From memory it was possible to get down to circa 0.0001" or so tooth flank error by adjusting the advance periodically.

I think he scaled for 0.01 degrees actually or something like that. Can't remember. Some one offered me a well made one once. I refused it as I wanted to make something myself. I regret that at times and along came a DW one with my miller.

For profile milling there is a simple answer about that is a little like ball turning. A rotary table with a bar that fits in the side to rotate it and an angle scale around the rim plus tapped holes for stops. The stops have slots in them to allow precise setting to the scale. No back play at all and apart from the graduations easy to make.

If you do buy and fit a stepper Michael best make it one of the accurate ones.

John

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[Roger HulettParticipant @rogerhulett83124]

Yes, it was the sector arms that I was adjusting incorrectly. Thanks very much for the advice.

Any tips on cutting the gear ? Speed ? Lubrication?

Roger

[Michael GilliganParticipant @michaelgilligan61133]

Observant readers, and fans of serendipity, will have noticed that adding a common 200 steps per rev. Stepper Motor to the BCA table converts it instantly to work in 1/100ths of a degree, instead of Minutes of Arc.

… Isn't that nice.

MichaelG.

[Enough!Participant @enough]

Posted by Michael Gilligan on 04/11/2015 11:33:33:

I shall [in the fullness of time] probably add the facilty to drive it with a Stepper Motor.

Be sure to use a double-ended stepper – so that you can add a handle to the shaft for manual setup.

[AjohnwParticipant @ajohnw51620]

Speed depends on the dia of the cutter and if it's hss or home made from silver steel. As far as hss goes similar to what you would use turning bar of that dia with a hss cutter. Lubricant, cutting oil if you have it and that can be used on any metal and will give an improvement but would be a bit messy if it was caste iron / some brass due to bits rather than swarf.

I suspect this is an optical dividing head. They cost a fortune. CTS later Vickers did have a number of military contracts and were bought out by BAS who then promptly bulldozed the place making sure to bury all the bits. Some reckon to make sure nothing was ever made there again. Rather similar to certain other things that "disappeared" during this era.

Ebay 151873513112

John

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[Michael GilliganParticipant @michaelgilligan61133]

John,

As a fellow CT&S / Vickers enthusiast … I think you will enjoy browsing this photographic archive.

MichaelG.

[Thor 🇳🇴Participant @thor]

Roger, there is an online cutting speed calcualtor here, that may be useful.

Thor

[Roger HulettParticipant @rogerhulett83124]

That has gone in my Favourites……..Very useful. thanks very much

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 04/11/2015 17:28:41:

John,

As a fellow CT&S / Vickers enthusiast … I think you will enjoy browsing this photographic archive.

MichaelG.

It's improved since last time I looked Michael. I have several microscopes by Vickers and some CTS bits.

This scope is the only one I have managed to resolve Amphipleura Pellucida using oblique illumination and a vickers 100x na 1.25 achromat. An M15C with the separate lamp for if the link doesn't work.

**LINK**

The first time I did it something looked a bit odd so I did a stria count and that was wrong. Several times since that it comes out correct and I can see mounting defects. I have some fine stuff by Zeiss and Leitz and they don't match up in a number of respects. I wonder if this is down to a comment I read in an old august journal – this use of the light cone emitted from an objective to measure NA has to stop. Leitz optics are poor in some respect but it has to be said that they made every conceivable microscope bit imaginable. Zeiss – hard to find good objectives that aren't delaminated and some are awful even when ok. I also have some Nikon gear bought to obtain DIC but to be honest that doesn't really measure up either but then it's more modern in some respects.

John

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John

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[Michael GilliganParticipant @michaelgilligan61133]

John,

Perhaps we should compare notes occasionally … either on or off the forum.

I seem to be collecting the larger CTS / Vickers instruments … Currently have 3 and a bit of the M4000, quite a promising Patholux, and parts of an M55 [plus lots of 'that might come in handy' parts].

Almost everything is a 'project' … but I'm headng in a good direction!

That will have to do for now: I have a rather "interesting" day ahead, tomorrow.

MichaelG.

.

P.S. I am a member of the Postal Microscopical Society, and Treasurer of he Manchester Microscopical Society.

[HowiParticipant @howi]

Posted by Michael Gilligan on 05/11/2015 21:44:5John

P.S. I am a member of the Postal Microscopical Society, and Treasurer of he Manchester Microscopical Society.

I would imagine that to be a rather small society 

[Author]

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