Member postings for Sam Stones

Hi Andrew (Williams 1)

The trouble with certain Myford saddles (I had a 1946 ML7 and worked on a Super7 in the late 50's), and the way the saddle can rotate (very) slightly) also relates to the narrow guide principle (NGP) and the wear on the saddle's shorter contact length with the back edge of the front shear.

There was a modification in Model Engineer by J A Radford of NZ (which I never got around to executing), that switched to using the rear face of the back shear.

Although I haven’t bothered to read further, starting with ‘Chipswitheverything’

**LINK** that hints at where and why the existing design is as it is.

For a better understanding of the NGP see here ...

**LINK**

I'm sure there's other stuff on the subject, including Jack Radford's ME article, but needs digging for.

Hope that helps.

Sam

Edited By Sam Stones on 10/07/2020 04:05:09

Nigel,

I sent you a couple of MPs

Sam

No promises that you'll get your answer directly, although I'm sure you'll find Big Clive both informative and entertaining. He specialises in using reverse engineering and many other ways to reveal faults.

Lighting and associated electronics is one of his particular skills.

However, you might have to wade through his many videos.

**LINK**

Sam

Edited By Sam Stones on 05/07/2020 01:14:08

Not just insects Neil ... the eyes are an important point of focus.

Again not a macro but ...

What I find fascinating, especially with insects like mantis is how, due to their eye structure, they seems to follow your movements.

Another great result Nick!

As you would know, it takes a very steady hand and lots of patience to get those close-ups.

Sam

My thoughts too, Bandersnatch!

I held back on the basis that it was both cruel and cheating.

My one and only success from using a can of freezer spray, was locating a faulty IC in a friend’s radio. Or was it a wireless?

Neil, jump back to ‘My eureka moment’ at the top of page 14.

**LINK**

Sam

Splendid photographs Raphael.

If only they would cooperate for a few moments

The opportunity for focus stacking even less, let alone stereo pairs.

Sam

You could look here Martin ...

**LINK**

John McNamara has been doing some excellent work with reinforced epoxy. 

Somewhere along this table were samples of his efforts. Unfortunately, I missed getting up close. 

Good luck,

Sam

Edited By Sam Stones on 10/06/2020 22:30:05

Here's the pair for parallel viewing.

Another good subject Raymond

My straight answer Raymond is ‘Yes!’ I just happen to have a rather old copy (CS3 V10.0).

It took three minutes to copy your two images; place them both ways to check for (my x-eyed) viewing before <save image as ...>. Had I included parallel viewing, it would have added another minute or two.

Additionally, my skills with Photoshop are very limited. However, I’m sure there are others here who will have the ability to transform the L/R images into Red/Green or Red/Blue in the manner required for 3D viewing using two-colour ‘spectacles’.

In my (Photoshop) attempts, I found it easy to colour the images, but (at 50% transparency, if that was the way) failed miserably to overlay one with the other, producing instead a medium shade of purple.

Sam

PS - Now I'm already there, I'll add the 'Parallel' viewing pair shortly.

A fortunate dog, Brian.

Could some of the tick's legs have broken off, or is it just their angle?

Although like MichaelG I hadn't known of those ticks in the UK, of about 75 species of tick here in Australia, there’s one known as the paralysis tick ... Ixodes holocyclus.

Often hidden under the animal's coat, a single tick is capable of killing a large dog.

Sam

There you go Jed, courtesy Photoshop.

Sam

This picture is another break from true macro.

My main reason for showing it was that it was photographed through my macro lens; a Canon EF 100mm f/2.8 USM, also described as a medium telephoto lens.

A pleasing feature of this lens is the ultrasonic auto-focus. It is both extremely fast while being very quiet. There is no doubt I would not have captured this shot without the high speed focussing. As those who know, this bird keeps its eyes level during flight, so I have to admit that I’ve tilted and severely cropped this picture for more drama.

By diving at me from various directions, the spur-winged plover was protecting its young. Each ‘attack’ was ‘called off’ with a sharp disconcerting swerve about two metres in front of me.

Although it seems possible, there is no evidence to show they use those spurs to cause injury.

Sam

Raymond, I took the liberty of placing your fascinating pair of kidney images both ways.

Five minutes was all it took me in Photoshop.

Here is the pair for free crosseyed viewing ...

And now the pair for free (or stereoscope) parallel viewing ...

As I have realised, if the distance between this second (parallel) pair is greater than your own eye separation, it can't be free-viewed.

I think I've got that right. If not, can someone correct me.

It doesn't seem to matter that there is a slight vertical difference. Once the images are 'locked' I can tilt my head slightly either left or right and the images stay locked. 

Sam

Edited By Sam Stones on 07/06/2020 20:44:25

Purchased a considerable time ago, the primary use for a bellows was to get up close and personal with sectioned samples.

Electronically coupled between the lens and camera (predating digital), the bellows was an excellent adjunct to my Canon kit. At the time, it was particularly useful for displaying the results of how the screw threads of plastics lids, caps, and closures matched the respective threads and lips on bottles and containers.

To digress further from the ‘Macro’ theme, here’s a typical situation where a cap is screwed onto a bottle.

It can be only be surmised how the cap actually fits on the bottle. Inverted and potted in resin however, examination in detail becomes possible.

With some of the vagaries of crystalline polymers, aspects of shrinkage could result in small changes of thread profile etc. The ‘quality of fit’ was often a matter of torque tests versus leakage. Potting and sectioning could expose design and tooling errors; sharp notches are a significant cause of premature failure.

This was also an issue with the fit of snap-on container lids. By their very nature, thread profiles (and undercuts) of softer plastics could readily take up their own position during capping. With that degree of uncertainty, a way of accessing their actual position (after assembly) was not easy.

To gain access (after torquing), it was necessary to remove a portion of the bottle near the neck. Inverted in a suitable container, the epoxy resin was drizzled into the space. A vacuum removed trapped air. To avoid an excess of adiabatic heating and the consequential softening of the plastics components, it was important to minimise the volume of epoxy for any one pour. Several ‘pours’ becoming necessary for larger items.

After the epoxy had cured, it was my usual practice to machine the assembly; across the centreline with a capped bottle. Smoothed and polished, I then photographed the prepared face at a macro-level.

Returning to the bellows,

with an extension range between 50mm and 126mm, the bellows can take over from a typical set of extension tubes of say 12mm, 20mm, and 36mm that would only stack to 68mm, or 80mm as with your set Raphael. I have no doubt that both tubes and bellows could be stacked for even greater extension. Others here could perhaps comment upon the limitations, e.g. depth of field, etc.

Here are a couple of earlier images taken with my Canon EOS 300D camera, through the Novoflex bellows and a Canon EF 100mm f/2.8 Macro USM.

As with a variety of stuff accumulated over the years, I have to admit that the bellows is seldom in use these days.

Having ventured into stereo pairs, I intend to find a subject which will feature both the bellows and macro lens while providing a bit more 'fun' for us who are cross-eye 'gifted'.

Sam

PS - I'm looking forward to seeing any interesting bits you find in the bird pellet Michael.

Edited By Sam Stones on 05/06/2020 22:47:03

My eureka moment.

Never having tried free (parallel) viewing of a stereo pair, and pondering over the difficulties experienced by various members, I realised (as has probably been explained earlier) that the centres of the two parallel viewing images need to be about the same distance apart as our eyes.

It then dawned on me why Nick’s method of displaying the images on his phone worked.

I took a screen snapshot off my PC monitor with my phone, practiced a bit, and was delighted to see the 3D image slide into view. Backing off was necessary in order to achieve sharp focus.

Using the zoom of the phone screen to adjust the centres of the two images to about 7cm (the centre distance of my eyes), didn’t work so well. It worked better when the two phone images were about 5cm apart.

On this basis, it is now clear (to me) why parallel viewing won’t work when the centre distances of the two images don’t (roughly) match our eye separation. I suppose if you can do ‘wall-eyed’ then viewing a large screen (tablet etc.) is also achievable?

Sam

Edited By Sam Stones on 04/06/2020 22:09:47

Nick,

Try your method on this pair.

I've swapped them left to right for parallel viewing. When I view them my (cross-eyed) way, bits of the image are in the wrong place.

Great photographs everyone.

Isn't this thread amazing?

Sam

PS - Raphael, I haven't forgotten about the bellows question.

PPS - Bandersnatch, I had to look up 'Windows Violation'. Guilty too!

Edited By Sam Stones on 03/06/2020 20:42:56

Bandersnatch,

I couldn't resist for those who view things cross-eyed.

Sam

Hi Craig,

Check you mail box, I sent you a PM.

Sam

Raphael, those images are superb.

I'll mention a few points about the Novoflex bellows shortly.

This morning, I explored the CAD file-viewer’s rotation adjuster using the full clock file. It was pleasing to discover that not only could the image be rotated, but it could be set incrementally.

It took a couple of tests to determine what appeared to be the better ‘Z’- axis ‘increment’.

1° was insufficient while 10° was excessive, so I used 5°.

Having forgotten to set what is called ‘Environment Map’, the image doesn’t look as shiny as before. However, it instantly jumped to 3D when I went cross-eyed. There are still a few twitchy artefacts from the outlines, but overall it was a pleasing result.

For those that need to switch left for right, go to …

**LINK**

Lots of great pictures and lots to learn.

Again, this is not macro Raphael.

For those who can ‘do’ cross-eyed, I thought I’d try another slant along the stereo branch. [There could be a pun in there somewhere.]

Over the years, having gone through iterations of moving the camera and/or small objects around, it became clear that rotating the object on its vertical axis was a better option. (I feel sure this would be obvious to those into microscopy etc?)

However, it occurred to me that the CAD viewing package I have, might allow me to manoeuvre my skeleton clock file. The original file is quite ancient, and the CAD viewer ‘knows’ this. It always opens my files with a typical reminder of the fact.

After a bit of fiddling, I ‘rediscovered’ the X, Y, Z manipulation device that allows rotation of the image about any (or all) axes.

Chancing getting it right first time resulted in this.

When viewed, it became clear that the respective image differences are not so much position, but artefacts from the outlines and the ‘false’ reflections from simulated metal.

Your persistence payed off Nick. The above should jump out.

Good viewing guys.

Sam

PS - Take a look at the posts and the interest. Brilliant subject Raphael.