Member postings for Sam Stones

This anecdote won’t be much help to you Richard, but …

My first or second visit to the Model Engineer’s Exhibition at the Manchester Corn Exchange as a young apprentice was back in the early 50’s. A railway layout being exhibited was so small it must have preceded ‘N’ Scale. The lengthy layout was small enough to fit in three banjo cases.

My chaperone Bill, an outstanding toolmaker in the shop where we worked, began asking various questions about the layout, but especially the engines themselves. So that he could inspect them more closely, they handed him one of the engines. Sitting in the palm of his hand it was quite an outstanding piece of workmanship.

They told us they wound the motors themselves. There was nothing else available.

“But how did you make the spokes in the driving wheels?’ asked Bill.

“Oh, we just made a tool and bashed them out!”

Sam

Quite right Larry.

The more we know the more we don't know.

Then there's the stuff that we don't know, we don't know.

And can't even find out!

Have fun,

Sam

Some company down here in Oz advertises "Oils ain't oils"

Here's a bit more to go off re the ANZAC group.

I ran through the very shaky video again a few times, and grabbed these three.

While I was struggling to adjust the focus setting back to auto, the left hand aircraft had peeled off. It only became obvious when I re-ran the video

This first one is the lead aircraft.

This is where the LH aircraft peeled off.

And here's the tail-ender, clearly an Ozzie roundal.

Does it help?

Thanks for your interest.

Regards,

Sam

Derek,

I’m guessing the Wilding maintaining spring looks like this, and relies on support from the central boss.

Of course this one shows round wire whereas yours is square in section.

John Stevens cut his from an old 1/16” slitting saw which he annealed before filing to shape. Lots more work than plain rod/wire.

He then followed up with H & T (harden and temper) to blue.

I chose gauge plate (high carbon steel similar to silver steel in terms of carbon content), before hardening and tempering.

Have fun,

Sam

Edited By Sam Stones on 25/04/2018 22:44:55

Stewart,

Instead of batteries (or winding), you could have used the air spring.

Sam

Gone in an instant.

These four aircraft passed overhead on ANZAC Day south east of Melbourne.

This picture was a single frame snapshot, the best I could muster.

What are they?

Sam

Thanks Tim and John (H),

The animation here ... https://en.wikipedia.org/wiki/Involute_gear#cite_ref-1

other than throwing me back to constructing an involute in prac. drawing at secondary school, satisfies my curiosity completely.

Have fun,

Sam

I prefer your approach Norman.

Leave koobecraf for the kids.

Sam

Likewise Bill.

In 1950 when I started my apprenticeship, the toolroom hardening shop was separate. The three baths, two gas fired, the third electric arc for HSS hardening were cyanide filled. All were equipped with hoods and extraction fans.

I often wondered about the toxicity aspect.

A bit of a worry

Regards,

Sam

Probably chlorine gas Mark

The same thing (rusting) happens in factories processing PVC.

I'd guess it could be toxic, but other Forum members might like to clarify.

Good luck,

Sam

Hi John (F)

Big Clive has done a large number of interesting LED light strip-downs. Worth a look if you are prepared to search his website.

One thing he seems to emphasise is the need for adequate heat-'sinkage' and heat-transfer 'paste'.

Sam

http://bigclive.com/

Hi Derek,

To some extent, Jon has beaten me to it.

However, I wouldn’t bend (off the shelf) silver steel cold.

It will bend, but chances are that it could break in a sort of delaminating fracture. If the spring design includes sharp bends, failure would be even more likely.

It would be advantageous to make ready any radius formers before you start bending. Heat the steel to cherry red and bend it while it is at this temperature. Reheat as necessary.

In the ME forum (as elsewhere), there are many versions of heat treatment for silver steel. [Search the M.E. Forum files for Silver steel.]

Having successfully hardened silver steel over the years, I have found (the easiest home workshop method) that heating it to cherry red (my only means of assessing temperature), then quenching quickly and evenly into clean cold water.

Carefully polish off the oxide layer before tempering. For springs, they need tempering to a deep blue. This can best be achieved by having the spring almost covered in brass filings/swarf and gently applying only enough heat to turn the spring blue.

Chris of **LINK**

has several great videos which describe aspects of the above in more detail.

Have fun,

Sam

Thanks for your replies Hopper, NDIY and Richard,

If only I had the time and stamina to read the outstanding intelligence in Hopper’s `Gear Technology’ link.

Including gestation, I’m on my 83^rd trip around the sun, I was hoping for a simple answer. It rather serves me right for being Devil’s Advocate.

In summary, and as I imagined, who ever started the ball rolling (pun?) i.e. that correctly designed gear teeth roll over each other was wrong, and that sliding (albeit it minimal?) takes place; other than where the pitch circles meet.

In acknowledging Richard’s first-rate explanation, does the frictional heat generated from sliding, account for the need to submerge the gears in lubricant including heat dissipation?

Sam

Thanks Bill and Murray

That is where my confusion resides. It is easy (for me) to see that rolling takes place the instant both pitch circles coincide but …

Statements I have read seem to imply that rolling takes place immediately two teeth make contact. Yet any two points on opposite teeth which are about to make contact will (relatively speaking) be travelling in different directions and at different velocities as they begin to merge or separate.

Or am I missing something?

Sam

My first reaction Robert, was one of the painful sensation when my knuckles dipped into swarf under the hand-wheel. Not enough clearance as has already been indicated by other posters.

Only wish I still had one.

Have fun,

Sam

Where is the truth to the assertion that properly designed gear teeth only make rolling contact?

If this is the case, why lubricate?

Sam

For a butt joint, I would interpret that to mean lightly clamped, VE !?

Does this help those who have never seen or heard of H7/j6 ?

https://en.wikipedia.org/wiki/Engineering_tolerance 

'Go to the back of the class, Sam!"

Edited By Sam Stones on 14/04/2018 20:37:26

Sam,

Did you read the piece that I quoted from, earlier ?

MichaelG.

Guilty as charged, Michael

I knew I read it somewhere.

Is this what happens when we get old?

Keep smiling,

Sam

Back in 2010 when I resumed work on my skeleton clock, there were about half a dozen small brass parts outstanding.

Cost precluded buying minimum quantities of plate and bar-stock, so I chose to fabricate from smaller sections rather than cut them from solid.

My M.E. photo album ‘John Stevens Skeleton Clock Part 1’

**LINK**

… shows parts which I silver soldered.

• Minute-wheel Cock (this is in 3 pieces)
• Lifting piece in place (minute-wheel cock in position)
• The Maintaining Detent (2 pictures … in 2 pieces before and after)
• The Bell `Standard' & Nut (the standard is in five pieces)

The faces to be joined were hand filed to shape and adjusted to as close as possible, i.e. no gap. Parts were held together and either weighted or, in the case of the maintaining detent, I built a jig. In every joint, the solder ran instantly. As required, the joints are hard to detect, although it was a bit careless of me to miss some of the fillets during cleanup.

I read somewhere that, during the process, brazing material can actually alloy with the parent material thus producing five layers. Any thoughts about this?

Sam

How well I remember the Empire Ken docking in Valletta Harbour before sailing on for Limassol. It was late February 1957, and we had four hours ashore.

For some reason, which wasn’t obvious (to me) at first, Strait Street was the place to visit. As a very naive 21 year old, I had never heard such bad language coming from one of the woman standing in a doorway. She must have been all of 60.

In fits of laughter perhaps from the shock, we (about ten RAF GWMs) turned and hurried back to the safety of the ship.

Edited By Sam Stones on 12/04/2018 02:30:08