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Member postings for Sam Stones

Here is a list of all the postings Sam Stones has made in our forums. Click on a thread name to jump to the thread.

Thread: Clock #1
07/11/2019 18:19:30

In a word David - 'MAGIC'

Thread: Polishing Acetal/Delrin and other plastics
02/11/2019 02:02:12

I didn't have this picture loaded in my albums, hence this delayed follow up.

This device for testing rotary switches features various uses of polyacetal. Black for bearings, and I think there's a slab of white with all those 'spikes' poking through. It may however have been high density polyethylene but I can't remember.

Sam

crw_6651---eaton---02.jpg

02/11/2019 01:47:32

Nice work Ian, and I trust you didn't mind my interjection re the fumes. I'm no chemist, but I think burning POM liberates formaldehyde.

Compared with nylon and polypropylene, I much preferred machining p.acetal.

Sam

02/11/2019 00:05:21

And ... don't sniff the smoke if you happen to overdo the flame treatment of polyacetal. You'll know why (and never forget) if you do.

Other than this (after a bit of practice on something which doesn't matter), I'd go along with Ian's 'flame polishing'.

It's also a useful (actually a commercial) technique for oxydising (oxidizing US) the surface of a crystalline polymer (plastic) prior to painting.

Incidentally, there are many grades of amorphous plastics which are blended or otherwise modified with other materials, rendering them less polish-able (Ugh!)

Sam

Play safe

01/11/2019 22:21:30

The two basic families of materials being discussed here are either crystalline or amorphous.

I'd like to suggest (although I haven't tried), that polishing items of crystalline materials, e.g. polyacetal, Nylon, polyethylene, polypropylene, etc. need to be deep frozen, or at least taken below their glass transition temperature.

I have machined (trued up) with some success, polyester (rubber) skate wheels directly from the freezer.

I also question, during the abrasion and polishing, if the surface of crystalline materials is being continually 'pulled apart', thus introducing (let me call it), a broken surface. Someone with good microscopy (and photographic) skills might like to intervene here.

Acrylic, and other amorphous materials on the other hand, are (generally) a breeze to polish.

Good luck,

Sam

Thread: Internet searching
17/10/2019 00:05:40

Many thanks Michael.

Yes, it was a Google search. I had been thinking that their 'speed-of-light' results was them just showing off.

Not knowing of such a simple device, your explanation shows clearly that I have much to learn. [The more we know, the more we don't know.]

By the way, I had never realised how popular I was with 12.7 mega-hits cheeky

Sam

16/10/2019 22:11:46

I often wonder about the benefit of a search result that might look like this ...

About 1,940,000,000 results (0.60 seconds)

It's obviously a very impressive result. But who would ever consider wading through 1.9 billion references?

What's your take?

Sam

Thread: Clock #1
03/10/2019 23:58:47

Thus 'seduced' by the idea that the finest silk resolved the problem attributed to rayon , would anyone in the EFHC care to repeat the test with rayon (filament), thus dispelling my thoughts that some other effect might have fixed the endurance issue?

Just curious, Bob.  cheeky

Personally, I would be concerned for the longevity of rayon versus silk in terms of environmental factors, none the least being UV.

Here in Australia we have lots of it scattered around. Don't ask me how I know.

Sam

 

Edited By Sam Stones on 04/10/2019 00:00:11

Thread: nutcracker
02/10/2019 01:44:57

I highly recommend the Clickspring video of the player card press mentioned above by not done it yet.

It would have to be one of Chris's best.

http://www.clickspringprojects.com/

Sam

 

Edited By Sam Stones on 02/10/2019 01:46:16

02/10/2019 01:32:36

This was my version of a nutcracker which I designed and prototyped to be injection moulded in polyacetal. Several metal parts formed the mechanism.

12.jpg

11.jpg

I based the action on a typical mastic-gun mechanism. The (fly-back) release was spring-loaded using the same lever seen at the front of this picture.

Please excuse the poor quality images, they are rephotographed (digitised) from paper prints.

Although parts were eventually injection moulded (and could be snapped together with integral 'undercuts' minus those crude 'U' shaped clips), I never got to see the finished article. I was informed by a colleague however, that they were 'perfect' for cracking lobster claws.

The acid test for a nutcracker would surely be opening macadamia nuts?

BTW, there are more even poorer images in my nut-cracker photo album.

Sam

Thread: Alternative metal sources?
24/09/2019 23:03:50

Then there is the situation where, in my case, I had disposed of almost all my stock, and had nothing suitable left to make a winding key for my clock. Buying a small piece of 1/16" brass from a locally inaccessible source and perhaps what I needed being far less than the minimum they would supply was no longer an option.

Instead, the cheapest approach seemed to be to visit the local hardware store and select a brass hinge.

You can see in this photograph taken in May 2011 how I managed to dodge around the screw holes. Not very pretty, but it does the job.

crw_5778---winding-key-from-brass-hinge.jpg

Incidentally, the tip of the key is actually a steel band supporting the remains of the weakened brass into which I'd cut a square hole to suit the clock's winding arbor.

Sam

Edited By Sam Stones on 24/09/2019 23:07:47

23/09/2019 00:06:33

I'd go along with Andrew and Mike if I were still making swarf.

A neighbour offered me a couple of winding shafts from a (Melbourne) city building where the old lifts were being completely refurbished. The shafts were about 3 inches in diameter and thinking they were mild steel, I imagined the steel could be turned into cutter arbors etc. for my milling machine.

Actually, to carry them home, my neighbour had them chopped into several smaller pieces with an oxy axe, leaving the burnt ends rather rough. That wasn't the problem however.

When I did get around to making something (a dovetailed adjustable milling head), the stuff was a nightmare to cut. The finish was rough, and the cutting edges of my tools, especially a dovetail cutter were dulled in minutes.

OK, it was free, and all I lost was my time and a blunt cutter, but Ugh!

Sam

PS - Watch out for case hardening and nitriding.

Thread: Hieroglyphics on a Wehlen & Co clock face
03/09/2019 22:50:34

Yes, that's it Michael.

I did wonder if the corners of the square were a continuation of the diameter. A clock/watchmaker showed me how to hammer out a pivot oiler from a tiny piece of wire was my first experience of forging at that level.

Impressive work especially if the hole is both square and tapered.

Finding too many bent (cotter?) pins around the assembly, the thought of a complete strip-down to find out, is no longer an attraction.

crw_7410---wehlen---movement---right-side.jpg

Maybe I will one day.

Sam

03/09/2019 20:14:09

A bit further to the right, Michael.

It was the hole through the pallet piece which looks round. But on closer inspection, what I'm seeing could be a lead-in chamfer.

crw_7420---wehlen---escapement---top-view---cropped.jpg

How curious too that the edges of the square have had their corner removed, yet appear sharp in the hole and beyond.

Nick, many thanks for your valued input. From now on, the clock will be treated with even more respect. I intend to lean on the local library to locate/purchase a copy of your book.

As before, many thanks to members for your interest and help.

Sam

PS Please remind me to blow the dust off before moving in for a tight shot embarrassed

03/09/2019 01:18:00

Are my eyes deceiving me but is that a square arbor going into a round hole?

crw_7420---wehlen---escapement---top-view.jpg

03/09/2019 01:09:45

It would be helpful if I could close this thread with a clear conclusion. However, despite the many useful comments, links, and various ideas, there is still no clear resolution.

I certainly found it an interesting excursion with several entertaining distractions. It has been a clear learning curve for me. I’d never heard of rubrication, ashler walls, and until I pulled the clock apart, I hadn’t realised that the dial was enamelled. Sorry Michael.

There were questions as to whether Gustav Paul (& Co) Wehlen was one person, a father and son, or brothers. The company, listed as importers, raised other questions. Were they also clockmakers, did they just assemble the main parts, or did they just sell them? Some of the marks on the back of the dial appear to be a close (colour) match to the hieroglyphs on the front. Could this be coincidental? The same substance (paint or ink?) and flourish appear to link the letter ‘G’ of Gustav and the ‘9’ of the number 9664.

Having seen some of its development in the plastics industry, I never realised that the pad method of printing was so old. Closer images reveal certain unrepeated irregularities suggesting hand painting, guided by some addition device, ‘ … and nerves of steel … ‘.

In closing and assuming that the clock is a middle-of-the-road standard, could it pass as a French marble clock?

My thanks to all eighteen of you for your input.

Sam

Edited By Sam Stones on 03/09/2019 01:11:27

Thread: Piston/Cylinder Materials
21/08/2019 03:00:01

Following Nick’s remark about dissimilar materials, I’m certainly no tribologist, but … since Steve’s engine is ‘just a demonstration project’, does life expectancy really matter?

Clearly, it shouldn’t seize during operation, and as with ‘normal’ practice, the two materials should be dissimilar or at least dissimilar in (surface) hardness.

Not that this has been suggested, but for new comers, the very worst situation in my opinion is fitting an aluminium piston into an aluminium cylinder. Once it grabs, forget it!

I’d probably be correct in assuming that the topic addressing ‘dissimilar materials’ has arisen many times before, and that those ‘in the know’ will come to my aid or … ?

However, here are a couple of ten bobs worth …

When I removed the substantially worn and scored gudgeon pin from a small 2-stroke petrol engine years ago, the replacement pin was a near perfect fit in the small end (bronze?) bearing.

In a similar vein, tests on a lawn mower spur gear made from high density, polyethylene meshing with a similar steel gear resulted in the steel gear wearing out.

Also, we used custom-made expandable brass laps for opening up holes a smidgen.

Let us know how you go Steve.

Sam

 

 

Edited By Sam Stones on 21/08/2019 03:01:23

Thread: Hieroglyphics on a Wehlen & Co clock face
17/08/2019 22:31:17

Thanks Roy,

Your advice is most welcome and much appreciated. I have a faint memory of a member telling me that some time ago. Was it your good self?

Can I presume that moving the 'collet' in this case is how the pellets (anchor?) would rotate on the arbor? I can only see this as requiring removal of the mechanism, and (perhaps) setting it in an upright condition on the bench or similar.

With declining patience, increasing clumsiness, and only an office desk, removing the mechanism has lost its charm.

Thanks again,

Sam

 

Edited By Sam Stones on 17/08/2019 22:39:09

17/08/2019 00:24:22

I pondered whether to open a new thread about clock dials, but …

It had been suggested elsewhere that I investigate the clock for any other marks on the movement that could indicate who made the clock. While this is potentially heading away from identifying the ‘strange’ hieroglyphs, it opened another aspect - the dial itself.

What I was very reluctant to do was pull the clock apart and remove the dial. I ain't as steady as I used to be.

However, it turned out to be an opportunity to add a very tiny drop of clock oil to those pivots I chose to leave on a previous occasion. There was also a slight issue that the escapement wouldn’t work with the mechanism (and therefore the dial) truly vertical. Twisted a few degrees ACW and it would tick merrily. Otherwise, it would stop. The fault lay with either the crutch (and/or the fork) being out of line with the pendulum, see here ...

**LINK**

and here ...

crw_7413---wehlen---movement---top-view.jpg

With the mechanism back in place, judicious bending of the crutch arm restored most of the misalignment.

As for the dial itself, I found evidence of traditional enamelled copper methods used during its construction. A very shallow copper ‘dish’ retains the glazing powder during firing, similar to that seen in this video …

**LINK**

… and (presumably) provides better control of glaze thickness, especially at the edges.

On the back was the number 9664. It’s the same number stamped on the back plate of the mechanism. Perhaps of greater interest was to find Gustave written on the back. Was it his writing or simply a means of identifying that the dial was for him?

crw_7398---wehlen---back-side-of-dial---gustave---9664.jpg

Several possibilities come to mind. What do you think?

Sam

PS - For a closer look, there are now three photo albums applicable to this thread and marked - Wehlen A, B, and C .

 

Edited By Sam Stones on 17/08/2019 00:26:42

15/08/2019 21:59:45

John Robey’s biographical notes are an excellent source of historic information, Michael.

I’m now exploring another direction which needs me to remove the clock's mechanism, and expose the false plate if there is one, and perhaps determine what material was used for the dial.

Sam

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