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Member postings for Donhe7

Here is a list of all the postings Donhe7 has made in our forums. Click on a thread name to jump to the thread.

Thread: Force on welding cables
18/07/2013 15:15:47

When working in the agricultural industry in the 1960s, we attended a meeting of the local Agriculture Bureau at which we were shown a coiled extension cable which had fused together due to being used to power a reasonably heavy load, but still within its' rated value, but whilst coiled on a sheetmetal spool, so I've very severe doubts about the wisdom of using a coiled extension lead.

Back to welding cables, if anyone has ever looked at a welding lead lying through a sprinkling of iron (or steel) filings, after the arc has been struck, and the cable not moved from its position during the welding run, you would see a series of filings arranged in a number of rings around the cables.

I first saw this effect whilst using an AC welder in this situaion, and was surprised at the time, it is quite intriguing, when seen for the first time

donhe7

Thread: The things you find at a garage sale!
02/06/2013 02:19:58
Posted by John Stevenson on 01/06/2013 12:59:46:

I must be the worlds most unlucky guy.

Went to a car boot sale and all i got was a mini boot lid........................crying

Did it have a big dent in the centre? ................. If not, it's probably worth a fortune!!!!

donhe7

Thread: I think my dividing head makers needs....
14/05/2013 03:04:55
Posted by Dusty on 13/05/2013 14:50:53:

I don't think it matters if it is a rotary table or an all singing all dancing dividing head. If it was sold as a unit with all parts compatable. It must fall into being 'not fit for purpose' if part of the set up is defective.The plates must fit and be usable on the dividing head/rotary table without modification.

The suggestion was made, that "maybe the plates and the table were supplied as separate articles", seems to have been missed by most of the respondents to this post.

What I believe was meant, was that the plates were made to suit a differernt table, and so when supplied with the table for which they were intended, (and made), they were correct. As they were supplied with the wrong table, (which they were never intended to fit), of course they were drilled wrongly, (Try fitting your aforementioned Fiat wheel on your Ford, bet you it doesn't fit)

donhe7

Thread: HT leads
02/05/2013 11:33:50
Posted by Graham Meek on 01/05/2013 21:20:02:

The problem with the modern suppressed ignition leads, (pre-engine management days and a coil per plug) was that they had a graphite type yarn core, with the flexing due to vibration from the engine and the extremes of temperature, these items would break down.

It was one of those Automobile manufacturers cost saving ideas that usually cost the mostorist more, in the days of the real Mini these new fangled leads were replaced with good old copper leads and suppression plug caps, fitted once they could be forgot about as long as the outside was kept dry and clean.

Gray,

Regarding the "Mini", here in Oz, it seemed that you only had to hold a PICTURE of a puddle of water in front of them and they would stop!!

donhe7

Thread: LED Work lights for milling machine
20/04/2013 15:06:07
Posted by peter walton on 16/04/2013 10:16:07:

To get rid of the strobe effrct you will need some capacitance smoothing added.

If the amps are quite high then a lot of capacitance will be needed.

Peter

 

Just a little bit late with my post, I hadn't read the posts following Peter Waltons, and the purpose of my post here has been covered in subsequent posts, so is "surplus to requirements"!!! ............. please ignore it!!

As he is using 24v AC, he would need to rectify it first, then measure the DC voltage (It could possibly be 36v DC, after rectification and fitting of a capacitor to smooth the DC), then adjust the LED units so they have approx. 12v DC across each module, other than that, he would need to fit a fairly substantial resistor in series with the LED units so that their current ratings are not exceeded, with resultant shortening of their life

donhe7

Edited By Donhe7 on 20/04/2013 15:25:05

Thread: Cheap surface plate ?
30/12/2012 12:58:50
Posted by Russell Eberhardt on 28/12/2012 14:04:29:

Posted by Billy Mills on 27/12/2012 14:14:58:

You need to be VERY careful in handling CRT's- think of it as around a ton of force acting on that glass bottle. I would suggest that anyone not trained in handling CRT's stays well clear.

A bit off topic but when I was working at the Mullard research labs in the 1970s we had some special CRTs sent over from Eindhoven for testing. The customs paperwork specified that they should be returned or destroyed after a certain date.

One day a customs officer came into the lab where I was working and asked to borrow a hammer. A couple of minutes later there was a loud explosion from across the corridor!

Russell.

I personally have destroyed a number of CRTs, and have NEVER had any trouble with "implosion" or flying glass, and have always released them "to air" by gently tapping the neck of the tube after removing the deflection coils etc, until I hear the gentle "Hisssssss" of the air entering the tube, after which the tube can be converted to whatever suits your purpose, in my case, landfill!!!

donhe7

Thread: Alibre 11.2
30/12/2012 11:14:46
Posted by KWIL on 30/12/2012 09:47:08:

What sickens me about all of this, is that some people think that other people's property should be free ro use, copy, share, give away or pirate. It does not seem to matter that those other people have spend their money and time writing computer programs, music, it does not matter what is is, just let me abuse your rights!

The point of this thread is, not to be able to illegally copy, use, sell or otherwise gain advantage from the software, but simply to recover the details of a series of projects created using a "legal" version of the software.

At no time does the OP express the desire to use the actual software itself, but wishes to recover the "intellectual" property, unfortunately concealed within the software, with the permission of the estate of the creator of the projects

donhe7

Edited By Donhe7 on 30/12/2012 11:18:09

Thread: Offensive language
08/11/2012 01:50:00
Posted by jason udall on 08/11/2012 01:27:21:

OK how about....

nano parsecs per micro fortnight?

And what happened to Metric Time??

donhe7

Thread: Design a covering mechanism
03/11/2012 13:56:43
Posted by Wolfie on 02/11/2012 19:48:06:

OK in my day job as wagon driver we regularly have to sheet steel loads. Such as the one in the photograph. Now we are getting trouble from the HSE because it involves drivers clambering around on top of the load trying to handle a heavy sheet often in windy weather and usually alone. So we need to design something that will do this automatically.

So HSE don't like it ............. WHAT SUGGESTIONS HAVE THEY COME UP WITH????

donhe7

Thread: Which collet set to purchase
16/10/2012 02:52:12
Posted by chris stephens on 15/10/2012 19:27:31:

chriStephens

PS if DC1 is reading this, why does the spell checker not recognise "collet", seems a bit odd for an engineering site.surprise

Not having looked myself, but do remember seeing a "dictionary" section (or function) in some "Spell Checkers", does this version have one?? ------ this function allows the user to add a new word if it is not in the basic "'checker", when it is present

donhe7

Thread: Boiler Design
12/10/2012 01:56:43
Posted by Stub Mandrel on 11/10/2012 21:55:27:

.. but we can all go out and buy pressure cookers and cappuccino machines made of metals and with construction methods we would never be allowed to use for model boilers...

Neil

I might suggest, that this could be because we cannot produce a certificate which says that model was safe to use in the home environment (or similar situation) ............

donhe7

Edited By Donhe7 on 12/10/2012 01:58:04

Thread: Measuring a taper pin and how do you do it
27/08/2012 16:26:15
Posted by Wolfie on 27/08/2012 16:16:55:

When you buy a taper pin or a taper pin reamer, it only gives one size. Eg 1/8"

Now is that the large end or the small end of the pin/reamer?

Secondly, how do you ream a hole for a taper pin. I'm guessing you simply drill it to the larger size and then use the reamer.

Might I suggest that it would be more likely to be drilled to the smaller size then reamed

donhe7

Sorry, our posts crossed!!

Edited By Donhe7 on 27/08/2012 16:27:31

Thread: Buzz Coil Condenser/capacitor
25/07/2012 11:57:59

Without going into too much detail, I seem to recall in some automotive tome, the capacitor (condenser, in their parlance), was chosen in value/design, to resonate with the coil and points circuit, and also to quench the spark at the points, and the value was specified by the particular vehicle/engine, to which it was fitted, also, in some cases, the "supressor condenser",(!) was to be removed, in some cases when a different coil was fitted.

donhe7

Thread: Is this model engineering
20/07/2012 09:00:56

Here in South Australia, we had a "Meccano" like series called "Ezi-Bilt", from a local(?) firm called Colton, Palmer and Preston, the components consisted of green perforated strips, red panels with perforations along the edges, shafts, several sizes of wheels, etc, in sets numbered from one to eight, with the amount and complexity becoming more so as the kit number increased.

Whatever happened to the brand (or in fact, the Compay), I don't know, I guess that some readers of this forum may remember the product, or perhaps it (They) have vanished into history .........

donhe7

Thread: Back to front parting tool.
30/06/2012 13:24:11
Posted by Eric Clark on 30/06/2012 12:28:47:

Eccentric Engineering of Australia

I have attempted to email Eccentric Engineering alerting them to this as their sales blurb makes no mention of this problem.but their web site contact page will not accept my message as the telephone number field would not recognise a UK phone number even with the usual international prefix.

Eric, I have pasted a copy of your post in the "Contact Us" section of their Website, on your behalf, and await an acknowledgement from them, but it being late on Saturday evening here in Oz, I don't expect a response from them until possibly Monday, but it seems that my email was accepted, we'll wait and see what happens

 

donhe7

Just checked my emails and your / my message has been acknowledged, so it at least made it to the company!!

Edited By Donhe7 on 30/06/2012 13:28:24

Thread: Solar Power for the Workshop
30/06/2012 04:57:24
Posted by Russell Eberhardt on 29/06/2012 18:44:51:

It is far too generous when it only costs about 5p/kWh to generate it in a nuclear power station which also generates zero carbon emmissions.

Russell.

Maybe so, Russell, but not everyone has the space to install a nuclear power station ............

donhe7

Thread: Big End Lubrication
27/06/2012 10:09:09
Posted by Alan Worland on 26/06/2012 21:04:14:

Thanks for that. I think what I have is a grease cup (it did have grease in it)

I have fitted it to the con rod journal which has a very small feed hole into the bearing, I shall fill it with oil and run it on compressed air to see the quantity of oil used, I could fit it with a wick to slow feed rate down if it all flows through too quickly.

I like the idea of the cup on the crank end, this could be used for all crank bearings I guess.

In hindsight I think oil might be more suitable than grease?

I think a lot of small steam engines seem to have lubricators for main bearings etc but the big end gets forgotten about!

Alan

The IHC engine to which I referred, used a grease cup on each crankshaft bearing, and one on the "half-time shaft", besides the one on the crankshaft end, and used a drip-feed oiler to lubricate the cylinder (about 6-10 drops per minute), hopper-cooled, and was called a "kerosene engine", which we found would in fact, run very well on deiselene!!

donhe7

26/06/2012 12:25:45
Posted by Alan Worland on 25/06/2012 22:10:37: a suitably sized oiler with a screw cap which would be capable of retaining a more generous amount of oil.

Would it be better filled with grease and given a part turn every so often?

This method was used in a full-sized stationary engine which was built by IHC in the 1920s, which used a deep "grease cup" on the end of the crankshaft, from whence the grease was forced through a passageway to the big end , a periodic "pat" on the end of the grease cup would keep things lubricated.

The grease cup could be removed while the engine was running as required, by quickly spinning it between the hands faster than the slow-running engine was rotating, and replaced VERY carefully, after refilling.

donhe7

Thread: Where to get anodised extrusion and sheet?
11/05/2012 03:33:01

For very thin aluminium sheet, if curving doesn't matter greatly, cool drink or beer can material used to be .006", if recall correctly

 

donhe7

Edited By Donhe7 on 11/05/2012 03:34:14

Thread: A useful Stirling engine.
22/04/2012 15:16:12
Posted by Ian S C on 22/04/2012 13:27:07:

As bike dynos go, a Sturmy Archer hub dyno would give you the most power output, you need to find an old junked bike, think they were about 9V, were as the ones that run on the tire are 6V, the hub dyno gives a good voltage at a fairly low speed, they all need a rectifier, but thats not much of a problem. Ian S C

Further thoughts on the Sturmey Acher Dyno-hub, they must be driven at a slow speed, as they drop off in efficiency at too high a speed, as an old friend found out a number of years ago, when he tried to drive one with a model engine, it seems that the stator saturates above a certain speed and reduces the output. However, if a small steam engine or an efficient Stirling engine could be coupled to it, it could answer the OPs prayer.

donhe7

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