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Member postings for David Jupp

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

Thread: Plans and prices.
30/06/2013 11:50:47

You also have to pay for the facilities to (large format) print / store / retrieve them. I suspect the 'the amount that must have been sold' isn't actually all that many to spread the costs over.

For each order somebody has to either retrieve existing copies from storage, or 'print on demand' the required sheets, then fold, pack and ship. It all takes time.

If you look at it as buying the designer's time and ingenuity, it's a lot better value than if you think of it as buying paper.

In many ways we are spoilt with so much in the way of plans and designs available for free on-line.

Thread: EN16T
22/06/2013 21:14:14

See table of BS970 Temper condition codes asbout half way down page on this site **LINK**

22/06/2013 16:36:26

T = 850MPa - 1000MPa UltimateTensile Strength or 55 Tsi to 65 Tsi in old money.

So no not fully annealed, but not terribly hard either

Thread: Remote control for 3 phase inverter.
16/06/2013 22:21:56

Neil - that doesn't sound quite right -

Fwd-off-rvs, if wired via momentary start p/b, then the 'off' of the 3 position switch can't do anything (except act as a disable).

Not familiar with the Jaguar - some inverters offer more than one switching mode dependent on how you want to control it.

One that I use here is set to mimic a NVR contactor behaviour (3 wire mode) - n/o button to start, n/c button (and any interlock switches) to stop. The same inverter can also be set to have a single contact - closed for run, open for stop (2 wire mode). On my drive, fwd/rev is done via a simple on/off toggle switch, as is jog mode.

Mine is not a Jaguar drive though - so the handbook should be your ultimate guide.

Thread: Re-hardening annealed coper tube
15/06/2013 11:28:48

From my original training in metallurgy, and some quick checking of a few technical web sites, I'm not convinced that there will be any significant age hardening in copper as used in typical ME projects.

If age hardening did occur, it could be speeded up by heating to the correct temperature (to speed up diffusion) - heating too much would drive the precipitate forming elements back into solution and hence soften the metal.

There is age hardening in materails like Beryllium Copper, and Copper is used as an age hardening alloy addition in Aluminium and some other metals.

As commented by others, very significant work hardening does take place in copper.

Edited By David Jupp on 15/06/2013 11:29:18

Thread: Thread Milling
05/06/2013 16:41:30

It is even possible to buy tools which can be used to both mill the hole and the thread - biggest benefit is cutting down on tool changes.

Thread: Looking for a supplier of 20mm and 25mm hardened and ground shafting
03/06/2013 14:05:44

Marchant Dice stock this kind of stuff. They already do (or certainly did) kits for the Rockliffe router. They trade on line and via e-bay. Probably lots of other options out there.

Thread: Taps and dies
26/05/2013 08:37:43

The size will usually be marked on one face of the die. Should allow a quick check.

Thread: Cutting metric threads
21/05/2013 08:35:05

I think that I might be tempted to try using loctite (or similar) to hold the ends on - would save all that very fine threading - unless the screwed cap also pinches the rod seal...

Or maybe try to find some off the shelf brass steam fitting nuts that could be modified.

Or drill/tap thru, add male threaded plug - solder plug to seal, drill for rod.

Thread: Drawing Projections
18/05/2013 07:29:04

The 3D CAD system that I use assumes by default 3rd angle for inch based templates (US paper sizes), and 1st angle for Metric (ISO paper sizes). This is simply down to the way the provided 2D templates are set up.

This can catch out the unwary, especially as the projection method can only simply be changed before adding views to the drawing.

For this (and some other reasons of style/preference) I recommend that users set up their own drawing templates, customised to give their desired 'look' to their drawings.

Thread: Are your cap head/grub screws filling with swarf?
16/05/2013 12:17:22

If using the Silicone sealant method - be aware that most of these sealants evolve acetic acid during curing, which can lead to rusting.

Suggest only using on non-critical (or protected) surfaces.

If you look hard you can find 'neutral cure' Silicones (typically used in electronics).

Thread: Boiler testing and regulators (ie throttles)
14/05/2013 18:52:01

Pleas calrify by 'leak' do you mean not tight between inlet and outlet, or do you mean leaking to atmosphere?

If former I agree, a blank on the outlet should adequately check system integrity.

If leaking to atmosphere - maybe OK from gland (though as a tester I would wonder why you couldn't be bothered to fix the gland for the test), if leaking elsewhere to atmospehere I'd say unacceptable.

13/05/2013 18:58:24

As someone who works professionally with pressure systems, it seems to me that there is some confusion between 'leaking' and 'passing', one indicates a flaw which may become dangerous, the other is more of an inconvenience in most cases .

Clause 10.9 as shown in Steambuff's post should be clear enough, passing of the regulator is not a concern - leaking may be.

As for cylinders, yes they are part of the pressure system, but the probability of catastrophic failure is low, and likely consequences less severe than a rupture of the boiler or of items close coupled to it.

All recent UK/EU led directives are 'risk based' - most effort / testing / inspection is concentrated where there is highest risk of harm to people ot the environment. Cylinders would have to be very large for a model to become subject to PED, boilers very easily fall within PED.

Thread: Harrogate show
09/05/2013 08:02:00

Or just turn up a little after the start - there is usually a big queue at opening time, but this soon subsides

Thread: Thread identifacation
05/05/2013 11:54:07

4BA may be closest to measured dia, but the tpi doesn't match

5/32 BSW (32tpi, 0.156" dia) might be possible. If you are measuring the existing male thread it may be quite a bit under nominal size.

2BA (31.4 tpi) and 3/16 BSF (32 tpi) are both OK for tpi, but major dia. larger than measured.

Good luck...

Thread: High Tensile: What Steel Grade?
03/05/2013 08:55:26

Stiffness (modulus) of all steels is close to identical - did you really mean 'stiff' or did you mean strong?

Thread: Criteria for article in Me or MEW
22/04/2013 19:34:42
Posted by David Clark 1 on 22/04/2013 18:51:30:

Hi There

I use my own pc and the office will not buy software for own PCs.

regards David

And they don't need to - the server bit would sit either at a central office or 'in the cloud', client end (free) or web access would be used from your PC.

Added advantage that the magazine is not totally reliant on your PC (if it dies, stolen etc).

There are good solutions available - companies don't have to use them.

21/04/2013 19:27:00

Norman,

There are Document Management systems which allow a variety of information (metadata) to be entered against a document (or indeed about a 'project' or 'article' or whatever... to which documents are linked). Information would likely include author, keywords, maybe process(es) or category. Files can be searched/displayed by any of these, or by occurence of a word in the document, depending upon the current requirement.. In comparison folders are restrictive, and/or tend to lead to multiple copies (a nightmare to maintain) in an effort to over come this.

It becomes trivial to display (say) 'all unpublished submissions in the steam category'.

I am involved in selling/supporting a particular package, but there are many options available out there.

21/04/2013 09:41:32

Les - you'd be surprised (or maybe not) how quickly such a folder based system would end up in a complete mess. There are however fairly simple and relatively low cost ways to organise documents that would overcome the problems of a folder based approach.

Thread: Cutting matching inside and outside tapers
19/04/2013 16:07:45

Yes - perhaps should have been more explicit! I carefully wrote 'suitable to run in reverse' rather than 'can run in reverse'.

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