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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: CAD program that can import PDF for scaling
24/10/2021 16:25:34

Be aware that depending on how the originals were scanned to PDF - and if they'd ever been held on microfilm during their life, there may some lens distortion embedded in the PDF. Lines that should be straight may not be so.

I once tried to scan and convert to CAD some 1970s drawings that had gone via microfilm - it ended up being quicker to manually re-do the drawing from scratch just using the original as a guide and to give dimensions.

You could be lucky, and technically you can use software to correct for lens distortions, but it certainly isn't a 'press the button' process.

Also to extract the meaningful lines, you need a very clean print to start from. There will usually be some speckles and marks to remove manually, which also takes up a lot of time.

Older 'pre-CAD' produced drawings often contain features which are simply not correctly sized - it was always intended that the dimensions would be used to drive manufacture, not the profile on the paper. The paper drawing was good enough to convey the intent, but 'DO NOT SCALE' was on the drawing for good reason.

Thread: Sewage dumping
24/10/2021 10:31:39

In many locations surface runoff water goes into the same sewer system as foul water (sewage). Heavy rainfall can lead to huge flow rates, many times more than the usual sewage flows.

Thread: Paint stripper
07/10/2021 19:13:56

I've used Biostrip previously - you do have to be patient, and it may take several applications, but it is not unpleasant to work with.


Thread: 12volt three wire fan connections,
11/09/2021 17:46:40

Control = Violet perhaps ?

Control could connect to battery positive or to ground to turn fan on...

It could expect a PWM signal, or even an analogue variable voltage if variable speed control is expected.

Maybe check the wiring diagram of the donor vehicle for clues....

Thread: solid edge community edition woes
09/09/2021 16:32:25

Several companies will tell you their CAD product is 'Industry Standard' - whatever that is supposed to mean. It is marketing people that pen such meaningless statements.

Take it all with 'a pinch of salt', and just worry about if the particular package does what you need it to do.

Thread: 2D and 3D Cad Software Recommendations
06/09/2021 14:43:28

Some of the proposed fields may either not be clear, or may be used differently by different companies (or both).

Several terms are very subjective, hence potentially difficult to get a fix on.

Don't let me put you off though....

06/09/2021 07:38:29

One slight problem with a comparison based on what others report is that there are some reports in this thread that contain factual errors. I've noticed it with regard to the products that I know, so it probably also applies to others.

I doubt that the errors are deliberate - but they could be important to somebody making a choice.

05/09/2021 17:10:42


Yes Atom3D (as with all Alibre software) is a perpetual licence. The charge for 12 months of updates is entirely optional. If you choose not to purchase updates, you remain on the version initially purchased. Of course radical changes to future versions of Windows might mean that an older version may not work on a new computer, but that is a risk with any software.

Atom3D can export DXF from its 2D Drawings workspace.

Atom3D is perfectly capable of dimensioning drawings, I can't comment on why a user might choose to do that step in another software package.

Thread: What features do you like to see in Youtube videos.
17/08/2021 11:58:00

Clear concise introduction, be that speech or text.

No music!

Thread: DIY Compression spring
10/08/2021 09:30:06

Music wire springs are typically stress relieved after forming, and a domestic oven can be hot enough for that. The stress relief can reduce chances of breakage in service.

A domestic oven won't be hot enough to temper steel (i.e. controlled softening after hardening).

'Heat Treatment' covers a variety of processes, and the names are often used somewhat loosely, which can confuse.

Thread: 'Puter upgrade recommendations
28/07/2021 11:52:19

3D CAD is pretty taxing on the graphics adapter. It may be that an upgrade there would be helpful. Display size can make a big difference, more pixels to manage means more work for the graphics adapter.

Before any hardware upgrade, you might be able to get a useful performance boost by -> ensure Win10 is fully updated, ensure you have latest driver for the graphics adapter, then check to see if Win10 offers 'Hardware accelerated graphics scheduling' - it's only available in fairly recent Win10 builds, and IF your graphics adapter and driver has the capability.  Enable it if it is available.

Check the settings for the Nvidia card - make sure it's set for 'performance' rather then power saving.

RAM - that all depends on how large/complex your designs are, and if you are running other software at the same time. 12GB may be plenty, or you may need more

Edited By David Jupp on 28/07/2021 11:53:25

Thread: Rockwell hardness of collets
02/07/2021 08:10:16

HRc 44-48 corresponds approximately (you'll get different figures from different sets of tables) to 415-445 Brinell, 440-475 VPN, or a tensile strength of roughly 94-104 Tsi, 1455-1590 MPa. Don't expect these different units to be exactly equivalent - they are just indicative.

Thread: 4MCAD from Mintronics
01/07/2021 16:52:25


I note that you mention difficulty printing from the 2D workspace in Atom3D. It might be worth detailing your issues to Alibre or Mintronics support - printing shouldn't be problematic, and I know of a number of issues that have been resolved either by simple fixes, or by advice on how to get the best from the software.

Thread: 2D and 3D Cad Software Recommendations
22/06/2021 10:04:29

I have a commercial connection, so won't give a recommendation for a particular CAD package.

I would suggest that you try before you buy, both the software itself and look at training materials and any other available resources (user forum, help documents, etc.)

You may well find that some packages are a more natural fit than others for the way your mind works.

Thread: Machin guards
15/06/2021 08:28:14

If using Polycarbonate for guards, never use acetone for cleaning. It leads to severe stress cracking.

Thread: An explanation of CNC machining terms
10/04/2021 11:07:14

MeshCAM is aimed very much at ease of use. In trying to keep things simple, maybe the explanation is sometimes a bit thin.

Rob at MeshCAM is pretty helpful if you send queries to him at the support address given on the MeshCAM web site.

I believe that 'unified' means the software will do its best to combine whatever finishing strategies are appropriate for the part.


Edited By David Jupp on 10/04/2021 11:14:30

Thread: Mad Modder site not secure?
08/03/2021 11:24:23

Yes - that's normal for sites without a security certificate.

Thread: Mystery material
01/03/2021 10:14:41

At least one other steel producer in Sheffield had their own trade names for standard 'EN' steels.

I have a (1950's) handbook from another steel supplier (not Sheffield) - their '' product is EN32.

01/03/2021 08:52:20

The name may (or may not) give a clue. 'Sil...' could refer to Silicon, or maybe to the name of the manufacturer, or something else entirely.

Do you know the original manufacturer? What is the application? Do you have any original parts available?

Thread: What is this? Something to do with hardness?
23/02/2021 17:03:49

It's a calibration standard for the Brinell hardness test. Used to verify that the test device / microscope / operator are giving sensible results.

The ID of the standard, and the square used will be recorded in the calibration log.

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