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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: Dunlop Taper Bushes
20/01/2020 13:35:56
Posted by Ian Parkin on 20/01/2020 11:56:53:

My supplier calls them weld on hubs

That is yet another type.  The 'hub adaptor' is a split bushing (with or without a keyway) and sits in a cylindrical hole.

Edited By David Jupp on 20/01/2020 13:53:54

20/01/2020 11:28:18

Fenner produce adaptors beyond the bolt on style for Taper Lock Bushes, their 'hub adaptors' may be worth a look.

Thread: Punching holes in metals
02/01/2020 17:23:27

If the holes happen to be a standard size, hole punches used when building control panels can be surprisingly inexpensive (e.g. Q Max brand).

Thread: Colour matching.
02/01/2020 10:08:23

Be aware that the type of light source used to illuminate will affect the perceived/measured colour.

Matching the colour under one light type, won't always give a match under other lights.

Good luck.

Thread: Advice on mobile phone etc
20/12/2019 11:29:49

Check what speed WiFi your router or Access Point supports - if that is the bottleneck, updating the client devices won't help.

Thread: Omron Varispeed V7 - external potentiometer HELP
13/12/2019 13:17:46

Diagram at bottom of page 65 of the manual shows how to wire it.

Thread: VFD Switch on Frequency
12/12/2019 14:01:31

The front panel knob may be an encoder rather than a pot (to sense rotation, not absolute position). The smaller Schneider VFDs are like that for example. In that case the VFD only knows the knob has rotated 'so many clicks, plus or minus from starting point' - At power off the position will be lost unless of course there is a parameter setting that can retain the position/frequency.

A 'start up frequency' may have been set.

Best thing to do is check the manual carefully for the precise model, different brands/models have different capabilities. If it is a mainstream brand, try calling their technical support line or drop them an e-mail.

Thread: Annealing Brass
01/12/2019 08:49:43

It is the time at elevated temperature that does the annealing - the quench is not involved in the annealing. With Brass, it is possible to quench, because that doesn't cause a phase change - whereas with Steel, quenching can often harden the metal, by the production of martensite (so when annealing steel, slow cooling is the norm).

Thread: Remote speed control pendant
20/11/2019 09:23:35

The precise details can vary, depending upon the inverter in use and how it is configured to operate, so there is no single generic circuit. The manual for your inverter should give the information required, though it may take a bit of digging around to find.

You'll almost certainly have to change a setting to tell the inverter to use a remote potentiometer for speed control.

If somebody offers a circuit diagram - first check that that your inverter is (or can be) configured to suit.

Don't get disheartened though - there are a limited number of variations on a theme, and most of the work will be matching control terminals of your inverter to those from whatever example you choose to follow.

Thread: Learning CAD with Alibre Atom3D
03/11/2019 09:35:13

For a quick method - Emgee's tip (which I had forgotten all about) is probably simplest.

For ease of future editing, Jason's suggestion to fully define the positions is a good one.

My earlier comment about using 3D pattern doesn't apply to the example you have shown.

02/11/2019 10:56:11

Alibre Atom3D is cut down from Alibre Design - mainly to simplify the interface and make it easier to learn. That does result in some functionality being lost, but it is also much less expensive than the Professional or Expert versions.

If you use the 3D feature pattern, rather than 2D sketch pattern to create your arrays (if I'm interpreting your words correctly), then repositioning the array is simple.

Thread: Unusual Pliers tool?
28/10/2019 16:30:15

SMC TK-1 or TK-2, RS amongst others sell them and have tube size details.

28/10/2019 16:12:39

It's a pipe cutter. SMC do a lot of stuff for pneumatics, a tool like this cuts the tube nice a squarely. The 2 rounds in the jaw will be for different sizes of tubing.

Thread: VFD Instructions
18/10/2019 14:25:32

Note that the 'understandability' of manuals supplied with VFDs does vary widely.

Some are poor translations or include poor use of English.

Some assume you have lots of technical knowledge, but don't give any basic guidance - or offer a huge wealth of settings and just confuse you.

One advantage of major brands is you can have access to e-mail or telephone based technical advice of a high standard included in the purchase price.

For any VFD with a brand and model number, you should be able to locate the manual on line and then decide if you could work from it.

Thread: Inverter reset?
12/10/2019 16:08:06

It is quite common (but not universal) to define fault reset to the same terminal as Start when configuring an inverter drive. Some might prefer a separate reset button.

Thread: Good practice for lathe circuit design
04/10/2019 14:53:54

On your last point - the E-Stop should stop anything that might cause harm to people, or cause damage to equipment.

On that basis it should power off the motor, and probably the ELS.

It's probably advantageous to leave lights and DRO powered during an E-stop event - those circuits aren't going to move anything, but should be fused, or have equivalent electrical protection.

If you progress to a VFD you might want to consider if injection braking with delayed power off would be preferable to a simple power off - though it is harder to provide this.

Low voltage lighting would be preferable to mains (hurts less when you poke a screwdriver through the lamp), lots of good LED lamps around these days.

Thread: PC problem #2
23/09/2019 13:33:21

Check for new firmware for the card. If you are managing card via Windows, try the utility that came with the card, if using the utility try doing it directly via Windows.

You might just be unlucky and have a card that doesn't 'play nicely' with your WiFi base station - in which case, try a different brand of card, one that uses a different chipset.

I once wasted half a day trying to get WiFi connection to a PC working - the fix was to change the card, then up and running in 2 minutes.

Also check for new firmware for the base station - though once I've had to roll back to previous firmware to maintain connections to a particular device.

Though built to a common standard - not all devices are completely interoperable!

Thread: Drawing
03/09/2019 11:47:47

Taking that a bit further.

triangle.jpg

 

So if stock is a square, or you have a square marked out.  Start in one corner - draw 2 lines at 15 degrees to sides of square, join the points where these 2 cross the other sides to make 3rd side of triangle..

 

Or set callipers/compasses to 3.106" ,  start from one corner of square, where compass arc crosses sides of square gives other 2 corners of triangle.

Edited By David Jupp on 03/09/2019 11:48:18

Edited By David Jupp on 03/09/2019 11:52:25

Thread: Pivot Steel - Machinability
01/09/2019 19:35:35

Interestingly a search for EN 4454 on the British Standards site, doesn't find any matches.

There is an Indian Standard IS 4454 Part 1 for Patented & Cold Drawn Spring Wire - could well be derived from an obsolete BS. BS re-cycle numbers, which can be very confusing.

Thread: CH Motorised Valve Radio Interference
01/09/2019 12:29:11

I have had a tank stat that started to 'chatter' rather than switch off cleanly. The symptoms were that the pump would cycle rapidly several times at end of water heating. I initially thought issue must be the diverter valve, but no. I bought a new tank stat (different brand, as the problem one wasn't old). Fitting new stat solved the issue.

Not suggesting that is your issue, but tank stats can degrade in odd ways - so don't rule it out as a possible source of problems.

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