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Member postings for Nealeb

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

Thread: Free Fusion360 subs ended
26/06/2022 08:19:27

I do my main CAD work indoors in my office so might leave F360 running there, but quite often want to tweak a toolpath so would also use it on the workshop PC in the middle of a job. Can't do that now without one shutting down - and as it is about as quick to go back in the house than start/restart F360 on the very slow workshop PC, in practice it's not a big deal. Not two at the same time, but close...

Another case where I suspect Autodesk want to make it more difficult for commercial organisations to use the free edition?

Thread: Fiber optic cable
14/06/2022 13:14:29
Posted by Speedy Builder5 on 14/06/2022 09:51:36:

Our factory earth was reading +40 volts and we were an electronic equipment manufacturer !!

I guess that there's a reason why ethernet connections include ground isolation!

Thread: HOW FAST - ANEMOMETER CALIBRATION ?
26/05/2022 09:40:05

(Double post deleted)

Edited By Nealeb on 26/05/2022 09:41:31

26/05/2022 09:40:03

The anemometers fitted to the masthead of small sailing boats used to have the "three cups" style speed measurer together with a vane to give wind direction, both feeding instruments in the cockpit or elsewhere. Some newer systems use just the "three cup" device, but one cup has a notch cut out so that rotation speed varies during each rotation based on wind direction, and clever electronics can use the signals to give both speed and direction from this single sensor. I mention this because it must use a much more sophisticated sensor than the "one pulse per rev" system - doesn't it? Another of those "I wonder how they do that?" questions!

Thread: New To CAD? No, but....
20/05/2022 08:55:00

One of the secrets of using any of this software, at least when you are still learning, is to understand the minimum number of commands that you need - and where to find them! - and mentally label the other 95% as "do not touch!" A lot can be done with relatively few commands but the trick is to find someone or something that can guide you through. Once you start climbing the learning curve you start to get a feel for how things work and can explore more ambitious areas of the software.

At first glance, the range of menus and commands is intimidating - you could almost do with a mask to put over the screen to hide the bits you don't need yet - or possibly ever!

I think that that is one reason why I think F360 is easier for someone starting from scratch - the number of tabs, drop-downs and so on in Solid Edge is pretty off-putting.

14/05/2022 08:46:37

As mentioned, if you set out to create a tube then extruding the space between two concentric circles is the way to go. But if you need to make a hole through an existing solid, then typically you can define its depth by specifying an exact depth (most useful if you want a blind hole), or link the depth to another point (e.g. the opposite face of the solid so that if you change the solid's thickness, the hole still goes exactly through it), or, depending on the CAD package, specify "through this part" or "through all parts". It's a matter of finding the right tools but there is the principle (sometimes overlooked in tutorial videos) that if you link ("use constraints" components then the model is usually more robust when changes are made than if, as here, you just make two dimensions equal.

Thread: Ambiguous words
10/05/2022 22:27:33

My wife and I both use the word "threads" in our respective leisure activities, but with rather different meanings...

Thread: New To CAD? No, but....
10/05/2022 22:24:34

I was also a TurboCAD user and went through a number of updates of the product. I spent quite a lot of time trying to get the 3D bit to work, carefully followed the manual to try to learn it, and eventually gave up as too difficult! I then moved to OnShape, then Fusion 360, then Solid Edge. I still use both the latter two although I have given up OnShape.

Briefly, constraints are a bit like snaps, except that because you can generally move things around and redimension them in a 3D CAD package, they are more than just a snap as they define a permanent relationship between two objects. For example, if you constrain the centre of a hole be on the midline of a component, it will stay on the midline even if you change the size of the object. It's a very powerful technique, to the extent that the mantra "don't dimension if you can use a constraint instead" is generally valid. Failure to use constraints properly is where a lot of models fall apart when you try to modify them later.

I see from MichaelG's post (arrived as I was typing this) that TurboCAD is now using the same core engine as Solid Edge and other products, so perhaps they are actually moving away from a 2D drafting package to a 3D modeling package.

But we all bring different baggage to the table and the fact that I'm more a software than mechanical engineer is probably a useful attribute!

Edited By Nealeb on 10/05/2022 22:26:27

Thread: Boxford AUD/BUD single phase conversion
10/05/2022 19:15:42

As regards keeping the machine 3-phase compatible - that is probably trivial. Most VFDs accept single-phase but have input connections for 3-phase input. Take out the single-phase mains lead, wire in the 3-phase cable, and you retain all the VFD, pendant, etc, capability.

Thread: New To CAD? No, but....
10/05/2022 19:10:04

I noted the comment a few posts ago about how careful you need to be to make sure that a sketch encloses an area for extrusion to a 3D body with no gaps, and suggesting over-length lines which are trimmed back. I would suggest that this indicates someone coming from a non-3D background and who is not yet up to speed with using the 3D tools. In particular, using constraints to control things like lines meeting at a point and using dimensions to control line length rather than drawing correct length lines.

I have done some tutoring for local club members amongst others and one thing that quickly became clear is that it is probably more difficult to transition from years of 2D engineering drawing experience to 3D CAD than it is from a position of ignorance! For example (from among many) on a drawing board, a line is a line and while it might be possible to lengthen it, position and angle are fixed. On a screen, a line can have length, position and angle changed as you wish. It changes the way you approach things. I often create an object - line, circle, rectangle - of roughly the right size and in roughly the right position, but deliberately not exact. I then apply constraints and specific dimensions as required to tweak it into the right place/size. It's a mindset thing, and it's the thing that is often missing from Internet video tutorials. A quick whizz with the mouse and a "that was easy" doesn't always explain the underlying principles!

Edited By Nealeb on 10/05/2022 19:11:23

Edited By Nealeb on 10/05/2022 19:12:29

Thread: Ambiguous words
23/04/2022 12:34:47

I discovered the first time I ate in a US restaurant that I was required to pay my check with a bill, rather than my bill with a cheque as I did at home in the UK.

22/04/2022 11:08:25

When I bought my first lathe and began using it, the instructions said, "Chuck the work and face it." So I threw the work across the workshop and looked at it, but nothing happened!

Thread: Before calculators
19/04/2022 18:59:47
Posted by JA on 19/04/2022 18:04:18:

All will give me the square root of 40 but none will give me the square root of -40!

JA

Well, just imagine that!

19/04/2022 15:42:50

In the past, I've used a "manual" method of calculating square roots. There's a description here. Pretty simple application of differential calculus - surprised no-one has mentioned it!

Back in the seventies when my wife (then girlfriend) were at university, she had a pile of statistics to analyse. This involved many square root calculations and she had a four-function calculator. I was able to derive the Newton-Raphson formula from first principles (ah, the days of understanding that stuff!) and it all went quite quickly. Essentially, you guess an answer, plug it into a simple calculation, and it gives a better answer. Repeat until bored! Or, at least, until successive answers are close enough that you know you are there. It actually gets to a decent approximation fairly quickly.

As you can do the sums on a four-function calculator, clearly you can also do it with pencil and paper but the formula does involve long division which slows things down.

I've just tried finding sqrt(6) by this method. Daft initial guess (sqrt(6)=1) gives us 2.4495 after 4 iterations. Better guess (by inspection, answer is between 2 and 3 so assume 2.5) gives us 2.4495 after 2 iterations. Well, it's quicker than drawing and can get to any arbitrary accuracy. And some of us like doing sums... But just as pointless as the drawing method given today's technology-in-the-pocket devices!

Thread: Sigh, practicing a skill I would rather not need
18/04/2022 11:45:32

Looks very like the job I did building my CNC router. Lots of M5 holes in steel tube. The tube was nominally 3mm but backed inside with 4mm strip for more thread depth. I used a spiral-point machine tap in a cordless drill, Trefolex, and straight through in one pass. Can't remember how many holes now but there were two rails 1800mm long so quite a few. Was I lucky? Have to say that in general I use machine taps these days even tapping by hand.

Thread: Help with Excel
21/03/2022 17:46:55

No argument, Andy - I was thinking "general case" but if you are cutting a truly circular arc, then the tool path follows a similar arc struck from the same centre but reduced by the radius of the cutter. I had completely missed the "special case" nature of this one where the sums actually become very easy. The technique that I described is of use for anything other than a circular arc - possibly for aesthetic reasons it is a part-ellipse, for example. My loco wheel flanges fall into this category. All the same, personally speaking, I would probably still use the CAD/CAM route, justified by this quote from Leibniz:

"It is unworthy of excellent men to lose hours like slaves in the labour of calculation which could safely be relegated to anyone else if machines were used."

I guess that it's the difference between needing to look for an elegant solution to avoid lots of calculation or similar effort, and just throwing lots of CPU cycles at a brute-force solution!

21/03/2022 16:58:58

Unfortunately, while it's pretty simple trigonometry to work out the coordinates of the curve, those aren't quite the coordinates that you need to machine said curve! Possibly not even good enough (given that this curve swings through near 90deg) for this cosmetic-not-bearing-surface curve. The reason is that in order to position the tool, assuming that you are using a circular button tool, you need the coords of the centre point of the tool. The actual contact point - where the cutting takes place - is a bit more difficult to calculate than just the curve itself as there is an offset of tool position from the curve that depends on the curvature of that curve at a given point. At the largest end of the curve you are using the side of the tool so need to offset along the lathe axis while at the small end this offset is near zero but the infeed offset is now maximum - and these change all the way along.

It's unfortunate that the OP is not a CAD user. I reckon the easiest way to get the required list of coordinates is to draw the profile in CAD and use its CAM module to calculate the path. I guess you could do this by generating the lathe tool path needed although not having any experience of doing that, I would pretend that the profile is going to be machined on a mill, specify a tool of the diameter of my lathe tool button, and generate the gcode accordingly. It's then easy enough to edit out the XY coordinates from the gcode and put that into a spreadsheet - or just print as text. I'm sure I could do the work needed to come up with a formula for the correct tool path manually but it's very much a case of letting the software and the PC take the strain, and a whole lot less error-prone!

For doubters, I (and plenty of others) have taken this path to get "manual numerical control" coordinates before; I use the technique to machine loco wheel flanges because I'm a whole lot better with CAD/CAM than I am grinding a form tool... A DRO on the lathe helps a lot as well.

Thread: Home CnC
16/02/2022 22:30:48

I'm a bit late to this party but I am a Wabeco mill owner, at least!

Some time back I was playing with the idea of a CNC conversion for my Warco VMC, going for ballscrews and all, but was still worrying about how all the bits would fit without stripping it first, given various comments on various forums about maybe having to machine clearances under the table.

My wife persuaded me to take one last look at eBay for something second-hand and. lo and behold, a Wabeco turned up for sale - fresh on the market and only about 25miles away. Turned out to be a 1410LF hs. Can't quite remember the difference between the 1210 and 1410, but the LF and the hs are significant. LF means Hiwin profile rails instead of dovetail slides, and hs means the high-speed 2KW 7500RPM spindle. I think these are standard Wabeco upgrades, but this machine had had been upgraded by a US outfit and had ballscrews, driven by servos not steppers. In place of the standard (and not very highly regarded standard Wabeco software) it used Mach3 and an Ethernet SmoothStepper. The spindle was also BT30, not MT2, and it came with the full enclosure and stand, plus coolant system. In all, a pretty good bundle. I'm not sure if the standard machines have a counter-balanced head, but this one does.

I doubt if you will find another same-spec machine in the UK, but in terms of structure and build it is still Wabeco. It is not as stiff as the Warco - there is just not as much iron in it. The swivelling head has swivelled by itself once due to me trying to take too heavy a cut by accident as the clamping arrangement is not that great. However, within its capacity I have found it to be an excellent machine, even down to a recent experiment machining a HSS form tool using a carbide cutter. I have used cutters down to 1mm in steel where the high speed is really useful - it does 140-7500RPM without belt change. The axis handwheels all have fold-out handles for manual operation but because there are no table locks and the ballscrews move very easily, this is not a great idea. However, using a wireless MPG and keeping it under CNC control works well for me.

I did replace the Ethernet Smooth Stepper with a UC300ETH and UCCNC software, partly to get rid of Mach3, partly because I was having random comms issues with lost connections from time to time, and I decided to make them all go away by replacing the obsolete hardware and software with something current and supported. Pretty easy job to do, by the way.

Not sure that I have answered many of your questions but happy to help if I can.

Thread: Wire EDM - an amazing capability for the home shop
02/01/2022 19:15:40

In fact, the man in the blue coat is me.... Norman has already mentioned me a couple of posts back! I'm a bit behind in reading this forum, unfortunately.

I actually joined the group who built the machine at about the time that the bulk of the work had been finished and just needed some fine tuning. It still does need a bit of fine tuning, but it was built as a demonstrator/proof of concept rather than "production" machine (even by amateur standards) and so lacks a lot of the refinements that would make it usable for actually making things as opposed to demonstrating the principles. It has been a great success. though, as a demo machine at quite a few exhibitions as well as some presentations to clubs. The machine is currently residing in my own workshop (in Devon, indeed) but has not seen use for a while now given the lack of exhibitions to which to take it!

Happy to answer any questions.

Thread: Solid Edge - Community Edition
16/11/2021 12:19:46

Thanks for note about Gearotic - it's always looked interesting but a bit too expensive for a toy! I have plenty of toys on the list to get first...

Helical gear needed because the TDI body is fixed - and this is a Smart and Brown machine, built like a battleship (the TDI body is something like 2x1x1 cast iron) so no chance of swinging it. And it was an interesting exercise, even if a friend did point out that for this job, a bit of brass sheet with rough teeth round the periphery would have done it. Now I have the 3D model, even if it does wear, it's only minutes to make another one with negligible effort.

Coming back to SE - I did have a play with the gear generator afterwards, although it took a bit of doing. Seems that you actually have to generate a pair of matching gears (so it's done in the "assembly", not "part", environment), and then it starts getting complicated. In an effort to be useful, the process gets bogged down in tooth load calculations, so it sits and sulks until you put in a combination of gear material, speed, and power transferred, that it believes to be acceptable. Printed PLA is not on the list of materials, I was astonished to see. I did figure out in the end that miniscule power at quite a high speed lets you concentrate on useful data like non-integer module pitch...

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