Here is a list of all the postings Steve Skelton 1 has made in our forums. Click on a thread name to jump to the thread.
|Thread: New To CAD? No, but....|
There is a lot of good stuff on here, however, I think you are approaching 3D CAD with the wrong mindset, let me explain.
I was in a similar position to you. I had come through learning to use a 2D CAD package, gaining a reasonable 2D proficiency, enough for what I needed to use CAD for. I had been using 2D CAD for about 25 years.
When I retired bought a 3D printer for a specific task which it did admirably but then started to think, what if I could design stuff and print it myself.
At the time MEW started the 3D CAD series with Alibre Atom3D so I took the free trial and started on it. It was an absolute disaster despite me following the tutorial in MEW. I kept tying myself in knots because of all of the 2D experience I had. Then I had a lightbulb moment when I read somewhere that said words to the effect of "forget everything you have learned about drawing and think that you are trying to machine a lump of metal and what you would do to it". Then it all started to make sense.
I find when making a 3D CAD drawing that you are either adding or taking away material with a positive or negative extrusion and make sure you are doing it on the right plane. You have to make a number of sketches, one for each separate machining process you are performing on the part you are producing before the positive or negative extrusion.
I would not profess to be an expert, in fact, I am far from that, but I have been able to produce everything I have set out to do so far, maybe not in the most elegant way but at least it has always worked.
I have no commercial interest in Alibre or know anyone connected with it but I find that it is simple to use once you have grabbed that first fundamental that it is nothing like 2D CAD and it is just about making a sketch, extruding it into a shape then adding or subtracting other extrusions to it via other sketches. It really is so simple - I think you are overcomplicating it and are taking all of your 2D experience into producing a complex drawing rather than using simple sketches to make a complex object.
Others may disagree with my views. I almost gave up with 3D but now find it useful and straightforward, but what is most important, it is satisfying and rewarding when you produce something.
|Thread: Drilling 38 x 1.5mm 316 polished stainless tube.|
Hi Ches, I only used the vice once - for the other holes I held the jig in one hand whilst holding the drill in the other so it will not be a problem having to find some way to clamp the jig.
Thanks everyone for your help.
I bought an off-cut length of 38mm polished stainless tube and manufactured a crude jig out of a lump of oak I had lying around.
Using a Dormer split point A108 drill in a Bosch battery drill on slow speed with a lot of pressure, along with CT-90 cutting oil I had no problem in cutting a number of 6mm holes in the tube.
So all I have to do now is to take all the kit with me and try it in situ (in about a month).
Photos as below:
|Thread: Inverter Tripping RCD|
Three-phase RCD's work in exactly the same way as a single-phase RCD.
It does, however, have four terminals one for each of the phases and the neutral.
Due to the 120-degree phase rotation if all the phases are balanced then there is no current flowing in the neutral but if any phase is pulling more than the other two phases then there is an equal current (to the imbalance) in the neutral. The three phases are wound around the sensing coil as if they were one phase, but obviously insulated from each other.
|Thread: Drilling 38 x 1.5mm 316 polished stainless tube.|
Hopper I had thought of that and even using a diamond tile cutter as the main cutting device but felt it would be too slow.
Sorry for the delay in getting back.
DC31K and David-Clark 1 like the idea of a wood block, I was originally thinking of 3D printing something but think that would not be robust enough.
Noel I am also thinking a centre punch may not be a good idea, as Paul points out work hardening on a minor scale may result.
Peak4 and old mart - this is what I am planning to do.
I have some hardwood blocks kicking around in the shed so will experiment with them using a sharp drill (I cant use a centre drill as it would need to be long enough to go through the wooden block) using slow speed and maybe flooding with cooling water as it will be done outside where water will not be a problem.
I will try on some scrap SS and see what happens, I cannot do the actual job until May but wanted to get ahead of any likely problems.
Looking for some advice please.
I have to drill a number of 6 mm holes in polished 316 stainless tube which is 38mm diameter and 1.5mm wall thickness. The added complication is that it is nowhere near my workshop (and power) and will need to be carried out using a battery-powered drill (although powerful).
Would I need to use a pilot drill first? How to start without skidding all over the surface – center punch start or a clamp-on guide? What spec drill bits – I am worried that by using high cobalt drills it may be difficult to prevent them shattering using a handheld drill. Obviously need to drill at slow speed and use a cutting fluid but has anyone got any specific tips.
Thanks in advance
|Thread: Plasma cutter at lidl|
Certified 1.5mm^2 flexible cord has a 16 A current carrying capacity at 230V AC so should be adequate for the purpose. I suspect the unit would overheat before the cable did.
|Thread: British Gas Price Guarantee|
I was with Peoples Energy when they went bump. I was automatically transferred to British Gas. BG sent me an e-mail on 23rd October 21 with the new tariff which although 50% higher than Peoples Energy I had to accept.
In the e-mail from them, it states that the new price was "Price guaranteed until 30th June 2022". I have now just received an e-mail from them stating the prices are going up on 1st April 2022. Again another 50% increase.
Needless to say, I have raised a complaint with BG, I wonder how they will explain this.
|Thread: missing parcel|
We sell using eBay via Royal Mail most days. If you have proof of delivery from Royal Mail then eBay will accept that and you should not have any comeback. EBay go on the tracking info and if it is shown as delivered then it has been in their view.
I use an extension on Google called "Cookie AutooDelete" which, surprisingly enough, does just that when you leave the site. You can add white lists, like this site for instance, so that it doesn't delete cookies etc when you leave.
It works well and keeps your PC clean.
|Thread: How can I bond ABS (plastic) to NRL (rubber)?|
"I am using strip of rubber to create a hinge between two plates of ABS."
Why not redesign it using polypropylene so that you use one piece of material - PP make perfect natural hinge material? May be easy to 3D print it? Would be a much more elegant solution.
|Thread: Silver solder resist|
I'm also with Massimo on this one.
Jewellers rouge lasts forever and is easily mixed with a little water and if it goes dry in storage just add a little more water.
Works a treat and is low cost - £4 for 50g (eBay) which will last for a lot of soldering.
|Thread: Saving the Planet … or is it ?|
Thanks for that Peter and the offer of borrowing your old unit. I am thinking that a split system, which seems to operate at a higher output temperature, maybe my best approach.
I am in no hurry to jump into buying something yet as it is mostly an academic study as my heating costs are not excessive, even with bottled gas! However, I would like to do my bit to reduce my carbon footprint.
My concern has always been that the efficiencies are never what the manufacturers quote, I have tried to discuss this with them but they refuse to answer my questions - I have approached two of the major manufacturers with technical departments in the UK and they have not got back to me despite repeated requests. They just quote the DIN tests as this is all they have to quote on their technical specs. The trouble is the values quoted are for laboratory conditions with much lower humidity values than we experience here in the South West and I am still unable to determine whether the water removed from the test air is replaced as it is condensed. If it is not then the efficiency of the unit will rise as the test progresses.
The thermal conductivity of ice at 0 deg C is about 2 W/mK compared with a heat exchanger material conductivity of about 385 in the case of copper and 205 for ally. So any build-up of ice (which will occur at air temperatures of less than 10 C) will have a seriously detrimental effect on the ability to remove useful heat from the air.
Maybe this has been taken into account in the design of these ASHPs, I do not know.
Anyway, I will watch what happens in the heating industry with interest.
Thanks for the information. Likewise, we are also a new build, from 2008, but with lots of insulation – 140 mm in walls, 150mm in floors and 200+ in ceilings. We have a lot of windows (D/G) so that is the main heat loss. We also have whole-house ventilation with heat recovery which as you say is excellent – never seen any condensation on windows in any room except bath/shower rooms and then for only a short time.
We have a 500L thermal store with wet solar panels and a wood burner with a back boiler feeding the store. Main heating is an LPG boiler through a coil in the T/S – this is the biggest restriction we have in using a heat pump, the contact surface in the coils is only 1.2m2 which limits the size of heat pump I can strap onto it – probably to about 5kW. Pipework to this coil is 22mm and is about 28m from the boiler (and proposed ASHP site). I do not really want to change the store at this stage.
Feeding new ASHP feed pipework to the store would be very difficult due to the UFH in all rooms and therefore lifting floors is not an option so I was looking to use the same pipework for the ASHP as the boiler uses. I would do this with interlocked motorised valves to isolate each system and use a control system to send appropriate signals to the LPG boiler, ASHP and valves.
Our house thermal loss is between 225 and 275 W/K so in theory, a 5kW pump should be adequate for all but the coldest of weather. I would like to keep the LPG boiler as it can be run in a combi mode for hot water if the store temperature is not high enough ( ie when using an ASHP). We like to run the wood burner in the evening when we are in the house so again this helps with heating the store.
Our annual gas heating bills on bottled LPG are less than £500/yr although that does not take into account the wood that we burn which is free (we have a lot of trees).
I am very interested in the fact that you still get a high efficiency from the ASHP when it turns into a block of ice – I was under the impression that ice acted as a good insulator to prevent heat transfer. It has been this one issue that has prevented me from experimenting with an ASHP.
Where in the country are you? We are in the South West.
Peter did you change your hot water tank when you installed the bigger ASHP?
Edited By Steve Skelton 1 on 24/10/2021 14:47:56
|Thread: 3D printers, health concerns and nasty niffs.|
Yes, you are right as a species humans have done all of those things, but in the scheme of things the fumes emitted by a 3D printer are completely insignificant.
Do you stop having a cup of tea on a dark windless day because the power station is going to have to produce the electricity to boil the water and all the environmental impacts that has? I will say no more.
Michael, are you really inferring that the fumes from a 3D printer are a real environmental problem?
|Thread: Saving the Planet … or is it ?|
Ground source heat pumps are much better than air-source but are so much more expensive to buy and install.
Air-source does work in dry climates but my research indicates that they do not perform very well in damp environments, like the majority of the UK, as their COP drops off due to ice build up and the need to constantly de-ice them by reversing the cycle.
I would like to do my bit and install one but I fear I would still end up using the same amount of energy to heat my house as I am doing now.
Roy, you can still get them but they are not really cost-effective.
We built our house in 2008 and I installed them when the roof was put on. Buying the panels at trade prices and installing them myself still cost around £1250. We probably get about £50 worth of free energy a year giving us a payback of 25 years. Paying to have them retrofitted to an existing house would cost a minimum today of £4000 - 80 years payback!!
Even so it is great to turn off the boiler in March/April and not put it on till October/November and still have a supply of hot water - it does get a bit lukewarm in prolonged periods of overcast weather though.
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