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Member postings for not done it yet

Here is a list of all the postings not done it yet has made in our forums. Click on a thread name to jump to the thread.

Thread: Warco WM18 lead screws upgrade
12/01/2020 18:20:26

90 degrees now, so question might be how much when you got it? (and was it new?). 360 degrees will be point of failure. smiley

Thread: Clarke CL500M Mill Head
12/01/2020 13:55:35

Are the belts fitted?

Thread: magic 127 TOOTH ?
11/01/2020 19:17:52

As you have noted 127 is half of 254. 245 teeth would convert 25.4mm to inches for a metric lathe or vice versa for an imperial item, but 254 teeth would be a bit crowded! So half that number will work just as well - as Dave SOD says - with other gears.

Thread: Electric motor ratings
10/01/2020 22:22:48

know he's right, though I (obstinately) disagree with him and quite possibly the rest of the scientific world. I'm old enough to remember the debate over whether kilo should be an upper case character because all the other multipliers are upper case - e.g. Mega, Giga etc. And the lower case qualifiers are all divisors - milli, micro etc. In my opinion the small k for kilo is an anomaly better resolved by accepting the coincidence with an upper case K for Kelvin and allowing the context to resolve the conflict.

One must remember that kg is not a multiple - it is the basic unit of mass - so that is the reason for the lower case ‘k’. A carry-over from the previous systems perhaps? But I expect there was a quandary of adopting the gram as the basic unit of weight (there is a problem with mass and weight if both do not have have the same equivalent base unit). There was always (well, for a long time) a standard metre and kilogram in existence, as well as a lot of standards copied from those standards.

I remember several measurement systems over my time, one being the cgs system (centimetre gram second). They all had to make some compromise or have some idiosyncrasies within those systems.

Hence it is kg, not KG. Everything else falls into place quite well using upper and lower case multipliers. But I don’t think they will ever decimalise our normal time units.🙂

 

Edited By not done it yet on 10/01/2020 22:41:24

Thread: Co2 emissions.. Steam or diesel best?
10/01/2020 21:04:00
Posted by Robert Atkinson 2 on 10/01/2020 20:37:11:
Posted by not done it yet on 10/01/2020 19:03:50:

There is not really any advantage of coal in comparison with electric.

Near 50% of electricity is currently (on average) generated by low carbon technology (nuclear, wind, solar, biomas, hydro, imports)

Most of the fossil fuel generation is with closed circuit gas turbines and these are greater in efficiency (over coal burning) by something close to 50%. It also produces only about half the carbon dioxide emissions, compared to coal generation (per unit produced).

Perhaps you should study the likes of:

**LINK**

or others of similar ilk. Plenty of information to be gleaned (if one is understanding the different statistics of electricity generation).

Biomass is NOT low carbon, The reports say the Drax power station is now carbon neutral because it runs on biomass. Unfortunatly the biomass is wood pellets at least some of which is produced in america. The CO2 emitted in harvesting the wood, drying it or transporting it (ships burnig dirty bunker oil) is not counted. And biomass produces more CO2 per Watt than gas.

Robert G8RPI.

Perhaps you should have a look at the link. Not particularly low, but 87kg/s for 2 1/2 GW equates to 360kg/s of emissions (according to the link) for10GW, which is what CCGTis currently running - producing 1100kg/s of CO2.

I’m not a fan of even cutting down trees for this ‘phoney’ biomass generation (for subsidies) but it is NOT classed as high CO2 by those that should know.

I also do not count pumped hydro as zero carbon emissions, as they do. I consider it as derived from the highest carbon generation at the time of pumping. Clearly gas or coal generation in my book!

10/01/2020 19:03:50

There is not really any advantage of coal in comparison with electric.

Near 50% of electricity is currently (on average) generated by low carbon technology (nuclear, wind, solar, biomas, hydro, imports)

Most of the fossil fuel generation is with closed circuit gas turbines and these are greater in efficiency (over coal burning) by something close to 50%. It also produces only about half the carbon dioxide emissions, compared to coal generation (per unit produced).

Perhaps you should study the likes of:

**LINK**

or others of similar ilk. Plenty of information to be gleaned (if one is understanding the different statistics of electricity generation).

Thread: VFD Question
10/01/2020 09:27:05

a motor driven by a 240v inverter would have to be connected in Delta as you already know. (my underlining)

Tell us again, ‘cos I’m not hearing you!🙂. Fact - My mill is currently running a 240 volt output VFD into a star connected motor. If there is something wrong with it, I’ve not noticed it yet. Works far better than the one horse single phase motor I replaced (that motor would not start the machine in top gear from cold).

I believe another motor on the mill is also connected star and is supplied from another 240V VFD. Not checked that one, but it, too, works fine for the variable speed duty required.

10/01/2020 00:01:00

2 pole induction motors gleefully turn at 2800rpm with a clear safety margin on the mechanical side, so I would expect a 4 pole motor to likely emulate the higher speed motor on the mechanical side, if of similar construction. Most 4 pole motors have the same form for 50 or 60Hz operation, so I would consider 80Hz as only a 25% increase.

As I’ve said before (somewhere), motors with plain bearings may well be over-speeded but those with rolling bearings would likely cope. I don’t exceed 80Hz - as long as the rest of the machine is still within maximum design spec.

That could up my lathe spindle to 2800rpm. The lathe was made with a 2500rpm design spindle speed for some versions, but did not run gears for screw cutting, so I don’t go there! Those who over-speed their motors need to consider the machine; those who run more slowly need to consider the motor

Thread: The blind leading the blind
09/01/2020 18:39:08

At least the first lady was almost dressed suitably, even if not in ‘working togs’. The one in the second pic is asking for trouble. If one needs to protect ones eyes, lower body parts might also be in the firing line! Perhaps not so potentially ‘life changing’ but not comfortable...

Thread: Electric motor ratings
09/01/2020 16:11:23
Posted by Steviegtr on 09/01/2020 15:53:00:

It may be that the motor as in this picture. Is power rated at 550w = 0.75hp. But takes 5.1A of power because of the losses discussed by some above.

myford motor

About right at cos theta of 0.8 and motor efficiency of 60%

I take it the CR denotes ‘continuous rating’?

A very good reason for not being tight on the sizing for VFDs. A cheap 750W inverter might not manage to supply enough power for that motor (had it been a three phase example).

Thread: Great experience buying a dehumidifier
09/01/2020 15:20:31

I have bought four(?) second hand Meaco desiccant dehumidifiers over a period of time - all were ‘dead’ as purchased. Total cost was less than a hundred (plus delivery/collection).

First runs quite well on low speed setting as the fault was within the heater element (I removed the offending resistance wire). Everything needed new lubrication as the chinese ‘stuff’ was not grease as we should understand the term!

Second also finished up with a similar heater element (I bought it just thinking I would have a spare heater for the first, should it be necessary).

As I expected to enlarge my workshop, I bought two more scrap machines, but one water tank and filter was missing, so have only finished with three working machines (two in operation and a working spare).

They work brilliantly but clearly they were not one of the most reliable items around. But easy to fix.

I have only needed to run one at a time this winter, although I left both running (at different times on E7) while we were away over Christmas - just so one did not fill the two litre tank and turn off.

If there is any air exchange, damp air from outside will percolate in, there will be moisture from below (unless a damp-proof sheet was laid under the floor) and we breathe out water vapour, so there will always be some water to collect (I leave mine on the ’laundry’ humidity setting and just run for two or three hours at night).

I’m currently collecting about half a litre per night. Not sure if it is running two or three hours. Running costs are either less than 6p or less than 9p per night, I think the former. The heat is likely as important as the humidity reduction.

I expect the innards of the ecoair are much the same as the meaco - possibly built to be more reliable than the early meaco machines, but same principle of a rotating desiccant wheel with desiccant recharging, by blowing hot air through the drying medium in part of the revolution.

I had one good experience with appliances direct - I collected a chest freezer. But since then, they have not quite cut the mustard. I got a better deals for each of the dishwasher, tumble dryer and washing machine from more-local suppliers. One often finds their model numbers are slightly different to the usual brand code for that item - and nobody wants to explain any differences.

Thread: The blind leading the blind
09/01/2020 11:48:15

Video or pic? Could be a difference between ‘looking at’ and ‘using’. However, eye protection should be the order of the day whenever in that working area - there may be others making flying chips! Most certainly not a good advert.

Thread: Case Hardening
09/01/2020 11:43:23

BMS should mean Bright Mild Steel, not a carbon steel.

Thread: soldering stainless steel
09/01/2020 11:38:28

I think I might use ‘alumite’ rods or perhaps mig/tig the parts.

Thread: Have a look at this, view from the chuck
09/01/2020 11:30:59

The shaper vids might depend on how fast the auto focus might work, if in use and able to work?🙂

Thread: Identifying Light Alloy
09/01/2020 11:25:00

Not too difficult in calculating the volume if the sheets are square and of uniform thickness?

Thread: VFD Question
09/01/2020 11:19:37

The repair crews just dug up the road - well, both pavements - down from us (generator running 24h for several days over the Christmas/new year period🙂.

Apparently each pair of semis are wired on the same phase. Don’t know how they wired the detached dwellings. Bungalows at one end and larger detached houses at the other...

Thread: Have a look at this, view from the chuck
08/01/2020 22:40:06

Could’ve done it all in one go with a variable speed lathe. I’m in the Baz camp.

Thread: Electric motor ratings
08/01/2020 19:10:04

No idea, but might it be its continuous rating? Some motors are particularly inefficient and sellers quote input rather than output power. But 50% would be poor for an electric motor - but could be, if the duty cycle is low.

I see things like band saws, of similar capacity, having widely differing power ratings.

Same with compressor ratings. Good kit quotes free air delivered, cheap ones quote pump displacement. Not the same thing. You can guess which appears as the higher figure, numerically!

Buyer beware these days!

Thread: Identifying Light Alloy
08/01/2020 15:42:03

An indication of location might help. Metric thickness and imperial dimensions could put you anywhere on the globe?

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