Member postings for Sam B 1

i'm quite new to the hobby and so far i've only used Macc Models to purchase stock, but of my 3 orders so far none have been without problems; the first order let me buy things that ended up being out of stock, in the second order some of the stock came in multiple smaller lengths instead of the length that was advertised, and in the third time there were items left out of the order that, as of this post, still haven't appeared after nearly 3 weeks

not an impressive track record to say the least, but at least their prices are good and they've eventually rectified all but the latest problem (fingers crossed)

with current gas and electricity prices heat pumps generally work out to be about the same to run as gas boilers and can even be cheaper if you make use of off-peak hours

(**LINK**)

the COP drops as the difference between the input and the output gets larger. if we go by the coldest recorded temperature in the UK of about -27c in 1995 this COP graph suggests that if we wanted to heat a home to 15c (42c difference) it would still be close to that 3.5 COP, so should still economica

(**LINK**)

Edited By Sam B 1 on 19/11/2021 15:17:37

hi paul, i'll give it a go!

the efficiency of heat pumps comes mostly from them providing more useful heating output for the energy put in since they're moving heat that already exists instead of directly creating more of it. they're typically around 2.5 - 3.5 "coefficiency of performance" for air-source heat pumps (ground-source are higher but they're more complicated to install), so 1kw electricity in would provide 2.5 - 3.5kw of useful heat out

losses on the grid seem to be at most 10% from this national grid eso document https://www.nationalgrideso.com/document/144711/download

the EEA lists efficiency of thermal electricity generation hair under 50% https://www.eea.europa.eu/data-and-maps/indicators/efficiency-of-conventional-thermal-electricity-generation-4/assessment-2

with these numbers if we put 1kw of gas into a power plant we'd generate 500w of electricity, there'd be 450w at the home after transmission losses, then the heat pump would be able to provide 1.125 - 1.575 kw of useful heating

i'm not sure about the losses on the gas network because i can't seem to find anything about it online for the UK (for reference it's about 9% in the US), but even assuming zero distribution losses the gas heater would only provide 940w of heating from 1kw of gas (modern condensing boilers seem to top out at 94% efficiency)

as an aside, a COP of 3 would mean that even if your electricity costs 3x more per kw/h than your gas it would still cost about the same to heat your home

one of the youtube people i'm subscribed to has a fairly lengthy video talking about heat pumps and they're really quite interesting things https://youtu.be/7J52mDjZzto

edit: fixed the links!

Edited By Sam B 1 on 19/11/2021 02:48:42

burning gas to make electricity and then using that electricity to run heat pumps is a far more efficient way to heat homes than burning gas directly; switching over to heat pumps allows our limited resources go much further

i managed to find and grind a bit of metal tubing of the right sort of diameter to make a wrench and on a completely 100% unrelated note it seems the metal part of my hoover's pipe has gotten a few cm shorter

the donor piece of tube had some cutouts in it already so no need to find the hand drill to make holes for leverage!

great success!

Edited By Sam B 1 on 15/04/2021 17:03:42

I couldn't find any screws of the right size nor any bar or tube big enough to make one from (calling my available tools and materials sparse would be an understatement), but luckily tapping it with the drift like Jason suggested was enough to get it loose. I'll definitely have to get around one before it comes time to reassemble it of course, but for now everything is golden so thank you all for the help! :D

Sam.

I'm trying to do some work on my pillar drill and I've come across a retainer that has stopped me in my tracks.

https://i.imgur.com/r7jMsRA.png

I've tried the spanner that came with my angle grinder but the pins are too short (about 10mm) and don't go deep enough into the pulley to properly engage the slots so clearly I need one with bigger pins, but I'm not entirely sure what it is I should be searching for online ("pin spanner" just seems to result in similarly short-pinned angle grinder tools). Can anyone tell me the name of the tool I'm looking for?

Thanks :D

Edited By JasonB on 09/04/2021 14:13:06

Thank you both! I didn't even know Facebook marketplace was a thing before now and having looked on there briefly I've found what looks like a decent machine which is also fairly local :D

Hi Matt, can I ask how did you find it? I'm also looking for a first lathe and I'm not sure where to look aside from eBay.

EKP Supplies have some M2 x 3mm ones one their eBay store (oddly they're not listed on their website) if 3mm isn't too long for what you want them for **LINK**