Member postings for Dave Martin

Sam,

It might be worth looking at the design of the hooks used on the falls for ship's lifeboats, as they are remotely-releasable whilst on-load.

Dave

Frances, agree re Manx folk being comfortable with Gill Gill !

Re your suggestions on the Killey surname:

For those not from or familiar with the Isle of Man, It is not pronounced “Kill ee” like Kelly. Killey is pronounced “Kill” followed by a short “y” as in yacht or you; some older Manx folk pronounced a longer “y” so it sounded like “Kill yer”.

In terms of its derivation, Killey, like most of the Manx surnames that start with C, K or Q, have their roots in the “son of” Mac prefix; in the case of Killey the root patronymic suggested (AW Moore and JJ Kneen) is Gale, Gell, Gill, Kill or Kelly.

Dave

Actually - that sounds you're drilling it perfectly and the dowels are fitting perfectly! Sounds to me like you're getting a vacuum lock. Solution: (i) if the workpiece will stand it, a tiny vent hole all the way through; (ii) a tiny hole through the dowel pin; or (iii) use a removable pin with either a vent flat or a spiral groove (have a look, for example, at the range of removable dowel pins in the MSC/J&L catalogue).

Dave

Cheers Bill,

Yes, geologically in the 'British Isles' archipelago, but not British. We are, give-or-take a little for scale, as much a part of Britain as Canada or Australia are. We have our own legislature; we have our own currency; we have a Manx passport and we're not entitled to a British one unless one parent/grandparent born in UK. Those from the IOM aren't even entitled to NHS assistance (other than A&E) if they fall ill in the UK.

Because of our situation as you say in the British Isles, we do have a number of convenience treaties with the adjacent islands such as what is now being described as a Customs Union in wider British context, so goods, services and people can pass without hindrance.

Dave, a proud Manxman! (not so much pedantry as pride in my homeland!)

Edited By Dave Martin on 06/08/2018 21:25:30

Bill - I'm delighted to see Roger Smith's team mentioned here, but his watches aren't make in Britain, or Great Britain, or in the UK - they are made here in the Isle of Man !

New Holland = yellow, but MF, Intl Harvester, Laverda = all red; Fiat = red or orange; Claas = green & white, some John Deere = green.

Known as Crocodile clips (not to be confused with the feeble things used to join electrickery circuits!)

Fastyr mie yessir!

Dave (Andreas)

Dave (SOD) - its the adjustment for 'Full Load Motor Amps"

Dave

and here are two RS data sheets that list the contact materials used for different types of thermocouple
**LINK**
**LINK**

from which:

[quote]

  All THERMOCOUPLE connectors use true thermocouple alloys for optimum accuracy, Except for Type R, S & B which use compensating alloys.

  Thermocouple Pins

  Type /  ‘+’ Positive Pin  /  ‘-‘ Negative Pin

  J  /  Iron  /  Copper Nickel

  K  /  Nickel Chromium  /  Nickel Alloy

  T  /  Copper /  Copper Nickel

  E  /  Nickel Chromium  /  Copper Nickel

  N  /  Nickel - Chromium - Silicon  /  Nickel Silicon

  R  /  Copper  /  Copper Alloy

  S  /  Copper  /  Copper Alloy

[/quote]
(Edit: - table format disappeared so separate columns with /  - crossposted with MichaelG at the same time!)

Edited By Dave Martin on 16/06/2018 18:42:37

Sorry Muzzer, but not so. That's why, even in the same form factor, you have a range of connectors which are appropriate for E, J. K etc. - they use appropriate connection pins or plating. e.g.: http://www.precision-measurements.com/pdf/connector-systems-for-thermocouples.pdf

Dave
(Edit: corrected link)

Edited By Dave Martin on 16/06/2018 18:27:19

You're right Nige, it will work, but not as well. The thermocouple effect - in which the genuine signal is very small - arises from dis-similar metals at a different temperature to the 'reference junction'. Every change of material, such as using the wrong wire, introduces at least one extra thermocouple which will bring an error. Using connectors, there will be several changes of material, and with plated pins, there may be a number of transitions. Wrong wire and wrong connector errors can introduce errors of maybe up to 10 degrees or more; and they won't be just fixed errors - each transition is a separate thermocouple, so depending on ambient and temperature inside the enclosure, the errors won't even be fixed.

Sorry Neil, but I think it does matter, I haven't time to dig out my Physics/ElecEng degree text books to calculate it though.

The article talks about "affordable precision" and "with great accuracy" - but then spoils it.

Proper thermocouple connectors are probably no more expensive than the XLR connector used. No excuse not to use them.

Also, re-reading the article, it describes using "thin gauge stranded wire for the thermocouple connections" - it should be the appropriate thermocouple material wires that are used to extend the thermocouple appropriately, not generic copper wire for both cores.

An interesting article, but anyone considering building something similar should note that the author has used an XLR connector for the thermocouple instead of a proper thermocouple connector that should have been used.

Golly, that takes me back to my student days. End of Autumn term, a house/course-mate and I had a lab report to submit before going home for Christmas, so we finished it late at night. There was a just-opened bottle of Baileys, which we decided would have gone off by the time we got back in January; after we disposed of that bottle, for some reason we decided the other bottle - even though un-opened - might suffer (loneliness?) - so that was seen off as well. When our lab reports were returned, they were marked "marvellous prose style but light on factual content".

Just to make it easier to find if you're searching on-line, I've no connection but their name is Walker Midgley

Daniel, although the underlying material and dimensions are the same, there is a subtle distinction in the description in the advertisement. They describe the yellow ones as "Impregnated and especially stiff. For preliminary...." and the white ones as " soft ....For high shine polishing ....Adapts to the workpiece contour. "

Re Michael's comment about using colour-coding to distinguish between grades of polishing compound, you would almost certainly use different grades with the these two wheels. I actually use more grades, and more wheel types including sisal to start sometimes, so I use a 'sharpie' to mark each wheel as to what compound I use it with.

I have no connection with any vendor, I personally buy mine from the range sold by Caswell UK, they also have a useful guide to buffing and polishing, including wheels and compounds.

Edited By Dave Martin on 28/04/2018 09:28:06

What happens when a capacitor vents and then ....

Admittedly a somewhat larger capacitor than any likely to be used in a home-workshop VFD – have a look at the debris spread Fig. 3 on page 13 of the report.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/691440/R052018_180320_Guildford.pdf

Edited By Dave Martin on 22/03/2018 22:25:38

Andrew - just out of interest, when you come to use these, how will the bolt be held whilst you tighten the nut?

Brian,

Depending on how many you need, and the finish required, it might be worth considering using standard rectangular material and then machining the bevel, much as you might on wood using a spindle molder. There are off-the-shelf metal bevelling machines – the one in this link only goes to 14 degrees but I’m sure something similar could be found to do a shallower bevel.

https://www.baileighindustrial.co.uk/beveling-machine-cm-6-1