What Did You Do Today 2019

[Joseph Noci 1Participant @josephnoci1]

Posted by Cornish Jack on 21/05/2019 11:29:17:

Joe –

.-. — -… . .-. – –.—.. .-. .–. ..

rgds

Bill

Bill, you are too literal. Yes, – .-. — -… . .-. – –.—.. .-. .–. .. means 'Robert G8RPI.' , but how do you send the picigram in morse…

Joe

[Cornish JackParticipant @cornishjack]

Thanks, Joe

Ask me another on sport … equally rubbish at that!!

rgds

Bill

[HacksawParticipant @hacksaw]

Hardly engineering or model engineering .Made a stainless steel horse shoe for a friends daughters wedding posy..

That's knackered my tools a bit . Hard to forge, is stainless steel… I did sweat a little! Cripes, digital picks up every blemish and micro scratches .

[IanHParticipant @ianh]

Set about modifying a Jag rev counter for the Morgan. I removed the defunct clock from the bottom of the old instrument and made a “medallion” with the JAP logo on the CNC machine to go in its place.

Ian

[HacksawParticipant @hacksaw]

That's nice. When i was a lot , lot younger , and had hair , and a mum , i built a kit car…a Burlington SS , that looked a bit like a Morgan ..and Morgan drivers used to wave at me ,and i didn't ever wave back, as mine was a fake!! Me mum loved going in it , me wife hated it ..I put a 2.5 Triumph engine in it and drove it like an idiot and frightened her …I gave it away to a school mate .. I'll find a picture…

 

 

Edited By Hacksaw on 21/05/2019 18:08:08

[Mark RandParticipant @markrand96270]

It wasn't what I actually went out to the shed to do today, but I fixed a little niggle on the milling machine. The table feed trip lever is very unbalanced by design and has a tendency to cause the feed to cut out when going from right to left. I finally found a use for a bit of the lump of copper-tungsten alloy that I got off ebay 15 years back:-

[Ex contributorParticipant @mgnbuk]

The lead pellet weighs about 1.2 grams and would have been travelling at about 220mph on impact, about 8J of energy.

I don't think that your energy calculation is right, Dave.

Working in the more conventional units for airguns in the UK, 1.2 grammes pellet weight equates to 18.52 grains. This seems high for a .22 wadcutter. The pellet you show looks like a H & N Excite (12.82 grains) or RWS Hobby (11.9 grains) ? 220mph equates to 323 feet per second, which is round about what my recently departed Webley Tempest put .22 Hobbies over the chrono at, so seems about right..

However, 11.9 grains at 323fps works out at 2.76 ft pounds energy (3.74 Joules) – quite a bit short of 8 Joules. Even if your pellets are 18.52 grains, that is still only 4.29 ft pounds (5.82 Joules) – closer, but still no cigar. Still, you do seem to be comfortably on the right side of the law for the UK air pistol power limit of 6 ft pounds (approx. 8.13 Joules).

I don't think you should be too suprised that 3.5mm of polycarbonate stopped a pellet – I seem to recall seeing a demonstration on TV some years ago of a 1.5mm polycarbonate visor designed to clip on to a standard UK policemans helmet stopping a full power air pistol pellet at point blank range.

Nigel B (now enjoying a Weihrauch HW40 in .177)

[SillyOldDufferModerator @sillyoldduffer]

Posted by mgnbuk on 21/05/2019 20:35:24:

The lead pellet weighs about 1.2 grams and would have been travelling at about 220mph on impact, about 8J of energy.

I don't think that your energy calculation is right, Dave.

Working in the more conventional units for airguns in the UK, 1.2 grammes pellet weight equates to 18.52 grains. This seems high for a .22 wadcutter. The pellet you show looks like a H & N Excite (12.82 grains) or RWS Hobby (11.9 grains) ? 220mph equates to 323 feet per second, which is round about what my recently departed Webley Tempest put .22 Hobbies over the chrono at, so seems about right..

However, 11.9 grains at 323fps works out at 2.76 ft pounds energy (3.74 Joules) – quite a bit short of 8 Joules. Even if your pellets are 18.52 grains, that is still only 4.29 ft pounds (5.82 Joules) – closer, but still no cigar. Still, you do seem to be comfortably on the right side of the law for the UK air pistol power limit of 6 ft pounds (approx. 8.13 Joules).

I don't think you should be too suprised that 3.5mm of polycarbonate stopped a pellet – I seem to recall seeing a demonstration on TV some years ago of a 1.5mm polycarbonate visor designed to clip on to a standard UK policemans helmet stopping a full power air pistol pellet at point blank range.

Nigel B (now enjoying a Weihrauch HW40 in .177)

Oh no Nigel, looks like I messed up again! I admit to not weighing the pellet, I quoted a scribble in my notebook. (From an experiment where I used an Arduino and tin foil to measure muzzle velocity.) And I have a poor record doing sums.

The pellet might be a valuable antique. It's a Milbro Caledonian, possibly bought with the pistol about 50 years ago. Seems like yesterday – how the years fly, scary.

I was pleased with the test. An obvious cost saving on a cheap lathe might be to use ordinary plastic shields, but they fitted the real thing.

Another airgun test I've not seen any figures quoted for is the real-world maximum range a pellet travels. (Not that I've done any research!) Had a notion it could be done by firing pellets at various elevations along a canal and watching for the splash. Quite hard to spot a small pellet landing when it's nearly out of energy I expect. And there's a risk the public won't appreciate my interest is science!

Dave

[Martin Rock-EvansParticipant @martinrock-evans77799]

Today I cut the final tooth on the final drive gear of my 3" Burrell.

I was really chuffed when it fitted with the drive pinion, right up until when I tried to turn it all the way around and found one tooth that didn't fit! Turns out I missed one on the final pass.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, yesterday afternoon I made up a cross brace and welded it on the back end of my stand.

Just need to drill a few holes in the top paint it and fit a draw unit.

Regards Nick.

[Mark RandParticipant @markrand96270]

Posted by Martin Rock-Evans on 21/05/2019 22:04:05:

Today I cut the final tooth on the final drive gear of my 3" Burrell.

I was really chuffed when it fitted with the drive pinion, right up until when I tried to turn it all the way around and found one tooth that didn't fit! Turns out I missed one on the final pass.

Good catch!

[Neil WyattModerator @neilwyatt]

The curious thing is that perspex (acrylic) doesn't scratch as easily as polycarbonate.

This makes acrylic a good choice if you just want to stop swarf getting out and hands getting in as its working life is longer.

Polycarbonate is best if flying chuck keys are a risk in your workshop.

[brickyParticipant @bricky]

Set the dividing head on packings to allow a 9" disc, mounted on a face plate to be gear cut .Only a segment of the disc was required as I need a curved rack,a result.Now for the pinion.

Frank

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, yesterday with the absent of a Mag-drill, I resorted to an old tech solution. Bit more fiddly to get lined up on the centre pop, but it worked very well.

Regards Nick.

[paul raynerParticipant @paulrayner36054]

went to castle Howard today and saw this unusual steam waggon. i've never seen one before seemingly the owner says theres only about a dozen left.

[Rik ShawParticipant @rikshaw]

Repaired the cast iron axle on the village white lining machine. Together with new plastic goal posts the chillun will now be able to play footy with white lines on their pitch instead of having to use bollards and jumpers for goal posts.

Rik

[Neil WyattModerator @neilwyatt]

Yesterday I picked up a 'new' combo amplifier, a bit of a classic

Today I added the external speaker sockets missing from the combo version so I could use it with an extra cab and tweeters.

I don't think it can stay in my workshop though…

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Neil, nice piece of kit. What size are the units in the combo and power rating?

Regards Nick.

[Danny M2ZParticipant @dannym2z]

Today I heard that (in the U.K.) the end of May is going to be a week later than it's usual date

(I was born in Mile End Hospital so qualified to comment)

* Danny M *

[V8EngParticipant @v8eng]

Posted by Danny M2Z on 26/05/2019 10:25:55:

Today I heard that (in the U.K.) the end of May is going to be a week later than it's usual date

(I was born in Mile End Hospital so qualified to comment)

* Danny M *

😀😃 Yes from all the headlines I gather it will finish on 7th June this year.

Edited By V8Eng on 26/05/2019 10:54:31

[KWILParticipant @kwil]

Trouble is May never really started at all. A lost month or is it years?

[Anonymous]

Sadly May is going to run until the end of July, when the fisticuffs are over and a new incumbent emerges.

Andrew

[Neil WyattModerator @neilwyatt]

Posted by Nicholas Farr on 26/05/2019 08:34:46:

Hi Neil, nice piece of kit. What size are the units in the combo and power rating?

Regards Nick.

Combo is the classic 4×10" but the original celestions have been replaced with Eminence Alpha 10As rated 100W each. The cab on top is 2×12" Mackenzies (not sure but probably 100W each).

That's the original Trace Elliot GP11 Mk V combo so it's an apparently feeble 150 watts, but they have a reputation for being very loud and I am sure it's as loud or louder than an 500W ashdown amp and head I played with recently.

Trace gave very conservative ratings and headroom is more important than RMS for bass. The power supply is easily sufficient to put around 400 watts into 4 ohms. Today that would probably mean an amp with a sticker saying "1000 watts"…

Neil

Edited By Neil Wyatt on 26/05/2019 12:30:30

[Neil WyattModerator @neilwyatt]

Let's steer clear of getting political…

Neil

[SillyOldDufferModerator @sillyoldduffer]

Posted by Neil Wyatt on 26/05/2019 12:27:16:

Posted by Nicholas Farr on 26/05/2019 08:34:46:

Hi Neil, nice piece of kit. What size are the units in the combo and power rating?

Regards Nick.

Combo is the classic 4×10" but the original celestions have been replaced with Eminence Alpha 10As rated 100W each. The cab on top is 2×12" Mackenzies (not sure but probably 100W each).

That's the original Trace Elliot GP11 Mk V combo so it's an apparently feeble 150 watts, but they have a reputation for being very loud and I am sure it's as loud or louder than an 500W ashdown amp and head I played with recently.

Trace gave very conservative ratings and headroom is more important than RMS for bass. The power supply is easily sufficient to put around 400 watts into 4 ohms. Today that would probably mean an amp with a sticker saying "1000 watts"…

Neil

Edited By Neil Wyatt on 26/05/2019 12:30:30

This table from Hyperphysics lists the power outputs of various instruments and rates a large orchestra at under 70W. I'm always a bit surprised how weedy musical instruments are. Are big amplifiers only needed because loudspeaker efficiencies are so low, or is it because rock and roll sounds best with the Volume at 11?

Source	Power Output (watts)
Large orchestra	67
Bass drum	25
Snare drum	12
Cymbals	9.5
Trombone	6.4
Piano	0.44
Trumpet	0.31
Tuba	0.20
Double bass	0.16
Flute	0.055
French horn	0.053
Clarinet	0.050

As all true music fans know even the best amps and speakers are garbage unless connected with Industrial Gauge Oxygen Free Gold Plated Silver Litz Wire Tri-filar wound on a helical PTFE core, and then fitted with bespoke insulating jackets hand-knitted in special-mix Kevlar, Carbon Fibre, and Vucana by nubile maidens. Nothing is too much trouble for proper audio pleasure…

Dave

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