What did you do today (2015)

[John Stevenson 1Participant @johnstevenson1]

Posted by Muzzer on 24/03/2015 11:14:45:

JS – is this the stuff? Cementone brand.

Yes exact one, other places do it as well but some have greener in the title which means it doesn't work.

[James BParticipant @jamesb]

Hi John / Jon,

Brilliant – thanks. I have some gears from an old dividing head in a similar state, I will be trying this myself..!

I'm guessing having this inside the workshop could create rust problems on other components?

James

[James BParticipant @jamesb]

Posted by John Stevenson on 24/03/2015 12:37:10:

Posted by Muzzer on 24/03/2015 11:14:45:

JS – is this the stuff? Cementone brand.

Yes exact one, other places do it as well but some have greener in the title which means it doesn't work.

Ahh you mean like the new Nitromoors, specially formulated to protect paintwork…!

[Clive HartlandParticipant @clivehartland94829]

I mentioned a few days ago that I was going to make a sound suppressor for my PCP air gun, well, it was a waste of time and effort as it does not reduce the muzzle report one bit.

I now think I will have to add some sort of sound absorbing materiel, I have some Zorbzote which I can punch out plugs that will fill the 3 chambers I have designed into the suppressor. Its either that or the pellet is exceeding the speed of sound! It has not affected the MPI of the pellet.

Clive

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 24/03/2015 11:20:21:

… for those interested; the solution apears to be just dilute hydrochloric acid

Here is the MSDS

.

Just checked the bottle that my builders left for us …

Apparently a very similar product, branded Everbuild. … MSDS here.

MichaelG.

[MuzzerParticipant @muzzer]

Aha – weak HCl. At least the MSDS actually tells you what it is.

A lot of the Mercan MSDSs claim "trade secret" so you don't realise that the expensive product you are buying is a mundane commodity with a vast markup. Makes the MSDS rather unhelpful but allows them to pay top dollar for "special" products.

[IanTParticipant @iant]

Interested in the label on your Drummond lathe Michael (nice find by the way – even in it's 'rustic' finish) – as it gives the address as being "Rydes Hill, n. Guildford"

I mostly grew up in Guildford (latterly in Rydes Hill in fact) and I know where the old Drummond factory used to be. What has always puzzled me is that all the adverts I've ever seen for Drummonds (old pre-war MEs etc. ) always gave their address as being "Rise Hill, Guildford".

And yet on your lathe it's spelt the way I would expect…?

Anyway – I'm sure it will clean up very nicely with some elbow grease…

Regards,

IanT

[Neil WyattModerator @neilwyatt]

Took the dogs for a walk, and noticed it was bright and clear, and once out of the trees spotted venus clear in the blue sky. I've been trying to get a correct exposure of venus for ages. After some experimentation I finally got a reasonable shot set at ISO80, f8.3, 1/1000 sec – in other words it is VERY bright. Still just a blob with the faintest brown colour, but after some judicious resampling the 85% the phase shows quite well (see my new astronomy album).

Also got a nice shot of the moon in a sky which still had some colour in it. I'm most pleased with this one (unshopped, just cropped) of Jupiter with all four moons visible in a blue sky, the slight trails are because it was a 1/2 sec exposure.

Michael G. has treated me to what some other folks have achieved and believe me, these pale by comparison… so I'm costing up bigger scopes right now!

Neil

<edit> Thanks to the Sky and Telscope app, I can tell you its Callisto, Europa, Io, Jupiter, Ganymede from the bottom left up.

Edited By Neil Wyatt on 24/03/2015 19:36:13

[Michael GilliganParticipant @michaelgilligan61133]

Keep up the good work, Neil

As for the appropriate exposure for Venus; it's worth remembering that the planet is not radiant … it's just very reflective [Albedo about 0.65], so the brightness is only about a third of a stop down from the Sun.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by IanT on 24/03/2015 19:06:12:

… I mostly grew up in Guildford (latterly in Rydes Hill in fact) and I know where the old Drummond factory used to be. What has always puzzled me is that all the adverts I've ever seen for Drummonds (old pre-war MEs etc. ) always gave their address as being "Rise Hill, Guildford".

And yet on your lathe it's spelt the way I would expect…?

.

Very interesting, Ian … Maybe they didn't have sophisticated Voice Recognition Software in the advertising department

More seriously though; it reminds me of a local hamlet which was originally called Bugsworth, but was then 'gentrified' to Buxworth.

It would be worth investigating.

MichaelG.

[Oompa LumpaParticipant @oompalumpa34302]

Posted by Clive Hartland on 24/03/2015 17:09:08:

I mentioned a few days ago that I was going to make a sound suppressor for my PCP air gun, well, it was a waste of time and effort as it does not reduce the muzzle report one bit.

I now think I will have to add some sort of sound absorbing materiel, I have some Zorbzote which I can punch out plugs that will fill the 3 chambers I have designed into the suppressor. Its either that or the pellet is exceeding the speed of sound! It has not affected the MPI of the pellet.

Clive

I did say Clive

So everyone can see what you are talking about here is a selection of Moderators.

From left to right we have a cheap Chinese thingy, a Brocock moderator in Delrin, a Swift Stumpy, a Parker Hale, a Hogan Decimeter, a Weihrauch and two T8 Centrefire Moderators.

 

So what makes them work? Well actually, the one on the extreme left doesn't actually do anything. The next up, the Brocock in Delrin actually takes the report out of the shot but you can hear it clearly. Then one of my favourites – he Stumpy. Works brilliantly.
Next up, the venerable Parker Hale, these work really well on the .22 Riimfires and using subsonic ammunition you can't hear the shot ten yards away. Fifth along is the Hogan. I don't mind buying these as you actually get something for your money, fitted to a .22 cal Precharged Air Rifle putting out 30ft lbs all you can hear is the click of the trigger.

Now the Weihrauch – this design became the benchmark of quietness for quite a while. Someone copied the design and Weihrauch sued but unsuccessfully as the copier claimed they were using Blue 'J' cloths and not the white ones Weihrauch used…… or something like that anyway. Bet there are a few people quite ticked off when they took it apart and found a couple of hair curlers wrapped in J cloth – of all the small calibre gun suppressors this is the most expensive.

The two T8 cans are for centrefire rifles, the one on the left for up to .25 calibre and the one on the right for up to .30 calibre. But their capacity for suppressing the shot are very dependant on what, exactly it is trying to suppress. A .222 calibre round is easier to quieten than a .220 swift for instance.

Also, the issue is the actual velocity of the round. Once in a while I will fire a .177 air rifle in the garden and it doesn't matter – suppressed or not – if the pellet goes supersonic there is always an almighty "CRACK" as it breaks the sound barrier. I am working on a suppressing a shotgun right now and fortunately I am able to buy subsonic cartridges otherwise it would be a non-starter.

Sorry, the T8's are not for dismantling and the Carbon fibre moderator to the right is of my own design using K-Baffles as the suppressant (the one in the pic is not yet finished – it needs a couple of holes drilling in yet) and it is for a .17 HMR. Works well if I don't mind saying so myself.

graham.

Edit: forgot to mention K-baffles.

Edited By Oompa Lumpa on 24/03/2015 20:09:58

Edited By Oompa Lumpa on 24/03/2015 20:11:49

[Neil WyattModerator @neilwyatt]

My old 'Panther' air pistol didn't need a silencer. It went 'thwop' and you could see the pellet droop on its way in the vague direction of the target.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by IanT on 24/03/2015 19:06:12:

… all the adverts I've ever seen for Drummonds (old pre-war MEs etc. ) always gave their address as being "Rise Hill, Guildford".

.

Ian,

Confirming your recollection: I've just found this 1927 example on ebay.

MichaelG.

[roy entwistleParticipant @royentwistle24699]

My Drummond shaper has Rydes Hill on the name plate

Roy

[Neil WyattModerator @neilwyatt]

I can't stop this evening! This cold forecast means it's the clearest sky since Christmas.

I took 16 pictures of Jupiter at the same setting, using 2x digital zoom so ~2000mm equivalent.

Here's a typical one, not one of the best, cropped down:

I dumped two that showed no signs of banding, and put the remaining ones in Registax which chose the 11 best ones, stacked them, and then I tweaked the gamma up a bit:

Now I think that's getting as close to the limit of what I can achieve with a bridge camera.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 24/03/2015 21:32:45:

I can't stop this evening! …

Now I think that's getting as close to the limit of what I can achieve with a bridge camera.

Neil

.

Neil,

When you do get too cold to play outside … watch this, by Damian Peach.

I was there, and it was well worth the two hour wait.

You will see that your image compares very favourably with the early ones through the big telescopes … and you will see what can be done with small equipment these days … [mind-boggling progress]

MichaelG.

.

Edit: [Quote from the YouTube page] … "Damian Peach was running late so his lecture starts at 1:50:16 into this live feed."

Edited By Michael Gilligan on 24/03/2015 22:08:10

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 24/03/2015 21:00:12:

Posted by IanT on 24/03/2015 19:06:12:

… all the adverts I've ever seen for Drummonds (old pre-war MEs etc. ) always gave their address as being "Rise Hill, Guildford".

.

Ian,

Confirming your recollection: I've just found this 1927 example on ebay.

MichaelG.

.

And yet another variation, here

MichaelG.

[IanTParticipant @iant]

I've never seen it called "Rhide" before Michael – although this was back in 1909.

I was told where the factory used to be, although Drummonds were obviously long gone when I was a lad. The building itself was just past the Convent in Rydes Hill, where you'd branch off to Woodstreet Village from the Aldershot Road. The building was just down on the left and I think there may be some industrial units there now. The whole area has changed a lot since I used to bike down there with my mates – it's much more built up around the back.

Guildford was a fairly quiet market town back then, although (like a lot of places in the South at one time) there was "industry" about. Dennis fire engines used to get built where Surrey University stands now..

Anyway – enjoy your '£5 Investment' – Remember "The Price is Against it – until it is seen and examined!"

Regards,

IanT

[Nathan SharpeParticipant @nathansharpe19746]

Clive /oompa lumpa,

I,ll back up Grahams opinion of the Hogan, on my Webley Raider 10 (pre 2006) at 11.7ft/lbs all I can hear is the hammer spring! I doubt the rats hear anything before.

I'm also playing with K baffles just for fun and in the past have used the "hair curler" with scotchbrite type material to good effect.

Nathan.

[Clive HartlandParticipant @clivehartland94829]

Having now made to mountable outer case i can start playing with ideas about the noise suppression, Maybe a central tube with slots or holes and a sound deadening materiel to pack into the cavity of the body. Also more, thinner baffles but I want to keep the weight down as much as possible. I need more ideas .

Clive

[Ian S CParticipant @iansc]

I have a copy of ME for April 14 1910, and the add says Drummond Brothers, Ltd., Ryde's Hill, nr Guildford, Surrey.

Ian S C

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Clive Hartland on 25/03/2015 08:09:54:

Having now made to mountable outer case i can start playing with ideas about the noise suppression, …

I need more ideas .

.

Clive,

It may be worth looking to automotive silencer design for some inspiration.

… This is the classic work.

MichaelG.

[Oompa LumpaParticipant @oompalumpa34302]

Posted by Michael Gilligan on 25/03/2015 08:41:18:

Clive,

It may be worth looking to automotive silencer design for some inspiration.

… This is the classic work.

MichaelG.

Or you could just talk to the Formula 1 guys, they have managed to make a once roaring snorting spectacle sound like a lady's beauty parlour with the hairdryers on!

[jason udallParticipant @jasonudall57142]

Re suppressor/s

In holiwood a pillow seems to work.

[Harry WilkesParticipant @harrywilkes58467]

Some guy's have maybe already thought of this but it was only yesterday when the penny dropped for me ! Over the last few months I have been working on the crankshaft off my 3" Burrell and I'm one of these people who take photos as I disassemble thing and have been using my phone to do this so it's been getting a bit grubby at times it then accrued to me that I had an old Samsung mobile laying aroound so I cleared all the 'junk' off it loaded on the photos I have taken so now I have the visual references I like to hand and a clean mobile in my pocket

H

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