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Member postings for Howard Jones

Here is a list of all the postings Howard Jones has made in our forums. Click on a thread name to jump to the thread.

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Thread: Technical and engineering drawing.
18/04/2011 15:06:41
sorry terry but I think an article on how to read a technical drawing would be as dull and boring as you could possibly imagine.
I dont buy all the model engineers or workshops and articles such as you suggest are issues I put back on the news stand.
 
I want to be inspired not bored to death by what I read.
 
Mogens Kilde is solving your problem by leading from the front I would suggest. the 3 view cad pictures and solidworks images he creates for his articles have actually inspired me to buy issues because I thought what he was presenting was interesting.
 
so if you want to navel gaze, or reminisce about "how I usta do it when I was great" for gods sake stop yourself from going any more senile and get a life, as the saying goes.
 
if you want to produce an inspirational article on a new project then submit away!
 
I think David was entirely correct in the original rejection of the concept.
Thread: Making wheels by casting in the spokes
12/04/2011 12:57:10
keith
the method I'm aware of involves frenetic activity just toward the end of the first ladle.
the second ladle commences to pour while the first ladle is still going. then takes over the pour.
the second bit of frenetic activity is involved bringing the third ladle to pour just before the second ladle completes and so on.
 
nevertheless the foundry work involved in making the hub casting in situ was quite impressive. it looked to me to be a seamless combining of greensand technique with resin bonded sand for some tiers of the mould.
howard
11/04/2011 14:18:49
the videos are excellent. however one thing has me quite puzzled. the video shows two separate pours, I thought, into the one mould.
was there an obscured detail there or something I missed because a successful casting only occurs when the pour is uninterrupted. two pours, or an interruption to the pours means a ruined casting because of a cold shot?
Thread: Miniature welding
08/01/2011 11:03:47
the results are quite variable, quite problematic, but you can arc weld these sizes.
2 mm welding rod, around 60 amps or less on the electrode and an angled rod
if the metals are perfectly clean. you'd need a fairly practised hand.
 
however a damp rod, slightest hint of oil on the surfaces and you will go insane.
 
as the guys suggest Tig is a gentler weld. ask whaterver the PFA have become for the name of a nearby aircraft welder if you or a friend cant do it.
Thread: DIY Vacuum heat treatment oven
31/12/2010 14:17:02
  can I pass on a piece of experience from another model engineer.
he found that when the wire element was heated it expanded.
suggestion was then made that coiling it would keep the wire respectable when hot, but it didnt.
what was needed was to coil the wire into a long tight coil then coil this into a bigger coil,
the compination of the coiled coiled wire allowed it to go somewhere without sproinging out of the holder and making a nuisance of itself. this nuisance usually involved shorting on the job being heated.
 
if the heating in a vacuum idea is to get rid of surface scale can I relate that a very good heat treaters in melbourne (which I suspect was the ansett setup) actually does its work in an argon environment.
Thread: Lament for a lost grease.
25/12/2010 05:33:00
grease is typically an oil in a mineral soap to make it stay in position.
lime, bentonite and a few other minerals probably work equally as well.
 
if you want a lovely honey coloured grease try Shell aviation wheel bearing grease, it is lovely squishy stuff in the fingers and lubes taper rollers really well. it is great!
 
I used to use BP water resistant boat bearing grease, lovely honey stuff as well but it is no longer made.
but it is not a problem Castrol make a beautiful water resistant boat bearing grease, lovely squishy stuff and to prove we arent curmudgeons is bright blue.
 
of course the real test of a good grease is whether it ever freezes solid. good ones dont.
 
water resistant boat bearing grease is a good all rounder if you need one.
Thread: Aircraft General Discussion
25/12/2010 05:11:28
aerolite 306 (in australia the equivalent is selleys 308) is no longer seen as suitable for aircraft. if you apply to much formic acid there is some remaining after the joint is put together and over time this eats the wood just beside the joint leading to it failing.
 
resorcinol formaldehyde glue has something like 70 years in existence and still going strong.
 
believe it or not casein is still ok for use in hot dry environments.
 
me? I use epoxy.
Thread: Humidistat? for Andrews De-humidifier
24/12/2010 06:20:12
does  just sitting the wet bulb there actually work?
 
when we were doing survey barometery (using paired sets of Mechanisms Ltd Baromech instruments )we needed this info to correct for air density, the instrument we used was a psychrometer. this blew air over the wet bulb at either 2 or 5 meters per second. only after the wet bulb had stabilised in the air flow could we make valid humidity determinations. the wet bulb sitting there before the fan was turned on never gave valid values.
Thread: Aircraft General Discussion
23/12/2010 05:01:26
john you echo a very common fear but it is a misplaced fear.
the -4.79g you mention is not the failure limit it is the normal operational limit to prevent damage. if the aircraft you mention has a margin of safety of 150% then the structure could be expected to break around -7.2g not -4.79g.
dont be perturbed though. aviation is a specialist engineering environment and many of the fundamental concepts are incorrectly understood by the man in the street.
dont be ofended either. the disciplines of aeronautical engineering are a fascinating study that not many venture into.
Thread: Which slideway oil is best?
23/12/2010 02:35:48
typical automotive oils will leach the zinc out of the brass oilers turning them a coppery red colour.(castrol gtx certainly does).
 
I have followed charlie's recommendation for a decade now and used Shell Tellus 46 on my machine tools without detriment. Tellus 46 leaches silver and since mine is a cast iron lathe with brass bits  it hasnt had a problem.
 
that is in a workshop that hits 46 degrees celcius on many days of summer so I have different problems from you in england.
Thread: True Diesel Models
20/12/2010 11:02:16
by the way if you want absolutely consistent diesel fuel use avtur.
aviation turbine fuel.
20/12/2010 11:00:39
I've never seen a true diesel model engine but something that piqued my interest last week was a farm type water pump that was powered by a diesel engine not much larger than the typical villiers 5hp engine. this was a commercially built portable pump.
 
I dont know how they did it but it seems that we need to try harder.
Thread: Artillery
09/12/2010 10:19:59
back to my suggestion re a legal form of gun that could be made by a model engineer so disposed.
if you look on the internet for 'very pistol' you'll find very few entries. however the world opens up with information if you do a google search for 'flare pistol'.
 
in my country flare pistols dont need to be licenced so they may be a valid topic for a model engineer to take on as a machining exercise.  especially one in stainless steel.
Thread: Brake Discs
04/12/2010 02:04:21
Mr Pudney I have to disagree with you there.
Stainless brake disks were introduced on japanese motorcycles to remove the ugliness of rusted disks on otherwise neat motorcycles.
yes there was a problem with braking in the wet.
however it was solved by changing the friction pad materials not by reverting to cast iron disks. to my cursory knowledge japanes motorcycles still use rustless brake disks.
as they say however, our mileages may vary.

Thread: home castings / metal alloys
03/12/2010 03:38:32
Nicholas it is dangerous stuff so only a complete idiot would ever try the experiment. from my experience with casting you will get the explosive effect if the moisture is trapped by themolten metal. if it isnt trapped it will dissolve into the melt with some being driven off as steam.
 
my experience with hydrogen came when I accidently used some old pistons, that had been out in the rain, in a melt. unknown to me the insides of some of the pistons was a wet pulpy mass. the resulting casting was like a plastic foam in appearance
 
btw the indicator that you will have a hydrogen embrittlement problem is the formation of lots of dross on the surface of the melt. if you get  an abnormal amount of dross then you will need to use the aluminium chloride blue pills to rescue the melt.
 
if you want to see good casting practise search youtube for a set of 14 videos by myfordboy. the guy uses a different furnace (mine was a waste oil burner)   but his technique is impeccable.
02/12/2010 06:38:14
To answer a few of the comments preceeding.
the blue degassing chemical is Aluminium Chloride. it is the same chemical used to impregnate the blue dot on those weather prediction wooden doohickeys.
when you plunge the pellet to the bottom of the mix it dissociates into the aluminium melt with the aluminium part just adding to the melt. the chlorine part gasses off through the melt combining with with the hydrogen to produce hydrogen chloride gas. if you get a wiff of this it is incredibly pungent, the gas combining with moisture to form hydrochloric acid in your nose. I suspect my own bad sense of smell to be due to scar tissue on my olfactory bits from use of degassing pellets.
 
Ian's comments about swiss cheese are certaily hydrogen embrittlement.
aluminium in the molten state can absorb huge amounts of hydrogen in solution which all comes out of solution as the aluminium cools from molten. it is the trapped bubbles of hydrogen that cause the swiss cheese effect in the aluminium.
you would think that if you placed water on molten aluminium  the temperature of the molten metal would just immediately evaporate the water. well it doesnt do that. the water dissociates into the molten aluminium just as salt does when dissolved into water. If you avoid melting aluminium on days of high humidity, if you make sure all your feed stock is scrupulously dry and clean, then you will avoid most of the hydrogen problems.
 
molten aluminium dropped on to moist anything will flash the moisture to steam and cause one hell of a grenade with molten blobs exploding out everywhere with lethal consequences. not something that you ever want to see. personally I like terry aspin's sand tray idea and have made about half a dozen for use while casting. they keep it safe.
 
01/12/2010 09:20:54
the alloy description I've seen is 80% copper and 20% alooominum (as the yanks describe it) to produce aluminium bronze so the name is a misnomer.
Bronze is actually Copper and Tin in alloy. Just be careful replacing bronze with aluminium bronze, the subtly different properties have killed people.
 
mixing copper into the aluminium is non intuitive but is actually dead easy.
you get a melt of aluminium and take a piece of copper (tube or rod) and just stir away in the aluminium. the copper dissociates into the aluminium quite easily.
 
if you want light aluminium castings never mix a diecast piece in the melt. the diecasters use zinc which makes the aluminium flow nicely but makes the piece almost as dense as cast iron. ( I have the Tee shirt )
Thread: Home produced cutters
01/12/2010 04:38:54
ramon what information are you working from?
I bought the book but couldnt find enough detail to work from.
I later found the articles done in model engineer, are you working from these?
beautiful work, no doubt about it.
Thread: LBSC Locomotives
29/11/2010 11:02:46
David I think that the preservation of LBSC's designs is a bloody good move.
pat on the back to whoever had the idea to do it.
 
I've just finished reading the MAP book on Speedy. is the info in the book sufficient for what you seek? We have it in the club library.
Thread: Sundials
25/11/2010 10:38:51
one way of copying flat metallic objects is to photocopy them. the photocopys make easy full size plans.
however you are sometimes plagued by glare reflection obliterating detail on the copy.
find a clean thin white plastic shopping bag of the supposedly detestable type given away by shopping centre occupants.
place a single layer of this thin plastic film crease free on the photocopy glass.
then sit the object to be copied face down on the  plastic, close the lid and take the photocopy.
it may take some experimenting but I have taken blemish free images of shiny stainless steel items by using this dodge.
 
the item was a DC3 load and balance sliderule made here in western Australia.
it was engraved polished stainless steel.
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