Here is a list of all the postings Andy Stopford has made in our forums. Click on a thread name to jump to the thread.
|Thread: Barograph 'stiction'|
The space programme thing is a myth - PTFE was discovered (more or less by accident) in the thirties. Its first notable use was in the Manhattan Project to protect the plumbing of the Oak Ridge Gaseous Diffusion Plant from the corrosive effects of Uranium Hexafluoride.
Interesting about the poorer performance for oscillating systems. I wonder if its the same for other slippery plastics like nylon and acetal.
|Thread: Emergency Radio Format|
100 megatonnes? Standard Russian TV propaganda bombast.
The most powerful nuclear weapon ever tested was the Tsar Bomba with a design yield of 100 MT, but reduced to 50 MT to reduce fallout or, some say, because the design team (led by Andrei Sakharov) feared the fireball would extrude out of the earth's atmosphere, and they didn't know what the consequences of this would be.
The Tsar Bomba was a completely impractical willy-waving exercise and modern nuclear weapons have far smaller yields, which isn't to say they're inconsequential - see this link (which has been receiving a lot of visits lately):
|Thread: Which Collet Chuck?|
I have a WM180 and an ER32 backplate-mounted collet holder. I have no problems with lack of registration, you can take the assembly off, turn it around, put it back on, and the work remains true. The mating spigot seems very accurately made with absolutely minimal clearance (I recently read that this mounting method is an ISO specification).
The chuck/backplate came from ARC, so no connection between the manufacturers of lathe and chuck, except that they both apparently took note of that ISO spec.
I use it a lot, and I think a MT variety without a through hole would not be nearly as useful.
re. collet chuck accuracy - I do have an ER20 2MT holder (for the mill) which displays considerable run-out - it was a very cheap ebay purchase. I replaced it with one from ARC which is far better (I can't remember the figures off hand, but I think the cheapo one was at least 10x worse).
|Thread: Is it really a joke|
There was a chap from National Grid on the radio a few months ago. He said that they weren't worried about increased demands from charging electric vehicles - much of the load (managed by smart chargers/meters) would be in the small hours when other demand was low, and existing infrastructure could easily handle this.
He did say that a widespread switch from gas to electric heating would be more of a problem, and National Grid are working to increase capacity to cope with this when it comes. Improving insulation in domestic properties would presumably help to mitigate this.
|Thread: Rumely Oil Pull engine|
I think you're very likely right about the float bowl. I would guess that the aluminium corrodes to form aluminium hydroxide gel which is what you found lurking in the carburettor.
re. using octane booster, unless this does something else apart from increasing the octane number, I'm not sure it would help, since the only significance of octane is its anti-knock properties (probably not important with the compression ratio you are using).
The simplest course of action is probably to drain the fuel from tank and carb if laying up the tractor for any period of time, e.g. over winter - I'm sure it wouldn't do any harm leaving it fueled for a few weeks.
Lovely model by the way - it sounds great!
Ethanol absorbs water which can cause corrosion of aluminium float chambers, etc., so definitely worth draining for storage.
Mind you, old school petrol deteriorated over time too, with the lighter fractions evaporating off (and possibly other chemical changes taking place) leaving an oily, stinky, not very inflammable goo.
Avgas (aeroplane petrol) is reputed not to suffer from this problem, perhaps because its all all 'good stuff' rather than mostly cheap stuff, blended with a small quantity of good stuff. It smells nicer too.
|Thread: Why aren't carbide chop saws used?|
I don't know the thickest stock an Evolution saw will cut, but they work amazingly well with very thin sections. I once had to adapt a curtain pole to fit a bay window. It was made of very thin-walled steel tube. I didn't fancy trying to cut the mitres on-site with a hacksaw so I decided to give my then new Evolution saw a try, despite the coarse tooth pitch. There was a fair bit of surplus length in the tube so I was able to do a couple of test cuts first.
I gingerly lowered the blade and it made a perfect burr-free cut - the only thing to watch for was lifting the blade back up while it was still turning - this would result in it catching and putting a little dent in the cut edge.
I should emphasise that the blade was pretty much brand new at the time.
|Thread: Rulers - my pet peeve|
Donald, those are Rabone Chesterman No 47 R rules Rotagrip are selling the 600 mm version on ebay:
|Thread: Mill DRO X/Y axis + and - on readout|
I might look into doing that - though I bet they are crimped!
|Thread: Advice on Cluttered Dimensions in Drawings|
Ordinate dimensions can help with 'de-cluttering', and work well with a DRO-equipped mill.
Take care though, that you don't do what I did last weekend and read the last hole position as the length dimension of your workpiece. Its exceedingly annoying to find that the last of the numerous holes that you've so carefully, so precisely, drilled lies on that misplaced edge...
|Thread: Mill DRO X/Y axis + and - on readout|
I have this problem - on my mill the only way to mount the X axis DRO is with the scale moving and the pick-up fixed. Vice versa for Y. I can make the display increment or decrement in the correct sense using the setup page, but the displays for ARC and ARRAY are then reversed - it doesn't really matter, you can ignore the pictorial representation and just step through as normal, but it is slightly annoying if you get distracted and forget which step number you did last.
|Thread: Milling - first cuts|
And just to make life complicated... climb cutting can sometimes be better, with less vibration and a better surface finish.
This is true even for small mills. I have a Sieg SX1L, which is about as lightweight as you can get, and often climb cut with it. Be cautious at first if you try this, and make sure your gibs are adjusted properly, but not too tight or you won't be able to feel what's going on.
edit: NDIY beat me to it
Edited By Andy Stopford on 16/03/2022 21:19:53
|Thread: yet another angle plate|
I've got one of the ones in the second link - the minimum hold down spacing is about 100 mm, maximum about 115. You have to be careful with the length of the studs and nuts, otherwise they foul the table adjusting nuts. Some time I might make a couple of dedicated toe clamps which would put the hold down nuts outside the base of the table.
It is good and rigid.
|Thread: Any advance on the highlighted comment ?|
I did quite like the cable crimper - it looks like it works better than some of the (not cheap) ones I've bought.
Think I'll pass on the power hammer though.
|Thread: Tomato seed recommendation?|
Tomato yield depends on 'Heat Summation': in order for the fruit to develop and ripen satisfactorily, they need a certain number of hours above a certain temperature (the exact figures depend on the variety). I can't have a greenhouse (shared garden) so my toms (and chillies) are at the mercy of the elements. Last year, after a good start, was terrible in the south east with weeks of cold weather and consequent almost complete failure of the tomato crop, and the ones that did ripen were tasteless. The year before was great, and I was giving the things away.
If you're limited to outdoor growing, I've tried and recommend the first three varieties on this page (unfortunately sold out now):
Being early, you have a better chance of sufficient heat summation, and they seem pretty blight resistant. They also don't require pinching out or anything elaborate in the way of training.
There's no problem saving seed from these, use the method described by Dave Halford above, and save at least two separate batches, just in case.
|Thread: Cross-slide fixture plate considerations|
I'd suggest drilling and tapping the holes as and when you need them. I've made 'universal' pre-tapped fixture plates in the past, and the holes never seem to be in the right place.
And a Henry can survive multiple tumbles down the stairs - try that with the products of James (Winner of the Queen's Award for Hypocrisy) Dyson
It might be quite exciting as a coating for licorice sweets too...
|Thread: Songs about Engineering|
For a problematic interface between man and machine, how about "The Widowmaker" from "Captain Lockheed and the Starfighters"?
Come to think of it, "Death Trap" by Hawkwind describes mechanical failure
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.