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Member postings for Iain Downs

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

Thread: Steam Engine Number One
21/11/2021 18:07:36

It turns out I have a question.

Gland packing. The two options I can see from a search of the forum are PTFE tape or (Jason's recommendation) graphite twist packing Sadly, the link for the latter doesn't seem to go to anything which is purchasable.

Is this the same sort of thing? I have a feeling that square isn't great and 3mm may be a bit big for my model. Not sure if it compresses.

If I go for PTFE is that just the plumbing tape or is it something more specialised?

Many thanks.

Iain

21/11/2021 17:19:11

The marathon continues!

Today's episode was all about heat. Two successes and one abject failure.

I wanted to

  • Finish off the piston rings
  • Heat treat the flywheel key
  • Silver solder the piston gland to the bottom cylinder plate

The first thing I found was that the piston rings didn't fit the grooves in the piston. Either I cocked it up or didn't check a couple of years back (see Page 7 of this epic) when I made them or they've grown in the intervening time. Take your pick...

One appeared to fit in the grove and also fit down the cylinder. The other two not so much.

First task was to thin down the ones that were too wide. 30 mins or so with some wet and dry got me there. Probably should have started off with something a bit coarser, but there you go. A this point when I tried it, I noticed that the groove didn't seem as deep as the rings. Indeed. One was 2 mm and one a tad under 2.5. So I put the piston (it's been on the piston rod for a while now) in a collet and dug the grooves a bit deeper. I had to go very carefully here as the parting tool (carbide) would jam fairly easily.

But I got there (no pictures of that, I'm afraid). I suspect that this opened up the grooves slightly as well, as the 3 rings fit better.

A few more minutes breaking the edges (probably another reason why they weren't entirely fitting) and the three looked good.

Now for the scary parts. First to break the rings.

finishing 06.jpg

This is a posed picture of course. I wasn't going to try this delicate act whilst holding a camera in my other hand.

Somewhat to my surprise, all three rings broke fairly cleanly (and not in two!).

Next tidied up the broken ends with a diamond file and on to the other scary bit, the widening.

finishing 07.jpg

I expect there are better ways. I'd seen something like this on you tube and expected the ring to just drop off the screwdriver into the oil poised below it. Needless to say it didn't, so I had a fine time trying to knock it off with another screwdriver whilst attempting to hold the screwdriver it was mounted on steady with the torch hand.

Had one that got away (on the floor!), but no damage was done and simply re-heated and next time dropped it in OK.

finishing 08.jpg

One spare to break when fitting on the piston. Gap is a little over 2mm. struggled a bit to do this scientifically as I could no longer find the articles which provided the calculation, but I don't think I want or need much of a spring.

Next was the key. Made a cage and smothered it in boric acid, heated to dull red and then dropped it in the oil. Seemed to work OK. File made the right sort of skittering noise.

Not much oxide on it due to the boric acid, but shined it up and tempered it. Well. Differential tempering as it turned out. One part straw, one nearer to blue. Still, I imagine it will do.

The last item on the list was silver soldering the piston gland to the bottom plate (which can be seen a few posts up). This just didn't work. The flux was gone early and the plate never got hot enough to melt the solder.

Me and silver soldering have yet to have a success and it's so long since I last tried I'm not even sure I'm using the right flux and solder.

So I expect I will buy something known from Cup Alloys and try again (I'll do some practice first). If that fails, I will hang my head in shame and resort to JB weld.

Nearly there. However, the advent of winter my further slow down what has been a glacial build. Today was about as cold as it gets (5 degrees or so) when I can realistically get in the shed. Mind you if it's the soldering, I could make an exception!

Iain

Thread: Texas Instruments TI-5020
12/11/2021 14:43:31

The first significant purchase of my young life was a Sinclair calculator. I blew something like 80 quid on it (which was a VAST sum of money in the 70's) and 3 weeks later they reduced the price to 25 pounds.

Those of a certain age will know that it was a deeply unreliable beast and I had to fix the on off switch with a dab of solder if I remember. Probably the most use was in clever stories which ended up spelling Shell Oil upside down...

Iain

Thread: So what design software will you use in 2022?
12/11/2021 14:38:21

I'm an onshape user.

It's an online type thing, so runs through a web browser, very functional (comparable to Solidworks) and free if you don't mind your jottings being public.

I'm very happy with onshape. I've tried a few of the low cost / no cost / trimmed down for domestic versions and this is one of the easiest to get to grips with.

Has a decent forum with reasonable responses to questions.

Iain

Thread: Steam Engine Number One
07/11/2021 17:20:46

Next the collar.

The idea here was to make a bit with the same bore and external diameter bold it to the end of the stub in the centre and hold it with some grubscrews.

First to chuck up a piece of 30mm mild steel face it and bore it to size. Checked this with a bore gauge and a try fit with some 22mm silver steel from the same stock as the crank. Turned it round and face the other end.

Next, put the flywheel on the mill, the same piece of silver steel in the centre and clock it under the quill. I've recently got a quill mount for indicators as the big boys (Stefan and Joe) seem to think this is a good way to do things. At a tenner the quill mounted thing isn't bad. However, the cheap as chips indicator I just bought is less good. My Christmas could feature a mitutoyo or similar.

Nonetheless I got it centred within a thou or two. Actually, I'd not checked the width of the heads on the allen key bolts and I might have gone with M3 rather than M4 as they needed just a little bit of fettling once fitted.

Drilled through the collar into the flywheel centre, then removed the collar drilled and tapped. Seems to work!

flywheekl collary drilling.jpg

next stop was to put the holes in for the grub screws. This took a bit of thought, but I ended up finding a piece of scrap aluminium which was square (more or less) and about the size of the collar. Drilled 4 holes to match the collar and then used some pins to align it on top of the vice.

flywheel collar grub.jpg

4mm 2 flute end mill (I know not in a drill chuck, but I was just flattening the top). 4mm spotting drill to centre (I'm a spotting drill boy on the mill, but centre drill on the lathe. Don't really know why, it it seems to work OK). finally tap drill then tap.

Turn the collar over, replace the pins and to the other side. I've ended up putting 2 grub screws in at 90 degrees to the keyway.

I spent some mental effort working out how to then trim this down to size. Or more accurately, how to hold the flywheel accurately.

My first thought was to hold it in the 4 jaw and centre it. However, I needed to hold the thin side and it soon became clear that holding onto a 4mm deep recess with the 4 jaw and getting it centred was a mugs game. Just not enough to hold on to . I occurred to me later (just now, actually), that I could have supported it with a revolving centre, but probably would not have held on anyway.

Instead I made a mandrel. I chucked up another piece of 30mm mild, faced and then drilled and tapped to M6. The idea was to bolt the flywheel and collar onto the mandrill.

The turn down the outside of the mandril down to a tight fit for the flywheel, push it on and bolt it down.

flywheel collar trimming.jpg

The tool appears to be a trepanning tool I made a while back and I could have probably done with something a bit more rigid, but it got the job done.

Whist I was at it, I attempted (unsuccessfully) to shine up the stop and the outside (with a bit more success).

And here we have a flywheel on the crank secured with a key and held in place with collar and grub screw.

flywheel done.jpg

Oh - and here's my question of the day. Should I harden and temper the key or will it be OK as it is?

Iain

07/11/2021 16:55:10

When I made my flywheel I'd not quite thought through how I would mount it on the crank. I mean, I know enough to put a keyway in the crank, but there the inspiration stopped.

I could have bought a 2 inch wide piece of cast iron and trimmed back to an inch bar the collar, but that was clearly just a silly idea.

What I've ended up doing is putting a keyway in the flywheel and making a collar to attach to the flywheel.

First was to make a keyway cutter - 4mm wide.

flywheel keyway cutter 01.jpg

This ended up being somewhat of an epic. I did it using the 'square hole' approach in a recent (I think) Tubal Cain video. Which is to say cut a slot, glue something on top of it and the remove the surplus in a lathe.

The main problem, however is the tool bit material and the gauge plat I'd got which were meant to be 4mm were both a bit over. By the time I'd trimmed down the HSS toolbit, I'd gone too far, though I had a bash anyway.

flywheel keyway centering.jpg

Here I am centring the flywheel and here is some cutting.

flywheel keyway cutting.jpg

This actually worked quite well, but the cutter was just a bit too narrow and the keyway not quite deep enough (I can't explain the last aspect given as I was using a DRO).

So I made the cutter again, re-centred the flywheel and had another go.

that worked quite well.

Next the collar.

Thread: What Did You Do Today 2021
30/10/2021 21:05:34

I had a similar problem to some of the posters above.

About 7,000 paperbacks mouldering in a garage (mainly sci-fi / fantasy). I lost about 1000 with decomposition, rot and the like. I've ended up scanning two thirds of the remainder into my PC - almost exactly 4000 - with the others (books I could never see me reading again) into charity shops.

It's taken me a little over 10 years to do it.

What's slightly depressing is that kindle unlimited feeds my trashy reading requirements so I rarely go back to my now online collection.

Of course it does NOT look anything like as good as Colin's rather marvellous collection.

Iain

Thread: First Clock in Metric
24/10/2021 17:24:54

Firstly, thanks for the book recommendations. I've received and read the Wild and I think it excellent.

At the moment, I'm looking at John Parslow's 15 day skeleton as the basis for whatever I do.

My questions on this clock (so far!) revolve (mainly) around the gears. The outer dimensions (particularly the pinions) don't seem to match the calculated OD, the third wheel is slightly smaller than two others with the same pitch and module. This is made worse as some of the text appears to be missing from the original ME articles.

I'm thinking that the pinions are odd because they've been slightly deformed to work with the same pinion cutter. I *think* the wheels are reduced in size to provide clearance.

I'm planning to make my own cutters (Pride and Fall come to mind) so I will make a 12 pinion and an 8 pinion. Hopefully things will fit then..

I'm in the process of drawing this up in Metric. Here's the frame..

frame 211024.jpg

Iain

21/10/2021 20:49:51

Sam, I'm torn between awe and depression when watching Clickspring. Does the man never get anything wrong?

It certainly sets a bar to achieve, though I seriously doubt I will ever have that competence.

And I'm keeping his latest video well away from my wife in case she gets ideas. I would fall short.

Iain

21/10/2021 19:36:32

Thanks Martin and Bob.

It turns out I have the D'Carle book and will try the Timmins. Not sure about the Wilding. Although I like the clock it does look a bit complicated.

Iain

21/10/2021 16:43:39

magpie. your clock looks wonderful - but too hard for me for a first clock

various. I quite liked the dark lady, but I can't work out if I can tolerate a weight and pendulum. I accept that this is easier than a spring driven clock.

Russel. the Parslow clock looks good and I'm tempted, though I would probably redraw it in metric first - in which case it would end up as a variant.

Dave. I've bought the Heinmann book (for 11 quid from ebay - rude not to!) and will see what I can pick up from that.

someone mentioned the elegant scroll clock by wilding and I love the look of that, but the book seems hard to find (ritetime seem to do it). It might work for a second clock ...

Sam - the clock looks nice, but my subscription started after your articles ( and well after John's).

Thread: What Did You Do Today 2021
19/10/2021 21:17:11

In a quest to (perhaps) work out how to get nice finishes on the junk I machine, I bought a cheap linsher. I think it cost me around 70 quid new from eBay.

I wasn't terribly happy with it and decided it needed some attention. The first thing I found was I couldn't get the sanding belt off very easily. A bit of fiddling got it off and I ordered a set of various grits. I immediately found that the reason for for the belt as supplied not coming of is that it is just a little shorter than the machine is designed for (100x915). Now I can swap belts with the greatest of ease. Though where to store them in my overcrowded shed is another issue.

I'm operating the machine in the vertical mode and the shelf thing which should support the work is just rubbish, so I replaced it.

linisher stand 01.jpg

The bits which are not painted are mine. The nasty red thing sitting on it is the original which would bounce up and down with great excitement with the least load.

Here's a close up.

linisher stand 02.jpg

And I decided to make it a bit more versatile and tilty as the tilting platform supplied with the disc sander is of equal quality to the rest...

linisher stand 03.jpg

I've still not quite got the hang of nice finishes, though, but I'm getting there.

Iain

Thread: First Clock in Metric
19/10/2021 17:38:45

Just a quick note to say thank you for all the feedback so far.

I rather like the look of the Parslow clock (as Russell sent). I actually prefer the look (overall) to Clickspring's clock - but I would never try that in any case as I would be embarrassed to let my version out of it's kennel when it was made!

I will look at the others though - and thanks again!

Iain

18/10/2021 19:44:27

Hi, all.

I'm close (close for a 3 year project) to completing my first major build - a vertical mill engine. I'm starting to think of what to do next.

Mainly, I think I'd like to try a clock. For the engine I kind of designed it myself (stealing much from many places), but for the clock, I fancy an easier approach and would like to start from a known design. Later I may chance my arm with my own design, but not now!

I would like metric because all my kit is metric and I don't want to convert and re-draw from imperial.

I would like simple (no chimes, no woodpeckers coming out the top, just seconds, minutes hours). Will skip seconds if needed.

I would like something that is attractive without a case, though I'm prepared to tune the design to accomplish that.

I want to make the gear cutters, gears and all the bits from stock.

I would prefer it if there was some build log or book rather than just drawings.

From what I can see I could fulfil my needs easily if I was OK with imperial, but I'm not.

Any and all advice gratefully received.

Thanks in advance

Iain

Thread: Steam Engine Number One
10/10/2021 18:34:30

First off, for any reading this thread, I found a very useful video on setting timing by Keith Appleton which you will find here.

All the parts made? Well. actually all made (except one bracket - I think), but still some finishing off needed.

Here are the parts

finishing 01.jpg

I still had to finish off the bottom cylinder plate and mount the piston guide (originally my thought was silver solder, but laziness makes me consider JB Weld. Terrible of me). More of that below. I also need to split the piston rings - that one does worry me, despite having a brief tutorial from Richard Gibbons at the start of my adventure. Oh and put a keyway in the flywheel.

First though was doing a bit more scraping of rhe bearings. For some reasons I got quite good results with the lower main bearings, but didn't seem to get some a level of blueing on the upper shells. I got somewhere with it and moved on. the big end bearing, I scraped until I had a nice free running fit without worrying too much about points per inch. Slack, again.

Next was finishing off the bottom cylinder plate which was mainly about milling an inset and then some nice clean circles round the support holes.

As so often, I got to the end having realised I started in the wrong place. The work on the circles round the support holes clearly needed the rotary table so I lugged that up onto the mill. Either it's got heavier in the last year or a year of working from home as sapped my strength! Phew!

I spent some time working out how to ensure that the edge was aligned - requiring (so I thought) to make some engineers clamps which fitted the table.

finishing 02.jpg

The 1 2 3 blocks on the edge were indicated aligned with the X axis an adjustable parallel used to align the piece. You can see the clamps - made so that the lower part fits in the T slot.

The end result of this manufacturing and set up effort was that I milled a flat inset by eye along the edge of the piece. Frankly, I would have been better of doing this in the vice.

I realised this later after understanding that that was the only operation that actually required parallelism with the axis. For the corners I realised that would be better off moving the piece around so it could be clamped more easily and so I did.

finishing 03.jpg

The support holes on this were not 100% as one might desire. I can't recall now which of my many errors led to this, but I decided I would take indent the short ends a little and then somehow across the flats to join the recesses.

finishing 04.jpg

I had a few goes at how to set this up and came up with the above. There is a parallel clamped in the vice jaws. In from of that a couple of short parallels as packing and then some wider ones at the top. in the milled recesses I put two pins (sadly, I like the thousands of super accurate pins available to some Youtubers and mine are just sliver steel with a very minimal set of size ranges!). Push up the plate to the pins, settling them in place and then clamp.

If I was doing it again I would try and get the side to be milled to face forward so I could see better what was going on.

In the end it worked well enough and here is the finished plate.

finishing 05.jpg

One thing which I have yet to learn is the fine art of removing machining marks. My patience and emery paper don't seem to be a good combination. My dremel tools seem to strong or too weak. I have mind you just ordered some sanding belts in a variety of grains for my dirt cheap Chinese belt sander. Perhaps they will help.

Next the flywheel keyway and then the piston ring splitting...

Iain

Thread: Air regulation for my Engine
25/09/2021 12:31:48

Thanks, Jason.

I've had struggled my way through amazon to work out the ancillary bits needed to hook up the regulator and so on. And purchase them.

I got to the end to find that the Amazon version of the regulator will take a month, so I went back to bearing boys. Should have stayed there in the first place.

Many thanks.

Iain

24/09/2021 18:24:42

Soon (in a relative way) I will have got my engine in a place where I can push some air into it and hope that it turns round.

What I'm looking for is a regulator which I can control at the bottom end of the pressure scale (I hear posters boasting of their engines turning over at 2psi or less).

So I want something to do two jobs. Firstly to regulate up to a couple of bar with some granularity and secondly to have a tap on so I can turn it off quickly.

Or do you professionals just turn the regulator tap to start and stop?

Any advice welcome!

Iain

Thread: Small bandsaw needed
22/09/2021 16:55:04

I have the smaller femi and i love it.

Iain

Thread: Steam Engine Number One
20/09/2021 21:05:37

Now what questions

So I have all the parts made, nearly 3 years on.

I need to scrape the big end bearing and I want to do a bit more on the main bearings.

I want to lap the face of the valve chest and D Valve.

I haven't put any balance on the crankshaft, though I can refer back to some articles on that in ME or MEW. I don't know important that is in practice, bit I expect I should do something.

I've only trial fitted things so far. There's a good bit of fixing a thread sealant for when I finally decide to put things together.

I don't know how to tune up the engine. I know that I need to balance the D Valve so that it exposes the same amount of valve port on the up and the down.

What I don't know is how to set the timing. the engine is roughly based on A Stuart 5A, certainly in terms of the valve timing (though converted roughly to metric).

Any help on that (or pointers) would be much appreciated).

Iain

20/09/2021 20:53:17

What TWO postings in one day!!!

This is a gasket cutting post.

I was much inspired by a couple of articles in MEW recently and also a hint from Joe Pie in his recent model steam engine build.

I had 3 sets to build. First gaskets for the steam inlet and outlet ports (brass in the previous picture).

I found I had a leather punch with a hole about right for the steam hole, so I started by punching a hole in some gasket material. next I mounted the port over the hole and carefully trimmed round the edge with a craft knife.

gasket steam inlet01.jpg

next I mounted the port upside down in the vice and put the gasket material over it. Then knocked out the bolt holes with an automatic centre punch.

gasket steam inlet02.jpg

That went reasonably well. I think I only ruined one or two.

Next for the steam chest. I needed two here one for the top and one for the bottom.

I started by slicing round the steam chest for both pieces in one go.

Then I clamped the chest walls and top with the gaskets between them and carefully drilled through with a 4mm end mill.

gasket valve chest01.jpg

I'd had a previous go at cutting out the centre on a surface with just the chest walls, but this just resulted in a mess.

I also found later that I could have just put the end mill in a spare chuck and done it by hand.

gasket valvechest02.jpg

The cylinder end caskets were more tricky. This is mainly because I kept getting the end wrong. Despite what you may think would be ideal, the two cylinder ends are NOT quote the same. One a fraction wider and they seem to have subtly different hole patterns. A couple of bits of gasket material went in the bin there, as well.

So I started by placing the cylinder on the gasket material. then careful cut round, except where the valve chest stuck out. Then rotated the cylinder 180 and lined up on the cut circle then cut the rest.

Turn the cylinder upside down and clamp the material to it in 3 places.

gasket cylinder01.jpg

Cut the inside out with a craft knife and then punched through the mounting holes with an automatic punch. I actually found this could leave a bit of a ragged edge so I tidied up with a 4mm reamer followed by a 5mm reamer (the bolt circles are 5mm).

gasket cylinder02.jpg

I'm quite pleased with how these ended up.

Iain

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