What Did You Do Today 2021

[BazyleParticipant @bazyle]

Two days later and another long club night zoom session this time with Exeter DMES. The great thing about club zooming is that it is location agnostic so I can join from 250 miles away. There is a ot of potential in this if you only try it. We have been able to have a remote speaker who would never be able to come to an actual physical meeting.

[duncan webster 1Participant @duncanwebster1]

Posted by Nigel Graham 2 on 10/03/2021 21:31:59:

Machined the venture for my wagon's chimney – there isn't really room in the smoke-box for a broad petticoat but I've achieved something near.

The only reference I could find to help me design it, is a single diagram and brief notes in Martin Evan's Model Steam Locomotive Construction – but the 1-in-6 part he gives, applies to a short loco chimney, not 20 inches of nearly-3-inch diameter stovepipe. His advice probably relies on relatively much higher blast pressure, too, than my engine is likely to produce. Still, I managed something.

I've a little finishing work on it, but it's another step forwards.

The material didn't help me much though. It was a tubular iron casting good enough for a chimney choke but useless for fine work. It looked as if poured in a fence-post hole, and is so rich in blow-holes I reckon they cored it with a wet loofah.

I think the 1 in 6 defines a minimum length of chimney, more is not very disadvantageous. It works out at having a chimney at least 3*diameter, which is easier to imagine. Similarly, the 1 in 3 defines the maximum height of the choke, having it lower won't cause problems except for tube sweeping. Porta had his right down level with the blastpipe. He must not have been involved in tube sweeping!

[Nigel Graham 2Participant @nigelgraham2]

Thank you Duncan.

I'd no sooner managed it than what happens?

The latest ME plops through the letterbox, complete with Norm Norton's more comprehensive article on designing locomotive chimneys.

This only confirmed what I'd feared when I looked at the finished choke a few kWh later,. I have made it much too large.

The only consolation is that the casting I used was a scrap item from somewhere, and of too poor quality for precision machine parts.

Unfortunately too, there is a big difference between Mr. Norton's project and mine; so I don't know how applicable the formulae and geometry will be.

His is a 5"g 'Britannia' – a simple-expansion 2-cylinder locomotive pushing a near-constant stream of healthy vapour at some pressure through a venturi only a few inches from the valve-chests.

My 4"-scale wagon's engine is a mid-mounted compound, and by the time what had left the boiler as un-superheated steam has found its way through the engine then something near two feet of pipe to the smoke-box, it will probably be wet fluff needing helping up the spout.

I have just produced a new drawing, to Norm Norton's advice (and will also fit a blower to his design); but I have also placed an appeal for advice on the TE section here.

'

I made the chimney cap-ring last night- more swarf than item – to resemble fairly well the original's basic beading. Today I cleaned the lathe down and started modifying the wagon's flywheel I'd made, ooh, ages ago but recently realised was too heavy. (I'm simply thinning the over-thick web and rim.)

[Gerhard NovakParticipant @gerhardnovak66893]

Installed a DRO for drilling depth measurement to my SX2. Was straight forward and I am happy I did it. The crankshaft I had started to look at has to wait, as I have sold my lathe. Went in less than half a day. Of course I am asking myself if I didn't ask enough for it, on the other hand the new owner should enjoy it. I am now "latheless" until the 25th of March. No fear, my wife can easily fill the spare time with DIY projects…

Edited By Gerhard Novak on 15/03/2021 21:20:39

[David George 1Participant @davidgeorge1]

Did a bit more to Potty mill. Turned the flywheel and finnished the parallel running gear.

Nigel

The base is an aluminium plate.

David

[Nigel Graham 2Participant @nigelgraham2]

Thank you David. it looks good!

You've given me an idea for fabricating my connecting-rods, though with a circular-section middle, and possibly welding as I'm not sure I can heat fairly hefty lumps of steel adequately for brazing.

[Grindstone CowboyParticipant @grindstonecowboy]

Been doing a bit of cold blueing of Myford ML7 parts. I've previously tried a Jenolite paste blue which did work, but not a great finish, so I splashed out on some Phillip's Cold Blue Solution and I'm much happier with the results. Method used is as follows:

Immerse part in general purpose thinners (modern equivalent of cellulose thinners) and shake it around for a bit to degrease.

Remove from thinners with tweezers, wipe with paper towel and hold in the flame of a blowtorch for a few seconds (until any condensation disappears).

Immerse in solution – I used about 1 part blue to 2 parts tap water – and then, what I think is the most important part, keep brushing all surfaces with a new, clean paintbrush.

Keep doing this for at least five minutes, I went as high as ten minutes on some parts.

Remove from solution, dunk in clean cold tap water.

Remove and spray with WD40, then use fingers to liberally coat all surfaces with new motor oil (20W50 as I had some handy, not synthetic).

Leave for about 24 hours, wipe dry and apply a thin coat of Renaissance Wax with fingers, wait a few hours and buff with soft cloth.

Lovely dark blue, almost black finish that seems to improve slightly over the next few days. I think the heating and brushing are the key points to make it work well.

Rob

[Nigel Graham 2Participant @nigelgraham2]

Thoroughly vacuumed the bedroom carpet.

The relevance to engineering?

The steel swarf glinting in the bright morning sun!

++=

Rob –

Thank you for that report.

It was hard to track down blueing chemicals, and eventually I found Birchwood Gun Blue in a country-sports supplier's catalogue (after turning the PC's search filters down to permit the G-word). This was for my Worden T&C Cutter parts.

The results are a bit patchy but that was me, not it, to blame.

The necessity for thorough cleaning was soon clear, as is protecting the blue, or more black in my case, steel immediately afterwards from all those promiscuous Oxygen atoms. I used white-spirit then a wipe with xylene paint-thinners; and applied the blue with cotton-buds.

Being for a grinder, I could not use oil or grease, but spray-on furniture-polish seems satisfactory even on unprotected steel for quite a long time (for indoor use – the grinder will live in the front room though my house still has plenty of rust germs.)

[Grindstone CowboyParticipant @grindstonecowboy]

Nigel – yes, I had seen on YouTube that selenium dioxide solution was the stuff to use, and that Ebay was full of people selling it for pennies. However, I couldn't find any, so went for the Phillip's product instead. Furniture polish sounds a good idea though. In the dim and distant past, I have used Birchwood Casey's Gun Browning paste, which worked well, but I don't think brown looks so good on machine parts.

Rob

[Roderick JenkinsParticipant @roderickjenkins93242]

The recent discussion about vernier height gauges prompted a thought. The problem I have with my vernier gauge is that a) It can't be zeroed and b) more importantly it's really hard on the knees since I have to squat down to read the scale through the bottom part of my varifocals. It occurred to me that I have a caliper type scale left from my budget milling machine scales. This is what I made:

Not particularly elegant – made from the oddments box. I checked it against my workshop gauge blocks and there appeared to be a slight systematic error checking up to 4" height. I then had the thought to check the verticality of the scale against a square and after a tonk with a hammer it reads 4.000" and 0.500" against the appropriate gauge blocks. I am very pleasantly surprised and it's definitely good enough for marking out and it cost me nothing. Although the scale is hardened stainless the body is not since I had no problem drilling and tapping for the thumb locking screw.

Cheers,

Rod

[mechman48Participant @mechman48]

Continued on with pieces for my Scotch yoke engine; did the piston rod & piston. A note to others FWIW, after careful reading of the dwg I decided to make the piston in two peices, why you ask?.. well the piston OD is 26mm, the undercut for the pistonring is 19 mm, the ring is to be made from Nylon or PTFE , now tell me how to fit a 19 mm ID over a 26 mm OD without splitting the ring, with the correct gap, to ensure a seal.

I decided to machine the piston as per dwg but machining the outer/top part as a seperate flat plate. As the piston assembly is tapped M5 it all screws together to become one unit with the ring captive. Will take pics later.

George.

[Iain DownsParticipant @iaindowns78295]

Today I managed to puzzle my way through the worst Chinglish I've ever seen to find out how to set the top pressure in my compressor. Previously, it would run hit the end stop and keep running as the overpressure valve cut in. Take of a nasty plastic cover and turn the nut counter clockwise till it turns off a bit below 8 bar. None of those words being in the instruction.

Also grew my compressor tools skills slightly, but finally ordering a coiled extension with the right (Euro) connectors on. I now have an air gun by the mill and by the lathe.

That and a little bit of tidying up left me with a feeling of progress. I also started on the 3rd version of my reversing link and have yet to mess it up. Plenty of time yet.

Iain

[Grindstone CowboyParticipant @grindstonecowboy]

Iain – not keen on those coiled hoses, I would advise saving your money (if it's not too late already)

Rob

[Martin DowingParticipant @martindowing58466]

From time to time I was busy with repairing rotary vacuum pumps for a a guy who is servicing these.

This was usually involving making stellite ball valve seats to work with ceramic balls.

Such valve is virtually indestructable.

Hovever I got one small old fashioned pump which had spindle damaged and was completely naked.

He gave it to me as "irreparable – do with it what you want".

So I have enlarged damaged working bore a bit (turning and honing), made from scratch new spindle which is of very interesting construction, made sliders which fit into a slotted section of spindle, replaced valve seats and balls as usual into stellite – ceramic set and pump was assembled.

Also bearing bore was lapped and a flange used for bolting of pump to its oil tank was repaired by welding.

So really I can say that I have made new pump from castings.

Spindle and sliders were made of 45 HRc material.

Already tested and it easily goes down to 0.01 mbar – pretty good.

Taken quite a while to make it – few linear dimensions had to be made up to a single thou tolerance.

 

Edited By Martin Dowing on 18/03/2021 21:42:51

Edited By Martin Dowing on 18/03/2021 21:49:03

Edited By Martin Dowing on 18/03/2021 21:51:24

[Martin DowingParticipant @martindowing58466]

Continuation:

Few more photos:

[mechman48Participant @mechman48]

Posted by mechman48 on 18/03/2021 18:00:53:

Continued on with pieces for my Scotch yoke engine; did the piston rod & piston. A note to others FWIW, after careful reading of the dwg I decided to make the piston in two peices, why you ask?.. well the piston OD is 26mm, the undercut for the pistonring is 19 mm, the ring is to be made from Nylon or PTFE , now tell me how to fit a 19 mm ID over a 26 mm OD without splitting the ring, with the correct gap, to ensure a seal.

I decided to machine the piston as per dwg but machining the outer/top part as a seperate flat plate. As the piston assembly is tapped M5 it all screws together to become one unit with the ring captive. Will take pics later.

George.

As mentioned, pieces for my Scotch yoke engine… note piston made as two pieces..

Marking out piston gland follower..

George.

[Nigel Graham 2Participant @nigelgraham2]

Commissioned my Worden Tool & Cutter grinder. At last!

As advised in Hemingway's instructions, I took it outside into the sunshine for the Wheel Dressing Ceremony, followed by putting a shine back into the edges of a slot-drill and an end-mill, and truing an off-hand ground single-point threading tool.

Though I made and fitted the optional feed-screw mechanism, and used for the wheel-dressing, in practice I found it easier to manipulate the slide directly by hand, resting both my hands on the machine's sides so as to give plenty of control.

Another user had queried why the lathe-tool holder seems too high, but I had worked out, and proved to myself, that it isn't. It holds a lathe-tool across the cutter slide axis so you can grind its flanks without swinging the slide right round to odd angles.

The cam-shaft that sets the table slope is very stiff but I think that's me not quite getting the last one or two "thous" off somewhere. I've also not calibrated the angle-indicator as on the drawings. I think using an adjustable-square or simple templates, would be easier, for the few and not super-critical tilt angles likely to be needed.

The red rings are ordinary fibre-washers – my addition, for better friction-locking with less paint-stripping.

'

One thing I'd not realised I'd missed until picking out a couple of cutters for my little practice session, was making a holder for 12mm dia shank cutters. The drawings (or the edition I bought anyway) are for an Imperial set but I chose to make a metric set in parallel, indicating those with a marker groove as on Clarkson 'Autolock' collets. Evidently I missed the 12mm one.

 

Otherwise… I now have much less excuse for my machining errors being inaccurate and poorly-finished!

'

The paint-work by the way is just ordinary gloss from Wilko's finished with a rub down and couple of sprays of gloss-white acrylic car paint. The black-ish finish is Birchwood Casey 'Gun Blue', followed by spray-on furniture-polish as these chemical-colour treatments are not rust-preventatives.

The photograph shows it with the lathe-tool holder mounted, though not clearly. The extra brass thumb-screw protruding from the side of the cutter-holder base, is part of a slitting-saw sharpening attachment that still needs one or two details finishing.   

'

Then found an area of kitchen work-top where it can live, reasonably far from any cooking activities.

 

Edited By Nigel Graham 2 on 22/03/2021 20:23:02

[Dominic BramleyParticipant @dominicbramley60728]

Made a house for an abandoned baby squirrel out of a Warco DH1 vice box. He seems to like it.

Dom

[Martyn Edwards 2Participant @martynedwards2]

Started to plan out a steam plant for my two lockdown built Stuart engines. Decided to incorporate an economiser/condenser although it's probably overkill.

[martin perman 1Participant @martinperman1]

Dom,

Is the little fella in your workshop, he looks happy enough.

Martin P

[Dominic BramleyParticipant @dominicbramley60728]

Posted by martin perman on 25/03/2021 18:18:50:

Dom,

Is the little fella in your workshop, he looks happy enough.

Martin P

He's actually in our kitchen in that photo – but has since been moved to our utility. That said if you look carefully in the background of that picture you can just make out an ME boiler, Stuart 10V and a set of Minnie Rear Wheels which have also taken up residence in the kitchen. The wife showed a picture of the boiler to a colleague recently and was asked "why is there a bulb of garlic in your workshop?!"

In other squirrel engineering news – I have been finding it hard to feed the critter milk from a syringe without accidently squirting it too hard and choking him. So I have 3D printed a screw dispenser to help feed the syringe in more gently. After a bit of running in, it is as smooth as silk and I'm genuinely amazed how well 3d printed threads can work. I wish my lathe dials worked this well!

Dom

[roy entwistleParticipant @royentwistle24699]

Dom You do realise that it will be illegal to release him into the wild. ( Unless he's a red one and it doesn't look like it )

Roy

[Steve Skelton 1Participant @steveskelton1]

Dom, it is also illegal to keep grey (or red for that matter) squirrels in captivity without a license (which is now next to impossible to get).

https://www.rspca.org.uk/documents/1494935/9042554/Living+with+-+grey+squirrels+%28V2.0%29+-+2015.pdf/4a8dc4a9-8461-7dfc-2ac5-420832d08cb5?t=1553171457866&download=true

Steve

[peak4Participant @peak4]

I went to use my on-demand hot water handwasher earlier; water everywhere, except out of the spray head.
Spot the deliberate error.

The screw head was rattling around in the outer casing, but I manage to drill out the remaining self tapper shank with a small carbide bit and re-threaded the case M3.
All leak free now.
 

 

Edited By peak4 on 26/03/2021 22:12:49

[Chris CrewParticipant @chriscrew66644]

I spent the day on the hacksaw chopping an 8" long piece from an 8" x 20mm steel bar and then making the resulting square approximately round as the basis for an interstitial plate between a Colchester L.0 lathe mounting and a cheap Chinese chuck. It took most of the day, off and on. I then spent the next hour rubbing Voltarol into my right shoulder!

Edited By Chris Crew on 26/03/2021 23:32:51

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