What Did You Do Today 2021

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Looks neat, Iain

... You could probably replace that M5 with a ‘differential screw’ arrangement, as famously used on the Norris woodworking planes.

MichaelG.

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Wikipedia mentions a very suitable mix of threads:

For example, an M5x0.80 thread paired with an M4x0.70 thread will produce a differential motion of 0.1 mm, or 100 microns per revolution.

Ref. https://en.wikipedia.org/wiki/Differential_screw

and here’s a bit about Norris:

https://www.leevalley.com/en-ca/discover/revisiting-the-past-the-lee-valley-antique-tool-collection/featured-patent-norris-plane

Edited By Michael Gilligan on 26/04/2021 23:19:11

Edited By Michael Gilligan on 26/04/2021 23:24:04

Thanks for this, Michael!

That's very interesting. I spent a bit of time thinking about how to apply this on the gauge. The most likely implementation would be like this clamp (referenced from the wikipedia article).

There are two challenges that I see (well three, but we'll leave my technical ability out of it). The first is the one mentioned in the article, which is that the torque required to shift the differential screw may be significant. I don't think that would be an issue with the gauge, but I would need to build it to find out.

The one which concerns me more is that the centre threaded rod must remain static with respect to the outside holder. If there is any movement (as the differential screw is turned), then that will overwhelm changes from the differential.

Before I saw this diagram I was lying awake trying to think of ways to hold the nut (in the other model) rotationally rigid and was somewhat daunted by the size of the apparatus that would be required and the level of precision engineering. I'd imagined the nut running in some splines on the outer body - or something.

So am M4 / M3 combination seems to come with quite a few design / construction challenges which I've not quite got resolved. The idea above seems easier in this context if it works in practice.

I may well have a go at this at some point, but it will have to find it's place in my queue of half started projects.

Many thanks again!

Iain

Iain,

Unless I've mis-identified the 5mm screw in question, it looks like you may have room to use one of these for ultra-fine adjustment:

I've blanked out the supplier's name that I lifted the image from but they are quoting a gnat's over £10 each (plus P&P). Looks like it's from China, judging by the delivery lead time but it's the principle rather than the specific article I'm suggesting. The anvil is square, so, if I were to use it, I'd have it pushing onto a ball bearing or similar arrangement to take up angular changes.

John

What I Did Today was over-do things on my still-poorly leg and I've now a very stiff and painful back!

Still, I completed sorting out a fault on my steam-wagon's smoke-box door, then re-arranged a rather inelegantly fabricated stretcher that supports the boiler-barrel when the smoke-box is removed from the chassis.

There is another reason for this Modification, Number Hell-of-a-lot. If drawn to formal standards the sheets would be all 'Modifications' boxes leaving no room for the images!

It already did that supporting, but I realised moving it back along the chassis solved another problem. It can also suspend one of a pair of hangars for the ash-pan / grate hangars, fore-and-aft of the cylindrical firebox. The obvious places for those, at each side, are hampered by the firebox brackets and the steering drag-link.

I have yet to make the grate and ash-pan but that mod has given me a clearer idea of how to suspend it, in a large space under the boiler, a long way from the chassis rails. (I think the original, full-size boiler shell was extended downwards to form the ash-pan wall.)

'

Next mod. is to the smoke-box mountings because as they are, their bolt-heads won't let the bunkers sit down on the frame! It's alter them or the bunkers. The brackets will be the easier.

'

The whole project, dragging on for a ridiculous time, has been one modification, re-work or replacement after another; often of parts made some years ago, because even if I draw them first, I can't visualise far enough ahead how making parts in one way will affect others much further on. If I draw them I tend also to over-complicate them, and I have a sinking feeling what I am making is a more complicated confection than the Edwardian vehicle I am trying to replicate.

It's a bit like chess - having to forecast complicated, alternative combinations of moves and results a long way ahead. I was never any good at playing chess. .

Got sent to Wickes on a DIY project and found a floor tile which looked to have possibilities. At <£1 I'll give it a go. Son in law has a diamond wheel tile cutting machine, so chopped the tile into suitable shapes and here's the result. I'm quite pleased with it. In reality it's quite a bit darker than it looks on the photo, and as it is for floors it hasn't got a very shiny glaze, more matt. I mixed cement die with the grout to get the dark colour. You don't need a lot, and be warned it gets everywhere if you're not careful

A combination that I have used when making a grinding jig to do the reverse face of my mill,s column ways was 1mm (M6 etc.) against 26tpi (brass or CEI). That gives 0.9 thou or 36 microns per turn.

Posted by duncan webster on 06/05/2021 18:34:47:

Posted by duncan webster on 12/04/2021 18:14:19:

Neat

Rod

Changed the oil in the GH1322 lathe yesterday, first change since new this time last year!

Its supposed to be done at 6 months but as I haven't been using the lathe much over winter I wasn't too worried. The cleaner (lighter) oil is from the headstock and shows no contamination other than a bit of moisture maybe. That from the gearbox is quite dark and seems to have some very fine casting deposits in it. I flushed the gearbox and will change that again in a few months time and see what comes out.

Hi, replaced the brushes in my Bosch GWS 7-115 angle grinder after postie delivered them this morning. I think the old ones are well past their use by date, the little pin that pops out to tell that they need replacing was several months ago, but just lately I needed to give it a nudge now and then to get it to go.

Regards Nick.

Today EDMES had their last Coffee Morning Zoom after nearly a year of having them weekly. The actual coffee and bacon butties cafe at St Katherine's Priory where we meet is back open so members will go back there. Unfortunately as I live 25 miles away and am at work anyway I can't go there. And of course it is just as my clashing work Webex got moved half an hour earlier.

The Weymouth society is tentatively back in meeting mode, but with a limit of numbers and a booking system.

Still limping so not doing anything too drastic, but I managed a little detail-designing on my steam-wagon.

Also re-visited a self-imposed but totally pointless "exercise" in drawing the basics of the wagon in 3D CAD. I should really be concentrating on producing its parts drawings then making the parts!

Took the car out for a run round the village, to get back into driving and to assess how I might fare with an 80-mle round-trip next week - second Covid inoculation. It also meant I could park it further back along the one-way street so no longer in the way of the gang relaying the water mains.

The Gauge One 3D Circle weekly zoom call this evening was treated to live video of Flying Scotsman passing through Ashford station. The wonders of zoom calls and mobile phones.

I shortened an edgefinder to fit an MT3 collet. (Angle grinder required).

Inside it has 3 components, a buzzer, an LED and a resistor. I decided a single, 4LR44 6V battery would suffice and it does

Yesterday I couldn't find my boring head so I bought another and 10 minutes later the original turned up. Fate tricked. Destiny cheated. Job done. Success.

Today my £13.79 with free Amazon shipping cheap Chinese replacement arrived c/w MT3 M12 shank, 9 cutters, 3 Allan keys and plastic case.

I was expecting to get a piece of junk but this looks fine and dandy. Why do I feel uneasy? Should I try it next time I need a boring head? If I never try it I can assume it has a major hidden flaw that justifies the stupid price

Not today, but yesterday. Back on making bits for my latest loco after a long period in the doldrums (the loco not me) I decided to set up the slide bars and make the little end pins. A right faff setting up the bars, but successful, so made the pins, went looking for the con rods and found I'd already made them. DOH

What I should do is make up a list of all the parts, down to nut/bolts etc and cross them off as I make/buy them, and note down where I've stashed them away. Wouldn't be the first time I know I've made something but can't find it. Smacks of being organised tho' doesn't it.

You be careful, Duncan, with all that organising. If all the posts about workshop gremlins, lost 16BA screws, repeat-purchases, plain-sight invisibility etc. are a guide, you'll be breaking with tradition!

I did use a slightly similar system for my 'Worden' T&C Grinder (Hemingway kit).

Using a partioned storage-box with a transparent lid, I stored parts by first and second operations, holding turned components labelled by part-numbers until I was ready to mill (mainly cross- and pcd- drill) them all. Then back in the box until assembly.

I'd also listed them by part-number, drawing sheet-number, material and general operations, to facilitate that grouping of similar components / materials / machining.

Two components needed holes on a pitch-circle - as did a couple of parts from a 'Stent' grinder and two for my steam-wagon - a ring of holes being their common feature. Not sure that 3 projects on the go (or the go-slow) is entirely a good idea though.

'

As for What I Did Today...

Very little time in the workshop while I concentrated on improving the drop-in bunk in the back of my car, an ex-'Motobility' vehicle built for moving large model steam-lorries. It is a very complicated wooden box, very narrow and a faff to set up for the night.

It has to accommodate me when most of the floor is occupied by said lorry. Going to bed involves carefully stepping over the chassis. Unusually for me, I thought ahead just in time to avoid measuring a sheet of 12mm ply twice, cutting once and still getting it wrong; by realising the capacious new bed (24" rather than 20" wide) might occupy the space wanted by the wagon's boiler.

Ah! Bother!

So I spent much of the afternoon in the back of the car, armed with tape-measure and pencil.

Nevertheless, moving the wagon to measure it for the above purpose made for a serendipitous moment when a temporary bracket showed a very simple solution to a problem that has dogged me for some months of made and scrapped steelwork.

Whilst typing this post has made me wonder if I ought just build a much simpler new bunk rather than attempting modify what I had not, err, "designed " to be modified in the first place.

Made a " Why The Heck Had I Not Made One Of These Years Ago? " Tool.

To whit:

Two oddments of steel bar, a bit of brass bar, 2 spring roll-pins and an hour or so's work produced a probe for measuring the thickness of a plate through a hole too small for rules, calipers etc.

It is simply a sort of reversed depth-probe, to be used with a rule or Vernier caliper. One roll-pin acts as the interior "jaw" . The other acts as handle and to stop the probe rod dropping right through the body, which would be embarassing as its first work-piece will be a welded steel boiler on a 7-1/4g loco.

The brass part is a knurled locking-screw, an afterthought but looking a bit more tiddley-like than the machine-screw I used first.

Started rewiring my new mill, think there may be a few bits left over when I finish

Today I made two adapters for my tailstock die holder to use smaller dies. I should now be able to thread the 2mm studs for the steam chest on the beam engine I am building.

Neat - I like the finishing touch, the blacking to match the rest of the set.

' ' '

Trying to make my steam wagon's ash-pan, which is cylindrical, not rectangular.

The top component is an angle ring that will also form additional support , via supension-rods from brackets on the chassis, for the boiler.

I thought the rest would be a handy exercise in sheet-metal forming, using steel from an old central-heating boiler panel given me by a friend in the trade. I verified its 0.8mm thickness is just within the capacity of my forming machines, which are:

- a rotary-shear of unknown make,

- a Warco 12" 3-in-one rolls/bender/shear press, and

- a manual "Rotary Machine" (a swaging-machine, or jenny) from WNS.

Rolling the basic cylinder was easy enough, from a strip two feet long, for a diameter slightly over 7" plus joint overlap. Rolling a flange on it though, to hold the base, even with what looked the right jenny rollers, proved impossible and I had to roll the mangled strip back flat.

Forming the base with the flange on that was worse still, despite carefully following the information in an old, industrial training-manual that makes it look simple. In reality, guiding the revolving disc through the jenny rollers while also bending it upwards with one hand while the other hand rotates the jenny, merely crunches the steel into distorted crumples and wrinkles nothing like the desired diameter and profile.

Thinking perhaps the steel was too thick I tried a far thinner disc, cut from an old 5-litre can, but that was even worse. The training-manual shows some very fancy over-locked joints possible with these tools... Errr, how?

Defeated, wondering if this is why we model-engineers tend to machine from solid instead unless absolutely unavoidable as in locomotive superstructures, I took Bernard Cribben's advice. I stopped and "had another cuppa tea" .

Welding? Out of the question. Machine from solid? From a great chunk of half-inch plate - hmmm. Sacrifice a stainless-steel saucepan? Tempting....

Then inspiration. The WNS instruction-booklet shows the jenny's "Turning" rollers produce a semi-circular embossing - or groove from the other side. This is often done for rigidity.

I jenny-rolled such an embossing right along the strip, leaving a very narrow land between it and the edge; then used the slip-roll to reform the ring, with the embossing travelling through one of the roll's edge-wiring grooves. This gives an internal groove all round the shell in which to trap the base, which needs now be only a simple flat disc, cut from 1mm zinc-plated sheet (ex-server panel). A bit like a loose-based cake-baking tin, though those rest the wire-edged base on an internal wired edge whereas the ash-pan's base will be locked into place. Anyway, I cannot wire-edge circular work.

'

I've concluded metal-forming beyond the very simplest cylinder-rolling, straight-line folding and bashing-it-over-a-block-of-wood, is of the Hermetic Arts. Although such sheet-metalwork is very long-established professionally, I have never seen any examples of, instructive literature on, or tools for, it beyond those basics, in model-engineering.