Let's roll - Finescale of a sort

[Peter Insole]

The principal seemed to be sound enough, but the means and method of actually holding everything firmly while drilling out the axleboxes had me perplexed for a while.

In the end I decided to use some short lengths of studding and penny washers, although for this first part, I was rather worried about the potential of the paired sideframes to slip at the critical moments when either the pilot bore, or the main drive broke through in between sections.



Trying to set the clamped assemblies onto the drill press platter became even more of an unexpected challenge!

I had to ditch the regular vice, as the jaws wouldn't open wide enough, but having done that none of the holes and slots in the exposed plate aligned with the protruding studs... and neither do I possess a nice, useful box of handy steel offcuts to use as spacers... but I do have almost too many bits of timber and plywood of various thickness lurking about the bench:



Such a wholly unsatisfactory arrangement filled me with much trepidation... even before the inevitably anticipated "wandering bit" trauma! It didn't exactly aid my constitution either being only too aware that any cock-up, however minor, would be irretrievable - as I had absolutely no spare aluminium bar available for replacement.

I found that I couldn't drill the pilot bore any greater that 6mm, as the clearance from the chuck jaws to the workpiece - with the platter fully lowered would mean that any larger bit would have to be gripped by the cutting portion. There was also only sufficient travel of the drill head to just about reach right the way through both axleboxes in this set up.

It follows of course, that any hope of opening the bores to the required 12mm in a single operation was totally out of the question!

The frames had to be split and drilled separately anyway... all the while in the rather vain hope that the pilot bores might (just) help to guide the large bit on it's journey?

Horrible!



Trying to avoid getting caught by flailing, razor sharp swarf that determined to tangle itself round the speeding bit was "entertaining" at times... Unfortunately, the little clear plastic guard provided for just such protection chose a prime moment to fail - right at the beginning of the struggle!

I suppose that the result of all this foolery was utterly predictable... and yes, every hole finished a tad wonky... with some even visibly off centre.

However, a very odd thing happened when I test assembled both sets of frames...



When the M12 nuts were tightened - the frames were pulled in absolutely dead square and true... ???!

I'm not going to even try working that one out!

Pete.

 

[ovener]

Ah Peter, that'll be the Beltane pixies looking after you!
Fine and ingenious work there.

Richard

 

[Osgood]

... Beltane...

I had to look that up

 

[simond]

Every day, as they say…

 

[David B]

The archbars are looking fabulous Pete - a right Proper Job (just as I knew they would be!).

David

 

[adrian]

... Beltane...

I had to look that up

For Jethro Tull enthusiasts it's familiar territory

Have you ever stood in the April wood
and called the new year in?
While the phantoms of three thousand years fly
as the dead leaves spin?

Beltane - Disc 2 Flawed Gems of "20 Years of Jethro Tull" one of my favourites.

 

[Yorkshire Dave]

For Jethro Tull enthusiasts it's familiar territory
Beltane - Disc 2 Flawed Gems of "20 Years of Jethro Tull" one of my favourites.

Beltane appears on the 2003 remaster of Songs From the Wood not the original 1977 album.

 

[Peter Insole]

It must be something ancient and mysterious like that, although I was thinking more along the lines of an old card trick, (the only one I can remember) of the innkeeper. Having said that, I do perhaps prefer the notion of elves or other unknown spirits secretly lending a helping hand... although I am worried that might come at a price... if it hasn't already?!

Yesterday, I did get the distinct feeling that my "guardian angels" had completely abandoned me as I underwent a particularly unpleasant medical procedure... and am now finding myself banned from any sort of workshop activity for at least the next four days! I can assure you all that my good lady wife listened very carefully to the surgeon's advice, and will be taking no prisoners hereon in.

As good a time as any for a catch-up post while I'm still on my best behaviour?

Ordering, and promptly receiving a full set of eight wheels was the first priority last year for this carriage project, and the neat little stack had been dutifully stored in the cabinet beneath the "Horwich" engine until they were required. At commencement of the bogie frames construction I bundled those wheels up, carried them downstairs and placed them at one end of the workbench.

When it came to the point where, as shown in the last image previously posted, I wanted to set up the wheels for a test, you might imagine my horror in discovering that there were only seven of them there?! My initial thoughts were in recalling that the rather severe deployment of a hammer during the bar bending exercise had caused all sorts of tools and tut to jump about on the bench top with each blow, and I lost count of how many times I had to stop, stoop and retrieve items that had pitched themselves over the cliff edge! It occurred to me that one wheel, made of nylon might have bounced unheard in the cacophony, and, err well, being a wheel, it might have rolled off into the distance?! Now I have a terrible confession to make; in being so preoccupied with every immediate task, I had wilfully, and for far too long ignored the accumulating mess under... and indeed across the entire environs of my workspaces. I had forgotten just how evil it had all become in the dark recesses, nooks and crannies of the cellar floor! Crawling around amongst a myriad of cobwebs, drifts of combined sawdust and entangled swarf, plus loads of lost rusty nails, screws, nuts and quietly rotting timber offcuts was a truly awful, but thoroughly deserved penance. It was also drawn out and completely fruitless. I then turned my attention to moving everything about upstairs, but equally to no avail. Despondently, I had to accept that as it would be impractical to create a "Del-boy Trotter" style bogie, I would have to order a replacement!

This is where it got silly:

We all know the irrevocable LAW: "A mislaid object will reveal itself almost immediately after any remedial action is fully undertaken and completed". With that in mind... and in a moment perhaps even slightly befuddled by it, I decided to order four (?) more! A mere couple of days later they arrived at the door... and I was able to immediately get cracking again:



I wanted to set the wheels up up in the frames, fully gauged and complete with all washers in order to be absolutely certain of the precise frame spacing required for the next stage.

Having three spare wheels in stock was still bothering me though.

A short while later, whilst munching on a lunchtime roll in our living room, my gaze happened upon a small box full of nuts and bolts under the little table I was using:



I had moved the box around several times during the "Grand Search", but as I stared, I thought: "What's that strange, whitish lump at one end in there?"

"Oh no... it can't be... surely?"...



I'd swear I heard a cuckoo... and a donkey braying when that lid came off?

Sigh!

On the bright side; at least I now have enough of the darned things to do yet another wagon?!

I have also failed to mention that on that original order of eight... and fortuitously, (it has to be admitted) for the second batch of four, I had made a one digit error in the supplier's part code - and ended up with wheels having 15mm bore bearings instead of the intended 17mm. I had all the parts ready for making the usual spacers to fit 12mm axles... so I had to think again rather than rely on the familiar and proven formula!

I was able to locate some (claimed to be 15mm) stainless steel tube - with a 1.5mm wall thickness that "should" be a fit...?!

It wasn't!

The 12mm inside dimension was bob on perfect. The outer diameter was only 14.94mm, so I expected a little bit of rattle. The wheel bearings, although quoted in the published drawings to be 15, were in reality a consistent 14.54mm! Not even close! The tube wouldn't fit in my chuck either, so it had to be clamped with nuts on a 12mm section of threaded rod to "spin" it down to size!



It was a bit of fun, but seven squeezed in nicely - eventually... although it was only much later that I discovered the eighth to be an awkward wrong-un!!

Apart from that one wheel being very slightly wonky on it's axle, (I will sort that out as soon as allowed) both bogies run very sweetly so far...




The next stage provided even more unexpected "entertainment"... but more of that later.

Pete.

 

[Osgood]

So one more axle is enough for a second carriage.
Just sayin'.....

 

[Peter Insole]

Bringing the account up to date for this week, as promised yesterday: While I still have the messy task of reprofiling the wheel flanges, I nevertheless was keen to get them set up to gauge the precise distance between the frames for the next task.

After studying as many different designs of arch-bar bogies that I could find, I had to make several of my own decisions based on what I felt was practically achievable within the restrictions, materials and tools available to me. With my axles firmly fitted into deep axleboxes creating a completely rigid setup, (something that has already proven, for various reasons, to be efficacious in our own peculiar operations) I still thought it would be wise to extend the lower, spring pads (common) into a continuous plank - thus adding additional stiffening to each structure. The idea appeared to be simple and straightforward enough... and as usual relying on the preferred process of clamping up and drilling through each screw hole for reliable accuracy, but the actual matter of doing so with the axles and wheels (necessarily) remaining in situ called once again for quite a bit of brain straining activity!

The recurring issues of drill travel, distance from column, platter height and clamping positions seems to have become a signature feature of these bogies so far - although I'm hoping the worst may be over now?!

After much frustrating experimentation, I finally settled on using a lump of timber offcut (again!) to clear the wheels and frames from the platter, but none of my clamps could be persuaded to grip on any part of the structures, so a bit of bodgery was required. A scrap of the steel bar was found that was just long enough to cut two straps from... but then the drill vice had to be reassembled in order to open out four holes in them. I then needed to find four lengths of suitable studding... but following much searching only enough for three was forthcoming! An overlong coach bolt was however discovered, and it eventually sufficed by the use of an extra pair of penny washers and a bundle of over sized nuts to act as a spacer! I had to dismantle the vice a second time to clear the platter and set it all up.

I needed to drill through eight holes for both bogies, but the location of the slots in the platter meant that each operation required the clamps to be completely stripped down and the bogie re-positioned - even when holes were paired immediately adjacent to each other.

I kept thinking "there must be an easier way to do this?"! Try as I might though, I damn well couldn't find it!



It did occur to me that using countersunk screws for this part would have been a neater approach, but the added complication was just too much to bear... so the "armoured fighting vehicle" appearance will have to suffice!



The trick was once again to drill each hole, and immediately bolt it up in turn... so each time reducing the possibility of unwanted movement between the pieces - and thus reducing the need for additional clamps in such a restricted space.



Above is the first plank fitted in place! I do still have to shape off and drill the ends for spring keeps... but that can be done later whilst flat on the bench, and with a degree of confidence that it will all line up true when the planks are bolted back on for the final time.

The screw positions will preclude placing the coil springs in a more traditional location within the frame box structure, but I'm hoping that might be an advantage in the overall design: The bogies are quite narrow by comparison with the overall width of the carriage... and the relatively high centre of gravity imposed when the vehicle is fully laden, (!) so from concern about leverage, or "bending moments", I felt that moving the suspension points as far outboard as practically possible might be an aid for the ultimate stability and comfort of the ride?

It remains to be seen if it all works in the end though?!

Pete.

 

[ovener]

Very proper looking bogies there Peter. Do you have a suitable name for them? Commonwealth is already taken so how about Centurion as that reflects their solid nature?
Richard

 

[Osgood]

Has to be:

 

[Osgood]

I can just imagine him rolling up in an old 359 Peterbilt!

 

[Peter Insole]

Whilst it was not exactly a Centurion tank, mention of such things reminds me of an occasion many years ago when I worked as a young Technical Illustrator at Marshall's of Cambridge in the Aircraft Design Office. Although the latter title gives a partial clue to our usual projects, we worked mainly on MOD stuff - which sometimes included specialist military vehicles.

One afternoon, a splendidly turned out gentleman from the "Ministry" turned up with a large roll of drawings... and a fabulously large scale model of what was then the latest design of "Fox" armoured car. Our department chief was there to meet him in the gangway, and directed the chap to a spare drawing board (with a large desk behind) in order to take the briefing. The "tank" was placed on the desk top, and the drawings were unrolled on the board. As the two men had their backs to the desk, and were busy discussing the details of the important commission, neither of them noticed that "someone", or rather three "someones" who were in on the wheeze, had sneakily removed the model and placed it on the floor... a couple of work positions behind. The perpetrators laid down around the machine, and at the very moment the two men turned to see an empty space; there arouse the sound of combined "tank noises"... including a very good representation of muffled radio coms!

We were all far too scared to laugh... and how the governor retained any sense of composure is quite beyond my comprehension. The poor fellow almost fainted! It was only when the "Gent" had recovered from a few moments of initial shock, and then started smiling, that we all relaxed and cheered as the model was sheepishly returned!

Incidentally, One of those wicked chaps (a senior draughtsman) got the job of doing a three-quarter "outline" illustration of the vehicle from above, with "ghosted" internals, and I was ordered to do the main point of showing the crew in action at their stations!

I am given to understand that large copies of the finished piece of work were distributed to Army recruitment offices around the country. I sometimes wonder if any survive and might surface again one day?

As for the "Guv", The lovely man was a bit like a sheep dog desperately attempting to round up a flock of starlings... and he gave up trying to keep us all in line a short time thereafter. He went off to work for the "The Welding Institute" at nearby Abington. I do hope for his sake that was nice, calm and sensible place to finish his long career?!

Pete.

 

[jcm@gwr]

Many years ago I worked in engineering (packing industry), one of the guys used to work for de Havilland,
and moved to Hatfield when they merged with Hawker Siddeley.
Apart from making long range pea shooters to disrupt the motorcycle Police hiding behind trees on the A1,
in front of the main building, the best story involved flies!
Because fly 'squish' could be corrosive to the outer skin of aircraft, there was a small department dedicated
to breeding flies, so they could be doped, and fired out of special guns at sections of aircraft.
Someone in the R&D dept. realised this could be exploited for entertainment, so they started to make small,
lightweight model planes. Then they would choose flies, super-glue them on, and have races in the drawing
office, which was really long!
This was great fun, and easy to hide when necc., but one guy got a bit carried away, designed a larger plane,
even spent time finding matching flies, unfortunately, during the maiden flight of this '4 engined bomber' (which
even sounded like a bomber, according to Derek!) the MD brought in an important client in the middle of a tour.
Of course by the time the MD recovered from the surprise, everyone was at their desks, and strangely enough,
no-one knew anything about it!

 

[Peter Insole]

This afternoon, my real life guardian angel said; "Oh all right then... but only light duties mind!"

At last I had permission to (gently and in measured fashion) tackle the one, odd "wonky" wheel that I mentioned a couple of posts ago, and has been bothering me since confinement.

You can see a larger part of the central nut is visible toward the top of the image below...



When the outer wheel nut (between wheel and frame) was tightened hard down onto the washers and inner race of the wheel bearing, it left a tapered gap where it met the frame, as below:



It might not look much, but it was more than enough to generate a bit of discernible drag... that could even be heard making a slight swishing sound on the rail head.

My thoughts had been throughout that the problem must surely have lain with an error in the home-made axle/bearing bore spacers, or maybe I had not noticed that one of the thick, pressed, M12 washers was distorted or badly burred during the initial assembly?

Today, down on the workbench, I stripped down the offending wheel and axle and carefully examined each part... but nothing appeared to be untoward! Nonetheless, I decided to change all three washers... and set it all back up.

No change whatsoever!

"Right" said this particular Fred"... "Nuts then?"... or words to that effect!

Stripped it all back down... and starting with the one furthest from the axle end... I replaced it with another brand new one, (as indeed they all were) fresh out of the bag:

Ah-hah!



Straightaway, straight as a die!

The same could not be said however of the offending nut... to the left in the view below:



Although it might be difficult to discern in the image - apart from the fairly obviously mullered thread, but the bore is actually slightly over size, off centre... and in that view, running downhill.

In fact, somewhat worse than if I had tried to cut it myself!

Ah well, that freed bogie goes like the clappers now... and the naughty nut - has been chucked in the wheelie bin, just to make absolutely sure it doesn't come back to haunt me!

Pete.

 

[Peter Insole]

If it were not for the persistently uncomfortable reminder of my recent surgery I would be cheerfully wading in to the next task on these bogies.

I did however take a chance yesterday of cutting the two lengths from the steel channel for the bolsters, and then offered them up for planning:



Whilst awaiting the delivery of two sets of both "heavy" and "medium duty" (for 7 1/4 inch gauge) springs ordered on Saturday, I placed four of those previously described, but ineffective die springs in position - just to get the impression of how it should all fit together!



I have an awful lot of chopping and shaping still to do on these bolsters, particularly at the open ends where I want to remove a large part of the vertical flanges back as far as the frame columns, primarily to allow sufficient fore and aft "float" for the bogies.

The benefit, if that is the right term, (?) of setting it up like this was to be better able to assess what other actions might be required... and sadly as a result, I realised that I had shot myself in the foot somewhat with the decision to extend the lower, spring plank all the way across to link the paired bogie frames!

It was intended to have the vehicle weight supported on the bolster at the centre pivot pin and a pair of bearings on angles, set just behind the frame bars, (which also would restrict side play) but with no vertical suspension at those points - as I am concerned about the likely deflection imposed when the carriage is running fully laden. The outer springs would only provide the absolutely vital roll control.

What I had not considered was that as the bogie follows rail unevenness or gradient changes, the lower plank will effectively move fore and aft in relation to the constant centre pin! Any thoughts of adding some form of spacer in between the plank and bolster are now clearly out of the question, so I guess there will have to be another, very sturdy spring - or perhaps some other device - applied in the middle?

Hmmm! Much to think about.

Pete.

 

[Osgood]

Are you trying to limit sideways movement of the channel which carries the chassis/bogie pivot?

Maybe some stops attached to the sides of the channel just inboard of the vertical bolts?
Perhaps some black nylon rubbing blocks held on by setscrews into threaded holes in channel sides - seeing how you so love tapping holes
Only 8 per channel!
Actually, just one per block would do, and if loose will allow some rotational movement to maintain full contact along side of side frame bolt as the spring compresses / extends although angle change of channel is minimal.
Not only that you'd get away with a block on only one side of each channel end -that's only 2 holes to drill and tap per bogie!

.

 

[Peter Insole]

Spot on thank you Tony! I intend to maintain lateral control by making bearings on angle brackets fitted in similar fashion (although modified slightly) - but further outboard... as indicated in the cropped image below:


(cropped copyright image shown for illustrative purposes only)

On this, and the majority of other examples, sideplay is restricted by the lugs cut or cast in the ends of the bolster (green arrow).

My problem was hoping to prevent vertical deflection movement of the entire bogie at it's axial point - with the bolster effectively only permitted to rotate. Pitch would be free by allowing the frames to rotate around the bolster ends, and roll would be controlled by the springs!

A simple idea, but it seems to have turned into a puzzle about what to do at the bolster centres.

I cannot afford to have much - if any - vertical deflection at the centre pins, as the carriage solebars and footwell were deliberately designed to be as low and close to the railhead as practically possible! I could do something about that... but remain concerned about issues with the centre of gravity?!

Pete.

 

[Peter Insole]

My sister sent me this cartoon via her Whatsapp messages recently:


(Copyright image from unknown source, but shown here for illustrative purposes only)

I think she has me pretty much sussed eh?!

With everything suspension wise up in the air waiting for me to make up my mind, I eventually decided to go ahead and order two sets of four springs from SMR Engineering. They market them as suitable for 7 1/4 inch gauge rolling stock, and are listed as; Medium, (standard) or "heavy (er) duty"! Although the initial expense was not that great, my reasoning was that I could try each type out as a minimum, and if it evidently required more of the same - or indeed something completely different, I wouldn't be left with too many items that I might have difficulty finding a use for?!

When they arrived it became immediately obvious was that I would at the very least need to install two of the "sturdier" springs on each end of the bolsters... and so I confidently started drilling more holes:



Firstly, 5mm in the lower planks for tapping out M6 to fit some spring locating "studs" there, and then after carefully aligning and clamping them on top of the upper channels, I used the fresh bores as a guide to ensure that the springs should sit perfectly upright in the frames when reassembled.



I initially pencilled orientation marks on each piece, but quickly realised something less easily erased would be a good idea... and reached for the box of alpha/numeric dies and a hammer!



As an interim measure I did feel it was worth seeing if the medium springs on the inner studs might have an effect on the overall compression rate, but I have to say that the arrangement made a negligible difference!

I also realised that the only realistic way to install the springs - especially the inner ones - was to have both planks out of the frames!

Fortunately, the metal is fairly thick, so there appear to be enough thread turns to lock the screws tightly, and I was therefore happy to be able to cut the free ends flush on both upper and lower faces:





Doing so made the process of sliding the complete assemblies back in position... and dropping the fixing screws into their holes between the springs, (with the aid of a pair of tweezers) was perfectly straightforward.

I am just awaiting the second delivery of springs, plus four new ball race bearings for the bolster top castors to reach the final stage of construction!

Phew!

Like the old military Generals of yore: They thought it would all be over by Christmas too...

Ha!

Pete.