Sorting out the accumulated part done and not yet started things workbench

[Martin Shaw]

So I made a bearing, it was dimensionally accurate and would have done fine, but that nagging feeling, if in doubt look in the most unlikely place, which I did.

Some words were expressed although somewhat less than had I made all six. At 71p each there is really no sensible reason to make them from bar, despite being able to, far better to concentrate on the things that have to be made. I blame the storekeeper, who lived up to his title.
Regards
Martin

 

[Martin Shaw]

Just to prove I can make things, todays offerings

the rear and intermediate frame spacers, the front spacer with motor mounting bracket which will also have the drag pin added, and the motor drive coupling. I was going to make this in steel and then thought it would be better if one half was wearable, this bit is easier to replace. Nothing very hitech I realise but it all has to work nonehteless. Tomorrow I hope to finalise the drawing now everything is decided upon and produce the frames.
Regards
Martin

 

[Martin Shaw]

Drawing finished. Martin

 

[Martin Shaw]

More progress today, the frames are milled to shape and just require the spacer holes drilled, I am probably not going to use plungers there will only be 1.4mm twixt wheel and frame, it might work, I need to erect it and see.
Kind regards
Martin

 

[simond]

Martin,

these pickups (my iteration of DLOS’ design) do not need any more than fag paper clearance between frames & wheels.

Second hand Duchess

If you want any details, please shout!

Atb
Simon

 

[Martin Shaw]

Last evening I realised over dinner and a glass that I had a problem, I'd eaten too much and I like drink, actually not those problems but more seriously the design of the front frame spacer was in the way of the front screws that hold the body to the frames. Fortunately nothing I had done was adversely impacted and an overnight thought showed a way forward. This involved some redrawing and additional front elevation and scrap plan view to make sure it all fitted, which was todays effort and isn't worthy of a picture, it should all come good tomorrow. I'll have another look at your Duchess thread Simon, thanks.
Regards
Martin

 

[Martin Shaw]

After two days of some tribulations where despite the supposed attempt at planning and drawings and stuff, and where things didn't work out initially, a revised set of thinking has produced this, you'll note the completely revised front spacer arrangements, the need for which which can only be put down to poor thinking through things on my part. The pick ups are still at a pre decision stage, SimonD 's Duchess is a good idea but I only need them on one side and the motor is in the way on the front wheel anyway so I think scrapers will be the answer.

At the moment you have to remove the middle spacer to take the motor out, desparate lack of thought on my part again, but I presume the motor shaft is hardened so presumably a grinder to shorten it?
Regards
Martin

 

[Mike Garwood]

A slitting disk will get rid of it easy enough. Just wear eye protection as it will generate sparks.

Mike

 

[Steph Dale]

Martin,

As Mike says - just block up any holes in the motor case (blue tack/masking tape) and make sure the bearings are protected (masking solution/blue tack). Oh, and hold the shaft when cutting, not the motor case, otherwise you'll stand a significant chance of damaging the bearings with the vibration.

Steph

 

[Martin Shaw]

Well it's taken it's first tentative steps all be it still on a lead.

I managed to find a way to insert the motor (up from underneath) without cutting off the rear shaft. Initially it ran a bit lumpy so I turned up a flywheel, which despite it's small size has made a perceptible improvement. What was shown up was the poor state of the locomotive part of the drive arrangements, there is a noticeable lack of concentricity around the joints of the flexible coupling which is definitely vibrating and there is a bit of end float despite it running in two ball races. The worm/wheel mesh is perhaps not as tight as it might be and the ration is too low at 14:1, the almost doubling of the motor speed makes low speed control less than ideal. Using info from the Guild manual suggests 26:1 would be idealish so a 30:1 is obtainable. I'm considering making a gearbox using some 0.75" ali channel 1/8" thick. It will mean putting in brass axle bearings and possibly a ball race for the input shaft, but brass channel of this size is exorbitantly expensive. Still thinking this through but whilst I understand how to do it, I am not actually certain whether I'm capable enough, more pondering as an excuse to do nothing.

Regards
Martin

 

[Steph Dale]

Martin,

No hard sell, of course, but a cheeky reminder we do a self-contained 26:1 gearbox as a variant of our 13:1 'Remote' - might help?
Planning template here: http://finney7.co.uk/Downloads/Planning_templates_Branchlines_v0,4.pdf

Steph

 

[victorianman]

Hello. I'm quite interested in all this as my tender locos all have the motor in the tender with drive to the loco.
Have you worked out how you will attach the tender to the loco, and whether there will be problems keeping/getting the drive shaft into place?

 

[Martin Shaw]

Steph
Two questions, how is the drive shaft captive to the geabox itself and what is the distance between the axle centre line and the input shaft centre line? I am hoping that by having a gearbox I can do away with the front thrust block, and investigation has shown the mesh of the worm to wheel is poor, excess play between forrard and backard, and hellish noisy, I think a well worn worm wheel but I don't want to dismantle anything until the course is decided upon.

Victorianman
I'll take some pics tomorrow that will show how it all fits together.

Regards
Martin

 

[Steph Dale]

Shaft to axle distance is approx. 8mm. The gearboxes hold the shaft by attaching the bearings into front/rear cover plates which are held in place with screws. I usually assemble the gearboxes 'free' to get them running with the input shaft and an appropriate axle. I can then release the axle and feed the axle through the chassis bearings/gearbox once I know it runs properly.

In your application, a torque reaction arm would be necessary to stop the gearbox winding itself around the axle.

Steph

 

[victorianman]

Thanks, Martin.

 

[Martin Shaw]

Especially for Victorianman
This shows the drag link between the loco on the left and the tender on the right. The two vehicles have an 8BA pin with a collar to hopefully minimise wear on the threads, and the link is held in place with nuts. This should keep the loco and tender at a fixed distance from each other along the centre line which is also the line of the drive shaft.



This is the separated drive components. The tender motor shaft has a bored out collar with a slit on each side, this bit of it is 10mm long. The loco has a ball with pegs that fit inside the collar allowing both radial movement on curves and also easy separation if necessary. Next is a bit of curtain wire that provides flexibility in all plains and final two thrust blocks with 0.5" OD ball races that keep the worm in place on the worm wheel. This is all pretty badly worn so I'm investigating how I might re-engineer it. It was obviously put together from the bitsa box and to be fair it worked well enough but I felt something a little more sophisticated was in order.


Regards
Martin

 

[victorianman]

Thanks, Martin. Yet another way of achieving both a draw-bar and a distancing piece.

 

[Martin Shaw]

All of the material arrived on Thursday, apart from the gears, which I am informed are on the way. Today I made the gearbox housing, I went for brass in the end and I have had to relieve the top edges which foul the throatplate. They need a bit more yet, fortunately the rear section is clear. I also cut the drive shaft overlong and mounted the front bearing with a turned spigot. It is an interference fit on the shaft and a snug fit in the gearbox, a drop of suitable Loctite to secure it on final assembly should be adequate. The rear thrust block needs a bit more thinking yet because there is really only the firebox to locate it and I want to minimise the unsupported overhang of the shaft at the rear to inhibit vibration.
Best wishes
Martin

 

[Martin Shaw]

It has moved on a bit, the basic driveshaft assy is complete and lying in front of the loco is the rearmost part which will be in an adjustable coupling to precise set the ball joint. I have found two issues, since it now has a gearbox which floats on the axle there is enough sideplay to axially misalign the shaft at the rear bearing which is going to be solved by a fixing to the frame which will also provide the torsion bar. Secondly the frame and it's spacers are all screwed together and as a I discovered relatively easy to get out of line so I need to strip the paint and solder the spacers in, as it is the paintwork is chipped in places so no great loss. This has turned into the massive rebuild that I was initially keen to avoid, ho hum. If you have looked at the small ads I am trying to move on stuff apace but a new kit is possibly on the horizon, I like most others don't need anything else but why let common sense get in the way.
From a very wet Scotland
best wishes
Martin

 

[Martin Shaw]

I've got it to the point of testing as well as some major aesthetic improvements to the loco frames, a lot of the surplus holes have been filled and cleaned back, and new hangers for the brake gear installed. The frame spacers are now all soldered in which has stopped the frame twisting.

It works, and quite well if I say so myself, certainly better than the original installation but perhaps not as well as I might have wished for, shaft alignment is critical otherwise the vibration is horrendous and I'm not at all certain it would remain adequate in service. I think that I was perhaps naieve in thinking that I could engineer a major improvement in what was a compromise in the first place, I couldn't but I would be the first to accept that part of the exercise was to try and if it wasn't and indeed isn't a stunning success then so be it. The alternatives are lying in front, it appears to be enough space in the firebox so a little trial will determine the outcome although I would rather not use the helical 2 stage if I can avoid it.The advantage is that in removing the metallic connection between the loco and tender suggests american pickup which avoids other issues. The motor and gears purchased for the project can be built into a motor/gearbox, that bit has worked quite well so the only real loss is some bearings, into the spares box they go. A cul de sac that I could have avoided if I hadn't been quite so keen to remain true to the original builders intention but most certainly not a complete waste of time, I have learnt some things.
Regards
Martin