|
Post by Deleted on Jun 7, 2018 17:59:56 GMT
That looks impressive Bob...as you know I'm in need of a stand and shall have to give it some proper thought soon..I like what you've done here, it removes the damage sustained when fitted by the buffers etc..I do have one concern though. perhaps your horns are secured better than mine but for me that would mean the entire weight hangs on the threads of 12 5BA bolts? I don't see how such a weight could be supported this way?...it may work if the hooks clamp onto stretchers though, I lift the chassis by these all the time, admittedly there's no boiler on her yet so much lighter but looks promising for jobs before fitting that...I like this possibility sir.. Pete
|
|
|
Post by 92220 on Jun 7, 2018 18:29:51 GMT
Hi Pete.
I am rotating only the chassis. Definitely not for use upside down, with a boiler in place! A different means of clamping could be worked out. If you have good solid stretchers then, as you suggest, these could be used to clamp to. Failing that, narrow clamps that go up between the wheels and the frames and clamp on the top edge of the frame plates, would also work. The judicious use of thin polystyrene sheet would protect the paintwork. I was going to clamp it that way, but then decided that making hooks to clamp on the axles works for me. I also have the advantage that the ends of the springs are captive in the spring hangers which are part of the stretchers. Another possibility is to clamp into the rear dragbox cavity where the drawbar goes, and by removing the front drawhook, that hole in the front bufferbeam could also be used. Another, possibly easier way would be to have a good size steel bar on top of the frame edges, front and back, and just clamp it all down using 2 pieces of M10 or M12 studding, with something to protect the paintwork on the top edges, under the clamp bars.
Bob.
|
|
|
Post by Deleted on Jun 7, 2018 18:58:41 GMT
I like the idea of clamping the top of the frames Bob, I can see that being very secure...nice design sir..
Pete
|
|
|
Post by 92220 on Jun 8, 2018 16:39:47 GMT
Hi Pete.
I thought about what you said about the weight being held on a few some small screws so decided to look at how anyone's loco chassis could be clamped. Like you, I've decided to go with the clamping on top of the frames. I've used some MDF to prevent metal to paint contact too. Hopefully the weather will allow me to get take the loco outside to get some photos of it on the stand.
Bob.
|
|
|
Post by springcrocus on Jun 8, 2018 22:50:05 GMT
I'm assuming that Pete is referring to the twelve (twenty in Bob's case) horn keep bolts at the bottom of the horns and agree that clamping the axles would be a vunerable way of securing the locomotive when inverted. I'm sure that Bob's new proposal will be a much better solution and am probably going to follow in his footsteps.
Regards, Steve
|
|
|
Post by 92220 on Jun 9, 2018 16:23:24 GMT
Well the weather decided to be kind. I was able to take the loco outside to put it on the build stand to take some photos. Here they are: This is loading the chassis from the lift truck, onto the build stand: These are showing the stand with the chassis strapped down and then rotated: and finally (promise it's NOT Photoshopped!): Hi Pete and Steve. These are the new clamps that sit on top edges of the frames, to clamp it all down, rather than clamping on the axles. I have to admit that it is a much better way to clamp down. I used MDF to protect the paintwork, and it did it very well. No visible damage whatsoever. Now I know what the word 'trepidation' means though!!! I have to admit being VERY wary when I turned it all upside down!! I really shouldn't have been bothered. 2 x M12 316 stainless studs and nuts, and 8mm x 25mm clamping bars, was more than enough!! I'm not sure how clear the pics will be so I took some more from the other direction, with the sun on it: Now I've just got to chop the workbenches about to get it where it can be used!
|
|
|
Post by 92220 on Jun 9, 2018 16:26:46 GMT
Sorry. These are the new clamps I forgot to include the PB code for: Bob
|
|
|
Post by Deleted on Jun 9, 2018 18:00:22 GMT
absolutely brilliant Bob, I'd be more than happy to support 4472 on a rig like that, I really, really like this stand..........next time my son visits I'll show him your pictures with a little nod that perhaps he might consider making it for me.... Kind regards Pete
|
|
|
Post by silverfox on Jun 9, 2018 18:22:55 GMT
Oh WOW
When you said rotating, i thought you meant along the longitudinal centre line, using the drag and buffer beams. No w iahve seen yours i cannot get it out of my head that you are going to rotated it very quickly and throw knives at lt, a variation of the old variety acts!
|
|
|
Post by springcrocus on Jun 9, 2018 18:25:26 GMT
That's me sorted! I will start saving my pennies straight away. Thanks, Bob.
Regards, Steve
|
|
|
Post by Oily Rag on Jun 11, 2018 2:21:33 GMT
"Proper job" A fully aerobatic 9F
|
|
|
Post by 92220 on Aug 8, 2018 17:58:17 GMT
It's been a little while since I posted but I haven't been slacking! I've been working on the Cab Platform and Underframe. I've been working with the works drawing and it is a minefield to understand (and I'm an indentured draughtsman!). They have views out of position and have omitted important views to show how parts fit Some parts are shown separately and fully dimensioned and some parts are just dimensioned on the assembly and everything looks a real muddle. Anyway, I finally worked out the shape and dimensions of all the parts, and have drawn them up. I have also made most of the parts and assembled them. How do you have around 40 separate parts, made from 0.9mm and 0.6mm BMS sheet, and silversolder them in place as a progressive assembly. By that I mean something like 8 or 9 parts were silversoldered together. Then some more parts were made and these silversoldered in place. All together I think I must have carried out around 15 separate silversolderings. How do you stop something like this being ruined through distortion? Actually quite simple. Model engineers tend to shy away from making jigs because it takes up time and materials, but that is the only way to prevent distortion, and with an assembly like this, ensuring that all the bits are in exactly the right place. . I am about to silversolder the platform arm webs that support the chequerplate floor that projects over the front of the tender, at the rear of the cab. I haven't got the chequer plate yet so have made up a jig to ensure everything ends up flat. The photo shows the assembly jigged up ready for soldering. To ensure the distortion is negligable, after silversoldering, the assembly was allowed to cool down naturally while still jigged. When cool, it was then boiled in water for around 5 minutes to clean off all the flux. I have the pedestal supports to fit and then it can be bead blasted clean, ready for painting. Again, when fitting the pedestal supports, these will all be jigged to ensure they are in exactly the right places, and don't distort. The photos show it all ready for fluxing and silversoldering. Incidentally, Although I have a full Seivert set-up, I hardly ever use it. My silversoldering is all done using oxy propane. The pieces that are actually being silversoldered in, are the 4 diagonal webs that splay out either side of the 2 main platform support arms. The places where they will be silversoldered can be seen in the cut-outs in the jig plate in this last photo. When the pedestal supports are in place, that will be it finished. It can then be bead blasted to clean off all the surface rust caused by boiling to get the flux off, then painted.
|
|
|
Post by 92220 on Aug 8, 2018 18:14:55 GMT
I've just realised I still have 4 more pieces to fit. There are some plates that fit either side and are fixed to those 2 side angles and the strips that project inwards at the ends. At first I thought these were bolted in place as they have bolt holes down each side, and where the seats are fitted. However on closer inspection of the drawing, it is just possible to see welds at the corners, and one reference to 1/8" welds for 3" spaced at 3". i.e. intermittent 1/8" welds, 3" in length and spaced every 3". I have made these but had forgotten to fit them. I shall have to fit them as a separate operation as the plate jig is in the way at each side.
Bob
|
|
Midland
Elder Statesman
Posts: 1,871
|
Post by Midland on Aug 8, 2018 18:30:55 GMT
These are a couple of pics of the hind steps fitted in place on the tender frames
Bob.[/quote]
As always an inspiration, we dubbers learn so much from your work, thanks D
|
|
don9f
Statesman
Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
Posts: 960
|
Post by don9f on Aug 8, 2018 20:10:57 GMT
Brilliant work there Bob.....please bear in mind that the support bracket for the injector water valves on the full size is also welded to the “I” section under the fireman’s side. I cheated on mine and bolted it on! You can just about see the bracket in this photo:- Cheers Don
|
|
|
Post by 92220 on Aug 8, 2018 22:12:33 GMT
Hi Folks. Thanks for those kind words.
Hi Don. Yes I know the water valve bracket is welded on. I've got the drawing out ready to scale it down.You say you bolted yours on but where it is it is the mounting is almost invisible so only you know. Oh. Sorry. Now we all know!!! Actually it makes sense to have it bolted on instead of welded. Why they went for welding I can't understand!!
Bob.
|
|
|
Post by vulcanbomber on Aug 8, 2018 23:06:31 GMT
That looks delightful Bob.
|
|
|
Post by Rob on Dec 25, 2018 16:50:24 GMT
Bob, how have I missed this thread?
I was admiring your chassis at one of the model engineering exhibitions a few years ago (Bristol or the Midlands perhaps?), and didn't realise it belonged to you.
I came across this thread when Googling for images of frame stretchers to design mine!
|
|
|
Post by 92220 on Dec 26, 2018 11:33:14 GMT
Hi All.
Hope you all had a Happy Christmas, and have a Happy and Productive New Year. I'm having a bit of a break from the workshop for the holiday time, so I thought I should get some more photos uploaded to Photobucket.
These are photos of making the wooden floor for the cab. The wood I used is sycamore. It has a very fine grain, which looks almost scale, and is as easy to machine as if it were metal. The only necessity for getting accurate parts is to use a brand new HSS cutter. HSS because I have found that they come in a lot sharper than carbide. Maybe that is because I buy cheap carbide cutters, but HSS has worked best for me with the wood.
In general, when machining the wood, try to hold it in such a way that you can use the side flutes. They make a better finish. I did say 'accurate' parts, earlier. That really is true. I was able to machine the wood accurate to 0.002" for fitting the mortices on the planks, together.
Some of these photos show some of the more obscure parts of the cab underframe, that I should have included in a previous post.
This is the front mounting angle for the underframe, and the underside/front of the pedestal mounting:
This is the top view of the pedestal mounting frame:
Sorry that one is a bit out of focus. I MUST stop using the auto focus on the camera, and set it up manually so that I use a smaller aperture to get the depth of field.
This is a small hinged access plate on the right hand side of the cab floor. I have no idea what it is used for. Note the diamonds are different from the main floor chequer, and also are orientated side to side compared with the main floor and the chequer in front of the firedoors.
This is making the hinges:
A hinge compared to a 5p piece:
When machining the wood, when the cutter is going to emerge from the cut, at right angles to the grain, and possibly split it, I pushed it up against another piece of scrap planking to allow the cutter to emerge into and so stop the plank being machined, from splitting.
The planks are all morticed down each side, to fit together when slid into the shelves on the inner faces of the frame cross-members. The central piece is morticed on both sides so that it fits into the front shelf and then can just drop into place onto the back shelf, where there is a cut-out in the main chequer plate, to accommodate it. The centre plank is locked in with a swivel catch through the plank and engaging underneath the shelf piece. The ring to twist the swivel catch is a 5mm od x 0.5mm sterling silver Jump Ring. Silver because I could buy exactly the right size and in a metal that would not go rusty if not painted. The nut shown for size comparison, is a 10BA.
This is the almost finished floor. I can't finish it completely, until I can mount the boiler in it's final position, because the front corners of the wooden floor, have to be shaped around the rear corners of the boiler to within 1/8" of the backhead and corner mouldings.
I have almost finished the smokebox front ring, and am machining the smokebox door at the moment. I machined up a former from a piece of 1/4" x 1.1/4" BMS flat, to the correct radius, on the mill, with the rotary table. This was then clamped to the lathe bed and a substantial BMS 'finger', with a ballrace, mounted on a BMS pillar, mounted, to follow the curved edge of the former. I then set the tool to near enough the centreline of the chuck, and the follower ballrace to the centreline of the curved former. This made sure the final machined door has the correct curvature. Once this was set up, it was just a case of setting the follower against the outer end of the former and adjusting the topslide to just set the tool cutting when the cross-slide was would in. I then took regular cuts of no more than 0.005" as I found that any deeper made the tool follower push away from the former. When I get back i8n the workshop tomorrow I'll get a photo of the set-up. It's dead easy to do and as long as the final cuts are made with a rounded nose cutter and a depth of cut of around 1 to 2 thou, the final finish comes out such that almost no further finishing with emery is necessary.
Hi Rob.
Yes those are the only 2 exhibitions I put it in. That way, at least there is some progress in the build, to see each time.
Bob.
|
|
don9f
Statesman
Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
Posts: 960
|
Post by don9f on Dec 26, 2018 12:20:20 GMT
Hi Bob, fantastic work as usual and Merry Christmas to you too!
Those chequer plate hinged flaps are a mystery to me as well.....first saw them in the cab of 92220 at York and again on 92203 one day so they are definitely a “BR” thing and not some preservation one. I cannot see anything underneath that would be given access by them and all the ex drivers and others that I have asked have no idea either.
I have an amusing piece of video somewhere, unknowingly recording a good friend of mine suggesting that they are “Driver’s and Fireman’s Pi55 flaps”!
Cheers Don
|
|