|
Post by Roger on Sept 17, 2019 20:32:54 GMT
This is the angled bracket with the twisted top that supports the end of the long bypass valve rod from the cab. It's only 1.2mm thick so I decided to make it from 5mm Gauge Plate so it's as strong as possible. The first attempt used what they call 'High speed pocketing', which turns out to be buggy. If you look at the far end of the LH raised flange, you can see it's taken a notch out of it! Exactly the same containment region with the usual pocketing operations gives the right result. I'll probably not bother with that again! High speed production of scrap isn't much use to me. 20190917_150654 by Timothy Froud, on Flickr This is the long rod push from the cab on the selector valve side. This would operate the front sanding gear on the real thing. The rod's quite long, so I'm making it from 1.5mm Gauge Plate and also making it a 'fish belly' shape, with the middle 1mm larger at 4mm compared to the 3mm ends. It's not that noticeable really and doesn't look odd but it's a lot stronger. This is the pile of swarf greeting me when I came back to it. 20190917_185307 by Timothy Froud, on Flickr You can just about make out the thicker middle section. I've left 0.6mm high triangular nibs 15mm long every 30mm to hold it in place. The rest of the profile it done to the exact depth of the stock. 20190917_185438 by Timothy Froud, on Flickr So here's the last couple of days worth of odds and ends almost finished. I just need to add the fixing holes to the angle bracket. 20190917_212034 by Timothy Froud, on Flickr 20190917_212053 by Timothy Froud, on Flickr
|
|
|
Post by Roger on Sept 18, 2019 21:53:37 GMT
This is the forked end of the long push rod for the transfer valve. (I've renamed this valve everywhere in the 3D model since it more accurately describes the function whereby water is transfered from the riding truck) 20190918_092259 by Timothy Froud, on Flickr I've finally figured out how to combine machining operation in different coordinate orienatations so they can stay in the same model. I've sawn away some of the stock to clear the tool when it goes round the back of the part. 20190918_094616 by Timothy Froud, on Flickr This is tidying up the step for the scarf joint. It's going to be riveted to the long rod then Silver Soldered. 20190918_102530 by Timothy Froud, on Flickr 20190918_113929 by Timothy Froud, on Flickr 20190918_115011 by Timothy Froud, on Flickr 20190918_115137 by Timothy Froud, on Flickr You can see how little has been left to hold this in place so there's not too much to clean up afterwards. I've tidied this up with a file, put it down somewhere and I can't for the life of me think where! I may have to make another one! 20190918_120233 by Timothy Froud, on Flickr I've also made the hex pockets in the valve elements... 20190918_122346 by Timothy Froud, on Flickr ... and machined the cross hole in the right orientation for the hex shaft. This is important because the stops on the arm decide the angular position of the valve element. 20190918_205036 by Timothy Froud, on Flickr Fortunately I've got the right size of 'O' rings so this can all go together for good now. There's a nice satisfying nip on the 'O' rings so I'm sure there won't be any leaks. 20190918_211807 by Timothy Froud, on Flickr I've cut the centre bolts down to the right length, but I've only just ordered the M1.6 Stainless Steel washers that are needed. 20190918_221224 by Timothy Froud, on Flickr
|
|
twombo
Seasoned Member
Posts: 120
|
Post by twombo on Sept 18, 2019 22:25:32 GMT
Where’s it at? Roger, that is a sure sign of CRS! Can’t Remember, Shhh.. . Stuff! ‘I got Dat’ Too! Practice makes.... something! Nice ‘stops’ in those Covers!
Mick
|
|
|
Post by Roger on Sept 18, 2019 22:31:27 GMT
Where’s it at? Roger, that is a sure sign of CRS! Can’t Remember, Shhh.. . Stuff! ‘I got Dat’ Too! Practice makes.... something! Nice ‘stops’ in those Covers! Mick I'm afraid so, it's happening more often these days. I think I was interrupted by a phone call from a customer, and I probably just put it down... who knows. The biggest part of the job is the planning and preparation of the programs, so it's not a big deal to make another one, even though it's about four hours machining. Such is life.
|
|
barlowworks
Statesman
Now finished my other projects, Britannia here I come
Posts: 877
|
Post by barlowworks on Sept 18, 2019 22:42:12 GMT
Of course you realise that once you have made the new part you will find the old one.
Mike
|
|
|
Post by 92220 on Sept 19, 2019 8:17:36 GMT
I'm afraid so, it's happening more often these days. I think I was interrupted by a phone call from a customer, and I probably just put it down... who knows. The biggest part of the job is the planning and preparation of the programs, so it's not a big deal to make another one, even though it's about four hours machining. Such is life. That's a BIG relief!! And thank goodness for that!! I thought I was the only one who could make something then put it down and 10 seconds later wonder where I had put it!!! Mind you. My workshop is not quite as tidy as yours Roger.......by a VERY long way!!!! By the way......superb bit of machining! Bob.
|
|
|
Post by Roger on Sept 19, 2019 8:26:08 GMT
I'm afraid so, it's happening more often these days. I think I was interrupted by a phone call from a customer, and I probably just put it down... who knows. The biggest part of the job is the planning and preparation of the programs, so it's not a big deal to make another one, even though it's about four hours machining. Such is life. That's a BIG relief!! And thank goodness for that!! I thought I was the only one who could make something then put it down and 10 seconds later wonder where I had put it!!! Mind you. My workshop is not quite as tidy as yours Roger.......by a VERY long way!!!! By the way......superb bit of machining! Bob. Hi Bob, I know this is happening more often, so I usually make a very clear mental note when I put something down. When I'm interrupted though, anything can happen. I don't think my workshop is any tidier than yours really, you just don't see what's out of frame! Anyway, I'm currently machining its replacement, so I ought to have that done by lunch time.
|
|
|
Post by Roger on Sept 19, 2019 20:16:47 GMT
Seconds out... round two! This is the replacement forked lever for the one I can't find anywhere. Because the programs had already been proved, it took only a couple of hours to knock this one off. 20190919_110512 by Timothy Froud, on Flickr 20190919_113805 by Timothy Froud, on Flickr It's held in place with a 1.25mm diameter Steel rivet while it's being Silver Soldered. 20190919_164723 by Timothy Froud, on Flickr 20190919_165610 by Timothy Froud, on Flickr 20190919_171929 by Timothy Froud, on Flickr 20190919_171938 by Timothy Froud, on Flickr That's a lot more difficult to lose! 20190919_173418 by Timothy Froud, on Flickr This is the removable bearing for the cross shaft that operates the Transfer Valve. The idea is that with this withdrawn, the links to the valve and cab can be disconnected and the whole shaft complete with the two arms can come out in one piece. I want to permanently attach the arms with pins and a drop of Loctite since there shouldn't ever be a need to take them off. 20190919_173520 by Timothy Froud, on Flickr 20190919_174403 by Timothy Froud, on Flickr I added the fixing holes to the bracket, and also realised that I'd put the big chamfer on the wrong side of the angle! Still, it's not that important and it won't be seen, so I'll just leave it. 20190919_175854 by Timothy Froud, on Flickr
|
|
|
Post by Roger on Sept 20, 2019 15:02:46 GMT
The balance pipe needs two union fittings to be Silver Soldered at 30 degrees from the horizontal so the connections don't foul anything between the frames. That poses a real challenge when it comes to holding it for machining. This is another case where 3D modelling trumps 2D drafting, because it allows you to easily create fixtures that mate with the parts you model. I've already got a fixture for holding the balance pipe in one orientation, so it was a simple job to modify that so it would hold it at a different angle. In this case I don't need a clam shell arrangement, just a nest to clamp the part into. Fixture model by Timothy Froud, on Flickr 3D modelling allows you to create 2D drawings from assemblies as well as individual parts, so this was an easy way to obtain the required offset from the edge of the fixture to the centre of the unions. Fixture drawing by Timothy Froud, on Flickr Here's the fixture part way through printing, I'm using a 15% gyroid fill which results in this fairly fine (0.15mm layer height) print taking just under four hours. 20190919_222221 by Timothy Froud, on Flickr 20190920_100050 by Timothy Froud, on Flickr 20190920_100228 by Timothy Froud, on Flickr I'm using the sprung centre that I use for tapping to do a sanity check on the position. 20190920_104635 by Timothy Froud, on Flickr I used a new 3mm Carbide 4-flute end mill with only 0.25mm depth of cut and very gentle cutting speeds because I don't want to risk anything moving. 20190920_110318 by Timothy Froud, on Flickr The clamp was moved to get to the other side. 20190920_114847 by Timothy Froud, on Flickr Two rings of Silver Solder were wrapped tightly around the stems of the unions, making them stand proud of their final position. Tippex was used around the area to be Silver Soldered in case the Solder decided to run. Everything was smothered in flux to reduce the amount of cleaning up required, and the ends were protected from the direct heat of the flame. 20190920_150118 by Timothy Froud, on Flickr Once turning a dull red, the tops were pressed down with a piece of Titanium Welding Rod to make sure they sat down and the Silver Solder had definitely melted. 20190920_150410 by Timothy Froud, on Flickr The joints filled nicely all round wihtout running everywhere. This is one reason why I like to fit the Silver Solder rather than add it by hand. Another is that you don't have to get it anywhere near as hot and you don't have to keep it hot any longer than absolutely necesary. 20190920_153438 by Timothy Froud, on Flickr I've used hexagonal bases to the unions so the spanners can be used on the fitting without straining the joints. 20190920_153500 by Timothy Froud, on Flickr
|
|
|
Post by simplyloco on Sept 20, 2019 16:16:26 GMT
SNIP I've used hexagonal bases to the unions so the spanners can be used on the fitting without straining the joints. 20190920_153500 by Timothy Froud, on Flickr Roger, that's very nice. Have you considered using Cupalloy's solder paste for this type of work? I'm using it for just about everything 'cos I don't have any Tippex... John
|
|
|
Post by Roger on Sept 20, 2019 17:10:50 GMT
SNIP Roger, that's very nice. Have you considered using Cupalloy's solder paste for this type of work? I'm using it for just about everything 'cos I don't have any Tippex... John Hi John, That's something I've never tried, I would imagine it's ideal for the really tiny fittings and awkward joints where you can't easily make wire to fit. I ought to get some and give it a try. As it happens, the Silver Solder didn't go anywhere other than where it was intended. That's probably because the amount was just about right for this job.
|
|
|
Post by Roger on Sept 20, 2019 21:06:56 GMT
Time to add the last holes to the pump stay for the Transfer valve and a couple of 3mm Dowel holes to make the Anti-Roll bar attachments more secure. I've modelled what I'm planning to do for that so I know that the pipes and valves will clear the torsion bar. I don't plan to fit that until it's been steamed and I can see how bad the waddling is! 20190920_200801 by Timothy Froud, on Flickr Setting up the frames is easy enough. I just clock the top edge to get it parallel with the X-axis and then clock around the large hole where the Weighshaft bush goes. I output the centre of that hole using the same offset used for the holes I'm adding, and just type the coordinates of that hole into the DRO. I Then output another hole and do a sanity check to make sure it lines up with the rest of the holes on the frame. 20190920_210318 by Timothy Froud, on Flickr 20190920_210325 by Timothy Froud, on Flickr There are only two extra holes on the RH frame. One for the Ashpan retainer and this one which is for the cross shaft needed for the Transfer valve mechanism. 20190920_211635 by Timothy Froud, on Flickr The same thing goes for the LH side, but this one has holes for the Bypass valve foot, the bracket for the actuating rod, the cross shaft for the Transfer valve which has two retaining threaded holes too. I've set it up, but I'm tired now, so I'll do that tomorrow. 20190920_215321 by Timothy Froud, on Flickr A further sanity check is the felt tip dotted to show roughly where the holes need to go. These days I tell the CAM software what drill sizes I'm using so that when I load the program I can see what they're supposed to be without refering to the drawing. 20190920_215327 by Timothy Froud, on Flickr It feels odd to look round and see there's not even a chassis any more!
|
|
|
Post by Roger on Sept 21, 2019 12:28:22 GMT
Here's a wobbly video of the blower finally in action today on my neighbour's American locomotive. I tried to show it with the fire door open, but at that moment the blower wasn't sitting down on the chimney to form a good seal since it's not designed for this locomotive. Anyway, despite the seal being a bit dodgy, we raised steam in short order so I'm calling that a success. What's interesting is that you can hold your hand over the chimney and the smoke isn't hot enough to burn it because there is so much cool air being mixed with it. The bottom part did get just a bit too hot to handle, but the isolation of that and the cooling holes are more than enough to prevent it from melting the plastic where it's attached. If you recall, the tiny holes are venting cold out outwards and keeping the sleeve cool. Once we switched over to the steam blower, I kept the power on for about another minute to take away the residual heat in the bottom part. After that time it was cool to the touch. I don't think it would melt even if you just turned it off, but there's no harm in cooling it off like that. 20190921_111804 by Timothy Froud, on Flickr
|
|
timo
E-xcellent poster
Completing 3 1/2 Rainhill .Building 5" Railmotor and waiting to start 3 1/2" King
Posts: 234
|
Post by timo on Sept 21, 2019 13:29:43 GMT
Roger,
Well done on the experimental engineering. It also means that when you come to start testing your loco you will have the kit ready to get the fire going. A bit like making the tender first so that when the loco is done everything is ready to roll.
Best Regards
tim
|
|
|
Post by delaplume on Sept 21, 2019 13:43:09 GMT
Societies of Model & Experimental Engineers ( SMEE )are we not ??...........Nice one Roger !!........all ready for the 1500's inaugural run...
Alan
|
|
JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,976
|
Post by JonL on Sept 21, 2019 16:00:20 GMT
I may try and rip off your design!
|
|
|
Post by Roger on Sept 21, 2019 18:28:15 GMT
I may try and rip off your design! No need, I'll send you the drawings if you like and the STL file so you can print the body.
|
|
kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 573
|
Post by kipford on Sept 21, 2019 19:26:58 GMT
Me too please Roger. Regards Dave
|
|
|
Post by Oily Rag on Sept 21, 2019 20:48:15 GMT
Snipped from Rogers post,
"This is another case where 3D modelling trumps 2D drafting, because it allows you to easily create fixtures that mate with the parts you model."
Now look here, this just will not do, Isambard Kingdom Brunel did not use this new fangled nonsense so there is no justification for this.
|
|
|
Post by Roger on Sept 21, 2019 22:08:48 GMT
Me too please Roger. Regards Dave Can you PM me your email address and I'll send you the model and drawings?
|
|