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Post by manofkent on Nov 29, 2017 15:49:16 GMT
I would welcome any advice on how to clean my loco firebox grate after a run. The loco is LBSC's Bantam Cock in 3.1/2 gauge. The firebox is wide as with LNER engines. The grate is in 3 parts. From left to right, a "ledge" of about 1/2 inches of grate, then a section about 2" wide that swings down to the back of the engine to dump the fire, and finally the third part is a fixed ledge grate like the first part. The ledges do not swing down, and the grate overall cannot be completely removed from the firebox. Looking at the drawings this seems to be how LBSC designed it.
To clean the centre grate is easy, just push it down and brush or rake it as needed. It is the side "ledges" that cause me problems as it is almost impossible to de clinker them, fixed as they are in the firebox. I especially can't get at the bits right behind the backhead. Result - on starting a run with a "clean" loco probably 1/3 of the grate may still have some bits stuck between the firebars.
Does anyone have any suggestions apart from build a different grate and ashpan please?
Many thanks
John
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Post by manofkent on Sept 28, 2017 21:34:31 GMT
George I once saw a 5" gauge tender loco. The feedpump had been put on one of the tender axles. The tender wheels always locked up as soon as the bypass valve was closed. The owner tried weights on the tender, and even laying on it. The wheels would not pump. I concluded that you always need a driven or coupled axle to power a feed pump. I have never seen a driven axle locking with a pump. John
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Post by manofkent on Aug 14, 2017 6:26:32 GMT
Hi I started my journey into CNC with the proxxon MF70 mill. It came as a standard mill plus a cnc conversion kit. It was very simple to set up mechanically, but I did struggle with the PC settings - the configuration of the PC printer port was very trying. However it was an excellent is small machine, and I learned a great deal on it. I used it in metal, brass or steel, making incremental cuts of 2 thou. I made some parts for valve gear, even making a gear frame for a 31/2 gauge loco. Eventually the X axis screw fractured. I got a replacement, but after a while that fractured as well, and the machine now rests on an shelf in the workshop. I used CamBam and Mach3 to program the cnc. I then built a larger CNC Mill. As Roger says it is not hard to do. Having cut my teeth on the Proxxon I use the larger mill all of the time - wouldn't be without it. It was an excellent machine at its .level (small), and I thoroughly recommend it. John
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Post by manofkent on Apr 12, 2017 6:37:58 GMT
Thanks Julian.
I have that copy of Model Engineer thankfully.
I am going to try and cnc turn the chimney from a big lump of steel on my homegrown cnc mill. The mill is an Amolco mill, and my Myford chuck fits it. So I spent an afternoon getting the profile of the chimney taken from your posting as close as possible in CamBam. Transferring it to the mill means using the vertical mill feed as the lathe spindle, with the tool bolted to the table ( about 2" high obviously to clear the stock). I haven't quite completed the CamBam bit yet, and will probably machine it first out of some soft wood with my hand hovering over the emergency stop just to make sure it works and the mill survives!
John
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Post by manofkent on Apr 9, 2017 20:22:20 GMT
Julian.
Thank you. This is very helpful.
John
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Post by manofkent on Apr 9, 2017 15:17:47 GMT
Thanks Julian. That all makes good sense. I had noticed the awkward placing of the snifting valve as you mention. I will move it to the front of the smokebox. I will see how get on making the Y joints, I might keep the horizontal bars between the exhaust ports (but blank) just to hold the arrangement in place.
Where would I find details of the larger chimney you mention?
Many thanks for your help as always.
John
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Post by manofkent on Apr 9, 2017 8:06:47 GMT
Thanks Julian. Yes I will be making the Petticoat pipe from thick walled tube so will go for 1/4 longer as you suggest. I did think the exhaust arrangements were unusual, and had thought that by having an H arrangement as drawn it would restrict the exhaust flow, and possibly blow into the opposite cylinder. Your suggestion of an inverted Y is welcome. Just to be clear is it a Y left to right or front to back? The blast pipe vent is a N0 10 drill size, although Don suggests in his words that it could be smaller. A 20% increase would take it to around 0.24" - is that what you Meant?.
Thanks Julian. Your suggestions are greatly appreciated.
John
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Post by manofkent on Apr 8, 2017 14:27:00 GMT
Thanks both. That makes more sense now. Pete - that's a really neat solution. Julian - I was reading from the model engineer page you quote! I often find I have to read these things a good few times to work it out. (That's what comes of being an accountant by training, not an engineer by any sensible measure).
Julian - why 2 degrees not the 3 that Don suggests?
Regards
John
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Post by manofkent on Apr 8, 2017 9:23:00 GMT
Hello.
County Carlow is progressing well, and I am now fitting the smokebox. Don Young refers to making a square brass plate to secure it in the smokebox, but his description of how this is done is (in my mind) bewildering. This will be the first smokebox I have made. Can anyone gently tell me how the Petticoat pipe is held in place please.
Many thanks
JOHN
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Post by manofkent on Mar 31, 2017 6:37:12 GMT
Once again I highly recommend 2D/3D ViaCAD , at about 130 US dollars bought direct from Punch Software online (it's dearer from other parties) for a lifetime license it is a bargain. There are more powerful tools but it does everything that a hobby user could possibly want , most importantly it is easy to use. A 3D drawing can be accomplished using a bare minimum of the available tools , but with experience other tools can be used to speed up the process , rather like the rest of the hobby. A 30 day trial version is available as a free download. I advise my castings clients to download ViaCAD because using SKYPE allows us to share screens , giving the client much more involvement at the design stage of casting. By using SKYPE I can also give basic instruction on using the software which gets people up and running quickly. Dan. Dan i have been trying Fusion 360 for a while, and like many others here am finding it very difficult. So I read your posting and downloaded a trial of ViaCad. In 10 minutes I was drawing shapes, tangents etc. So far so good. What I couldn't establish is if it will output to cnc code - G code if you like. Can this be done, and if so how? many thanks john
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Post by manofkent on Mar 20, 2017 13:48:19 GMT
Hi John, I don't know CamBam so I can't comment on how that compares to what I use. I also use Mach3 and I think it's ghastly and full of holes. I'm hoping that Mach4 will be better and I'll probably switch to that this year at some point. I'd like to customise it to get the screen into some kind of clean orderly state, but that's another story. I've spent some time looking at Fusion 360 with Paul while waiting for my boiler to cool down. I too find it confusing compared to Geomagic (Alibre) Design. It's probably more comprehensive, but the way assemblies are made doesn't seem as logical. The constraints don't seem as clear to apply either, but that may just be because of what I'm used to. It's a fantastic package though, and I'd certainly use it if I didn't already have one. If you have Fusion 360, you don't need CamBam though, because all of the CAM functions are built into it. Optimising programs is the key to productivity, and the only way to get good at that is to play with it. I'm hampered by having to keep the noise to a minimum and not having flood coolant. Still, time isn't really that pressing, so it's not a big deal. I'm not sure I'd bother converting a conventional lathe to CNC. You really need an indexing tool head for it to be of much value in my opinion. You can obviously make things like buffers more readily, but the number of times I'd use one for volume work wouldn't make it worth the effort and cost of conversion. I very occasionally use the Mill as a CNC lathe, but you need 20+ parts for it to be worth setting up. What sort of jobs had you got in mind for it? Hi Roger regarding the CNC lathe - you have made me stop and think now! My CNC mill was also sold as a myford attachment, and the spindle is threaded for a myford chuck, so I could always use a chuck from my ML10 lathe on it and use it as a lathe if I needed. the fact that I haven't probably is probably proof that I don't need a CNC lathe. Mach3 - I know what you mean. The computer interface doesn't really flow very well, and extreme care is needed if it becomes necessary to interrupt a job. But I guess like many other things we use we find acceptable work arounds where they could be better. I looked up Geomagic - it looks expensive! Anyway - finished making the inside valve gear expansion link and related parts this morning. Not one of LBSC's better designs I think. John
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Post by manofkent on Mar 19, 2017 10:29:28 GMT
Hi Roger. Did you use a ripper mill on the finish cutting shown in your photo? I built a small cnc mill (used an Amolco/ Rodney mill as a base), and I find I use it almost constantly now. I have not yet attempted a dish profile like yours shown, but might do so now I have seen your excellent photos. Thanks John Hi John, No, I used a 6mm 4 flute to finish off the inside of the door with 0.05mm overlap and 1M/min. That took about four hours. It's annoying that I didn't spot the error before I started that, it would have saved a lot of time. I couldn't use a ripper to finish that particular job because it wouldn't have got into the little corner at the end of the dished shape at the rim. For a shallow dish like this where the centre isn't important, you don't need ball nosed cutters. In fact, I rarely used them at all for anything 3D, flat bottomed cutters can achieve acceptable finishes and create tight concave radii. What CAM package are you using? Hi Roger I am currently using CamBam (and mach3 on the machine). CamBam is sort of 2d plus, great for carving out valve gear parts with forks and bosses. I plan to fabricate the smoke box saddle, door and ring rather than use a casting. i am trying to work with Fusion 360 but I find it quite hard to visualise in 3D. Still - keep at it and one day the penny will drop. The more I use cnc I am realising that there are often many ways to the same end - the slow way (usually mine) or other more efficient ways. For example I recently carved some trunnion links for my schools class build. The first one took 12 hours! i made another pair yesterday in about 3 hours! I did train as an accountant, not an engineer though! a friend gave me a MYford ML4 lathe recently - to be converted to cnc when funds allow. John
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Post by manofkent on Mar 19, 2017 8:08:21 GMT
Hi Roger. Did you use a ripper mill on the finish cutting shown in your photo? I built a small cnc mill (used an Amolco/ Rodney mill as a base), and I find I use it almost constantly now. I have not yet attempted a dish profile like yours shown, but might do so now I have seen your excellent photos.
Thanks
John
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Post by manofkent on Mar 19, 2017 7:51:23 GMT
Thanks Malcolm and Julian. That was a nice surprise. It is probably a bit big for my 3.1/2 gauge locos, but it would be nice to give it a try.
I searched this site for Linden injectors, and found a thread by Julian on injectors. There you mention Fred Laroche who I knew as a teenager. He came to our club most Saturdays (always I recall with Mrs Laroche) with either a blue Helian Lassie named "Great Northern", or a 5" 2-6-0 Southern tender loco named "Groombridge". I spent many happy hours driving one or the other. They were excellent locos, and of course the injectors were faultless. You could put steam on first and they would still pick up, almost any reasonable pressure. In fact I think many of the other locos at the club had his injectors - I didn't realise at that time that he made and sold them - probably sold many at the club as well.
I think he had a third loco but I can't remember what it was now.
Fred was a very practical, understated and down to earth man. He was very patient, not a cross word ever, even when I steamed "Groombridge" only to find that dreadful bubble in the glass, and blowing down left its true reading on the bottom nut! He just told me what to do "tender pump - quick". Groombridge also had a donkey pump that was put to good use that day!.
Happy memories - nearly 50 years ago now.
John
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Post by manofkent on Mar 18, 2017 16:11:05 GMT
Hi all. I had a big clear out of a cupboard in my workshop today. I found an injector - I would estimate about a 20 oz size. I would be interested to know if it is a commercially made item , as it has the markings "EJL" on one side, and the number 100 on one end. These markings are very neat, I would say they could be etched rather than stamped. I appreciate it probably won't work, but am curious about its origin. By the way I reckon it came from a Heilan Lassie, as I once had a lot if bits of this loco.
Any ideas most appreciated
John
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Post by manofkent on Mar 16, 2017 8:09:30 GMT
Hi Marc, I rather like the butterfly doors. As pault says they were treadle operated, and were ergonomic for the poor fireman shovelling tons of coal into a Bulleid Pacific firebox that was greedy of coal due to the poor Le Maitre draughting as applied by Bulleid. The NRM has a full set of drawings for the Bullied SR Merchant Navy Pacifics, and many details of same are in various books showing the butterfly door details. It was a USA design originally I believe, and much used overseas. Think of the weights involved in fullsize on the firehole doors and those small gears. The treadle cannot be operated manually. Hence the steam or air operation via the treadle plate. Cheers, Julian My Dad was a fireman and driver at Stuart's Lane in the days of steam. He described firing the Bullied Pacifics as "shovelling coal going downhill" - presumably due to the poor draughting Julian refers to. nothing really to do with butterfly doors but interesting anyway. John
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Post by manofkent on Mar 14, 2017 6:30:03 GMT
Roger, Apologies if i I have missed this earlier but what material do you intend to use for the smoke box O ring? I have always assumed the smoke box can get pretty hot. I remember a full size tank loco (in Germany) with a dull red glow to the smoke box after some pretty hard work.
I guess the usual silicon rings may not be sufficiently heat tolerant?
Thanks for all your postings - especially the pictures.
John
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Post by manofkent on Mar 9, 2017 9:26:42 GMT
Thanks Julian and Alan. I have many happy memories of driving a 3.1/2" schools around the track as a teenager. It was to LBSC's design, and ran well - you could load it with passengers and, provided you were careful pulling away it would cope with a good load. I do recall it could get a bit "lumpy" if you notched it back more than about 1/4 travel. But so did a lot of locos. At my club then there was also another schools - "Sevenoaks" again built to LBSC's design which ran well, and was steamed by some pupils of Sevenoaks school who owned it.
So I reckon at my skill level the LBSC valve gear will be "good enough for me!"...
I have worked out the inside valve gear measurements again - there is a rocking lever which attaches to the trunnion link which was not shown in the plans of the link. This takes up the 1/8" slack that concerned me. Ho hum - another part to make ..
John
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Post by manofkent on Mar 7, 2017 17:19:16 GMT
Hello.
Rodean is well underway in 3.1/2" Gauge - working to drawings from Reeves.
I have a query on the size of the trunnion blocks.
I have carefully machined out all the grooves to fit the expansion link. I was just about to machine the sides to 5/8" width per plan when I noticed how thin the walls would be. Checking the drawings I reckon the inside valve gear trunnion block should be 3/4" wide - not 5/8" as drawn. Similar size confusion exists with the outside pair, and even the drawings specify 7/8" before (what seems to be 1/16") bushes so 3/4" would be right for this as well.
Anyway - has anyone who has built this loco any recollection of "funny business" around the size of the trunnion blocks?
Any help gratefully received.
Many thanks
John
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Post by manofkent on Feb 28, 2017 8:24:22 GMT
When my (grown up) daughters decided to learn to drive my loco I built an electric pump fearing they would need something "easy" while learning. It was actually an electric motor moving the tender hand pump through a crank. Anyway, it never got used in anger. Much to my joy They preferred to use the axle pump and manual hand pump if needed. It is great for filling up the boiler from empty before steaming though.
John
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