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Post by chris vine on Sept 25, 2019 22:49:49 GMT
Hi Roger,
I think the trimming should go down to a level below the lowest level in the tank. Then the wick acts as a siphon, albeit a very slow one.
IE, the tail end should go down the pipe, below the bottom of the tank.
Chris.
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Post by Oily Rag on Sept 26, 2019 1:50:19 GMT
and use only worsted wool, not treated stuff, syringe any water out of the oil pots that may have found its way in and remember while the loco is not being used or moved, the trimming will drain the pot. The number of wool tails also influences the feed rate. All important stuff when dealing with the big choo choos. In my travels and reading I do not recall any one using small wool trimmings for oil feeds in model engineering applications, can any one enlighten me more, pics, drawings etc ? I could well imagine that with the small wool trimmings in Model Engineering that oil viscosity would have large effects ?
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jasonb
Elder Statesman
Posts: 1,231
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Post by jasonb on Sept 26, 2019 10:25:48 GMT
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Post by Roger on Sept 26, 2019 10:43:55 GMT
Many thanks to all for the useful information, I'll have to decide what I can use from all that. Some of my reservoirs are large ie the top of the axleboxes have them, so it probably doesn't make sense to do anything other than have a supply pipe to fill those.
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Post by Roger on Sept 26, 2019 21:47:50 GMT
Continuing with the Anti-roll bar, this is one of the torsion bar supports that bolt to the pump stretcher. It's reamed 7mm along the centre line of the split 20190926_093331 by Timothy Froud, on Flickr 20190926_101013 by Timothy Froud, on Flickr The bushes are Leaded Bronze, but they could just as well have been Delrin or Vesconite. I'm boring it with a 2-flute PCB fish tail router so I need to allow for the fact that the nose is slightly smaller diameter than the main one. I'm going right through, so I need to go an extra 1mm to make sure it cleans up. 20190926_103902 by Timothy Froud, on Flickr Ready for slittlng... 20190926_110946 by Timothy Froud, on Flickr ... using a 0.4mm thick wafer of a slitting saw. It's easier to hold and set up like this and part it off later... 20190926_113936 by Timothy Froud, on Flickr ... like this. 20190926_115631 by Timothy Froud, on Flickr I've centre popped the parts to make sure they go back the way they were made, even though they're probably good enough to go in any orientation and combination. 20190926_121548 by Timothy Froud, on Flickr The Piano wire is nominally 4mm but it's actually almost 4.1mm 20190926_122235 by Timothy Froud, on Flickr 20190926_122639 by Timothy Froud, on Flickr It's pretty snug, but it does fit and doesn't clash with anything when the suspension is moved to the extremes of travel. Whether this will impose enough force to make a difference is questionable. I've made it so that a larger diameter of torsion bar could be fitted. 20190926_203434 by Timothy Froud, on Flickr There's a slight twist on the torsion bar, I'll have to sort that out later. The split bearings have still to be made, so I'll make sure there's room to bore those out to a larger diameter too. 20190926_203443 by Timothy Froud, on Flickr A quick reminder of the inline clack valve that's on the feed from the axle pump. This is necessary because the RH top feed is used by the RH injector and the axle pump. Inline clack valve assembly by Timothy Froud, on Flickr This is the body, ie the part on the RH side of the above picture. The M8 x 0.75mm (fine) thread was screw cut and checked against a union.... 20190926_211010 by Timothy Froud, on Flickr ... then the hex goes on... 20190926_214218 by Timothy Froud, on Flickr ... then it's drilled an tapped M10 x 1 (fine) and the 'O' ring seating added, finally ending here to get the pockets that allow full flow even when the ball is displaced as far as it can go. It's pretty tight in there so I've used a 2mm cutter on a 3mm shank instead of one with a 4mm shank which would have fouled the thread. 20190926_221452 by Timothy Froud, on Flickr It's pretty compact. 20190926_222441 by Timothy Froud, on Flickr You can see the cutouts on the outlet side here. 20190926_222502 by Timothy Froud, on Flickr
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Post by Roger on Sept 27, 2019 12:40:09 GMT
Continuing with the inline clack valve, the part on the left with the seat and 'O' ring cord spring is next. Inline clack valve assembly by Timothy Froud, on Flickr The M10 x 1 (fine) thread was screw cut and the 'O' ring diameter added with a 1.2mm wide parting tool ground for the purpose. The inside bore and the pocket for the 6mm Silicon Nitride bass was then machined and this is how the ball was used to form the seat. It's easier to do in this orientation because the ball doesn't fall out of the hole. 20190927_105558 by Timothy Froud, on Flickr You can see the indentation the ball left in the Aluminium shim and the shiny edge in the valve where it shaped the sharp corner into a seat. 20190927_105715 by Timothy Froud, on Flickr Then it was on to the mill to add the 12mm hex 20190927_111651 by Timothy Froud, on Flickr Here's the M10 x 1 (fine) standard female Steel mount being used to hold the part by the thread I've just machined. Note that I'd machined a short length of the diameter during that operation so I had something to clock up on. You can never rely on something scewing into a fixture and not having runout! 20190927_112137 by Timothy Froud, on Flickr The rest of the union details were then added, again, screw cutting the M8 x 0.75mm thread. A Centre drill was used for the inside taper. 20190927_114303 by Timothy Froud, on Flickr Now comes the slightly trickier bit to find the position of the cross hole for the 1mm 'O' ring cord. I know the diameter of the black diameter is 32mm but I'm checking the runout here. Once I can see where it runs out, I turn it 90 degrees so I know that I'm half way between the low and high spots when I'm using it for measuring. 20190927_121604 by Timothy Froud, on Flickr Here I'm using a 0.8mm feeler gauge and I'm moving the black diameter closer to the ball until it just nips the feeler gauge. Obviously the spindle has already been set to the centre line of the job. Then it's just a matter of calculating where the centre of the 1mm 'O' ring cord needs to be to give 0.2mm interference with the edge of the ball when it's on the seat. 20190927_121829 by Timothy Froud, on Flickr I drilled the hole 1.2mm, you won't get the cord through the hole even at 1.1mm. I couldn't find an 8.5mm ID 'O' ring with 1mm section in my collection so I've used an 8mm one instead. As long as it's smaller than the required size, you can get away with quite a big error, they're pretty flexible. 20190927_131413 by Timothy Froud, on Flickr With the 'O' ring cord in place, you can see that the ball is sitting slightly to one side, indicating that it's sitting on the 'O' ring cord. It takes very little pressure to push it back onto the seat. 20190927_131621 by Timothy Froud, on Flickr Anyway, that ends up like this, pretty compact really. 20190927_131758 by Timothy Froud, on Flickr
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Post by Roger on Sept 27, 2019 21:36:26 GMT
This is the Soldered Tee that's going to be used where the two feed pipes from the injector and the axle pump meet. Solder tee by Timothy Froud, on Flickr I've turned the parts from Phosphor Bronze because they're going to end up very thin. The outside diameter is only 5.6mm so the wall thickness is only 0.3mm I've added a small hole in the middle to assist assembly. 20190927_210802 by Timothy Froud, on Flickr 20190927_211203 by Timothy Froud, on Flickr A piece of Titanium Welding wire has been formed into a shape to hold the parts vertically. A piece of 24% Silver Solder was wrapped round the top tube and some Tenacity 5 medium temperature flux was used. 20190927_212744 by Timothy Froud, on Flickr The flux is as hard as glass in places... 20190927_213658 by Timothy Froud, on Flickr .. but rather than soak in a solution to get it off, I mechanically removed it. 20190927_214909 by Timothy Froud, on Flickr Here it's being set up on the mill so I can machine the pocket for one of the copper pipes with a 2mm cutter to keep the forces to a minimum. 20190927_215734 by Timothy Froud, on Flickr
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Post by terrier060 on Sept 27, 2019 22:30:04 GMT
Thanks for that Ed, I see what you mean now. I was imagining something flexible going to the eccentric. So the idea is to have a long enough trough attached to the eccentric so that oil few from a fixed point will always drop into it? Yes the end of the oil pipe is motionless above the trough and drips into it whatever the position of the eccentric. Ed
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Post by Roger on Sept 28, 2019 16:41:34 GMT
Finishing off the 5mm pipe Solder Tee... The pocket for the pipe location was machined with a 2mm cutter to keep the forces to a minimum. The feedrate was only 10mm/min and the depth of cut just 0.3mm because the wall thickness is just 0.3mm 20190928_090529 by Timothy Froud, on Flickr A 4mm 2-flute was gently put through the middle and then drilled out to 4.3mm 20190928_102619 by Timothy Froud, on Flickr Once both sides were done it was parted off... 20190928_103613 by Timothy Froud, on Flickr ... and then the challenge was how to hold it. Another benefit of 3D modelling is that you can use a thing called 'boolean subtraction' to take one shape from another. So I created a block 20mm x 10mm x 10mm and subtracted the model of the pipe assembly to get this shape when cut in half. So here are two of them being 3D printed at 0.1mm resolution and 5 perimeters to get a near solid print that took just 40 minutes. The material is PLA with a silvery fleck. I intended to get a pure black, but this is what it turned out to be. 20190928_142020 by Timothy Froud, on Flickr 20190928_143300 by Timothy Froud, on Flickr It's held very firmly, but you can't go mad and machine it too fast because it will melt! 20190928_161410 by Timothy Froud, on Flickr 20190928_161503 by Timothy Froud, on Flickr Anyway, after a bit of tidying up, this is how it looks. 20190928_162816 by Timothy Froud, on Flickr It's pretty small but surprisingly strong, being Phosphor Bronze. I just need to make sure not to get it too hot when I'm Silver Soldering in the pipes! 20190928_162835 by Timothy Froud, on Flickr
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Post by delaplume on Sept 28, 2019 17:05:38 GMT
Hi Roger,
So it's the difference that's providing the grip on the pipe when the vice jaws are closed... is that the idea ??
I must say I'm enjoying these brief insights into other disciplines such as 3-D printing, CAD, CAM etc....
A touch of "Boolean Extraction" eh ??.......didn't I used to hear that on BBC's Around the Horn along with "Your actual French" and "Bona Machine Tools" ??.....LoL !!
Seriously though Roger please keep it coming----I can only dream of ever emulating all of that..
Many thanks
Alan
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Post by Roger on Sept 28, 2019 17:14:48 GMT
The axle pump only had a drill way and a 4mm hole above it as a reservoir, and I didn't think that was sufficient. So here's a little brass cup that fits into the hole which I tapped out to M4.5 x 0.5 (fine) which conveniently had 4mm at the tapping size. 20190928_160923 by Timothy Froud, on Flickr The cover in the foreground stays on and the idea is to fill it with oil using an extension on the oil can. I've been chewing over this business of oiling and come to the conclusion that I don't need any of these complex piped oiling systems. Each of the points that need oil have generous reservoirs on them, so I just need to make sure I can reach those . Even the eccentric straps have pretty large rectangular reservoirs in them, so I reckon those will be alright too. I'll just have to keep an eye on the levels and see how long it takes to use all of the oil. 20190928_180608 by Timothy Froud, on Flickr
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Post by Roger on Sept 28, 2019 18:06:14 GMT
Hi Roger, So it's the difference that's providing the grip on the pipe when the vice jaws are closed... is that the idea ?? I must say I'm enjoying these brief insights into other disciplines such as 3-D printing, CAD, CAM etc.... A touch of "Boolean Extraction" eh ??.......didn't I used to hear that on BBC's Around the Horn along with "Your actual French" and "Bona Machine Tools" ??.....LoL !! Seriously though Roger please keep it coming----I can only dream of ever emulating all of that.. Many thanks Alan Hi Alan, It turns out that when you 3D print something exactly to size, at least on my 3D printer, you get something which is slightly oversize. In other words, if I print a female and male part to a nominal size, they fit together with a nice satisfying interference. So when making a fixture, I can make it exactly to the size of the part and it will lightly grip it. I've increased the number of layers in the walls so that it will resist being crushed in the vise. In reality, you can't grip this sort of thing tightly anyway without it distorting, so you're better off just trapping it in a pocket and spreading the load. The great thing about all of this is that although it might seem clever, you really don't have to be smart to use these tools. The clever people are the ones who write the software and develop the ideas that then make the end user's job easy.
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Post by steamer5 on Sept 28, 2019 21:06:09 GMT
Hi Roger, Question time....
Love the non-return & the how to pictures etc, not sure if you have said before but have you any idea how much squeeze you put on the ball to get the seat to form? I ask as I’ve brought some to try in my loco, & was extolling the virtues of ceramic balls to another club member but couldn’t remember if you had said.
On the oiling front, as a suggestion put a piece of felt into your oil cups, this keeps all the cxxp out of them, nothing like oil & ash getting together in moving bits! What I’ve done is take an off the shelf oil can, removed the knob bit on the end of the spout & fit a longer length of copper tube, if you are keen step it down a second time, this then reaches all the tricky bits & you can force the oil thru the felt.
Cheers Kerrin
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Post by Roger on Sept 28, 2019 21:11:55 GMT
I'm afraid I'm jumping around between several jobs at the moment because they're presenting themselves as unfinished items that I need to finally stop procrastinating about and make a decision! Before I put the boiler back on I remembered that I'd only made and finally decided on the vertical portion of the firebox arch. I'd modelled a possible arch, but on reflection I think it was far too extreme in that it came back about two thirds of the way back. On reflection, I don't think that's a good idea for several reasons. Although I want to make sure the back of the firebox absorbs some heat and the radiant superheaters have hot gasses pass over them, I don't want to make too much of a pinch point and end up with erosion issues if the velocities are too high. Anyway, this more modest affair is what I've decided upon. One issue with a firebox with a narrow bottom is that the arch creates an ever widening Vee shape for the gasses to go around the side of the sloping top plate. The side plates are an attempt to force the gasses further back. That still leaves a vertical Vee shape where those end, and I'm thinking that some 'ears' to those might be worth considering to fill the gap as the firebox widens out. Obviously that would make the arch wider than the bottom, but it may well be that it's still possible to detach it, raise it up and then turn it to get it out. I'll experiment with some cardboard 'ears' when I've got it tacked up. I'm also concerned that the Stainless Steel bolts might gall in the Stainless Steel holes they're screwed into. In an effort to avoid that problem, I've ordered some Titanium tapered head cap screws from eBay which hopefully won't do that. I've checked about galvanic issues and there don't seem to be any. It's a dry environment so that ought not to be a problem anyway, but it's best to try to think of everything. Section showing arch by Timothy Froud, on Flickr
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Post by Deleted on Sept 28, 2019 23:06:19 GMT
Hi Roger
I'm a little puzzled by your arch design which seems to go against how I see it's opperation or perhaps I'm not understanding your 3D drawing correctly.
It looks to me that the sides are higher than the centre, like an arch upside down. Also the end drop which I think you're calling 'ears'. This seems foreign to what I've seen and how I understand the arch to work. Surely it should be an actual 'arch' in the true sense of the word that has nothing at it's firehole end so that the gases are directed along the inner roof of the arch and up and over the top and then drawn through the tubes. At least, that us how I understand an arch and it's function.
Pete
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Post by Roger on Sept 29, 2019 8:12:52 GMT
Hi Roger I'm a little puzzled by your arch design which seems to go against how I see it's opperation or perhaps I'm not understanding your 3D drawing correctly. It looks to me that the sides are higher than the centre, like an arch upside down. Also the end drop which I think you're calling 'ears'. This seems foreign to what I've seen and how I understand the arch to work. Surely it should be an actual 'arch' in the true sense of the word that has nothing at it's firehole end so that the gases are directed along the inner roof of the arch and up and over the top and then drawn through the tubes. At least, that us how I understand an arch and it's function. Pete Hi Pete, The sides drop down from the top sheet, so they are lower than the crown of the arch. If you took those away, the gasses would go round the sides because of the ever increasing gap where the firebox opens out. I haven't shown what I called 'ears'. Those would be little vertical infills at the back that go sideways. They would fill in the widening gap where the firebox gets further away from the vertical sides. Maybe this view makes it clearer what the problem is... Arch by Timothy Froud, on Flickr If you just had a plain arch, the gasses would take the easiest path and just go around it rather than head towards the back of the firebox. You don't have this problem with a wide firebox where the sides of the arch are the same distance from the sides of the firebox. The idea of the arrangement is to make sure that all of the gasses have to go around the arch.
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Post by Deleted on Sept 29, 2019 8:29:13 GMT
Ah..ok...I misread your drawing...I can see how...my eye read it as the side being an end drop, probably due to the corners not meeting which I guess is due to the thickness of the material. Not easy to explain..imagine the grey is the top surface rather than inner surface and I think you'll see what I saw when first looking late last night, I blame the cider.. My mistake... Pete
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Post by delaplume on Sept 29, 2019 9:12:33 GMT
Here's a view of a similar Belpair box on a 69xx GWR Hall looking forwards and inwards ( Standard No.1 boiler ).....You can see that the arch is made up of shaped firebricks which lock into place along the firebox inner walls and rest against each other in the middle.........
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Post by Roger on Sept 29, 2019 9:32:15 GMT
Here's a view of a similar Belpair box on a 69xx GWR Hall looking forwards and inwards ( Standard No.1 boiler ).....You can see that the arch is made up of shaped firebricks which lock into place along the firebox inner walls and rest against each other in the middle......... Hi Alan, Thanks for that, it looks like it's pretty hot! I presume the arch gets wider as it comes towards the diamond so it can still rest against the firebox walls as they widen?
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Post by Roger on Sept 29, 2019 11:02:34 GMT
Hi Roger, Question time.... Love the non-return & the how to pictures etc, not sure if you have said before but have you any idea how much squeeze you put on the ball to get the seat to form? I ask as I’ve brought some to try in my loco, & was extolling the virtues of ceramic balls to another club member but couldn’t remember if you had said. On the oiling front, as a suggestion put a piece of felt into your oil cups, this keeps all the cxxp out of them, nothing like oil & ash getting together in moving bits! What I’ve done is take an off the shelf oil can, removed the knob bit on the end of the spout & fit a longer length of copper tube, if you are keen step it down a second time, this then reaches all the tricky bits & you can force the oil thru the felt. Cheers Kerrin Hi Kerrin, That's a good question. I honestly don't know how much force, and of course that will vary depending on the size. The result you're looking for is to be able to see a distinct change to the sharp corner where you can see that the ball has definitely formed a shape. On mine I've not gone very far, perhaps the 'flat' is only 0.1mm Clearly it's going to take proportionately more force to make the seat wider as it deforms more. Quite how far you could go is open to question. I doubt if you'd ever want to make a seat that's more than say 0.3mm wide? The key thing is to make sure that the ball definitely created a seat all round, else it's not going to seal. The balls are Glass hard so you should still get a good impression of the ball on the face regardless of how hard you press, within reason! This is the difference between the Stainless Steel balls that are often available, they're way too soft to create a seat without deforming. There's no mystery as to why they don't want to seal, even if you put a new ball in afterwards, since the seat was formed by a deformed ball! I hear what you're saying about the felt, I suppose it's a filter. I'll have to put some in all of the reservoirs. I've bought one of those Reilang oil cans so I'll be making at least one adaptor for those. I've measured the thread so I can make something that screws into the spout.
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