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Post by delaplume on Dec 11, 2018 9:34:51 GMT
Hi Roger,
Yes, dimples or diamond but the idea was to provide an area for your boot to grip on......
Re, the thin flange}----The simplest way to give the impression might be just to make 4 rectangular plates out of some material that's approx. half the thickness of the main flange and slightly oversized......They are not a particularly accurate item as you can tell from the photo......
Keep up the good work, matey !!
Alan
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Post by Roger on Dec 11, 2018 11:17:21 GMT
Hi Roger, Yes, dimples or diamond but the idea was to provide an area for your boot to grip on...... Re, the thin flange}----The simplest way to give the impression might be just to make 4 rectangular plates out of some material that's approx. half the thickness of the main flange and slightly oversized......They are not a particularly accurate item as you can tell from the photo...... Keep up the good work, matey !! Alan Hi Alan, Yes, that's the sort of thing I had in mind. I'd have to turn back the flange to make it thinner so it could accommodate the square plate, but that's easy enough, I can hold the buffer stock on a mandrel. |
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Post by Roger on Dec 11, 2018 22:00:59 GMT
A bit more progress while I've been working today. The roughed out rectangular hole for the coupling hook had 1mm radius corners and I want them pretty square really. So this is a 1mm PCB two flute which has about 6mm of flute. It's not that common, most are burrs, but I found these on eBay for about £1 each. They're very fragile, but with a little patience you can use them. This was a 5mm deep cutout in 0.2mm depth increments and around 4mm/min feedrate.  20181211_145233 by Roger Froud, on Flickr This is the back buffer beam after the same treatment. The cuts took 2-1/2 hours each! It could be done much quicker with say 25-30,000RPM but there's no hurry.  20181211_213507 by Roger Froud, on Flickr And this is the rebait for the sheet metal that meets at the front of the buffer.  20181211_212404 by Roger Froud, on Flickr |
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Post by delaplume on Dec 11, 2018 22:13:53 GMT
Hi Roger,
Did I read that correctly ?---- 4mm per min ?---- so that's 1mm per 15 seconds then ??......Phew ! that's slow all right !!
Those rivets are looking very "Snappy" !!
Alan
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Post by Roger on Dec 11, 2018 22:47:38 GMT
Hi Roger, Did I read that correctly ?---- 4mm per min ?---- so that's 1mm per 15 seconds then ??......Phew ! that's slow all right !! Those rivets are looking very "Snappy" !! Alan Yep, that's right, it's very slow. If you take it any faster with the relatively slow RPM on my big spindle, you'll just snap them. These cutters are not designed for this sort of work, they're optimised for weird combinations of materials used in the PCB world. There you'll find sandwiches of things like Brass, with a thin layer of PTFE with Copper on the top. Good luck finding the ideal geometry and lubricant for that job! Actually, they use IPA for the coolant which is highly inflammable. I use these for reaching deep into corners where there needs to be a very small radius. You'll pay a small fortune for proper long series cutters for metal cutting. That's not really economic for me, whereas I can buy a pack of 10 cutters like this from China for between £10-15 |
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Post by delaplume on Dec 11, 2018 22:59:22 GMT
Highly flammable, eh ??..Is that the IPA you get from a Pub ??--------
Those sample carbide cutters you gave me worked a treat-----Opening up the Cylinder transfer ports on an old Simplex that had no-go !!
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Post by ettingtonliam on Dec 11, 2018 23:16:11 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----.
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Post by delaplume on Dec 11, 2018 23:26:40 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----. True--------- but each to their own wouldn't you say ? |
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Post by ettingtonliam on Dec 11, 2018 23:48:12 GMT
Oh, absolutely! Never in a million years could I hope to emulate what Roger does, how he does it, and the speed at which he does it, but I still get joy out of manual machining and 'blacksmithing' methods. Probably why I'm doing Locomotion, it wouldn't seem right to use sophisticated CNC methods on something built by very primitive methods. Somehow, yet, I've got to cope with the fact that whereas most people aim to get their axle centres and coupling rods within a few thou for smooth running, but mine, because the axlebox pedestals are fixed to the boiler, the axle centres will vary around 1/32" between cold and hot. Do I set it so its 'lumpy' when cold, but runs nicely when hot, or just go for making the split coupling rod bearings nice and slack, which, I suspect, is how the prototype was set.
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,990
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Post by JonL on Dec 12, 2018 8:37:14 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----.
I did that on my MoD apprenticeship.... I never was any good at it...
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Post by doubletop on Dec 12, 2018 8:42:41 GMT
Rodger
I'm a late arrival to the painting discussion. I've skimmed through the responses but don't see any mention of maintaining dimensional accuracy? If you paint all the parts first and then assemble you've now got 2 layers of paint, (say) between the stretchers and the frame. That’s something you probably didn't account for when you made them to the correct dimension allowing for the thickness of the metric frame material you were obliged you use because you could get hold of the imperial stuff LBSC used.
You could mask the ends of the stretchers and the mating surface on the frames but now you will definitely have a joint that needs sealing from water ingress.
So I’d go for (more or less)
1) assemble the frames,
2) mask the horns and prime,
3) mask the all but the inside forward of the stretcher in from of the firebox and paint red,
4) Mask the inside areas, now red and paint the rest,
5) Major, dimensionally critical, assemblies like cylinders etc mask the mating faces (inc the frames), and paint seperately. There will be plenty of oil around to keep the interface rust free
6) any parts that do not contribute to the critical dimensions paint seperately and be prepared to fettle a bit to make them fit after painting
Forget plugging all the holes, run reamers, taps or drills through after painting.
Pete
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Post by Roger on Dec 12, 2018 8:46:56 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----. Ah, but you're completely missing the point. I had no workshop time during the day, I had a programming project to do for a customer. The job was already programmed for the square hole, I just changed two dimensions, say 1 minute total? Set up took say 5 minutes and then I walked away. The machine would have been sat idle, so why not? Yes, I could have spent time on the bench but for me it's a no-brainer to use what I have and get it done in less of my time than it would take with a file. When you have a resource like a CNC mill at your convenience, the time any job takes is irrelevant unless you have a queue of jobs stacking up. I deliberately use feeds and speeds the make sure I can leave it for hours without having to worry about it. I'm sure I could have halved the time if I tried to optimise it, but what's the point? Long jobs are ideal for when you're too busy to be in the workshop. You have to take mult-tasking into the equation when considering CNC machining. |
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Post by delaplume on Dec 12, 2018 8:54:43 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----.
I did that on my MoD apprenticeship.... I never was any good at it...
me too back in 1965 but CAD--CAM etc didn't exist in those days........I managed to pay off a mortgage using those basic hand skills etc. at a later date on BR and then on the SVR as Self-Employed running a small contracting company, and finally as an"Apprentice Master" at ABRO Donnington.... so it wasn't time wasted after all.... |
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Post by ettingtonliam on Dec 12, 2018 13:13:15 GMT
2 1/2 hours each to open up 2 small square holes to 2 slightly larger rectangular holes? Plus programming and set up time presumably? I know they will be wonderfully precise, like all your work, Roger, but honestly, how long to put the buffer beams in the vice and open the holes up with a square file, 10 minutes each? It used to be part of apprentice training to make a square block to fit all ways into a filed square hole ----. Ah, but you're completely missing the point. I had no workshop time during the day, I had a programming project to do for a customer. The job was already programmed for the square hole, I just changed two dimensions, say 1 minute total? Set up took say 5 minutes and then I walked away. The machine would have been sat idle, so why not? Yes, I could have spent time on the bench but for me it's a no-brainer to use what I have and get it done in less of my time than it would take with a file. When you have a resource like a CNC mill at your convenience, the time any job takes is irrelevant unless you have a queue of jobs stacking up. I deliberately use feeds and speeds the make sure I can leave it for hours without having to worry about it. I'm sure I could have halved the time if I tried to optimise it, but what's the point? Long jobs are ideal for when you're too busy to be in the workshop. You have to take mult-tasking into the equation when considering CNC machining. OK, point taken Roger |
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Post by Roger on Dec 12, 2018 13:23:07 GMT
Ah, but you're completely missing the point. I had no workshop time during the day, I had a programming project to do for a customer. The job was already programmed for the square hole, I just changed two dimensions, say 1 minute total? Set up took say 5 minutes and then I walked away. The machine would have been sat idle, so why not? Yes, I could have spent time on the bench but for me it's a no-brainer to use what I have and get it done in less of my time than it would take with a file. When you have a resource like a CNC mill at your convenience, the time any job takes is irrelevant unless you have a queue of jobs stacking up. I deliberately use feeds and speeds the make sure I can leave it for hours without having to worry about it. I'm sure I could have halved the time if I tried to optimise it, but what's the point? Long jobs are ideal for when you're too busy to be in the workshop. You have to take mult-tasking into the equation when considering CNC machining. OK, point taken Roger I do appreciate that some of these decisions seem bizarre though. For example, today I'm making the four thin buffer spacers which normally I'd do one at a time. However, I'm busy today, so I've set the machine to make a long single piece that I'll part them off from. That does mean machining more depth than would otherwise be necessary ie I'm going to part off 3mm of profile that's wasted machining time. The total machining time of that long section is about twice as long as it needs to be.... but.... it can be left getting on with it unsupervised while I'm working and I can drill the holes through the whole lot in one go and save more 'hands on' time. I do enjoy bench work too, it's just time consuming and less accurate. |
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Post by chris vine on Dec 12, 2018 21:47:10 GMT
Hi Roger,
It just doesn't seem to rust in there. Equally if it did rust very slightly on the flat mating surfaces, it would be bonus in that the surfaces certainly wouldn't shift!!
I really don't think you should paint under these parts, eg cylinders and motion brackets etc. The paint (unless we are talking about 2 pack etch, which is very very thin) will mess up all of your beautiful accuracy. It is surprisingly thick, especially when on two surfaces.
Incidentally, the 2 pack etch primer which I used stated that it should be overcoated within something like 2 hours, so all these paints/processes are different.
Chris.
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Post by Roger on Dec 12, 2018 22:13:29 GMT
Thanks for that Chris, I'll probably prime the less important and lowly stressed parts then and leave the precision ones that are loaded as bare metal. Anyway, here's the recessed top on the front buffer and the clearance holes for the nuts on the back of the cosmetic bolts on the plate. There's a lamp bracket on that too, but it appears to be welded on so I can hide some rivets for that.  20181212_220135 by Roger Froud, on Flickr This is the section that's been machined today while I've been working...  20181212_150930 by Roger Froud, on Flickr ... and this is them parted off and flashed over on both sides to bring them to the right thickness  20181212_220026 by Roger Froud, on Flickr |
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Post by Roger on Dec 13, 2018 22:52:11 GMT
This is the back of the buffer stock being relieved to take the cosmetic back plate. The Delrin split collet was sawn almost in half so it could be opened out without falling apart.  20181213_212728 by Roger Froud, on Flickr All done, but the thread needs to be done differently now. I need to open out the ones in the front to be a clearance and the back ones need to have a thread.  20181213_224443 by Roger Froud, on Flickr On 1501 you can see that there's a thread showing and a nut on the outside. I need to make some bolts like that, ie Loctite some Nuts onto plain thread.  DSCN5610 by Roger Froud, on Flickr |
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Post by delaplume on Dec 13, 2018 23:32:47 GMT
Hi Roger,
Nice one matey !!.........makes all the difference to the realistic appearance, doesn't it ??
Just a pointer}--- notice that the treadplate is retained by slotted, snap-head screws and not rivets....
PS.. Have a look at thread GWR AUTOCOACH to see examples of the diamond style tread that I mentioned earlier.....He's really captured the typical long, slender almost fragile look of the early GWR coach buffer design ( and on their wagons as well.)..
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Post by Roger on Dec 14, 2018 6:16:35 GMT
Hi Roger, Nice one matey !!.........makes all the difference to the realistic appearance, doesn't it ?? Just a pointer}--- notice that the treadplate is retained by slotted, snap-head screws and not rivets.... PS.. Have a look at thread GWR AUTOCOACH to see examples of the diamond style tread that I mentioned earlier.....He's really captured the typical long, slender almost fragile look of the early GWR coach buffer design ( and on their wagons as well.).. Hi Alan, Yes, It's well worth the extra effort, I nearly did it when I made them but decided to press on with other things at the time. Yes, the slotted screws hold it on, but I'm going to use rivets because a slot is so small it will fill with paint and not be visible. I've made the same compromise on the backhead. This is my interpretation of the tread plate on the buffer stock, machined from solid.  20151021_114454 by Roger Froud, on Flickr |
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