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Post by Roger on Sept 30, 2019 21:01:31 GMT
This is how the Anti-roll bar looks on the model. I'm going to have to bend the torsion bar inwards slightly to go across the middle of the slots in the axle bearing. That's because it was designed around a 4mm torsion bar, and that wasn't strong enough. I know there's absolutely no need to do any of this at all, or to do it now. However, I know that if I don't do it now, it will never happen, it's just too awkward to do with the boiler in place. Anti-roll bar assembly by Timothy Froud, on Flickr This is one of the bearing caps for the Anti-roll bar being machined from Leaded Bronze. 20190930_103041 by Timothy Froud, on Flickr These are clamped together in a similar manner to a connecting rod in a car engine. The bores are under size by 0.2mm so those will be bored when they are clamped together. Here they're shown in the parted off state... 20190930_204249 by Timothy Froud, on Flickr .. and here each one is being machined to 12mm thickness... 20190930_210627 by Timothy Froud, on Flickr ... ending up like this. 20190930_215347 by Timothy Froud, on Flickr Next I need to add the bolt holes and bore them to size and also add the slots for the torsion bars.
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Post by gwr14xx on Oct 1, 2019 8:04:20 GMT
Roger, Would it not be better to make the anti-roll bar 'top hat' shape, so that the ends lie parallel to the axle? That way, the suspension movement would not cause the anti-roll bar to tip the axle boxes in the horns.
Regards, Eddie.
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Post by Roger on Oct 1, 2019 8:41:18 GMT
Roger, Would it not be better to make the anti-roll bar 'top hat' shape, so that the ends lie parallel to the axle? That way, the suspension movement would not cause the anti-roll bar to tip the axle boxes in the horns. Regards, Eddie. Hi Eddie, The rods float in the holes, so they won't try to tip the bearing one way or the other as long as the pressure point is in the middle. If you try to create a parallel portion at the end, it won't be parallel when the torsion bar twists anyway. The axle boxes that support the wheels to the frames are quite separate to this mechanism. The idea is to let that end of the torsion bar float in the bearing which itself can float on the axle. On cars these are flexibly mounted at all points because the torsion bar tries to twist, rotate and slide in the mounts. In my implementation the axle bearings will rotate on the shaft and the torsion bar end will slide in the slot and move slightly sideways, and the torsion bar end will rotate slightly when one wheel deflects more than the other. It's a complex motion that needs to accommodate movement in many directions. Trying to get all this in the confined space is something of a challenge!
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Post by delaplume on Oct 1, 2019 11:03:22 GMT
Hi Roger---I'm just having a mid-day break from mass-soldering snap connectors onto circuit lead ends...Whoop--eee, great fun !!! (not)
..Quote}-- "However, I know that if I don't do it now, it will never happen, it's just too awkward to do with the boiler in place."..........I may have missed this next idea earlier in your wright-up but a turnover stand will give you at least some access to these parts later when the loco is in service...
OK--If you already have one then ignore this......
Alan R
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Andrew C
Part of the e-furniture
Posts: 447
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Post by Andrew C on Oct 1, 2019 11:37:37 GMT
Hi Roger Awesome build sir. The title is totally wrong mind you "Help with 'Speedy' valve gear and other issues..." more like "1501 a build master class"! and no don't change it I'd never find it again. I have just noticed you are going to use what looks like a petrol filter, DON'T! just pop it in a jar of water for a few days you should find it will go rusty and then turn to mush. I had Identical looking ones in the tender of the Britannia and they were rubbish, they lasted about half a season. They are copper coated or at least the ones I had seemed to be. Regards, Andrew
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Post by Roger on Oct 1, 2019 12:06:22 GMT
Hi Roger---I'm just having a mid-day break from mass-soldering snap connectors onto circuit lead ends...Whoop--eee, great fun !!! (not) ..Quote}-- "However, I know that if I don't do it now, it will never happen, it's just too awkward to do with the boiler in place."..........I may have missed this next idea earlier in your wright-up but a turnover stand will give you at least some access to these parts later when the loco is in service... OK--If you already have one then ignore this...... Alan R Hi Alan, This is absolutely true, but it's just so much easier to do without all the pipes, pumps and valves in the way as well as the boiler preventing access from both sides. I can certainly maintain all of it using the turn-over stand though.
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Post by Roger on Oct 1, 2019 12:19:17 GMT
Hi Roger Awesome build sir. The title is totally wrong mind you "Help with 'Speedy' valve gear and other issues..." more like "1501 a build master class"! and no don't change it I'd never find it again. I have just noticed you are going to use what looks like a petrol filter, DON'T! just pop it in a jar of water for a few days you should find it will go rusty and then turn to mush. I had Identical looking ones in the tender of the Britannia and they were rubbish, they lasted about half a season. They are copper coated or at least the ones I had seemed to be. Regards, Andrew Hi Andrew, Well, the thread was just to ask a couple of questions... then I got carried away... Anyway, you're very kind with your praise, thankyou. I'll certainly test that filter, but I'm pretty sure the sintered balls are bronze because it's an Air Silencer, not a filter. I've just put a magnet against it and the screw thread is definitely Steel coated with what looks like Copper. The filter itself is not magnetic though, so I don't know whether that's going to be an issue or not. Presumably they use Steel to keep the cost down and Copper to protect it against rust. These are intended for use in Pneumatic systems, so I would have thought the protection they've given them ought to cope with the often damp conditions. Were the ones you bought sold as Petrol filters? Obviously you wouldn't need for those to be water resistant. Thanks for warning, I'll report back when the filter has had a good soak.
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Post by Roger on Oct 1, 2019 19:52:11 GMT
I want to locate the two halves of the Anti-roll bar bearings with 1.6mm dowels, so I'm machining them all from a designated reference face. In other words, each pair is marked up as having a reference face and that face is clamped against the fixed vice jaw. Only the middle in the other direction is set up each time using the wobbler on both sides and halving it. 20191001_112829 by Timothy Froud, on Flickr The top halves are threaded right through M4 for a stud. 20191001_120555 by Timothy Froud, on Flickr The top also has a small oiling point and a hole that goes right through to the bearing. This won't get as much load as the main axleboxes, so lubrication is less of an issue. The oil coming out of the adjacent axlebox will run into this bearing too. 20191001_143639 by Timothy Froud, on Flickr I've fitted two dowels here and holding the halves together only with the 4-jaw chuck. The middle is clocked as close as I can. It's not going to be great since it's milled, but it's good enough. The face is clocked too, that's more important. 20191001_164020 by Timothy Froud, on Flickr The bore was made with 40microns clearance on the axle to give a nice running bearing. 20191001_165606 by Timothy Froud, on Flickr I don't think I've shown this before, but it's a 3-point internal digital micrometer. I bought this one from eBay along with a couple of the anvils. You set the size against a calibrated ground set piece and dial in the size. The pistol grip applied a consistent force that gives amazing repeatability. It's idea for this sort of dead reckoning. 20191001_165649 by Timothy Froud, on Flickr Anyway, they fit really nicely, so I'm pleased about that. 20191001_170725 by Timothy Froud, on Flickr It does mean that the 7mm hole in the torsion bar mount is now too small for the 6mm bar, so that's getting opened out to 9mm 20191001_193214 by Timothy Froud, on Flickr That does mean that the bore breaks into the dowel holes, and that can be used to retain the bearing. Here's the 3mm diameter relief being added to a Delrin bush that supports the bearing. 20191001_200736 by Timothy Froud, on Flickr And this is how that end looks now. I'm just waiting for the Long Series 5mm End Mill that I need to machine the slot for the 6mm torsion bar in the axle bearing. Once that's done, I need to think about any further heat treatment that needs to be applied to the torsion bar. Ideally I'd completely re-harden the whole shaft and then temper it. 20191001_203310 by Timothy Froud, on Flickr
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timo
E-xcellent poster
Completing 3 1/2 Rainhill .Building 5" Railmotor and waiting to start 3 1/2" King
Posts: 234
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Post by timo on Oct 1, 2019 21:27:05 GMT
Roger,
"it's a 3-point internal digital micrometer"
That is a nice piece of kit, what is it's range?
Best Regards
Tim
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Post by Roger on Oct 1, 2019 21:49:23 GMT
Roger, "it's a 3-point internal digital micrometer" That is a nice piece of kit, what is it's range? Best Regards Tim Hi Tim, Well, each anvil has a pretty small range of about 2mm in the smaller sizes. I've got a larger set that covers 25-50mm I think with three anvils. We bought that set for measuring Air Bearings about 15 years ago and it cost over a grand even then. Actually, I've got three of the readouts, each having different sized threads to take the next range of anvils, but I haven't got every size yet. They don't come up that often on eBay and they're expensive. The ones I have are from Bower.
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Post by jon38r80 on Oct 2, 2019 8:22:01 GMT
Your in line filter is beautifully made as usual. I cannot help feeling though that from a maintenance point of view that the filter is screwed into the wrong end cap. I have no idea how strong the sintered filter is but when the brass has a bit of verdigris and the threads stiffen up I wouldn't want to exert much pressure on the nut shape on the filer end. If the filter were screwed into the cap end , not the shroud, you can always get a bit savage with it and it would make mechanical cleaning get of the filter easier should it need it. I'm probably being over cautious in my attitude to this but having struggled with small bits like that in RC cars , usually ending in destruction of the part, I like to make disassembly as easy as possible. It's particularly relevant if in 5 years time you can't get an exact replacement when needed and you have to mare make the whole thing.
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Post by Roger on Oct 2, 2019 8:59:52 GMT
Your in line filter is beautifully made as usual. I cannot help feeling though that from a maintenance point of view that the filter is screwed into the wrong end cap. I have no idea how strong the sintered filter is but when the brass has a bit of verdigris and the threads stiffen up I wouldn't want to exert much pressure on the nut shape on the filer end. If the filter were screwed into the cap end , not the shroud, you can always get a bit savage with it and it would make mechanical cleaning get of the filter easier should it need it. I'm probably being over cautious in my attitude to this but having struggled with small bits like that in RC cars , usually ending in destruction of the part, I like to make disassembly as easy as possible. It's particularly relevant if in 5 years time you can't get an exact replacement when needed and you have to mare make the whole thing. That's a very good point, it probably makes sense to liberally apply some Silicone Grease to the threads and barely nip up the thread. There's no force on it so there's no need to wind the thread in tight. Once I know it works as I hope, I'll buy a few replacements but I'm hoping these will last for years. Only time will tell.
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Post by Roger on Oct 2, 2019 10:17:18 GMT
So, as Andrew correctly predicted, the filter does rust which is a pity. It doesn't look like the filter itself is the problem, rather it's the Steel threaded adaptor. I'll let it run a bit longer to see exactly what's happening. I really want to use a Sintered filter if I possibly can because that will resist back flow. There are loads of different Sintered Silencers out there, maybe I can find one that's better suited to this application. Most seem to use Brass for the fitting, I think I've just been unlucky to pick one that isn't. I've ordered this one, which I'm assured is Brass and Bronze. It will probably mean making a different housing or modifying what I've got though. Alternatively, I've found this all plastic one which I'll give a try. 20191002_103527 by Timothy Froud, on Flickr
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Andrew C
Part of the e-furniture
Posts: 447
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Post by Andrew C on Oct 2, 2019 17:21:08 GMT
Hi Roger Sorry to have been the bringer of bad news. But at least you have found out before filling any tanks, unlike me And to answer Jon they crush very easily! I put a spanner on the end and one on the nut and it just collapsed as I attempted to undo it. Mind you it did look like the one in Rogers picture at the time. Regards, Andrew
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Andrew C
Part of the e-furniture
Posts: 447
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Post by Andrew C on Oct 2, 2019 17:24:56 GMT
Hi Roger Sorry to have been the bringer of bad news. But at least you have found out before filling any tanks, unlike me And to answer Jon they crush very easily! I put a spanner on the end and one on the nut on the pipe and it just collapsed as I attempted to undo it. Mind you it did look like the one in Rogers picture at the time. Regards, Andrew
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Post by Roger on Oct 2, 2019 17:41:43 GMT
Hi Roger Sorry to have been the bringer of bad news. But at least you have found out before filling any tanks, unlike me And to answer Jon they crush very easily! I put a spanner on the end and one on the nut and it just collapsed as I attempted to undo it. Mind you it did look like the one in Rogers picture at the time. Regards, Andrew Hi Andrew, That's not such bad news, it's extremely helpful and points me to a better solution. I'm very grateful for the warning. I've got two alternative types on the way which I'll try instead. I find this sort of development interesting and rewarding. I don't mind spending the time to get the solution I'm looking for.
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Post by andyhigham on Oct 2, 2019 18:36:40 GMT
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Post by Roger on Oct 2, 2019 19:47:52 GMT
Thanks for that, I may well get one of those too. I thought I'd got one in my stock, but the only ones I could find were much bigger. Whether they will have too much restriction with water is the only question. I'll have to redesign at least one of the ends to get access to the body of the filter when it's screwed in. That's no bad thing to do anyway really. With hindsight, I don't know why I designed it that way round anyway!
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Post by Roger on Oct 2, 2019 21:02:18 GMT
Wrapping up the Anti-roll bar, here's the torsion bar ready for heat treating. I've decided to go the whole hog and harden and temper the whole thing since I don't know what state the corners are in. I'm using cutting oil as the quench so it's not too vicious. I believe Silver Steel can crack if you quench it in water, although I've not experienced that myself. I know this component could get a hard time, so I want to make a reasonably good job of it. 20191002_155708 by Timothy Froud, on Flickr This is how one side looks after polishing it and trying to temper it to a nice Blue colour all over. 20191002_172355 by Timothy Froud, on Flickr This is the other side. The blue is really deep, but the photo doesn't really show it that well. Anyway, It's not as even as I'd like, so I cleaned it up again and had another go. 20191002_172405 by Timothy Froud, on Flickr This is much more even, and added to the other attempt, I reckon it's probably tempered all through and everywhere. 20191002_174052 by Timothy Froud, on Flickr This is the last operation on the bearing blocks that go on the axle. It's the slot for the torsion bar. 20191002_193306 by Timothy Froud, on Flickr So finally here it all is assembled on the locomotive. To be honest, at this stage it's hard to know if it's going to do very much. Everythiing is very stiff still and the amount of body roll will be limited by the horn block flanges. Still, you can definitely feel a noticeable if small spring force trying to restore the axle to being level if I get the chassis on its side and move the axle. Anyway, I can't see it doing any harm, so I'll run with it and see how it feels as everything beds in and loosens up. 20191002_214627 by Timothy Froud, on Flickr Time to stop playing about and get on with other things!
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Post by jon38r80 on Oct 3, 2019 6:36:10 GMT
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