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Post by delaplume on May 8, 2019 16:59:59 GMT
On the other hand Liquid Gaskets are very much to-day's preference.....for example I have a You-tube link showing the Maersk Container ships engines being assembled and they use buckets of liquid gasket !!!( I won't post it as that might be seen as going "Off piste" ... and that will make some of you "Piste off", eh ??...LoL !!)
I've mentioned before that I ( Ex-Royal Navy Engine Room Artificer ) finished up as an Apprentice Master at the local Army MoD Armoured Vehicle Repair Depot....Amongst other duties ( Home Office approved weapons de-activation for example ) I was part of a small team that refurbished and then re-built the Rolls - Royce CV8 and CV12 Diesel engines....The 8 for the Warrior APC and the 12 for the Challenger 2 MBT.......and in both cases the head gaskets and associated assemblies use Blue Hylomar ....and being semi-setting it did exactly what it's supposed to do....
My Classic Honda CB750 from the 1970's had a horizontal split case with a liquid gasket as did the big Kawasaki and Suzuki bikes....Thyatset-up is now regarded as the norm ....
Hi Roger----
I suspect your old Brit Bike gasketing was Red Hermatite ?? and possibly string as well ?............A God-awful product even in its'day, mainly due to the fact that it set Rock-hard !! Yes, O-rings are ideal and can be factored-in during the design stage.......For instance on the opposite side of the Motorcycling coin we have the Royal Enfield 500cc Bullet where the primary chaincase cover is sealed with a large diameter O-ring and held in place by only ONE central bolt !!
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Post by andyhigham on May 8, 2019 18:46:09 GMT
The best sealant around for metal to metal joints is Three Bond 1104, It is what the Japanese motorcycle manufacturers seal the crankcases with. It aint cheap but a little goes a long way
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Post by delaplume on May 8, 2019 21:04:42 GMT
The best sealant around for metal to metal joints is Three Bond 1104, It is what the Japanese motorcycle manufacturers seal the crankcases with. It aint cheap but a little goes a long way Hi Andy, Yes, that's quite true ------ I suspect it's the latest version of what they / myself were using when the CB750 etc. first emerged... My research shows it to be a synthetic Rubber compound in liquid form and is somewhat similar to that supplied to us at ABRO Donnington, although that came in MoD containers..
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Post by Roger on May 9, 2019 7:26:08 GMT
I was thinking of physical gaskets rather than metal to metal with sealant when I mentioned my dislike of them. Head gaskets being the exception of course. To be honest, I don't think anything would have sealed my old Bonneville, it was a piece of junk. How the British motorcycle industry survived as long as it did is a mystery to me. The Engineering was abysmal in my opinion. Wafer thin porous castings, too few bolts and tiny mating surfaces was never going to make an oil tight assembly. It was a revelation when I opened up my first Japanese bike and saw how it should have been done.
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Post by simplyloco on May 9, 2019 8:48:13 GMT
The head gasket blew on my new 1968 650cc Trophy, right next the the ninth stud which was added to prevent such an occurrence... The bike fell to pieces around me. Junk!!! John
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Post by Roger on May 9, 2019 10:52:41 GMT
Even though this is a crude test with a pretty rough and ready print to hold the magnet to the shaft, this works a treat. The magnet is pulled firmly inwards until it lines up with the outer magnets. Actually, the pocket could use to be a little deeper because it's lightly touching the bottom and that's adding to the friction. With the magnet in position, it takes next to no force to turn the gear and move the output shaft, so I'm calling this a success. It's surprising just how much torque these little magnets connect those two parts with, especially considering there's at least a 0.5mm total air gap at the poles. I was half expecting to need to reduce the air gap, but that really won't be necessary. In the test below, there's nothing to stop the magnet pulling towards one side, so one pole on the shaft piece is rubbing against the inside of the Phosphor Bronze tube. That's not ideal, and it's not how it will be on the final version. I suppose having a pair of outer magnets there's a balancing effect to some extent whereby the magnets cancel the radial forces so long as the air gap is the same on both sides. 20190509_111920 by Anne Froud, on Flickr So buoyed by the success of the experiment, here's the final design being trialled entirely in plastic to check that it all looks plausible. You can see there's a fair bit of support material around the outside of the Tank End Plate because there's an overhang at the top flange which is 1.6mm wide. 20190509_101133 by Anne Froud, on Flickr The pocket takes a 1.5mm section 'O' ring compressed by 15%, the screws being in blind holes outside of the seal. The two Brass screws will be countersunk and soft soldered to stop them leaking. There will be nuts on the other side to hold the plastic parts in place. So just to clarify the final setup.... the large plate on the right is going to be made from 6mm thick Brass plate so that the fixing screws can be blind. It will be held to the outer wrapper of the tank by Brass screws from the sides on three sides before Soft Soldering. The inside will still require a 3mm square section to be riveted to it since there's no room on the inside for that, and there would be no way to form the rivets in any case. The plate with the rounded edges is also going to be Brass, 1.5mm thick this time. The Phosphor Bronze bearing/magnetic coupling is riveted over on the outside and then Soft Soldered to seal it. 20190509_110938 by Anne Froud, on Flickr 20190509_111016 by Anne Froud, on Flickr So as usual, it's all over engineered, but it pleases me to do it that way. You could argue that the end plate could have been thin like the other side, with nuts soldered to the back of the plate, a gasket and a helping of gunk to seal it all. That would have required angles around the end plate of course so it's actually less work to do it this way albeit with more material cost. Each to their own. 20190509_111036 by Anne Froud, on Flickr So this is the final arrangement of the Magnetic coupling and test cock. There's an M5 x 0.5 (fine) thread and flange on the end of the test cock body so that it can screw straight into the pocket the magnet is fitted in. The Magnet is as before, just pressed into a 3D printed part which itself is pushed onto the end of the 1.6mm Stainless Steel shaft that has the handle on the other end. The angle of the handle can be adjusted by turning the magnet to the desired position. The long bearing should mean that the magnet can be held clear of the Phosphor Bronze tube so that there's even less friction. It should be more central than the test setup too, so that ought to even out the air gaps. I don't think that part is going to be problem though. This is all looking very promising. Final level gauge design by Anne Froud, on Flickr The weird cutout on the large quadrant gear is an artefact of the modelling process I used to create the gears as a pair. Just ignore that!
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Post by 92220 on May 9, 2019 13:05:54 GMT
Nice one Roger! It's good to see how new technology can be used in today's model engineering. Another way of indicating the water level might be using the quadrant gear to move a 'finger' up a slotted track on the inside of the tank, and tracking it with a mirror image on the outside, using another magnet or even just a steel/iron pointer in the form of the level indicators fitted to the BR1 series of tenders. Any comments on the feasibility of that idea Roger?
Bob.
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gwr7800
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Post by gwr7800 on May 9, 2019 14:16:07 GMT
I was thinking of physical gaskets rather than metal to metal with sealant when I mentioned my dislike of them. Head gaskets being the exception of course. To be honest, I don't think anything would have sealed my old Bonneville, it was a piece of junk. How the British motorcycle industry survived as long as it did is a mystery to me. The Engineering was abysmal in my opinion. Wafer thin porous castings, too few bolts and tiny mating surfaces was never going to make an oil tight assembly. It was a revelation when I opened up my first Japanese bike and saw how it should have been done. I agree with your statement about the old Triumphs in those days, In the seventies (1972/1978 )I had Japanese bikes never had a problem with any of them, unlike my friends on Bantams etc. I came back to motorbikes in 2009 with a Triumph Bonneville T100 865cc surperb bit of engineering no leaks always started and ran really well,from memory I think the engines were made in the UK as were the the fuel tanks but everything else was made in Bangkok? Perhaps this is why they ran so well? I sold the bike a year or so ago, I do miss it but not the cold and rain much warmer in the car!
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Post by Roger on May 9, 2019 18:17:16 GMT
Nice one Roger! It's good to see how new technology can be used in today's model engineering. Another way of indicating the water level might be using the quadrant gear to move a 'finger' up a slotted track on the inside of the tank, and tracking it with a mirror image on the outside, using another magnet or even just a steel/iron pointer in the form of the level indicators fitted to the BR1 series of tenders. Any comments on the feasibility of that idea Roger? Bob. Hi Bob, I think the biggest problem with any of these ideas is the force required to operate the indicator. The float can't be that heavy so the force it can transmit is small. This is the reason I didn't use an 'O' ring seal on a shaft, I couldn't see there being enough force available to overcome the friction of a seal on the shaft. The problem is compounded when you require a lot of movement of the output shaft or indicator. I think the friction between the two parts in your suggested arrangement would be too great for a float to move up and down if you were to use a single magnet and follower. I've side stepped the problem by having opposing magnets. I suppose you could use the same trick by having a 'U' shape in the tank so that opposing magnets could work against a single magnet in the dry inside side of the 'U'. The same arrangement could be made to work the other way around ie with water in a narrow channel and the follower on the outside of the 'U'. The first seems more plausible as it's more easily hidden.
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Post by 92220 on May 9, 2019 19:55:41 GMT
Hi Roger.
I was thinking that you wouldn't need a seal with the magnetic pointer idea. The float would move a magnet up and down, close to the wall and another magnet on the outside would follow the inside magnet and operate a pointer.
I only got the idea because I have been playing around with the induction hob and found it works perfectly well with 10mm of insulation between the hob and a pan of water so thought that using a thin brass sheet or a plastic sheet, would allow the magnetic flux to pass through, so no moving seals needed.
Bob.
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Post by Roger on May 9, 2019 21:13:04 GMT
Hi Roger. I was thinking that you wouldn't need a seal with the magnetic pointer idea. The float would move a magnet up and down, close to the wall and another magnet on the outside would follow the inside magnet and operate a pointer. I only got the idea because I have been playing around with the induction hob and found it works perfectly well with 10mm of insulation between the hob and a pan of water so thought that using a thin brass sheet or a plastic sheet, would allow the magnetic flux to pass through, so no moving seals needed. Bob. Hi Bob, The way you describe it is what I understood you to mean. The problem is that you have to reduce the friction of those to an absolute minimum if it's to be moved by the float. What linear slideway did you have in mind for that? If you have two magnets close enough to do the job, they will pull against each other enough to jam up the whole mechanism unless you can do something about that. Trap a piece of paper between a magnet and a piece of Steel and pull the paper out. That's the force your float mechanism has to overcome unless you take steps to keep an air gap and reduce the friction on the parts that move. This is why I've got opposing magnets so as to cancel out this effect. You can certainly do that in the way I described earlier. Can you sketch out in more detail what you have in mind in case I'm missing something obvious?
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Post by JonL on May 10, 2019 6:13:53 GMT
A little bit of friction won't hurt if you want to damp out every little slosh of the tank though, would it? A bit like a barometer, although I realise that the friction there is to allow you to see change.
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Post by 92220 on May 10, 2019 8:05:17 GMT
Good point Roger! I was forgetting that. Definitely needs more thought!!
Bob.
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Post by steamer5 on May 10, 2019 9:07:56 GMT
Hi Bob, We’ve got lots of level indicators on the plant I work at that use that principle. K-Tec is the make, but there are others. The ones we have have either a short tube of red plastic with a magnet inside it that is inside a clear tube adjacent to the float tube in a stainless tube, the float also has a magnet in it. The other version has small metal flip over indicators that the magnet in the float trip as it rises & falls. Hope that makes sense.
Cheers Kerrin
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Post by Roger on May 11, 2019 7:04:43 GMT
A little bit of friction won't hurt if you want to damp out every little slosh of the tank though, would it? A bit like a barometer, although I realise that the friction there is to allow you to see change. It all depends on what you call 'little'. The force available to operate the mechanism is very small, so unless you try to reduce friction to the absolute minimum I don't think it would work at all.
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Post by Roger on May 11, 2019 7:07:08 GMT
Hi Bob, We’ve got lots of level indicators on the plant I work at that use that principle. K-Tec is the make, but there are others. The ones we have have either a short tube of red plastic with a magnet inside it that is inside a clear tube adjacent to the float tube in a stainless tube, the float also has a magnet in it. The other version has small metal flip over indicators that the magnet in the float trip as it rises & falls. Hope that makes sense. Cheers Kerrin Hi Kerrin, Do those types have the indicator surrounding the tube with the magnet and float in it? I can see how that would be effectively what I've done, albeit for linear movement.
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Post by steamer5 on May 11, 2019 8:08:09 GMT
Hi Roger, Hopefully this works...... encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQOlyJZgoqot2dAd8jRACQcd16aG-XUdao4jPsVJb5hgt2Q7wxvIf it did you should see the layout! The indicator is mounted separate to the actual float chamber, both types are the same...except the housing. Last place I worked they were on the boiler, running at 100 bar. The floats are manufactured for the density of the liquid that they will be used in. Current job we have them in water, hydrocarbon, thermal heating oil amounts others. Cheers Kerrin
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Post by Roger on May 11, 2019 8:54:30 GMT
Hi Roger, Hopefully this works...... encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQOlyJZgoqot2dAd8jRACQcd16aG-XUdao4jPsVJb5hgt2Q7wxvIf it did you should see the layout! The indicator is mounted separate to the actual float chamber, both types are the same...except the housing. Last place I worked they were on the boiler, running at 100 bar. The floats are manufactured for the density of the liquid that they will be used in. Current job we have them in water, hydrocarbon, thermal heating oil amounts others. Cheers Kerrin Thanks for that Kerrin, it's very interesting. So it does look like you can have a direct coupling between a float and an indicator if you carefully control the gap to give just the right amount of force between them. They're stacking things in their favour by having a large float and a small indicator which is more or less neutrally buoyant in the indicator tube. I can see the advantages in this arrangement to a whole range of situations.
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Post by 92220 on May 11, 2019 9:04:10 GMT
That's the sort of arrangement I was envisaging but I was thinking the float could be inside the tank with the following magnet outside though I hadn't given any thought to how it could be done. To minimise the effect on the magnetic flux I was thinking a thin plastic sheet in the tank side could be incorporated, though tin brass sheet might be just as good.
Bob.
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Post by Roger on May 11, 2019 9:45:14 GMT
That's the sort of arrangement I was envisaging but I was thinking the float could be inside the tank with the following magnet outside though I hadn't given any thought to how it could be done. To minimise the effect on the magnetic flux I was thinking a thin plastic sheet in the tank side could be incorporated, though tin brass sheet might be just as good. Bob. Hi Bob, I think you'll need to run a few experiments to see what's possible and what the friction and motion is like. One of the issues you have to contend with is the stick/slip of the indicator. The indicator needs to be able to move with very little force else it's going to stay where it is until there's enough force to move it. Then it's going to jump to a new position. Those problems are massively reduced if the indicator is floating in a tube. If you're going to do that though, you might as well have a similar arrangement to the boiler water gauge. I'll be interested to see what you come up with. I think this is a really hard problem to solve. One thought might be to have the indicator in the form of a cylinder what can roll in a guide track. That would allow it to roll up and down with less friction. Keeping it central might not be easy though.
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