mike47j Posted January 10, 2015 Share Posted January 10, 2015 I think you could also move the pivot forward a little as well. Since most of the space to put weight is at the front it would help with stability (not that mine goes very fast). The centre of gravity should remain between the pivot and bogie according the gauge 0 guild manual. Link to post Share on other sites More sharing options...
chaz Posted January 11, 2015 Share Posted January 11, 2015 Pivot should be fine 3mm below centre line of axles - the very small fore and aft movement of the axles (which happens wherever the pivot is) can be ignored. Unless your trackwork is appallingly bad the movements of the compensation beams will be small (but important!). Suggest you drill new holes for your plunger pickups forward of the leading axle (if there is room) so that there is no clash with the beams. Best to put the pickups on the axle centre line or near it - but again if you can't the saver is the small vertical movement of the axles - typically a fraction of a millimetre. Hope that helps Chaz 1 Link to post Share on other sites More sharing options...
buffalo Posted January 11, 2015 Share Posted January 11, 2015 ...I'm thinking of perhaps dropping the pivot down by about 3mm. See red dot on the photo below... Why not put the pivot above the axle centres and just above that frame cutout? If you look at the 1366 photo that is what was done there, and is often done on other models. You may even be able to shape the beams to avoid the plungers and it will be less conspicuous that way. As to fore and aft movement, as chaz says, provide you allow a bit of space in the frame axle holes it will be irrelevant. There will be some minute movement wherever you place the beam centre. Nick Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Why not put the pivot above the axle centres and just above that frame cutout? If you look at the 1366 photo that is what was done there, and is often done on other models. You may even be able to shape the beams to avoid the plungers and it will be less conspicuous that way. As to fore and aft movement, as chaz says, provide you allow a bit of space in the frame axle holes it will be irrelevant. There will be some minute movement wherever you place the beam centre. Nick Morning Nick, I did originally think about copying the 1366 arrangement and having a higher pivot point but the compensation beams would have to be a complex shape to avoid the frame cut outs (which I don't want to obscure). Also Jim's instructions show that the upper frame area will be quite congested with the fake inside motion gubbins. See photos below to see what I mean: A real advantage of Jim's instructions is that you get a really good idea of what you're building and it makes it easy to identify and think through issues. My thoughts at this stage are that a low down compensation beam will be easier to accommodate. Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Ah, I see, I had forgotten you were doing like that rather than sliding hornblocks. Anything useful here?: http://www.clag.org.uk/41-0rev.html#section9 Thanks Mark, I had seen those comprehensive notes before but this time I have them a good read! They do cover Jim's suggested compensation method but conclude, whilst it's ok, there's better solutions. Later on it covers the effect of mounting the motor on a non-fixed axle. My reading is that it recommends moving the beam pivot point forward to take account of the motor weight. I follow the argument as, being a civil engineer, I was taught to work with moment diagrams. 1 Link to post Share on other sites More sharing options...
mike47j Posted January 11, 2015 Share Posted January 11, 2015 There is a weight casting that goes at the front of the chassis that would block moving the pickups forward. I've not fitted it as it would block a sprung coupling, but I might cut it in half and fit it. The motion plate comes from the angled slots above the plunger pickups to the bottom of the frame. I removed the lower part to clear the pickups. The large oval slot is almost impossible to see on the finished model. The front steps, brake gear and wheel all block sight of it. But the motion plate would be in the way again. I think putting the beams below the pickups is probably best. (Or just use sprung horn blocks on the rear drivers.) Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 There is a weight casting that goes at the front of the chassis that would block moving the pickups forward. I've not fitted it as it would block a sprung coupling, but I might cut it in half and fit it. The motion plate comes from the angled slots above the plunger pickups to the bottom of the frame. I removed the lower part to clear the pickups. The large oval slot is almost impossible to see on the finished model. The front steps, brake gear and wheel all block sight of it. But the motion plate would be in the way again. I think putting the beams below the pickups is probably best. (Or just use sprung horn blocks on the rear drivers.) Out of interest how much does your completed loco weigh? Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Ah, I see, I had forgotten you were doing like that rather than sliding hornblocks. Anything useful here?: http://www.clag.org.uk/41-0rev.html#section9 Well, following the maths in those destructions it would appear the the pivot point needs to be about 23mm from the centre of the front axle. The coupled wheelbase is 6'10" so 47.83mm, giving the distance from the pivot point to the rear axle at 24.83mm. All very theoretical but it helps avoid the frame cut outs. Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Pivot drilled. 2 Link to post Share on other sites More sharing options...
chaz Posted January 11, 2015 Share Posted January 11, 2015 (edited) Morning Nick, I did originally think about copying the 1366 arrangement and having a higher pivot point but the compensation beams would have to be a complex shape to avoid the frame cut outs (which I don't want to obscure). Also Jim's instructions show that the upper frame area will be quite congested with the fake inside motion gubbins. See photos below to see what I mean: rps20150111_093631.jpg rps20150111_093705.jpg rps20150111_093756.jpg rps20150111_093817.jpg A real advantage of Jim's instructions is that you get a really good idea of what you're building and it makes it easy to identify and think through issues. My thoughts at this stage are that a low down compensation beam will be easier to accommodate. I think that's right; equivalent to turning the arrangement on your 1366 upside down? Looking at the photos you posted I think you may have to sacrifice the bottom part of the motion bracket where it is intended to be soldered to the frames to allow working space for the beams. No real problem with that as there looks to be an adequate joint available on the top section. In any case if it were me I would rather have a compensated chassis than the (non-working) motion - if there were not room for both. Keep up the good work! Chaz Edited January 11, 2015 by chaz Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 I thnk that's right. equivalent to turning the arrangement on your 1366 upside down? Looking at the photos you posted I think you may have to sacrifice the bottom part of the motion bracket where it is intended to be soldered to the frames to allow working space for the beams. No real problem with that as there looks to be an adequate joint available on the top section. In any case if it were me I would rather have a compensated chassis than the (non-working) motion - if there were not room for both. Keep up the good work! Chaz Thanks Chaz, yes I think the bottom part of the cosmetic motion bracket will have to be removed but it will be covered be the motion above. First holes drilled (see above your post), beams to be cut next. Link to post Share on other sites More sharing options...
chaz Posted January 11, 2015 Share Posted January 11, 2015 You have probably already worked this out, but here are my suggestions for setting up the beams..... Cut your beams make the axle holes in the beams and the frames so that the axle bearings are a snug fit put the beams in place with the bearings pushed through both the beams and the frames drill the pivot holes in the beams put jig axles into the bearings and check the fit of the coupling rods if necessary drift the holes in the beams and the frames so that the rods fit nicely - Knowing Connoisseur kits the frame holes should be pretty well bang-on. reverse the bearings so that the flange is inside the frames and solder to the beams - don't allow the solder to get on the frames. You may need to shorten the bearings if they prevent the wheels from sitting at the correct B to B. remove the beams and enlarge the holes in the frames to allow the beams to move. For pivots you could use Slater's crankpin bushes. They can be shortened so that they are flush with the outside of the frames. If you find some brass rod which is a fit in the bushes you can cut a length to go right across and solder them to it so there is no risk of locking the beams with excess solder. It's also easy to dismantle the beams if you have to - just cut through the rod. Hope that's some help. Chaz Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Thanks Chaz, that confirms the method I've been mulling over in my head the past week. It helps having battled with the 1366! Jim has thoughtfully provided a good length of scrap on the chassis etch in NS.two 62mm lengths were cut and soldered together and pilot holes drilled for the axles. The top edge needs shaping to fit around obstructions. That job is next... 1 Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Beams now shaped. Axle holes to enlarge. Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 One down... Pub calls! 2 Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Pub slightly delayed and so we have the second bearing holes done... And the pivot holes drilled Now we're off to the pub! 9 Link to post Share on other sites More sharing options...
RMweb Premium wagonbasher Posted January 11, 2015 RMweb Premium Share Posted January 11, 2015 Pub slightly delayed and so we have the second bearing holes done... rps20150111_141048.jpg And the pivot holes drilled rps20150111_141817.jpg Now we're off to the pub! That's a hard life you've got there..... Anyway.... Is that a pair of mole grips.... Now that's finescale modelling! Andy Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 That's a hard life you've got there..... Anyway.... Is that a pair of mole grips.... Now that's finescale modelling! Andy I do industrial finescale Andy, no power tools, no lathes, just abuse of a variety of handtools. Molegrips were involved - just to make sure the two beams didn't split whilst I abused various reamers. No photos taken of methods so as not to upset those that do things properly. ;-p 4 Link to post Share on other sites More sharing options...
puddlejumper Posted January 11, 2015 Share Posted January 11, 2015 (edited) Looking good Chris although I think Andy is trying to keep you out of the pub which is technically emotional & physical abuse lol...........should I ring social services for you Edited January 11, 2015 by puddlejumper Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 Yes please. Link to post Share on other sites More sharing options...
chaz Posted January 11, 2015 Share Posted January 11, 2015 Pub slightly delayed and so we have the second bearing holes done... rps20150111_141048.jpg And the pivot holes drilled rps20150111_141817.jpg Now we're off to the pub! Crikey, that was quick! Looking good. It occurs to me that if your bogie is "floppy" with the sides able to pivot with respect to each other, then with the twin beams you will have the classic three-point suspension. Height adjustment (to get the loco to sit level fore and aft) will be available at the bogie pivot. Very neat. the only remaining problem will be getting the CoG right so that it tracks properly in forward gear. It should be fine running backwards. What a pity the GNR 0-4-4Ts disappeared well before nationalisation....... Link to post Share on other sites More sharing options...
mike47j Posted January 11, 2015 Share Posted January 11, 2015 My loco is 888 grams, center of gravity is about 1cm in front of the rear driving axle . Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 My loco is 888 grams, center of gravity is about 1cm in front of the rear driving axle . Thanks for that, I'm aiming for about 1kg for my build. Tricky things to add weight to 0-4-4s! Link to post Share on other sites More sharing options...
RMweb Premium wagonbasher Posted January 11, 2015 RMweb Premium Share Posted January 11, 2015 just jealous..... it was new tyres, a craft centre and a 4mm wagon today for me Andy Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 11, 2015 Author RMweb Premium Share Posted January 11, 2015 just jealous..... it was new tyres, a craft centre and a 4mm wagon today for me Andy Jealous of using mole grips? How's the tinny count today Banks? Link to post Share on other sites More sharing options...
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