CWJ Posted June 5, 2012 Share Posted June 5, 2012 (edited) If only I could prevent my own personal 'mid-span sag'... (apologies, someone had to say it) Edited June 5, 2012 by CWJ 1 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 5, 2012 Author RMweb Premium Share Posted June 5, 2012 If only I could prevent my own personal 'mid-span sag'... (apologies, someone had to say it) Hello Will, I'm hoping that my "construction", aka the "nuclear bunker" aka Ground Zero Tower foundations UK, will be rigid enough to avoid too much sag. Plenty more timber to go in and, so far so good as far as alignment is concerned. Depending on the type of personal sag you refer to, I recommend exercise or you could go and see your GP for one of those little blue pills. I've heard they restore rigidity in quick time!! Good to hear from you! Best wishes, Jeff Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 5, 2012 Author RMweb Premium Share Posted June 5, 2012 Don't worry Will - Jeff is clearly doing a very solid job but I was wondering how he was going to do the joints as those two timbers were apparently 'in final position' so I wondered if he wasn't going to half lap them but had some other idea in mind. Certainly a strong job with timber that size and with his scientific background I bet Jeff has very carefully calculated timber size to avoid any mid-span sag in the future. Evening Mike,. Nothing is actually fixed in place as yet. The timbers you've seen are a small part of the network (you've seen the subframe plan earlier in the thread). Junction points will be screwed together (I don't like using glue) and there will be a number of supports (see the post after this - I'll upload a "support plan"!!). And yes, I've calculated the relevant modulus of elasticity to check for the sag of extended cantilevers (like bloody hell I have - I'm a nuclear man, not a materials physicist. Lol). Isn't modelling fun? I've basically built a miniature house by the time I get to buy the track!! Cheers, Jeff 1 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 5, 2012 Author RMweb Premium Share Posted June 5, 2012 Mike, Enclosed diagram showing proposed positions of "legs" under the subframe... Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 6, 2012 Author RMweb Premium Share Posted June 6, 2012 Morning update... 2 hours of cutting have added a few more spans. Coffee, then more fun! Jeff 4 Link to post Share on other sites More sharing options...
Andrew P Posted June 6, 2012 Share Posted June 6, 2012 Construction looks good Jeff, Legs can be a pain but you do need them, more legs more strength. Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 6, 2012 Author RMweb Premium Share Posted June 6, 2012 Construction looks good Jeff, Legs can be a pain but you do need them, more legs more strength. Thanks Andy. First 4 legs will be fitted tomorrow morning. The subframe isn't the most photogenic part of a layout, but I'm a great believer in the principle "if you are going to build it, build it as well as you can!" The actual baseboards will sit 25cm above the subframe on a set of risers. Hopefully this will give me lots of scenic possibilities. Jeff Link to post Share on other sites More sharing options...
Andrew P Posted June 6, 2012 Share Posted June 6, 2012 Thanks Andy. First 4 legs will be fitted tomorrow morning. The subframe isn't the most photogenic part of a layout, but I'm a great believer in the principle "if you are going to build it, build it as well as you can!" The actual baseboards will sit 25cm above the subframe on a set of risers. Hopefully this will give me lots of scenic possibilities. Jeff Dead right Jeff, and as many pics as poss are good to look back on to write your own article with pics as a complete library of the work done and a reference for future projects Link to post Share on other sites More sharing options...
Allegheny1600 Posted June 6, 2012 Share Posted June 6, 2012 Mornin' Jeff! Long time no converse, sorry about that. That timberwork is looking mighty impressive, good job you enjoy it! Keep up the great work, John E. Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 7, 2012 Author RMweb Premium Share Posted June 7, 2012 Morning John, nice to hear from you again. I'm enjoying actually being able to start on something directly related to the layout. I loved converting the garage, but I've been itching to start on the "underbelly" of the layout for months!! Enclosed - 2 more pics, taken an hour ago. Hair cut, then it's into the garage to fit some legs... Best wishes, Jeff 1 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 7, 2012 Author RMweb Premium Share Posted June 7, 2012 Hey, hey...we have legs (following the KISS principle!)... 2 Link to post Share on other sites More sharing options...
Andrew P Posted June 7, 2012 Share Posted June 7, 2012 Good pics Jeff, Looks like you have a nice bright room, my den has no windows as it was originally the garrage and I lost half its length, now just one small extractor for when I do the smelly stuff but as the door goes into the hall I still get complaints from SWMBO. Keep the pics coming as it looks as though you will have some good contors. All the best Andy. Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 7, 2012 Author RMweb Premium Share Posted June 7, 2012 Good pics Jeff, Looks like you have a nice bright room, my den has no windows as it was originally the garrage and I lost half its length, now just one small extractor for when I do the smelly stuff but as the door goes into the hall I still get complaints from SWMBO. Keep the pics coming as it looks as though you will have some good contors. All the best Andy. Hi Andy, I've got no windows either, but the room is quite large at 16' x 12' and there is 800 Watts of lighting available - though I don't have it all on for very long as it gets too warm. Glad you like the photos - I sometimes wonder whether I'm boring everyone to death!! I will post another couple of pics shortly - I have to take them first! Cheers, Jeff Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 7, 2012 Author RMweb Premium Share Posted June 7, 2012 OK Andy, specially for you...the current state of play. It might make sense if you compare it to the plan in post 79, above. No sign of any trains yet (lol) but we'll get there in the end! Jeff 2 Link to post Share on other sites More sharing options...
RMweb Gold SouthernRegionSteam Posted June 7, 2012 RMweb Gold Share Posted June 7, 2012 (edited) That looks like a nice sturdy base to work from Jeff! I don't think that'll warp in a while, or ever, come to think of it. Glad to see you are making a lot of progress, I can't wait to get to the baseboard stage on The Old Road - only then will the real size of the layout become apparent I think. I guess I need to put a lot of effort into designing, let alone making my boards given that they are to be portable and therefore must be as light a possible in order to be transported easily. Looking good, I can't wait to see a few full length trains snaking their way around this big layout - at this rate you'll be able to do that in no time! Jam Edit: And yes, I've calculated the relevant modulus of elasticity to check for the sag of extended cantilevers (like bloody hell I have - I'm a nuclear man, not a materials physicist. Lol) Eugh, sounds like the kind of maths calculations I have to work out for materials in my degree. Bending moments, beams and deflections... what fun, not! Edited June 8, 2012 by SouthernRegionSteam Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 That looks like a nice sturdy base to work from Jeff! I don't think that'll warp in a while, or ever, come to think of it. Glad to see you are making a lot of progress, I can't wait to get to the baseboard stage on The Old Road - only then will the real size of the layout become apparent I think. I guess I need to put a lot of effort into designing, let alone making my boards given that they are to be portable and therefore must be as light a possible in order to be transported easily. Looking good, I can't wait to see a few full length trains snaking their way around this big layout - at this rate you'll be able to do that in no time! Jam Edit: Eugh, sounds like the kind of maths calculations I have to work out for materials in my degree. Bending moments, beams and deflections... what fun, not! Morning Jam, You are quite right about the perception of layout size. When the room was empty it didn't look too big. Now I've put some framing in place, the layout area looks huge!! Not that I'm complaining! As for bending and calculations - I get enough of them in my job, so I've taken a typical engineering approach to my structural work. "Think of what is adequate, double it, add another 50% and that should be ok!!" Hope your "pub studies" are going well. Lol! Jeff Link to post Share on other sites More sharing options...
Andrew P Posted June 8, 2012 Share Posted June 8, 2012 (edited) Hi Andy, I've got no windows either, but the room is quite large at 16' x 12' and there is 800 Watts of lighting available - though I don't have it all on for very long as it gets too warm. Glad you like the photos - I sometimes wonder whether I'm boring everyone to death!! I will post another couple of pics shortly - I have to take them first! Cheers, Jeff Question! you say you have no natural light but what is that on the right in post 85? In my den 9 ft x 7 ft I have a pair of 8 ft florecents. Also I DID NOT KNOW THERE WERE TWO 5.46 IN A DAY, ha ha Edited June 8, 2012 by Andrew P Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 Question! you say you have no natural light but what is that on the right in post 85? In my den 9 ft x 7 ft I have a pair of 8 ft florecents. Also I DID NOT KNOW THERE WERE TWO 5.46 IN A DAY, ha ha I see what you mean! I usually close the side door to the "bunker" (not a garage any more!), but on that occasion I'd left it open. Had it closed this morning, mind, as it's absolutely p*****g down here. 05.46 ... umm ... I'm an insomniac. Only problem is I want to start drilling and cutting at that time, but I think the neighbours might complain! Cheers, Jeff 1 Link to post Share on other sites More sharing options...
coachmann Posted June 8, 2012 Share Posted June 8, 2012 I found using the old 1960s method of half lap joints merely reduced the strength of the timber. As soon as a 2" x 1" was notched it had no more strength than a 1" x 1". But I am following your baseboard construction with interest seeing as a similar job is looming for me as well. Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 Hi Larry, You may be right about the joints, but I find it much easier to securely interlock all the sections this way. All interconnections are screwed together and the structure has tremendous rigidity. So much so that when I built my old layout - using 2" x 2" - I climbed on top of the baseboard and jumped up and down. Aside from normal flexure, no problems. The present structure is considerably more heavy-duty than the last. Totally over the top, but - what the hell - you only build it once and then it just does its job. By the way, many thanks for your input on the circuit plan earlier in the year. Best wishes, Jeff Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted June 8, 2012 RMweb Gold Share Posted June 8, 2012 I found using the old 1960s method of half lap joints merely reduced the strength of the timber. As soon as a 2" x 1" was notched it had no more strength than a 1" x 1". But I am following your baseboard construction with interest seeing as a similar job is looming for me as well. A lot of truth in that ... but ... My father was a skilled carpenter and joiner and about 52 years ago built the baseboard structure for my attic layout - in 2x1 with half-lapped joints, very accurate half-lapped joints in his case and all nice and tight. When, 7 years ago, we dismantled the layout prior to demolishing the bungalow in which it resided the joints simply would not knock apart in many cases and regrettably we finished up splitting timber - and lost the ability to re-use it in the future - and a lot of it wasn't even any good for firewood. So like you I do worry about the strength of half-lap joints, even in 4"x2", but if they are very well made they seem to turn out pretty solid and they were easily capable of taking my then weight. But the 'trick' also depends, I think, on the size of the rectangles formed by the structure and possibly from using a 'solid' top which helps to keep them tight. Another thing is gluing the joints - using a good quality pva white wood glue produces a joint which is normally stronger than the wood around it and which should help prevent splitting (although I've an idea that Jeff might not be gluing his half-lap joints?). 1 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 This morning's update... Nearly built the subframe now! Another day, then I can think about the "riser" positions for the baseboard itself. The top of the subframe corresponds to the "water level" datum at the foot of the viaduct (see plan). So the baseboard top will be about 23cm higher than the subframe, putting it 103cm from the floor. For a little fellow like me (168cm or 5'6" in old-fashioned currency) that's ok. Attached pictures of more wood. No wonder I'm dreaming about the stuff! Jeff 4 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 A lot of truth in that ... but ... My father was a skilled carpenter and joiner and about 52 years ago built the baseboard structure for my attic layout - in 2x1 with half-lapped joints, very accurate half-lapped joints in his case and all nice and tight. When, 7 years ago, we dismantled the layout prior to demolishing the bungalow in which it resided the joints simply would not knock apart in many cases and regrettably we finished up splitting timber - and lost the ability to re-use it in the future - and a lot of it wasn't even any good for firewood. So like you I do worry about the strength of half-lap joints, even in 4"x2", but if they are very well made they seem to turn out pretty solid and they were easily capable of taking my then weight. But the 'trick' also depends, I think, on the size of the rectangles formed by the structure and possibly from using a 'solid' top which helps to keep them tight. Another thing is gluing the joints - using a good quality pva white wood glue produces a joint which is normally stronger than the wood around it and which should help prevent splitting (although I've an idea that Jeff might not be gluing his half-lap joints?). Afternoon Mike, I've never glued the joints - though they are screwed together. Ironic really, but the reason for this has been in case I want to dis-assemble the structure - which in this case, I don't! Anyway, each to his own. If any problems arise I will have to take remedial action! Cheers, Jeff 1 Link to post Share on other sites More sharing options...
RMweb Premium Physicsman Posted June 8, 2012 Author RMweb Premium Share Posted June 8, 2012 Evening all. Just one more photo to add to previous, though it's been a very busy afternoon - sorting out 3.6m planks of wood and marking-up for some of the risers. Fitted the opposite "angle piece" - only 3 more short sections to fit now. Enclosed photo for continuity... Jeff Link to post Share on other sites More sharing options...
Andrew P Posted June 9, 2012 Share Posted June 9, 2012 Amazing structure Jeff, but as you say, it has to last and NOTwarp, at the rate you are going you will be laying track next week. P.S I cant sleep tonight as I am planning another project. 1 Link to post Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now