|
Post by doubletop on Feb 14, 2022 19:36:49 GMT
I had another look at this again this morning and thought "no I've got this wrong". My plan view is different to the orignal plan view (green). I went back to the CAD and no, I'm correct the angle in my version is the top edge of the front wing (red). The original drawing has it square, which maybe contributed to me struggling to reconcile the drawing. Todays problem is the CAD now won't create the flat pattern as the way I've cut the edges, from a side on view, doesn't make them square to each panel. Back to the drawing board. Pete
|
|
|
Post by doubletop on Feb 16, 2022 16:15:44 GMT
Didn’t sleep that well last night and found myself going through the next steps of the tank filler parts. Of course, that turned to “How did Gary do it?” and getting up to find out. Then I found he had the snippet of the works drawing for 15xx. As Swindon were into standardisation of parts I thought those for the 14xx wouldn’t be far different. Fusion 360 has a feature where you can import a picture, scale it to a known dimension and use that as the basis for your drawing. So how well do the parts drawn by John Smith, and redrawn by me, match? I do tend to redraw most parts before I start mainly because the dimensions can be spread across a number of sheets and I find I need dimensions for set up references. Rather than try to work it out with a calculator on the job, I add everything I need to the printouts of my drawings to take to the workshop. Allegedly there is less chance of a cock up So here my previously drawn parts overlaid on the 15xx drawing. There is room for some improvements here. But the same exercise to the JS drawing, which I hadn't done until now. You’ll also notice that I’ve gone down the route of machined parts rather than folding (there should be a post later on that). There will be a bit of fettling at the end to make them look more realistic rather than have sharp edges. Pete
|
|
|
Post by doubletop on Feb 20, 2022 9:18:08 GMT
The tank filler parts were made over a couple of days. First the formers, again using the DRO smooth arc function. I chose to make the small brackets and levers from solid using 1/4” and 3/8” bar and machining the slot to make the U sections required.
They have a number of angles associated with them. Again, I used the DRO’s, this time the “line of holes” function. With a step of 0.015” these angles can be dealt with reasonable accuracy and speed The lever. And the small angled support bracket The lids were made from 1/16” copper. My preference for trimming copper plate to size is to clamp them to the mill table and run around with an end mill. Small or large plates it works well. (I knew Gary's 10ba bolt and slitting saw approach would have ended baddly for me) Here is me doing the same for end plates for the boiler a few years back Parts coming on But this is as far as I’m going now as my order from Polly arrived on Friday I can now get back to the tanks that have been waiting for over 2 months now. In the order was the casting for the screw reverser mount. As designed, this sits on the shelf on the right-hand tank. As my tanks have been modified to be easily removable my intention has always been to mount this casting on a replacement for the existing reverser support bracket. Now, I’ve got the casting I can start looking at how I will do this. I have to sort the reverser first as the tunnel for the reach rod depends on the location of the reverser. A good part of the day has been spent drawing it up. I’m glad I waited as the casting is not exactly the same dimensions as some of the drawings. Actually, the dimensions on the drawings are correct. The drawing itself is not entirely accurate to the dimensions. One happy coincidence is that it does seem possible that the screw from the existing reverser can be re-used so I my not need to purchase some left hand taps and dies to make a new one. Pete
|
|
|
Post by doubletop on Feb 28, 2022 9:13:18 GMT
Well, it has been a week so time for a bit of an update. First off as how to hold the casting for machining. It is an odd shape so various possibilities were investigated, including “vice in vice”. In the end I didn’t need to use this method. No pictures of the actua setups for the machining I’m afraid but I wasn’t that traumatic and the casting is so good very little is required. One problem I did have was drilling the holes for the bearings for the screw. I have some long series drills but they were not a size suitable to get the reference hole drilled. Out came the “drill on a stick” My original intention had been to use the existing reverser stanchion and chop the top off and silver solder the new reverser casting on to it. I’m always a bit loathe to do butcher existing parts and if for some reason I wanted to run the loco before I’d finished the new reverser I wouldn’t be able to. (If I did want to run the loco it would take me less than a day to remove all the new parts and reinstate it with the original parts). The decision was made to make a new stanchion. The Martin Evans version is a 3/16” x 2.5” wide plate mounted on a stand-off with 4x2BA bolts to the inner frame. Using the CAD model, I established the height required so the reverser would sit nicely on the shelf. I only had some 5mm stainless that just a happened to be 2.5” wide so an easy job. A trial fit showed that it would sit too far back in the cab. Locating it on the forward 3 holes would do the trick So the plate was reduced in width to remove the excess As you will notice I’ve already recessed the running plate for the 2.5” plate. This will all disappear under the raised cab floor, so an irritation rather than a major problem. You will also notice that I have used the original screw and handle. It just about fits, but I think I may well make a new one. I have already done the die nut and left and right connecting links, but don’t have any photos. The next step is coupling up to the original reach rod. As you will recall, the reason work was stopped on the tanks is I needed to get the reverser done so I could establish the correct location of the tunnel for the reach rod in the right hand tank . I've now modelled the original reach rod to Martin Evans drawings, including the amendments introduced by Don Ashtons valve gear design. When I removed my reach rod it was nothing like Martins drawing. There is nothing that can be done other than source some material to make another one. So that’s the next step. Once that is done I should be in a position to lock in the design for the tunnel in the right hand tank. Pete
|
|
|
Post by doubletop on Mar 1, 2022 1:50:37 GMT
There will be a delay on the replacement reach rod as I don't have any suitable material. As the minimum purchase is a single bar so I have 6mtrs of 16mmx6mm on order but it won't get here until next week. It may seem that 6mtrs is bit over the top for a reach rod that can't be longer than 400mm but as it is only costing $20 (about £10) I can live with it and the extra will always find a job.
In the meantime I'll find something else to do.
Pete
|
|
|
Post by steamer5 on Mar 1, 2022 7:15:33 GMT
Hi Pete, I have a steel supplier just down the road that cuts to what ever you want……. would of thought you would have something simallar down your way. Still if you have a use for the rest not really an issue. Stay safe.
Cheers Kerrin, currently in the caravan, looking out to White Island over a lovely blue sea……. It’s a tuff life but somebody has to do it!
|
|
|
Post by doubletop on Mar 1, 2022 7:33:59 GMT
Hi Pete, I have a steel supplier just down the road that cuts to what ever you want……. would of thought you would have something simallar down your way. Still if you have a use for the rest not really an issue. Stay safe. Cheers Kerrin, currently in the caravan, looking out to White Island over a lovely blue sea……. It’s a tuff life but somebody has to do it! Kerrin I have 3 steel suppliers within 10 mins of the house (Steel and Tube, Easy Steel and Asmus). Only 2 have the size I need in their catalogue, 1 of those says they don't stock it. The one that does needs to get it from Auckland. The next truck is Wednesday next week. The joys of Covid and "just in time" supply chains. I've plenty of other things to get on with just a case of swapping from one to another Pete
|
|
|
Post by steamer5 on Mar 1, 2022 8:15:10 GMT
Hi Pete, Sounds like you are well catered for! Pity they don’t have what you need! been enjoying your build. Can see some time getting to grips with a few more functions on the DRO on the mill.
cheers Kerrin
|
|
|
Post by doubletop on Mar 2, 2022 7:04:57 GMT
Hi Pete, Sounds like you are well catered for! Pity they don’t have what you need! been enjoying your build. Can see some time getting to grips with a few more functions on the DRO on the mill. cheers Kerrin I think I have a pretty good grip on the DRO functions, although they sometimes do catch me out. I coined the term MNC (Manual Numeric Control) using the functions to machine complex shapes by daisy chaining the Smooth Arc and Line of Holes functions. I've only done it in 2D (X,Y) but there is a possibility to use Z as well. I'm carrying on with the tanks for now doing what I can that doesn't include the tunnel. I don't know about everybody else but I sometimes get to an "I don't want to do that bit" stage. I know it needs to be done but can't summon up the enthusiasm to do it. The job doesn’t need to be hard but there’s something that is holding you back. Anyway, I tackled one of those today so I can now move on. If I do get bored with the tanks I could tackle the whistle shroud now as I purchased some thin brass sheet. (Kerrin you know that Mitre 10 have K&S metals these days? I also found that they have Humbrol paints. Somebody is doing a good job encoraging them to become a stockist) Pete
|
|
|
Post by steamer5 on Mar 2, 2022 8:06:15 GMT
Hi Pete, Every time I use the DRO, other than the usual stuff, I have to sit quietly & read the manual, then do a dry run or two to make sure I’ve got my head around it, repeat the next time! Trouble being the gaps between using some of the functions is months. Yes had spotted that Miter10 had the K&S metals….haven’t looked lately so hopefully they still have it, as to Humbrol paint I hadn’t spotted that…time for a visit! Our local Toyworld has a pretty good selection of Humbrol & a couple of other varieties of paint, have to go & check & see if they have K&S metals too
Cheers Kerrin
|
|
|
Post by doubletop on Mar 2, 2022 18:35:18 GMT
Hi Pete, Every time I use the DRO, other than the usual stuff, I have to sit quietly & read the manual, then do a dry run or two to make sure I’ve got my head around it, repeat the next time! Trouble being the gaps between using some of the functions is months. Yes had spotted that Miter10 had the K&S metals….haven’t looked lately so hopefully they still have it, as to Humbrol paint I hadn’t spotted that…time for a visit! Our local Toyworld has a pretty good selection of Humbrol & a couple of other varieties of paint, have to go & check & see if they have K&S metals too Cheers Kerrin I had gone to the Petone Mitre 10 and the K&S rack was full, which is most unusual for K&S. In addiion there was box of packs ready to re-stock. Somebody is on the ball. Of course it is all online as well. Pete
|
|
|
Post by doubletop on Mar 3, 2022 7:23:54 GMT
I had something on mid morning so deided to use the time first thing to do the whistle shroud. Given that I’d been looking at the original drawings for some time (years on and off), the final steps were pretty painless now that I had worked out what was intended. Stuck a cutout of the flat panel drawing onto a piece of 0.032” brass sheet with glue stick. Cut the outline on the shear With the hand nibbler removed the bulk of the slot in the lower section Finished off with Swiss files The two inner folds were easily accommodated in the pan brake but it couldn’t do the outer folds so had to resort to blocks in the vice. (The marks on the back re from the brake.) I was happy with the resulting folds I was goig to make the lower mounting plate and solder it in but it was too small and could well have wondered around due to the effect of the flux. I decided to solder in a strip and then shape it after soldering For some reason I then forgot to take any more photos. Probably because the next steps were shaping the mounting plate, in situ, and drilling the three holes. Shaping the plate was pretty straight forward but drilling the 3 holes took me ages. I just couldn’t find a way of holding the job and then getting a datum to ensure everything would sit square. For some reason I entered ‘faff around’ mode and wasn’t happy with anything I tried. I got there in the end but the three holes probably took me longer than all the other steps put together. Anyway here is the end result. (I have just noticed the bottom plate of the shroud needs shaping to match the line of the bracket.)The dummy whistles are from Polly Model. Because I’m building my kit so the roof comes off easily the whistles cannot be fitted to the firebox cleading. I’m going to add a small bracket that will fixed to the front of the cab and the base of the whistles fitted to that. The whole whistle assembly will then come off with the cab roof. Not prototypical but meets my functional priority. Pete
|
|
|
Post by doubletop on Mar 7, 2022 8:08:54 GMT
You will recall that in order to confirm that the Polly kit would work on a Dart made to Martin Evan drawings, I had done the basic tanks, outer skins and base plate. I had then moved on to the cab roof and then the bunker. I am waiting for the steel for the new reach rod, so that I can finish the reverser and confirm the location of the tunnel in the right-hand tank. In the meantime, I restarted work on those areas of the tanks that I could work on. So now I’m back on the tanks, these are probably the least complete items in the kit, principally because the tank internals are dependent upon the size of the boiler and users needs. Like me making the tanks easily removable. I’ll admit here that I have been struggling somewhat. There are a lot of parts required and despite drawing everything in CAD, before I cut metal, I still get things wrong, or get to a point that I realise I could have done something differently. My usual approached these days is decide what I am going to do the next day and, in the evening, go over the CAD to ensure that I haven’t missed anything. The next day work on whatever I’ve decided to do until I get to a point that I’ve completed it or an “Oh Bugger!!” moment arises and I need a rethink. That may result in a quick re-work on the CAD over lunch, or a bit of a brainstorming session in the evening. For example, today I got to the point of the left-hand tank rear panel, which has to accommodate the original drain cock lever. I have steam operated drain cocks, operated by the original lever. The valve will now be hidden in the rear of the left-hand tank. I had done some basic work on this some time ago but now was the time to check. The mounting bracket is straddled by the rear panel and the lever would be inside the tank. A simple remake, or even modification to the lever would be all that is required. The mounting bracket and cut out for it will be hidden under the floor. Anyway here is where I am with the tanks The parts sat on the right hand tank are waiting for the reverser to be completed. You will notice some lengths of brass angle in the front of the shot. That was delivered today. I can’t believe the amount of the stuff I’ve been going through. This is the fourth delivery of a 3.6metre length. You may ask what am I doing with the stuff? I asked myself that after I used up batch two. I couldn’t believe where it had gone and thought I’d mislaid some. I went through the process of measuring every part I’d made with it and confirmed I had used it all. As for scrapped parts there are very few, I’d be surprised if they came to a metre. All in all, a very expensive addition to the costs, especially when I can only locally source 0.5”x 0.5”x 1/16” brass angle and half of it ends up on the workshop floor as I machine it down to 0.25”x 0.25” x 1/16”. Pete
|
|
Gary L
Elder Statesman
Posts: 1,208
|
Post by Gary L on Mar 7, 2022 16:43:23 GMT
Hi Pete What a pain! I think I estimated about 26ft of ¼"x ¼" x 1/16" angle was needed for Paddington (don't quote me) and it turned out to be not enough. Fortunately the ¼" angle is readily available here in the UK, so at least I didn't have the extra joy of machining it down from ½". The trouble is, you can add up all the lengths you need and divide by the length they are supplied in (usually 2ft over here) but that doesn't take account of the wastage when you can't quite cut the length you need from what is left of the last cut length... and so on.
Never mind, it is looking good, and all the grief will be forgotten when you have finished it!
Gary
|
|
|
Post by doubletop on Mar 7, 2022 19:47:33 GMT
Hi Pete What a pain! I think I estimated about 26ft of ¼"x ¼" x 1/16" angle was needed for Paddington (don't quote me) and it turned out to be not enough. Fortunately the ¼" angle is readily available here in the UK, so at least I didn't have the extra joy of machining it down from ½". The trouble is, you can add up all the lengths you need and divide by the length they are supplied in (usually 2ft over here) but that doesn't take account of the wastage when you can't quite cut the length you need from what is left of the last cut length... and so on. Never mind, it is looking good, and all the grief will be forgotten when you have finished it! Gary Gary The pain is more in the wallet than the effort involved. Although I've only got a mini mill (SX3) it will rip the ¼” off in one cut and after over 12metres of the stuff I've got it down to a pretty quick process. In a way I'm encouraged by the information that you used more than 26ft (8metres), and that’s when you don’t use it for your tank baffles. All my baffles and plates are attached using ¼” angle. At one point I couldn’t work out where a length had gone so initiated an independent search party in the workshop (SWMBO). The conclusion being “You’ve used it” You are right it will all be forgotten when I’ve finished it. Pete
|
|
|
Post by doubletop on Mar 8, 2022 8:54:11 GMT
Well, another of those days on the tank saga. I thought I’d make a start on the tank backs. I’ve rough cut the panels and thought I’d square them up and look at the cut-outs for the splashers. So, first job was a quick print of a sheet with the dimensions etc to take to the workshop. The first problem was obvious, the splashers for the left and right panels were in a slightly different location. A few hours were then spent back tracking on how I’d drawn them up, work out which was right and which was wrong and correcting the drawings **. It turned out neither as I printed a template and cut it out to offer up to the job. The radius of the splasher cut-out was completely wrong, back to the John Smith drawings and confirmed dimensions. The splasher radius should be 4.25” but they weren’t, it turns out the Polly splashers have an outside radius of circa 4.054”. More time spent on the CAD correcting that. Pete ** (I’m a bit of a CAD hacker and haven’t fully developed a method of working with it correctly. Bits get grafted onto designs here and there, so maintenance can be a bit tricky)
|
|
|
Post by doubletop on Mar 14, 2022 9:01:36 GMT
After discovering the anomaly between the John Smith drawings and the splashers supplied by Polly I was beginning to lose my confidence. Which dimensions had I used in my CAD model, were they correct, were the reference points I had used correct? The printed cardboard templates were used again to confirm the dimensions in the CAD represented the job and it was time to machine the back panels. First get them to size, they just about fitted my SX3. Only being able to clamp them at the ends the cast blocks helped stop any vibration as the long edge was bought to size. Once again, I was going to use the DRO smooth arc function to do the cut-outs for the splashers. As the centre point for the arc was off the mill table the template came in handy to confirm the cuts were going to be done in the right place. Not checking where the cuts will go when using offset datums on the DRO’s is not recommended. Each arc was around 400 plunge cuts at a 20thou step. Around an hour for each panel. I did think about doing them as a pair but I do subscribe to the law of sod. Had I a done that something would surely have gone wrong. Very little fettling required and quick rub with wet and dry to remove any sharp edges and job done Pete
|
|
|
Post by doubletop on Mar 20, 2022 9:05:35 GMT
First thing stevep had paid a visit to the Tiverton Museum and had taken some pictures of 1422 whistle shield. I’ll share them here. Thanks Steve It does appear that the shield was extended at some point and rather than re-make a bit was just tacked on. I remains to be seen if I re-visit mine. It would seem that I could just make another to my drawings and chop the top off the existing and take the top section of the other a rivet them both together. ===================================================================== The 6 meters of steel for the reach rod were collected from the supplier. As I was putting it into stock a short length of the same size fell out of the rack. I already had enough material avaiable! I could only source 16mm x 6mm bar when I needed 3/8” x 3/16” so I knew I had to machine it to size. That was going well until I realised it had turned into a banana. OK let’s try something else. I have some 3/16” by 1.5” so I set to and cut a length from that. Now three bananas.... Time for a cup of tea and a re-think. The next day I didn’t even go into the workshop. There was nothing for it but to make the most of the existing reach rod. Now I had this I was able to confirm the position and angles it took from full forward to full reverse. This information was fed into the CAD and the drawings updated. Now I had everything I needed to progress the tank interior’s. However, for some reason I was procrastinating again, I realised I just had to get on with it, no excuses. The CAD says the right hand tank should look like this And the result is Currently it is all pinned together with unclosed rivets, there are a few more small parts to make and then final assembly can be done. I’m paying attention to try to not paint myself into a corner with the riveting. As planned the reverser ‘sits’ on the shelf but the tank can be removed leaving the reverser in place. (tatty original reverser handle being used) The left hand tank is a lot simpler. The rear portion is going to hide the operating valve for the steam drain cocks with the trunnion for the operating lever just under the lower rear portion of the tank. The opening will be covered by the tank floor. I’ve taken a bit of artistic licence with the riveting of the tanks in the cab. The only reference I had was these photos I taken of 1466 a few years ago. I didn’t really want to replicate this and I am aware that there has been a lot of work done the tanks as part of the restoration of 1466. Suffice to say there has been a lot of work required to do these tanks far more than is required for the cab and bunker and plenty more to do. I’m not sure how I would have got on without having access to a CAD programme. Pete
|
|
samc88
Active Member
Posts: 42
|
Post by samc88 on Mar 20, 2022 22:50:55 GMT
Nice work, your one piece whistle shield looks a lot neater than the extended one. Whats the purpose of the shield out of interest?
|
|
Gary L
Elder Statesman
Posts: 1,208
|
Post by Gary L on Mar 20, 2022 23:21:20 GMT
Nice work, your one piece whistle shield looks a lot neater than the extended one. Whats the purpose of the shield out of interest? Very much agree, though Steve's pictures do explain the situation perfectly. The 14xx cab stands much higher above the firebox top than almost any other GWR loco, so the standard whistle shield pressing was not tall enough. Rather than tool up for a new pressing, it looks like they just took a standard item and added a bit of bent tin to make it taller. Makes perfect sense. The purpose BTW, to answer the question, was to direct the whistle exhaust over the cab roof, thus to prevent it fogging up the spectacle glasses. There is a usually a good reason for everything, short of invading Ukraine... Gary
|
|