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Post by doubletop on Dec 16, 2021 9:06:37 GMT
I’ve got the easier of the tank bulkheads done and now to start on the more complex. The area around the reverser and the reach rod needed to be sorted. John Smith’s drawing 52 doesn’t really help me as I intended to retain the Martin Evans pedestal rather than mount the reverser on the tank. Again my tanks are going to be removable, having the reverser mounted on the tank won’t allow that. I was trying to visualise the solution in CAD but more time can be wasted trying things out and sometimes it can be difficult to understand what you are looking at. The easy thing was to do it the old school way and then move to the CAD Once that was done it was over to the CAD to create the parts. I’m finding it far better to spend the time to get it right in CAD rather than fabricate on the fly and then try to may it work on the job. Do the CAD work, print the parts drawings and then off to the workshop with a degree of confidence it will all go together. I have spent a bit of time on the location of the tunnel for the reach rod and got to the point that I was about to fabricate something. Then a eureka moment, I’ve got some 1” square brass tube. Machine a slot down one side for the reach rod to pass through and it will also provide flanges for the removable tank back to be fixed to. A bonus. So ready to start, or maybe not? I’ve just ordered some more parts from Polly and got them to include the reverser casting. I plan to see if I can mount that on the Martin Evans pedestal and replace the original with something a bit more authentic. Pete
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Post by doubletop on Dec 16, 2021 19:56:35 GMT
I’ve got the easier of the tank bulkheads done and now to start on the more complex. The area around the reverser and the reach rod needed to be sorted. John Smith’s drawing 52 doesn’t really help me as I intended to retain the Martin Evans pedestal rather than mount the reverser on the tank. Again my tanks are going to be removable, having the reverser mounted on the tank won’t allow that. I was trying to visualise the solution in CAD but more time can be wasted trying things out and sometimes it can be difficult to understand what you are looking at. The easy thing was to do it the old school way and then move to the CAD Once that was done it was over to the CAD to create the parts. I’m finding it far better to spend the time to get it right in CAD rather than fabricate on the fly and then try to may it work on the job. Do the CAD work, print the parts drawings and then off to the workshop with a degree of confidence it will all go together. I have spent a bit of time on the location of the tunnel for the reach rod and got to the point that I was about to fabricate something. Then a eureka moment, I’ve got some 1” square brass tube. Machine a slot down one side for the reach rod to pass through and it will also provide flanges for the removable tank back to be fixed to. A bonus. So ready to start, or maybe not? I’ve just ordered some more parts from Polly and got them to include the reverser casting. I plan to see if I can mount that on the Martin Evans pedestal and replace the original with something a bit more authentic. Pete To add to this I was looking at the John Smith drawing last night and wondered why he had the tunnel set at 14deg and my measurement of the existing reach rod has it at 18-19deg (reverse vs forward gear, see note on cardboard version in the first photo). Looking at the CAD drawing it is because Martin Evans has the reverser too high. If it were to sit on the shelf it would be lower. All the more reason to put this part of the job on hold until the package from Polly arrives. It left the UK a week ago so should be in the NZ system somewhere. Of course having the reverser higher could be a bit more practical for driving. Let's see. Pete
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Post by doubletop on Dec 20, 2021 7:12:02 GMT
To add to this I was looking at the John Smith drawing last night and wondered why he had the tunnel set at 14deg and my measurement of the existing reach rod has it at 18-19deg (reverse vs forward gear, see note on cardboard version in the first photo). Looking at the CAD drawing it is because Martin Evans has the reverser too high. If it were to sit on the shelf it would be lower. All the more reason to put this part of the job on hold until the package from Polly arrives. It left the UK a week ago so should be in the NZ system somewhere.Of course having the reverser higher could be a bit more practical for driving. Let's see. Pete The tracking now says it is in Shanghai! However, taking the long route isn't unusual, I had a package from China to New Zealand go via Geneva. Something to look forward to in 2022. Plenty of other things to be getting on with. But, I'm conscious of the Gary L comment on doing stuff that later you wish you hadn’t as it gets in the way of latter work. I’m making bits but am reluctant to assemble just in case. Pete
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Post by doubletop on Dec 24, 2021 2:40:24 GMT
The tanks are done as far as I can go as I’m waiting for the parts from Polly The splashers are ready along with the bushes to go into the new tank floors for securing the tanks through the running plates. I can’t silver solder them in yet as I need to locate the holes in the running plate. It occurred to me that to get it right I needed the front spectacle plate ready to ensure the lateral spacing of the tanks was correct. So I moved on to that. Forming the 17” radius curve in the roof angle was done exactly as Gary L had done including the slot cut into the “Formit” rollers and the andyhigham suggestion to solder two angles together to stop them bowing out in the rollers. Soldering the two parts together was easy using solder paste used for soldering surface mount integrated circuits. Available from Element 14 or RadioSpares. You’ll notice I predrilled all the rivet holes to save spotting through. I don’t know what I was thinking but WRONG!! As a result of the rolling the spacing is incorrect. Two perfectly good roof hoops consigned to the scrap bin. Two more were quickly made and rolled. It is suprising how quickly things can be done when you know it is going to work. Before any riveting could be started it was time to ensure the opening for the boiler cladding was correct for my boiler. About 1/8” each side and 3/8” at the top. It was then apparent that there was going to be a problem that needed sorting. The location point for the lower hinges for the window will be affected. It could well require the boiler to come out and the cladding fettled. That can wait. It is Christmas eve here in NZ so time to stop work and think about it, shut down switch off, lock the workshop and start the festivities. Happy Christmas everybody Pete
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Dec 24, 2021 19:43:27 GMT
Well done Pete, it is coming along very nicely! Don’t worry too much about the hinges. I had the exact same problem on Paddington, and I was quite surprised about how much you can remove from the ‘bracket’ part of the hinge without affecting the function, or even the appearance very much- the lower hinges are very inconspicuous anyway, and your surgery will probably be largely hidden by various pipes and backhead fittings. Do it carefully, goes without saying. My worst case was either to add deeper lugs to the bottom of the window (to permit more filing away) or (at very worst) to fix the windows in position so they didn’t open, but neither was necessary in the end. In your case, it looks like you have quite a lot of metal to remove from the firebox aperture, but the scribed line doesn’t pass through the ‘glass’ area, which is the main thing! Good luck with it, it will be fine! Gary
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Post by doubletop on Dec 28, 2021 9:08:39 GMT
Well done Pete, it is coming along very nicely! Don’t worry too much about the hinges. I had the exact same problem on Paddington, and I was quite surprised about how much you can remove from the ‘bracket’ part of the hinge without affecting the function, or even the appearance very much- the lower hinges are very inconspicuous anyway, and your surgery will probably be largely hidden by various pipes and backhead fittings. Do it carefully, goes without saying. My worst case was either to add deeper lugs to the bottom of the window (to permit more filing away) or (at very worst) to fix the windows in position so they didn’t open, but neither was necessary in the end. In your case, it looks like you have quite a lot of metal to remove from the firebox aperture, but the scribed line doesn’t pass through the ‘glass’ area, which is the main thing! Good luck with it, it will be fine! Gary I thought I have another look at this today and try and reconcile how much I really needed to remove from the spectacle plate to accommodate my boiler. I was going around in circles taking measurements from the job. In the end I went back to first principles and compared the Martin Evans Boiler design with John Smiths and my updated version of Martins design. The outline of my boiler matches Martins design, however, I discover that they both sit 1/4” higher in the frames than the John Smith version. That, coupled with over generous cladding would mean the cut-out for the boiler would impinge on the cut-out for the windows. What also doesn't help is the clading appears to have 1deg slope left to right for some reason. It would seem that I may have to bite the bullet and get the boiler out and re-work the cladding. A bit painful really as it is only recently that I remade the front plate for the Belpaire firebox and if I’m going to have to reduce the height of the cladding wrapper the front plate could well do with some re-work as well. I’ll take another look tomorrow hopefully I'll have a eureka momement Pete
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Dec 29, 2021 1:05:29 GMT
Hi Pete
You can’t do much about the boiler sitting too high (though it’s only a scale 2”). It would (I think) entail virtually rebuilding the smokebox saddle and the cylinder block. So you are left with the cladding and/or the spectacle plate.
You are probably right, that altering the cladding significantly will be a big job, because to reduce the height of the firebox will entail alterations to the cladding throat plate/frontplate, though before you get that far, you might be able to set the top more level and maybe pare away a mm or two by some tweaking here and there. Check that the firebox top is level fore-and-aft obviously.
The alternative is to have a new Spectacle Plate cut, with the windows repositioned or perhaps reduced in size. It depends how much you want to stay “in scale”. In the case of Paddington I had to do both, though fortunately the windows had not been made by the time I discovered this*. (You might remember that it was impossible to use a scale Spec Plate because the Paddington boiler design is itself badly out of scale at the backhead.) I just had to accept it and move on; trying in the process to get a non-scale backhead that reproduces the character of the prototype. I did this by keeping the proportions of the windows, and also the surrounding platework ‘border’ as far as that was possible. That approach may not suit your aims, but I offer it as a suggestion, since your boiler height militates against a precise scale backhead in any case. Reworking or remaking the front windows is the drawback, but possibly still the path of least resistance?
HTH
Gary
*To be more exact, the ‘reduced size’ windows I drew for the first try of the Spec Plate were still too large, so the ‘reduced size’ had to be reduced again.
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Post by Jo on Dec 29, 2021 8:59:14 GMT
How about making a pair of replacement hinges that go the opposite direction? Not easy to describe...
The base of the hinge would go in the same direction as the top pair and you make it so that the eyelet part is off set below the hinge base. So you would make a double width hinge and mill the eyelet down from the top and mill the base down from the bottom (and hope there is something left to hold it together LOL)
Jo
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Post by doubletop on Dec 31, 2021 23:34:25 GMT
Gary, Jo thanks for your suggestions. I’ll sort of cover them off as I go through this post. What follows has an element of “Buyer Beware” because, if you have a boiler to Martin Evans’s dimensions then things are going to be very tight. I bit the bullet and started to remove my boiler and hadn’t got very far when I realised I didn’t need too. When I made the Belpaire throatplate cover the other month I didn’t solder the whole thing together, I’d used countersunk screws hidden under the front strap. In less than 1/2hour the firebox cladding was off. Then started a very long period of measuring, testing, comparing drawings, redrawing and printing cardboard templates. Tweaking the cladding and doing it all again. My height gauge has never been used so much. Now on the level Getting close, but look how close the boiler is to the window opening, that's without the window surround. ( note; this is about height not width, the sheet is A4 so not wide enough) Eventually the cladding itself was sitting on the heads of the 3/16” rivets being used as stays. The height from the running plate to the top of the cladding being 7.90”, theoretically this should be 7.860”, so as good as it can be. The John Smith platework has the tanks height as 5.75” and the opening in the spectacle plate 1.813” a total of 7.563” and a difference of 0.297” between the two. As I need my opening to be 2.15" which is 7.9” from the running plate. A difference of 0.338” The 1.813” dimension is the ‘as supplied’ opening. 2.15” is what I require for the height of my cladding. The 2.239” dimension is “as supplied” whereas the John Smith drawing show this dimension to be 2.3125”. My guess is this has been adjusted to accommodate Polly’s stock windows. It contributes to the problem. The window on the left inner ring is the opening in the plate and the outer ring the outside dimension of the window. You can see how tight it is. If I am to be able to open my windows it will require the cladding relieving at this point and hinges modifying. (Jo’s suggestion of making the hinges go the other way, they already do. The lower hinge is hung facing outboard and the upper hinge in towards the centre line) I’m not that concerned about scale. I want a functional, easy to maintain loco that looks about right. Gary’s suggestion of making a new spectacle plate has crossed my mind but it will need a new roof wrapper and cab rear plate. The window could be moved up slightly but it would only gain 0.078”. I’m going to let Matthew at Polly aware of this problem. I’m going to suggest they could offer a Martin Evans version of these parts for those of us retrofitting an original Dart. Interestingly when I spoke to him about the holes spacing in the running plates he said it was the first feedback he’d received and they’ve sold a lot of these kits. Maybe there are those out there who’ve solved this problem or are still grappling with it. Pete
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Gary L
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Post by Gary L on Jan 1, 2022 1:44:15 GMT
Hi Pete
Just for the record, I wasn’t suggesting changing the roof line, only the size of the window frames. (Polly will make excellent frames to any size and shape, though not necessarily quickly). But you are well on the way to resolving your problem without resort to this, which will be cheaper and much quicker.
On Paddington I had to carve away a substantial amount of the lower hinges, even after twice reducing the planned size of the front windows. It is still a bit close for comfort, and the RH window has a limited swing, but as I said at the time, I won’t need to open them to wipe them clean! It wouldn’t have been a total disaster if I had had to remove the hinge entirely, and glue or solder the window permanently shut. It is the appearance which is much more important than the function in this case.
Well done for making the throatplate cleading partially detachable- that was a neat trick which must have saved you hours!
Gary
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Post by doubletop on Jan 1, 2022 1:51:53 GMT
Hi Pete Just for the record, I wasn’t suggesting changing the roof line, only the size of the window frames. (Polly will make excellent frames to any size and shape, though not necessarily quickly). But you are well on the way to resolving your problem without resort to this, which will be cheaper and much quicker. On Paddington I had to carve away a substantial amount of the lower hinges, even after twice reducing the planned size of the front windows. It is still a bit close for comfort, and the RH window has a limited swing, but as I said at the time, I won’t need to open them to wipe them clean! It wouldn’t have been a total disaster if I had had to remove the hinge entirely, and glue or solder the window permanently shut. It is the appearance which is much more important than the function in this case. Well done for making the throatplate cleading partially detachable- that was a neat trick which must have saved you hours! Gary That is all it needs really slightly smaller windows and a pair of new cab end plates. Yours look fine and in keeping with the loco. Who would know? After I made the post I printed a new template, to the dimension I had established yesterday. It didn't fit so I grabbed a beer and am now having a pleasant afternoon sat in the sun. It can wait. BTW Happy New Year. )
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Jan 1, 2022 17:09:02 GMT
Hi Pete Just for the record, I wasn’t suggesting changing the roof line, only the size of the window frames. (Polly will make excellent frames to any size and shape, though not necessarily quickly). But you are well on the way to resolving your problem without resort to this, which will be cheaper and much quicker. On Paddington I had to carve away a substantial amount of the lower hinges, even after twice reducing the planned size of the front windows. It is still a bit close for comfort, and the RH window has a limited swing, but as I said at the time, I won’t need to open them to wipe them clean! It wouldn’t have been a total disaster if I had had to remove the hinge entirely, and glue or solder the window permanently shut. It is the appearance which is much more important than the function in this case. Well done for making the throatplate cleading partially detachable- that was a neat trick which must have saved you hours! Gary That is all it needs really slightly smaller windows and a pair of new cab end plates. Yours look fine and in keeping with the loco. Who would know? After I made the post I printed a new template, to the dimension I had established yesterday. It didn't fit so I grabbed a beer and am now having a pleasant afternoon sat in the sun. It can wait. BTW Happy New Year. ) Hi Pete Only one new cab end plate surely? The rear isn’t affected. Nobody would ever notice that the front windows are fractionally smaller than the rears, if the proportions are the same. Quite a lot of model engineering involves theatrical deceptions! If, despite all your fettling, you can’t quite make the existing front windows hinge open, my inclination would be solder or glue the windows into their frames, then cut the lower inner corners away till the Spectacle Plate has a working clearance over the firebox. As long as you don’t have to actually cut into the glazed area this will be quite discreet. Nobody (except you?) will know or care that they don’t open. You will still have better-looking front windows than you could ever produce by hand. If you grow to dislike the deception, you can always replace the Spec Plate with its windows at a later date. In fact if you used dummy rivets and a few very small RH bolts to secure it, changing it later for better would be a doddle. Happy New Year to you too! Gary
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Post by doubletop on Jan 1, 2022 22:47:59 GMT
Only one new cab end plate surely? The rear isn’t affected. Nobody would ever notice that the front windows are fractionally smaller than the rears, if the proportions are the same. Quite a lot of model engineering involves theatrical deceptions! If, despite all your fettling, you can’t quite make the existing front windows hinge open, my inclination would be solder or glue the windows into their frames, then cut the lower inner corners away till the Spectacle Plate has a working clearance over the firebox. As long as you don’t have to actually cut into the glazed area this will be quite discreet. Nobody (except you?) will know or care that they don’t open. You will still have better-looking front windows than you could ever produce by hand. If you grow to dislike the deception, you can always replace the Spec Plate with its windows at a later date. In fact if you used dummy rivets and a few very small RH bolts to secure it, changing it later for better would be a doddle. Happy New Year to you too! Gary Gary I came to the same conclusion, solder them in. The solder paste should make that an easy job. Unfortunate that the opening windows would not be able to be opened, however, given their size and proximity to the manifold and associated pipework, it would probably be the case that they couldn't open that far. Which would be dissapointing in itself. One of the benefits of these forums, a problem shared is a problem solved. Pete
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Post by doubletop on Jan 4, 2022 7:26:54 GMT
After days of pondering over this and numerous templates to check feasibility I got up this morning and decided today was the day and stop procrastinating. Because that is what it had come too. Spectacle plate in the mill and the DRO smooth arc function used to cut the radii with 0.020” steps and plunge cuts. Each arc being 112 steps but this isn’t as tedious as you may imagine. One you’ve got it set up, barring any error on your part, you are going to get it right. That said, the paranoia returned half way into the first arc. I wasn’t sure the cutter was going to the correct end point and I stopped to check. Stepping to the location of the last cut and zeroing the X,Y axis on the handwheels confirmed all was well and cutting resumed. Closing the gap between the two arc cuts is just a case of getting to the last point and continuing in the X axis, doing short increments. As an aside the DRO smooth arc and line of holes functions with plunge cuts is an easy form of what I call Manual Numeric Control (MNC). The DRO does the calculations and tells you where to go for the next cut. You manually zero out the display using the hand wheels and make the cut. You can do quite complex stuff. Here is an example of using these functions to make the side frames for the two bogies for the autocoach. The large arc at the top was something like 500 cuts. It did cross my mind today that if I did stuff up the spectacle plate I could always make a new one using these functions. Anyway back to the Dart. Spectacle plate modified and a little more fettling of the boiler wrapper and it sits where it needs to. And the bungee you ask? To enable rapid assembly/disassembly the tanks aren’t secured to the running plates. The bungee stops them falling off (again….). The next consideration is the windows. Are open window still possible, maybe? That is for tomorrow. Pete
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Post by doubletop on Jan 6, 2022 7:22:12 GMT
Before I made a start on the windows, I decided to do the spectacle plate angles so that the plate could be secured in its correct location between the tanks. That would give me better points of reference for the window fitting. You will see that I’ve tackled the roof line curve slightly differently to Gary. By his own admission he thought he was lucky that it worked for him. You will see that I’ve done it in two parts. The curve on the vertical again done using the DRO smooth arc function. Getting the cutter to miss the shoulder formed by the vertical section of the angle only skipped a few steps and the missing section quickly blended with a file. Moving on to the windows you will notice from the photo from the previous post that very little of the window frames protruded into the opening for the firebox cladding. With the top hinges fitted a little bit of relief in the bottom of the window frame the spectacle plate could be offered up. There had to be a way of creating a lower hinge and decided on an option I’d considered in the past in creating a slot in the cladding. A bit of lash-up in the mill and two slots cut. In the end even managed to use the unmodified windows and the original lower hinge riveted with one rivet and sandwiched with older paste before riveting. A quick zap with the torch and all secure. (The modified windows will go in the cab rear plate.)I think that worked out OK in the end. A bit of a drama, but taking your time and looking at options certainly pays off in the end. Better than leaping in and regretting decisions later. Pete
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Jan 6, 2022 17:41:46 GMT
Well done Pete, great result! Gary
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Post by doubletop on Jan 13, 2022 8:38:08 GMT
The time had come to think about rolling and folding the roof. In a conversation with Matthew Thomas at Polly he had suggested doing the large radius roll first and then the fold of the sides. Maybe common sense but it saved me having to work out the best approach. The roll was relatively easy running the roof back and forth between the two end points, removing it frequently to check against the cab end plates. I don’t have a photo. Then came the job to modify the “Formit” and create a David and Lily Attachment first created by Gary over here modeleng.proboards.com/post/195576/thread ( Gary L , dscott ) Mine isn’t much different from Gary’s but I use 6mm bolts into threaded bronze bar as back nuts between the Formit bars. My first bend was easy and as luck would have it exactly the correct amount to match the side and roof line on the cab end plates. I did need to check if I could get away with not annealing the roof before folding. Although it sort of did the job it took a lot of tightening of the bolts so annealing proved necessary. I then got back to the question of how to I check to see if the bend is sufficient. I had thought that there must be a geometary, a spacing of the lower bars that, when set, would determine the end point. The fold could go no further. I drew it up to find that at 1.5” the lower bars would need to overlap for that point to be set. That couldn’t happen and also the closing bolts for the David and Lily Attachment pass between the bars. Thoughts went to some form of limit stops but then it occurred to me a gauge would do the job.
Roof Bending Gauge drawing
I made this out of a piece of 1.5” x 1/8” brass bar. Those of you with CNC an easy job but the DRO’s came in useful again using the Smooth Arc and Line of Holes function. The 0.875” semicircle done first in two passes. Smooth Arc 0-144.67deg From the point the first part of the semi circle ended a Line of holes, at angle 234.67 deg stepped at 10thou increments using and end mill. The second part of the 0.875” semicircle using Smooth Arc 360 – 324.67deg followed by another Line of holes from the 324.67 deg end point. The 17” radius for the roof line, again using Smooth Arc. Smooth Arc allows the centre point of the arc to be defined out in space so the size of the mill isn’t a limitation. The arc only needed to cover 193-198 deg. The gauge tested against a cab end The roof was then annealed. It didn’t need much I noticed that the annealing temperature for brass is very similar to that of aluminium (circa 600degC) a trick I learned some time ago with aluminium was to cover it with liquid soap prior to heating. When the soap goes brown the aluminium is annealed. I thought Id give it a go, it worked fine and certainly sufficient to achieve these folds. No red heat and no panicking that the brass may melt. Next up was marking up the two lines 7/16” either side of the fold centre line e.g. spaced at the diameter to the D&L bar in the Formit. This enables the roof to be set up with a square Looking back I now realise Gary did it the same way. modeleng.proboards.com/post/195714/threadNext was the nail biting bit of committing to the fold With the guage there is no need to remove the job to test that the fold is complete, what is more the need to keep the tightening of the bolts in the D&L attachment too much in alignment, a few turns alternating on each side is sufficient. Reducing the amount as you approach the end point. I haven’t done a photo of the roof offered up to the can end plate yet, that should be tomorrow, suffice to say I was happy with the result thus far. Pete
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Jan 13, 2022 16:14:03 GMT
Brilliant idea for a gauge Pete, I did it the hard way, in and out repeatedly to check against the actual plate. Your gauge that straddles the pressure bar would have been a lot quicker.
There are a lot of under-used functions in a DRO. Not quite the equal of CNC, but there are a lot of possibilities there that go unused because the Chinglish manuals are so impenetrable.
Also, I had no idea that brass anneals at the same temp. as aluminium! I‘ve never looked it up and always assumed it was the same as copper and needed to go to red heat. So much easier if it doesn’t! Just goes to show, “when all else fails, read the instructions”. Or RTFM as the IT blokes say… !
Gary
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Post by doubletop on Jan 13, 2022 18:35:18 GMT
Brilliant idea for a gauge Pete, I did it the hard way, in and out repeatedly to check against the actual plate. Your gauge that straddles the pressure bar would have been a lot quicker. There are a lot of under-used functions in a DRO. Not quite the equal of CNC, but there are a lot of possibilities there that go unused because the Chinglish manuals are so impenetrable. Also, I had no idea that brass anneals at the same temp. as aluminium! I‘ve never looked it up and always assumed it was the same as copper and needed to go to red heat. So much easier if it doesn’t! Just goes to show, “when all else fails, read the instructions”. Or RTFM as the IT blokes say… ! Gary The driver for the gauge was not wanting to have to remove the job from the press. I was paranoid enough about getting it all lined up. If the job was to be removed after a press how well would it re-align when put back. Probably well enough, but I didn't want to find out the hard way. The DRO functions still catch me out. When I set up for the second part of the arc, from 324.67deg back to zero it kept wanting to take me the long way round, clockwise, then I remembered I was going to 360deg. 360deg and zero are the same place but determine which way the DRO will step you. (For those wondering why I didn't do the arc in one go, the DRO's won't let you pass through zero so you have to do it in two parts. In this case that proved beneficial as the end point defined the start point of the tangential cut. Then it came the 17" arc and I couldn't work out why the DRO's insisted I move the axis 22" off the mill table. Then I realised that the job was set up at 90deg to the drawing and the arc wasn't from 105deg to 108deg but 195deg to 198deg. It is times like that you begin to doubt yourself. The other gotcha is the X,Y,(Z) offsets for the Smooth Arc function work differently for the Line of Holes. To be safe Smmoth Arc needs the current X,Y to be zero however Line of holes doesn't. I haven't worked out why that is but have realised never just start cutting. I always step through the cutting sequence to confirm that it starts and ends up where you expect it to be. There may be those that say that annealing the way I did wasn't a complete anneal. Maybe it wasn't but it was sufficient. Looking forward to getting out there today and marrying up the roof and spectacle plate Pete
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Post by doubletop on Jan 14, 2022 4:05:05 GMT
Todays update Just to add when folding using the gauge you will find the fold springs back a little when the press is released. Just re clamp in the press and take it a little past the point the gauge indicates. Roof fitted to cab front and roof slideout. I had rolled the slideout at the same time I had done the lare radius on the roof. You'll see that the Polly kit does the roof differently to the John Smith drawings providing a slide out rather than a drop in. The kit also provides the roof hatch. Note. There is bit of a gotcha, not with what has been supplied but on the John Smith drawings. Drawing 60 shows that the line of holes on the angle that joins the cab roof with the cab front is drilled to Table W. Drawing 61 showing the roof specific dimensions. Drawing 60 has the hole spacing at 0.5" wheras drawing 61 has the spacing at 0.5625". Polly supply the roof drilled to the drawing 61 dimensions. I had predrilled the angle to table W when I did the cab front, so have extra holes, nothing that a bit of filler can't sort later. Pete
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