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Post by Deleted on Nov 3, 2020 23:03:30 GMT
Excellent work Chris...now if only you had built a spare...  Top work sir... Pete I nearly had to make another, the number of errors that crept in, but managed suitable recovery strategy  . Now I've made the mistakes you can make yours perfectly, bit like the rest of your build. Chris D Haha...I wish...I'm not immune to making mistakes my friend..broke a draincock yesterday, my own fault...fixed now along with a new length of bowden cable which I inadvertedly damaged when breaking the draincock. That's what happens when you try to tweek one of the exit pipes while fitted to the draincock rather than take it off again and do it properly....I was kicking myself for that one...lol Pete |
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Post by coniston on Nov 6, 2020 19:50:21 GMT
The two levers were the next on the list, I milled the edge of a piece of 16g SS straight then used a slitting saw to cut a 5/16" wide piece off enough to make both levers.  I used the mill to set out the holes on both levers whilst still in one piece. There is a third hole to go in the longer lever for the operating rod from the regulator handle(s) but that cannot go in until the lever has been bent with an offset for clearance.  The two levers after separating, and the holes match up with each other  After making the bends in the longer lever for the offset (done in the brake press of my multi-former - very useful tool) the third hole could be drilled at 3/4" centres. I lined it up by putting a piece of 1/8" rod in the chuck before tightening the vice. The mill had not been moved since drilling the other holes so the lever was still on centre in the Y axis.  Then the ends were rounded using filing buttons. The drawing calls for the levers to be tapered from 5/16" at the pivot to 1/4" at the end(s) but I dont see why other than aesthetics and who is going to see it inside the boiler? so I left them parallel.  Next thig is some spacing / bearing washers, I don't think the drawing is correct as Don shows the pivot and the operating spindles as being .820" between shoulders, this is to clear the sides of the valve which is .8125" (13/16"). However the regulator body is .75" and Don only shows a 4BA washer on one side and no thickness specified. Not sure if 4BA washers have 5/32" hole but I don't have any so I have made some washers 1/4" O/D and 4mm I/D, I had some offcuts of gunmetal castings (turning spigots) one of which was just the job for the material. I turned the O/D and drilled the bore then just sliced them off at 15 thou thick.  I made enough to have a couple of spares (hopefully)  Chris D |
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Post by coniston on Nov 7, 2020 18:18:12 GMT
I made the two pivot pins today, both from stainless steel. I held the rod in the collet chuck to get good access with the smaller tools and better concentricity than my 3Jaw chuck. Having machined one end I moved it out of the chuck to be able to measure the length between the shoulders. Using a parting tool to cut into depth making several cuts to get the length required before parting off.  Here is the regulator loosely assembled photographed from both sides along with the drawing of the parts.   I need to silver solder the operating arm onto the pivot spindle and lap the valve and body mating surfaces before I can finally assemble it. Chris D |
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Post by Deleted on Nov 7, 2020 18:25:07 GMT
Excellent work Chris...so, now that you've finished mine you best get on with your own...🤣🤣🤣🤣
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Post by coniston on Nov 10, 2020 13:50:56 GMT
Just a quick update, not really much to show. I threaded the 5/8" copper pipe for the steam pipe from regulator to wet header. Unfortunately my lathe gearbox cannot do 26TPI and I don't have the additional change gears to allow it so I have to use a split die. Not easy in this size threading copper but held in the collet chuck securely I managed it with reasonable result. The thread is a bit more slack than I would ideally want it but I think I will have to live with that.   Just need to cut it to length and silver solder it to the wet header bush. Chris D |
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Post by coniston on Nov 10, 2020 19:30:27 GMT
I am investigating using an O ring to seal between the boiler bush and the steam pipe bush so I have found a suitable size (although I need to purchase one of the correct material) and with the help of Tubal Cain's Model Engineer's Handbook I made a trial on a bit of scrap cast gunmetal. I have decided on 7/8" I/D x 3/32" section (BS No 118) or metric equivalent depending on what I can get. I ground a boring tool narrower than the 0.140" groove width and set it up to have a go. Not too bad for a first attempt, it is a bit small on the outer diameter, should be 1.060", it measures 1.045" so not sure what went wrong there but I need to take more care in setting the tool. Photo shows my first attempt with the O ring fitted and the 'real' part above it.  Chris D |
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Post by coniston on Nov 12, 2020 20:35:50 GMT
The O ring groove is now in the actual steam pipe bush, careful measuring once, twice and a third time for luck before taking the plunge (pun intended) here's a photo of the boring tool set up just after the second cut to depth and width and the finished part with a temporary O ring. Temporary because I have no idea what material this is made of. I have ordered some O rings in EPDM, Viton and Silicone, I'll make the final decision when they all arrive but I am leaning towards EPDM as comparing specifications it seems most suitable for wet steam and superheated steam, although Silicone has a higher temperature rating and being in the smoke box may be better. I really don't want to have to change it in the future as it will be a right bugger to get at and this part supports the regulator so need to make the best choice now.   As I am going to have to put this in and out a few times before final fitting to get the steam pipe length and regulator set up I am keen not to damage the soft cast gunmetal material more than I need to. I don't have a 1 1/4" AF hex socket only a 12 point bi-hex one which with the rounded corners of the bush I think will impart too much damage so I decided to make a 'special' Following Roger's methods but using a completely manual mill not even with DRO here's what I did. Firstly a suitable length of 1 1/2" BMS was found lurking under the bench which was initially drilled to 5/8" bore x 1 1/4" depth. It needs to be this deep as the bush will have the studs fitted which the wet header is attached by. The drill in the phot is a little bit odd in that it has a reduced 'pilot' at the sharp end, it also has unusual lands on the helix. This is a brand new drill never been ground and came in a job lot of tools I bought SH some time ago, I have other similar ones in different sizes. It certainly seems to chew into the metal ok. Anyone seen these before or know anything about them? I'd like to know of their intended use and reason for unusual design.  Then it was bored to 1 1/4" diameter, same as the AF of the finished socket.  The other end was then faced and turned to 3/4" diameter ready for a hex to be put on at a later stage but before that it will be used to hold in the hex collet block. Once the collet block was in the vice I set a tool makers clamp on the vice as a stop so the collet block could be set back in the right place each time it was indexed round. Then it is just a matter of calculating the length of cut required to go corner to corner taking into consideration the cutter diameter. For this I 'cheated' and quickly modelled it in 3D on the CAD and just measured between centres of tangential extrusions representing the cutter at each corner (if you get what I mean)  Then with care the hex was started and checked after one 10 thou cut jut to be sure. Everything seemed ok so the first side was cut. I used a 6mm FC3 cutter which doesn't object to down feeding and seemed to be the ideal cutter for the job. You can see a small step in the milled face, after a couple of cuts I adjusted the X axis a few thou as it was taking a bit off the 1 1/4" bore. And after a mind numbing time the hex was completed.   I had to mark the Y axis hand wheel so I didn't forget how far in each direction to go.  And the steam pipe bush even fitted in the socket   The other end then received a 5/8" hex for a normal socket or spanner to be used on, I had to use the rotary table for this as it is too big for the collet block. This is easy when it is a male hex as little setting up is required.  And here's the finished socket   And in operation it has certainly made life easier and hopefully less damaging to the bush  Now I can get on and finally bring the steam pipe to length, then prepare the wet header for the studs etc. I also spent a bit of time experimenting making lathe change gears but you'll have to look on the 3D Printing section for that. Chris D |
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 575 
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Post by kipford on Nov 12, 2020 23:01:35 GMT
Chris
Neat work
Dave
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Post by coniston on Jan 13, 2021 20:07:57 GMT
Thought it must be time to update again, not actually cut any metal on the A3 rebuild, most of my time has been spent 3D printing and other things like Christmas getting in the way. Anyway I mentioned on Greenglade's thread that I would copy/plagiarise his idea for the wheel/axel weighing device. I bought the same bathroom scales off Ebay and took them apart to see what needed doing. I decided to design a 3D printed housing for the 4 strain gauge sensors that are effectively the feet, keeping the basic plastic mouldings from the original scales to support the strain gauges and glued them to a 1/8" thick Al plate. The plastic housing I designed to incorporate a 15 pin D-Sub connector which I had in my RC plane connectors stock. This allowed the display to be remote from the weighing part. The existing plastic moulding was cut to retain lust the display and PCB, also the existing battery case was similarly cut out to re use. Then another 3D printed housing and lid designed and printed to house these item into. I hard soldered the extension cable at this end as I only need one connector to disconnect the two parts and less connectors/soldered joints means better reliability. One of my lifting/build trolleys has the rails made of 50mm x 4mm steel angle so to bring the weighing bit up to rail height I made a spacer block, another 3D printed part to include recesses to locate the feet. This will be convenient as at both clubs I belong to we have steaming bays made of the same or similar section steel angle so I can use the scales at the track as well as at home. Photos of the (nearly) finished item, I need to make some retainers for the packers which the wheel treads run up onto but that is about all.  You'll see I used the top as a handy scribbling pad to make sure all the wires into and out of the 15 pin connector went where they should go. View of the D-Sub connector and the back of the display box with battery box and an extended flexible 'button' which mates up witht eh original one on the PCB to change the units of measure etc.  View under the weighing scale showing the 4 feet which are actually strain gauges. And the support block to bring the whole assembly to near rail height. This is sat on a heavy gauge steel plate clamped under the rail angles.  And just to prove it works here it is weighing the front driving axel, this is without the boiler.  Total of all axels weighed without the boiler came to 65.3kg (143.66lb). With the boiler mounted total was 95.45kg (210lb) This seems to be a reasonable figure so although this method of weighing the axels may not be totally accurate it is within the scope I am expecting and I am sure will help with balancing not only the A3 but more importantly the B1 which suffers from being very front heavy. Hopefully I will now be inspired to actually get back to cutting metal and get this loco finished (or at least running). Thanks to Pete (Greenglade) for the initial inspiration for this project. Chris D |
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 575
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Post by kipford on Jan 13, 2021 20:27:27 GMT
Chris Very good. Can I just copy yours! If I could cheekily just ask can you send me the link for the scales and all the stl files for the printed parts that would be great. PS in good books with the FDM printer. Made a new surround for one of SWSBO's kitchen sieves which broke over Christmas, Then designed and printed a new holder for the bathroom for the electric tooth brushes, she was actually impressed!  IMG_2556 by Dave Smith, on Flickr |
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Post by Deleted on Jan 13, 2021 20:28:03 GMT
Excellent job Chris... Think I need to get myself a 3d printer... Interesting to note your weight, that's within 5 lb of my own (148lb) with no boiler, I haven't weighed the loco with the boiler fitted...yet. Well done Chris Pete |
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Post by coniston on Jan 13, 2021 21:24:24 GMT
Excellent job Chris... Think I need to get myself a 3d printer... Interesting to note your weight, that's within 5 lb of my own (148lb) with no boiler, I haven't weighed the loco with the boiler fitted...yet. Well done Chris Pete Trouble is Pete the 3D printer takes so much of my time away from loco building, although it is nice to spend the time indoors in the warm. Interesting to note the similarity of the chassis weights, maybe this kit and set up can actually be useful.  Chris D |
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Post by coniston on Jan 13, 2021 21:27:20 GMT
Chris Very good. Can I just copy yours! If I could cheekily just ask can you send me the link for the scales and all the stl files for the printed parts that would be great. PS in good books with the FDM printer. Made a new surround for one of SWSBO's kitchen sieves which broke over Christmas, Then designed and printed a new holder for the bathroom for the electric tooth brushes, she was actually impressed! IMG_2556 by Dave Smith, on Flickr Glad the FDM printer is going well, I'll email you the stl's although the design could still do with some tweaking, depends on when you want to weigh your axels, if it can wait until we meet at the track then you are welcome to borrow mine or at least see where the improvements could be made. Chris D |
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oldnorton
Statesman
5" gauge LMS enthusiast
Posts: 721
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Post by oldnorton on Jan 14, 2021 10:22:41 GMT
Hi Chris
Nice work on your thread, but interested in your discussion of the weighing scales. I appreciate that the idea comes from Greenglade's version, but I have a couple of questions that you might be able to help me understand.
Are the scales measuring both wheels on the axle at the same time, and if so is there a way of seeing if one side has a miss-matched spring or a sticking axle block in the horn?
Is the weight being recorded by running the flanges onto a small block, and can there be a correction for that lift adding a loading to that axle?
Probably obvious answers because I have missed something. Thanks.
Norm
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Post by coniston on Jan 14, 2021 10:51:57 GMT
Hi Norm, glad you liked the post, yes both wheels are weighed at the same time as the flanges run up onto spacers placed onto the scales, just the same as Pete's. it can be possible to weigh just one wheel by removing the other spacer but of course there will be some discrepancy due to friction of tilting the axel box. I think the most important thing is to get the wheel to just lift off the rail by only a few thou to reduce the inaccuracies of compressing the springs too much.
This device is pretty simple to make and use and has its limitations but for what we do I think it is adequate to get a close balance of each wheelset and individual wheels, we are not really dealing with total accuracy in our models, there are too many other variables to making them perfect, this just helps eliminate yet another problem.
Chris D
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Post by Cro on Jan 14, 2021 11:05:36 GMT
Look forward to the update on the B1, mine is the same and at the moment I cannot get the set up right so need to try something similar.
It doesn't help that it has a mix of springs all over and there was some binding going on. I had planned to look at it last March but that didn't happen.....
Adam
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Post by coniston on Jan 14, 2021 11:13:07 GMT
Hi Adam, unfortunately the B1 is currently not at home so until restrictions are lifted I can't get to it but as soon as we are allowed to travel again it will be an interesting exercise to see how the weight distribution is. We have three B1's in the club so I plan to arrange to check all three to do a comparison, certainly the other two seem to have better adhesion than mine so hopefully with a bit of investigation I can come to a positive conclusion.
Chris D
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Post by Cro on Jan 14, 2021 11:37:09 GMT
Chris,
Same here, it lives in a locker at the club so no access to it. And likewise we have 3 which all perform differently, the other 2 in a similar fashion but mine not so much.
Adam
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Post by coniston on Jan 17, 2021 21:13:14 GMT
A little more progress today and the 3D printer came in handy again. I need to add 4 holes for the fixing of the wet header to the steam outlet bush. So I decided the easiest way to get the holes in the right place is to make a drill jig, that's where the 3D printer comes in again. I have made two jigs as not sure if I will set up in the milling vice or rotary table. Only took a few minutes to do and hopefully the holes will be in the right place. I did notice when laying these out on the CAD that the DY drawing shows a 30 degree angle for two of the holes but on the CAD 32.5 degrees seems to give better clearance so that is what I've gone for.    That's all on the A3 I've done so far Chris D |
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. Now I've made the mistakes you can make yours perfectly, bit like the rest of your build. 
