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Post by geoffbr on May 27, 2015 9:30:40 GMT
Hi, I am slowly building a Prairie from Casting supplied by A J Reeves. Reading some of the other articles regarding Do or Don't I build and yes those errors in the drawings but I said yes. My background is I am a Tool Maker with a Plastic Injection Company (so larger machinery is available for me to use) and have been a member of the CSMEE club in New Zealand for a few years now but not getting as much time playing on the track as I would like. Anyway I have been cheating with some parts by Solid modeling and CNC machining some parts, one that has been a pain with some measurements missing was the Saddle Plate, but I think have cracked it. I have files in a shared folder on 'Drop Box' think the link will get you there if interested. I have jpg pics of the parts and a CAD file (.igs format), I drew them up in Solidworks but can save to most formats if need to. www.dropbox.com/sh/w9bth0my8etaucw/AADadq7lp5yy8H5BEnMwEng_a?dl=0You don't have to have a Dropbox account to view the files, when you first open link it comes up with a join box. Just click out of this (Top Right corner of this box) then you are good to look at folders. I have put Files and photos in separate folders for ease of viewing. Folders are CAD Models, CAD Screen Shots, Prairie Progress Photos regards Geoff |
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Post by Rex Hanman on May 27, 2015 15:28:31 GMT
Anyway I have been cheating with some parts by Solid modeling and CNC machining some parts Don't see that as cheating! Welcome and good luck with the build.  |
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dscott
Elder Statesman
Posts: 2,433
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Post by dscott on Jun 2, 2015 1:51:08 GMT
Another way of cheating is to do the cut out on the rear of the frames by the steps so that the joggle is easier to do!!
I made a form press tool but still had to heat it up!!!
Mark the rear up after bending!!
David.
Lovely drawings!!!
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Post by geoffbr on Jun 9, 2015 10:08:17 GMT
Hi Dave,
Thanks for the tip on the frame bending, I had the frames bent by a contact with a break press some time ago. My only headache at the moment is interpreting the Radial box Drawing and getting a picture in my head on how I am going to machine it all, the castings look good.
regards Geoff
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Post by geoffbr on Jun 9, 2015 10:22:38 GMT
I have machined the Saddle Plate out of Flat Bar in a CNC Mill, I have drilled the rivet holes and will fit rivets to add a more realistic look to the plate. I used a thicker plate to help with the machining process and Surface grind the back excess to the required thickness. Refer to the Photos in the Drop Box link in first post.
regards Geoff
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Post by Rex Hanman on Jun 10, 2015 13:50:46 GMT
My only headache at the moment is interpreting the Radial box Drawing and getting a picture in my head on how I am going to machine it all. I am in the process of doing the radial axle box on my 7 1/4" version. Should be able to post some pics in the next few weeks. |
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Post by geoffbr on Jun 14, 2015 1:35:52 GMT
I have added some photos of the Cylinder Block, Smoke box, Cross heads and Slides, I made the slippers out of Phosphor Bronze instead of having to inserting Metal ones. I have also made a start on the Cross head slides and just need to open the holes up to size.
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Post by geoffbr on Jul 1, 2015 7:35:03 GMT
I have re assembled the Pony Frame and have added some photos in my Drop Box folder.
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Post by Rex Hanman on Jul 1, 2015 21:15:23 GMT
My only headache at the moment is interpreting the Radial box Drawing and getting a picture in my head on how I am going to machine it all. I am in the process of doing the radial axle box on my 7 1/4" version. Should be able to post some pics in the next few weeks. Progress can be seen here..... britishmainlinegroup.org/community/index.php/topic,68.135.html If the link doesn't take you straight to it, see "Member's Projects", GWR large prairie, 4141. Radial axle box is on page 10. |
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Post by geoffbr on Jul 2, 2015 5:12:57 GMT
Thanks Rex, looking really good.
regards Geoff
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Post by geoffbr on Jul 2, 2015 9:22:43 GMT
I have added some more models and Pics, one is of the Weight bar. This was machined in 2 parts, the main shape then fitted the shaft - pinned and loctite into place.
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Post by geoffbr on Aug 17, 2015 9:47:34 GMT
I have added some photos of the machining of the Motion Plates and Spring Hangers. The hardest part was sorting the datums to machine the rest to size. I made a jig to hold the hangers for machining and has worked well. The motion plates I will finish machining once I have fitted them to the frame so as to be able to see positioning and get measurement while in place.
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Post by Rex Hanman on Aug 17, 2015 11:04:39 GMT
Nice, like the holding arrangement. |
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Post by geoffbr on Aug 18, 2015 9:31:12 GMT
Nice, like the holding arrangement. Thanks Rex, I see you have made good progress with your Radial Box. regards Geoff |
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Post by geoffbr on Oct 1, 2015 3:52:34 GMT
Well it has been a while since I last uploaded more photos, but I have been sorting a prototype Form Tool for making the Safety Valve cover. I have uploaded some photos of the tool into my drop box folder, but don't look to closely as I was working on the fly with the design. I have 1.6mm brass sheet which I will see how far I can draw it down so I have enough material to flare out for the top form, I have made the Die Form in 2 halves so as to help remove part once fully formed. If this prototype works I may remake a tidier version. I still have a Pre former to make to give the initial rough draw down of material but am happy with what I have got done to date. I will keep you posted on how it goes.
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Post by Rex Hanman on Oct 1, 2015 13:38:05 GMT
Interesting approach, I look forward to seeing the results! |
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Post by geoffbr on Oct 2, 2015 3:27:30 GMT
Thanks, I have my fingers crossed. Will keep you posted.
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dscott
Elder Statesman
Posts: 2,433
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Post by dscott on Nov 27, 2015 22:15:46 GMT
Hi geoffbr,
How has the forming of the safety valve casing gone?
I am sure that many builders would be interested in swapping some money for the results if you were interested!
I have just found another builder in our local Reading Club!! Such rare beasts being built!!
Best regards
David.
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Post by geoffbr on Nov 28, 2015 4:02:17 GMT
Hi Dave,
Progress has been slow, as have been busy with paid work. But I have had some success but also some back steps, I have made a Tappered pre-former on which cut brass sheet disks are Spin formed into basic Bell shape. This allows to get the material needed to form the wall and top roll out after the Press forming Tapper Boiler shape. I need to make a holder that holds the shaped form so it can have the Flare out spin formed as this gives an even flare. Will add some photos over the Christmas holidays. How is progress going on your Loco?
regards Geoff
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Post by geoffbr on Dec 1, 2015 5:50:36 GMT
Right, I have added some photos in Drop Box Folder of the Metal Spin former and some parts in various stages of press forming. Photos
Spin former 1 - is the base former for Spinning the Disk of Brass Sheet.
Spin Former 2 & 3 - is the Spin end product.
Spin Former 4 - 5 - is one I have trimmed shorter and Press formed in the Form Punch and Die
I have a bit more tweaking to do, as I have added another Punch to stretch between stages to help reduce the creasing when using the last stage form punch. Once all that is done and it looks ok, I need to have a holder that will be used to metal spin the Top Flare out of the Safety Valve cover. I have to admit, it has been an interesting process. It is a real work in progress but will get there, but think it will be in the New Year and work has settled down from the silly season.
I hope this has been of interest, happy holiday's
regards Geoff
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