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Post by Deleted on Apr 18, 2011 19:21:26 GMT
Pic245 The hook has now been roughly shaped to the lines using the band sander ready for the sides to be shaped next. Attachments:
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Post by Deleted on Apr 18, 2011 19:27:02 GMT
Pic246 The finished hook, the end profile is basically a taper from the 3/16 at the bottom to just over 1mm at the top and then everything is rounded off to finish. Thanks again to Trevor I have very good pictures of Mallards hook so could use that as a guide. Oh on a side note while looking through the pictures off Mallard I noticed that she also has rectangular shock absorbers for the loco being different to the tender. Attachments:
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Post by Deleted on Apr 18, 2011 19:31:41 GMT
Pic247 The finished Hook, now regarding the couplers Don asks for 7/64 to be used for these but I can't find this size in any material listed anywhere other than some welding rods. So my question is what do you guys use? 1/8 will fit but may look heavy and I'm trying to avoid having to turn some down to 7/64. All advice welcome as usual Pete Attachments:
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pault
Elder Statesman
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Post by pault on Apr 18, 2011 19:56:53 GMT
Hi Pete, this pic is of 60019, the shock absorbers are the same on the tender as well, same old story as someone else said they are all the same apart from the ones that are different. with regard to the scale material material what about using 3mm, its about half way between what you need and 1/8" scale is a funny thing sometimes when something is true to scale it can look wrong because it lacks bulk. Keep up the good work Regards Paul Attachments:
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Post by Deleted on Apr 18, 2011 20:14:46 GMT
Hi Paul I guess 3mm could be a good compromise, like you say it's more or less in the middle so may be ok. Regarding shock absorbers, yes the absorbers for the cartrazzi axle are the same as the tender, it's the ones under the main frames for the driving/coupled wheels that are a different shape. Mind you being rectangular should make them easier than the others, well a little...  Pete |
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Post by Deleted on Apr 23, 2011 15:10:41 GMT
Good day all, hope your having a great Easter weekend. The material for the shackles arrived this morning so while my wife was shopping I took the opportunity of finishing the couplings. Don starts with the screw first ( forgot to take picture) which starts off with 1/4 BMS bar, reduced to 9/64 over 1 9/32 length screwing the end 4BA thread for 29/32. Leaving 5/64 for rounding it was then parted , reversed in the jaws and rounded off as to drawing. Next was the shackle pins, Don's words and music started with two rectangular pieces of 9/16x3/8 steel , turning 1/8 spigots, mill top and bottom faces,turn the spherical centre radius, finish with files, drill both and tap one off. That's one way, I had another.. Pic248 Using brass( remembering these are not for operational use) I first faced ,centre drilled and then turned down some stock to 3/16 rad allowing enough for both shackles and an extra length for the next stage. I turned down the 1/8 spigots remembering to leave enough space for parting later. Remembering how JB tackled some of his back head fittings I made a profile tool following his method which worked out very well. In the picture you can see that one shackle pin has been done and the tool is lined up for the next. Note that I've stopped short of machining the full radius thus leaving a short flat area, this is for two reasons, first the radius is spherical ( finishing later with sanding sponge) and second I needed the pins to remain the same size dia as the stock again for the next planned stage. NB: this was a nerve racking stage taking small cuts with constant checks on the tailstock as even using a live centre the brass centre hole did wear a little. Attachments:
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Post by Deleted on Apr 23, 2011 15:19:40 GMT
Pic249 Next was to machine the top and bottom flats, this is the reason for leaving the small flat area at 3/16 so that the job could be held securely in the machine vice. 3/32 was then machined of both the top and bottom faces, both pins where then centre drilled , one at No.27, the other at No.34 and then tapped 4BA, final job was to saw off the shackle pins and file down the spigots to 1/8 length. Attachments:
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Post by Deleted on Apr 23, 2011 15:25:43 GMT
Pic250 There's a No.50 cross drilled hole for the handle, first job was to turn up the collar which is 1/4 dia by 3/16 and centre drilled No.28 for the screw. This was then cross drilled No.50 first before inserting the screw with the top pin slid on first so to get the hole in it's correct place which was then drilled as shown using the previous collar hole as a guide. Attachments:
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Post by Deleted on Apr 23, 2011 15:31:19 GMT
Pic251 The handle is a 3/4 length of 1/16 steel which has a rounded 1/8 one end and 1/4 ( personally this looks a little large but is to drawing) the other. This was silver soldered together once placed in the collar, also seen here are the two ends for the shackles themselves before being silver soldered to the shackle bends and sawn, filed to shape. Attachments:
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Post by Deleted on Apr 23, 2011 15:37:19 GMT
Pic252 The finished coupling/hook , Paul's suggestion of using 3mm worked well ( I could only find silver steel although had no problem bending it) I had to open the hole a little for the larger size but don't think that it'll be noticed. One other thing to note is the small flat area just visible on the top shackle which is for slipping the shackle through the 2mm slot, feeding around and thus trapped within the hole. Next I think I'll do the water gauge, back soon guys.. Pete Attachments:
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pault
Elder Statesman
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Post by pault on Apr 23, 2011 16:27:37 GMT
Hi Pete, I see you had trouble finding 3mm steel, I can recommend M-Metal in Darlington for materials. They have a big stock of materials, deliver quickly and are very helpful. Have a look at www.m-machine-metals.co.uk/ As always your work is looking very good. Its amazing how long the little bits take to do. Regards Paul |
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Post by Deleted on Apr 23, 2011 21:46:52 GMT
Thanks Paul, I was being lazy and just went with what ever my usual suppliers had plus I only ordered a small amount. Yes these little bits take so long, I'll have to get the paint soon or I'll be spending weeks taking it all apart again for painting, like you say so many little parts plus some bits I have to revisit such as the wheels which will need their final tyre cut after painting,still have to profile the axlebox covers too plus god knows how many other parts that need the final touch to finish...  |
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pault
Elder Statesman
Posts: 1,502
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Post by pault on Apr 23, 2011 23:23:49 GMT
Hi Pete
M-Metal will supply what ever lengths you want. Ah yes painting, probably one of the most underestimated parts of building a loco especially if it is an elaborate livery with lots of lining. I would say that doing a proper paint job with lining can represent as much as 10 to 15% of the build time of a loco. Good luck with it
Regards
Paul
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Post by Deleted on Apr 27, 2011 16:01:00 GMT
Hi all Today's instalment covers the water gauge which although it's a working item won't give the same results as the full size due to water not being scalable . However it does allow water to flow as in the prototype so adds interest to the model. Pic253 To start a length of 3/16 brass rod has a 4 degree taper turned over 1/2. With the topside still set at 4 degrees the brass is then replaced with 3/16 silver steel and the process is repeated, this will be used as a D cutter for forming the shape in the gauge block for the cone to fit. Attachments:
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Post by Deleted on Apr 27, 2011 16:06:33 GMT
Pic254 Here the D bit is being formed by removing half of the silver steel cone, I did this in the mill as can be seen rather than filing as to Dons words. I take my hat off to anyone who can accurately file away half of a cone and get it 100% which a D bit has to be to work properly. Attachments:
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Post by Deleted on Apr 27, 2011 16:18:00 GMT
Pic255 Next is the gauge block itself, 1/4 brass sq bar is chucked truly in the 4 jaw and once faced and centre drilled is turned down to 1/4 over a 7/32 length. The outer 1/8 is further reduced to accept 1BA thread to fit the water outlet in the tank ( should be 3/16x40T but I didn't have this tap when building the tank and since I wasn't going to use a commercial fitting here the thread wasn't important). A No.48 drill is then drilled to a depth of 7/32 , last job before parting at 1/2 overall is to machine a small v in the 1/4 section left between block and thread. Picture here showing all processes before parting. Attachments:
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Post by Deleted on Apr 27, 2011 16:25:55 GMT
Pic256 With the block placed into the machine vice a No. 38 hole is drilled straight through the block at 90 degrees to the 1BA thread and thus intersecting with the previously drilled No. 48 hole. Now using the cone shaped D bit the cone is shaped until it measures 11/64 diameter at the top. BTW before I did this I first threaded the block into the tank tightly and marked the top so that the cone would be machined on the correct face for when fitted to the tender later. Attachments:
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Post by Deleted on Apr 27, 2011 16:36:11 GMT
Pic257 Now I had to make sure that the cone is held securely and thus water tight when joined to the block so after refitting the 3 jaw and securing the brass cone the block was slid on and marked so that once the cone end had been turned down for a 8BA thread it would hold the parts together in their correct positions. Here you can see the parts before parting off which is done allowing for 5/32 material for the measuring tube to fit into. Attachments:
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Post by Deleted on Apr 27, 2011 16:42:42 GMT
Pic258 Measuring tube consists of a 6" length of 1/8 thin walled tube drilled at 1/4 intervals using a suitable centre drill, this is soldered to the cone having already been drilled No.30 for 1/8 for the tube to fit to and also further drilled 5/16 with No.48 that will intersect with the previously drilled holes that form the stop cock. Attachments:
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Post by Deleted on Apr 27, 2011 16:44:06 GMT
Pic259 The various parts that make the water gauge Attachments:
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