JIGGERY POKERY – BRYMSTON RR EPISODE 8
Its been an age since I reported any progress with The Brymston Railroad mainly because I have been distracted onto other things both for customers and playing with the real things in these strange Covid times.
The last few weeks have been very trying because an old circulation related injury has relegated me to an arm chair, a good book and pain killers. I really haven’t felt like modelling and when I have tried its been a painful experience. The result has been pushing myself to do the minimum business stuff I can get away with and then recuperating in the air chair. On the plus side I’ve been catching up on my reading.
Eventually though the pain subsides and the urge (need?) to do some modelling starts to reassert itself. Not quite up to the next stage in the Murder of a Garratt saga this episode covers a small job for the Brymston RR that prepares for some actual progress on the layout.
Here is another definition that I have just made up
For the Brymston RR module and for the later larger layout I have a lot of track to make. To aid this I have some of the excellent jigs and tools by Fast Tracks and, as they go, they are excellent and perfectly useable. They are made with a consideration to their mass production as one of the design criteria.
Once they’re with their new owner that criteria is no longer an issue and the opportunity is there to adapt them to the users preference. What follows is the tail of some alterations to two of these tools.
This is basically a clamp that holds a length of rail at the right angle whilst guiding a file to cut the rail at an angle to make the point Vee and the Point blades. The first picture is of an unmolested one.
This is a similar one to the one I have altered but for a different point angle. As you can see the rail is clamped in place ready for filing and the clamping is done by tightening the screws with an Allen key.
This sowed the seed of an idea along with the second tool so a chunk of brass bar was put in my mini lathe and knurled.
One of the by products of this little exercise has been the commissioning (or recommissioning) some of my workshop tools after the great shuffle and refreshing myself on using them. The learning point from this exercise being that the little lathe isn’t really butch enough for the forces involved in knurling.
Once patterned the brass was faced, drilled and parted off. It was then faced again and bored to be just a slight clearance on the screw heads. This is where a bit of bodgery comes in. If I were doing this properly I’d have made new screws with a larger head but they are some funny American imperial size and I don’t have a die for it plus they’re hardened shouldered screws.
Instead I bored the thumbwheels to just clear the heads, taped over the holes on the viewing side and stuck the screws in with slow setting araldite. It was warmed up in my drying cabinet to make the glue more fluid so it would flow into the joint before it speeded up the setting time.
As you may have worked out you need one of these tools for each vee angle and for different rail sections. However, the screws are common so I can swap these to whichever I am using.
No, not one of these!
Having filed the rails in our previous tool
they need assembling in a second jig that lines them up for soldering. This makes the Vee which becomes the common crossing to use some proper non amphibian terminology.
The tool for this as bought is called Frog Helper and is a chunk of aluminium with machined grooves for the rail to sit in at the proper angle so they can be moved along until they meet. The standard unit has nothing to hold the rails other than your fingers and as its intended that you only soft solder the rails that’s fine. Where the rails meet is machined clear so its not acting as a heat sink when you solder.
All that is fine if you’re OK with soft soldering. I want to silver solder the vee’s so they won’t unsolder when I do some other soldering around them. Silver soldering involves red hot heat and micro blowtorches so I surmised that something a bit more inert than my fingers will be needed to hold the rails whilst this is done.
Here the base was drilled and tapped for two lengths of m4 studding which was secured with some thread lock. The clamping faces are two pieces of double sided copper clad so there is a metal face to both sides but a phenolic layer between which will act as a heat break.
The springs are some I had but they needed some sort of bush to hold them concentric to the stud. As I was about to set my 3D printer off on a job I quickly sketched a stepped bush and squeezed them in the corner of the build.
The thumbwheels were made from the same chunk of brass as those for the point form. (Actually they were made first but that didn’t suit the narrative). This time they were drilled 3.5mm and tapped M4. This may all be over kill but it does mean you can have a light pressure on the rails whilst you get them aligned before a twist of the thumbwheel increases the pressure so they can’t move.
I haven’t done any actual silver soldering yet. I will report on that in a later blog post when I have done some. All I am doing on this module are #4 turnouts but I can see two mods I may yet make.
- Instead of the glued in studs it may get converted to countersunk screws screwed in from behind. This would allow holes to be drilled for the other vee angles on the plate with the screws just fitted to whichever angle I am doing.
- I may cut the plate away from behind the vee. This will really depend on how I get on with the first soldering job.
More soon I hope
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