HobbitFertang
Registered
Have you bench tested them??
What happened at your workbench today?
- Thread starter Henri
- Start date
Fezwig
Just a man in the middle of a complicated plan.
Deep breaths and relax, railcar etchings project has started, so first job drawing and comparing between the Accucraft and Worsley works to come up with a design for the chassis. The thinking at the moment is a heavy chassis for the light weight body, unpowered at this stage of head scratching?
I have this back of an old oven, which could be a good starting point, though it being galvanised could make for hard work?
Rhinochugger
Retired Oik
Unpowered would mean that you wouldn't have the same problems as the prototype
View attachment 361169
I have this back of an old oven, which could be a good starting point, though it being galvanised could make for hard work?
if you're going to run a pair
Fezwig
Just a man in the middle of a complicated plan.
More or less finished with the drawings except for the power unit which will depend on if the Mauler chassis is suitable in running with the Accucraft railcar and can have it's wheel base extended or a new unpowered one made, anyway at least the wheels are the right size!
Rhinochugger
Retired Oik
Northsider
Modelling the Northern half of the Isle of Man
Galvanised could be better -I think solder will take to the zinc better than steel. Or am I confusing galv with tinplate?
View attachment 361169
I have this back of an old oven, which could be a good starting point, though it being galvanised could make for hard work?
John Randall
Registered
Pete Just a reminder Galvanised fumes are poisonous and if you get Galvanised hot enough it will flare quite dramatically!
Fezwig
Just a man in the middle of a complicated plan.
Cheers John/ @Northsider at this point still floating ideas, I will more that likely solder some brass angle to the body side and bolt that to the galvanised base, my soldering skills need to be proved on the etched brass side joins before we go much further!!
Rhinochugger
Retired Oik
Brass is more difficult to solder than nickel silver because it conducts heat better.
You can get 145 degree solder for brass and there used to be a particular flux for brass - liquid flux has been more difficult to get of late, probably due to the tree huggers, but you used to be able to buy it mail order
The Yeti was a Worsley Works etch (albeit in nickel silver for the above reasons) but the kits don't come with tabs like some other brass kits as you will have discovered
. I used blue tac, and then tack soldered the joint until I was happy that it was fine and dandy, then I ran a fillet of solder down the joint ..................... that was quite a long time ago, possibly 20 years ago 
Fezwig
Just a man in the middle of a complicated plan.
Correct! As proven below, Mauler much too slow and gets dragged or shoved aroundUnpowered would mean that you wouldn't have the same problems as the prototype
so it looks like plan C, an unpowered trailer set up, by the way,
Plan A, was buy another Accucraft, expensive and virtually unobtainable.
Plan B the kit I have but motorised, but matching the motors/gears was always questionable unless I started from scratch and remotored the Accucraft one
Northsider
Modelling the Northern half of the Isle of Man
Well, once again @Fezwig inspired me to get out in the workshop! His winter railcar project sent me back to the possibly 16mm/ft railcar that I bought at the National, and more particularly the wheels that I bought as rough castings from Walsall Model Industries. I started machining them in the early spring, before life got in the way; I'm not certain that I have either the skill or the machinery to incorporate them into a working chassis, but thought that I would take them one step at a time until I hit a brick wall. So the first step was to turn them down to G1MRA standard thickness of 6mm: this meant removing the oversized backplate from the casting. Despite appearances, this was done at around 350rpm, taking 0.25mm off each time.
The wheels have two holes in them, which would require a special drill bit to break through the hard skin of the cast iron, so I took the easier option of turning a recess in the back of each wheel...
The final recess is 1.5mm deep.
The holes will need a bit of dressing with a Dremel, but so far, so good. The next stage is to turn up a mandrel so I can mount the wheels securely and cut the treads.
The wheels have two holes in them, which would require a special drill bit to break through the hard skin of the cast iron, so I took the easier option of turning a recess in the back of each wheel...
The final recess is 1.5mm deep.
The holes will need a bit of dressing with a Dremel, but so far, so good. The next stage is to turn up a mandrel so I can mount the wheels securely and cut the treads.
Northsider
Modelling the Northern half of the Isle of Man
I might have a cunning plan on that front...
Rhinochugger
Retired Oik
Fezwig
Just a man in the middle of a complicated plan.
Today's installment, cutting card board! To check my drawing are correct before cutting metal, I did a dry run in cardboard, all good except the curve of the cab front needed a bit of adjustment.
So next will be making up a list of jobs, ideas etc of how to make the thin etchings firmer, I have also had a brain (Barn?) storming session with my Northern friend in the South for the running gear, he has all the dangerous tool things I'm not allowed
So next will be making up a list of jobs, ideas etc of how to make the thin etchings firmer, I have also had a brain (Barn?) storming session with my Northern friend in the South for the running gear, he has all the dangerous tool things I'm not allowed
Northsider
Modelling the Northern half of the Isle of Man
Further work on a not-unrelated Irish railcar today! I made up a mandrel to hold the wheels when turning the tread/flange. It is meant to rely on friction to keep the wheel turning, but with only an M3 thread applying pressure, I didn't want to leave anything to chance. So the backplate was drilled, and two Ø6 brass pins were silver soldered in place to act as driving dogs, fitting in the holes in the wheels.
With the tool angled to give the flange angle of 20º, and the compound slide set to 3º for the tread, all was ready. My lathe only goes down to 100rpm -the advice is to run slower than this- but everything worked as it should. The castings are of excellent quality, free-cutting and without any hard areas.
The flanges ended up as per the G1MRA standards, 1.5mm thick at the root and 2mm high. The lathe tool didn't have a radius on its point, so I left a small step where the flange meets the tread, and used a needle file to create a radiused internal corner.
I'll have to wait now as I need to order a few bits and pieces in order to continue; one of the downsides of Chronos Engineering having closed.
With the tool angled to give the flange angle of 20º, and the compound slide set to 3º for the tread, all was ready. My lathe only goes down to 100rpm -the advice is to run slower than this- but everything worked as it should. The castings are of excellent quality, free-cutting and without any hard areas.
The flanges ended up as per the G1MRA standards, 1.5mm thick at the root and 2mm high. The lathe tool didn't have a radius on its point, so I left a small step where the flange meets the tread, and used a needle file to create a radiused internal corner.
I'll have to wait now as I need to order a few bits and pieces in order to continue; one of the downsides of Chronos Engineering having closed.
Rhinochugger
Retired Oik
One of the difficulties of soldering brass, and it being a good conductor, is that when you go to solder the next piece, you can melt the nearby recently soldered joint.Today's installment, cutting card board! To check my drawing are correct before cutting metal, I did a dry run in cardboard, all good except the curve of the cab front needed a bit of adjustment.
View attachment 361297View attachment 361298View attachment 361299View attachment 361300View attachment 361301
So next will be making up a list of jobs, ideas etc of how to make the thin etchings firmer, I have also had a brain (Barn?) storming session with my Northern friend in the South for the running gear, he has all the dangerous tool things I'm not allowed
Mole grips, or similar can be a good heat sink, to take the heat away from previously soldered bits, but you can also use 85 degree solder, which is used for white metal, for the tiny details if necessary.
I've no idea how Accucraft and others solder their models in the factory - all I know was that when I was using a Dremel to form an opening, a soldered joint started to melt
But I'm not telling which model was involved
there's nothing to see 
They likely use resistance soldering techniques, one if the many things that needed to se cleared out from Andrew's garage after he passed was a Resistance Soldering Kit, sadly went in the skip why I never saved it for my use I will never know.One of the difficulties of soldering brass, and it being a good conductor, is that when you go to solder the next piece, you can melt the nearby recently soldered joint.
Mole grips, or similar can be a good heat sink, to take the heat away from previously soldered bits, but you can also use 85 degree solder, which is used for white metal, for the tiny details if necessary.
I've no idea how Accucraft and others solder their models in the factory - all I know was that when I was using a Dremel to form an opening, a soldered joint started to melt
But I'm not telling which model was involved
