Friday, January 11, 2019

Alan Keef K12 Diesel: Part 2

Whilst I soon realised on Wednesday that I'd messed up the etches for the K12 I pushed on to assemble as much as I could in order to check the rest of the parts. Rather than building up another OO9 version, this time I've built one for OO6.5 around the a Busch chassis.

Apart from the known issues everything seems to have gone together well. I did have a few issues assembling the parts due to not spotting a slight issue with the chassis which caused the cab to fall apart, but that wasn't down to a problem with the parts. The only downside to this version is that the chassis is much taller than the OO9 version meaning it fills most of the cab. Hopefully when painted and with a driver stood in the door way this shouldn't be too obvious.

I don't really have anywhere to test 6.5mm gauge models (yet) so a battery and a short straight piece of track had to suffice, but I think it looks quite good with the peat wagon.

Thursday, January 10, 2019

One Right, One Wrong

So yesterday I grabbed a few minutes here and there to have a look at the new prototypes. First up was the revised peat wagon etches

On the left we have the previous OO6.5 gauge prototype that was very awkward to assemble. On the right the new prototype etched cage this time assembled onto a Dundas Models rugga chassis for OO9. The good news is that the new parts are much much easier to assemble, and once assembled are indistinguishable from the previous version, so I'm calling that a success. That means these should hopefully appear as kits in both gauges before too long.

Flushed with success I moved on to having a look at the new etches for the K12 loco. Unfortunately on the very first piece I removed from the fret I've found a mistake; a half etched rebate is on the wrong side of the sheet. Checking the artwork and the mistake is definitely of my own making, which is rather frustrating. In my defence it's on a rather complex part that involves two normal fold lines and an underfold and I simply got confused as to which side ended up where on the folded part. Fortunately with the artwork being digital it's easy to correct; I can't imagine how people stayed sane correcting hand-drawn etch artwork! I'm going to assemble as much of the model as I can to check the rest of the parts, but it's going to need another round of prototyping before it's finished.

Wednesday, January 9, 2019

New Year, New Prototypes

It's been quite a while since I had any modelling to show while I updated the designs for the K12 loco and peat wagons I was working on back in November. Well hopefully that will all soon change and I'll have something new to tell you.

The 3D printed parts turned up just before Christmas, while the revised etched parts dropped through the letterbox this morning. First glance and everything looks good, so fingers crossed...

Monday, November 19, 2018

Wasp Stripes: An Experiment

I hate the idea of wasps. Not only do I not like the variety that sting, but the idea of trying to mask up a locomotive to paint on wasp stripes fills me with dread, especially given the smaller scales I usually model in. One of the K12 diesel locomotives was fitted with extra plating that was painted with wasp stripes and while I wanted to be able to model that I didn't think it was going to be possible to mask the parts for painting on wasp stripes, so as a bit of an experiment I included a stencil on the test etch.

I spent a few minutes (spread over a few hours) this morning trying it out. The steps were easy enough; spray the part with primer, spray with yellow paint, stick the part to the back of the stencil using masking tape, spray with black paint, and finally remove the stencil. In theory there is only about five minutes of modelling there but you need to wait for the paint to dry (enough) at each step. The process was frustrated slightly as the can of yellow paint I had seems to have gone off so it didn't cover very well, but I think this proves that I can paint wasp stripes that are good enough.

I'll admit that it's not perfect (I didn't let the yellow full harden so it's bunched up a little around the rivet detail, and it may need a touch more black) but I'm more than happy with how it looks. Don't forget the picture is many times life size, and to the naked eye it looks spot on.

Sunday, November 11, 2018

Alan Keef K12 Diesel: Part 1

Having built the peat wagon I had a go at assembling the parts on the other etch, which turned into.......

You can probably see in the photo that the etch and 3D printed chassis are just slotted together, but hopefully some of you will recognise the loco as a K12 diesel built by Alan Keef Ltd. While I've managed to assemble all the parts around a KATO Centram chassis, I need to make changes to both the etch and the 3D print; there are a few niggling issues but more importantly I managed to mess up the design of the bonnet side panels by misinterpreting the drawings I was working from.

Even though there are issues with the model I think it looks the part, and I'm really happy with the fact that all the complex folds on the etch worked perfectly. It might be a while before I have more progress to show, so while you wait here's a short video of it circling my tiny test track:

Monday, November 5, 2018

Peat Wagon

This mornings post saw the arrival of test etches for a couple of potential kits.

I've hidden the labels in the photograph so as not to completely give the game away, but it wasn't long before I made a start on a quick test build of the simpler of the two etches.

As you can see the etch builds up in to what I think is a fair representation of a peat wagon. It's based on an example preserved at Amberley (from where I've shamelessly "borrowed" the photo). I've worked solely from the photos on that page, with all measurements based on the fact I know the track is 2ft gauge. The etch sits on a 3D printed chassis, based on the Hudson rugga chassis, to produce a 6.5mm gauge model.

A bit of paint and weathering and I'm really rather happy with how it turned out. Mind you the photo hides the fact that it was awkward to assemble, so there will be a slight redesign of the etch before I build any more or before it becomes a kit.

Tuesday, August 14, 2018

Insulated Driving Wheels: An Experiment

While the build of Ivor might be on hiatus, I now have four wheels which are effectively scrap (given that they are no no longer the same size) on which it is safe to experiment. The final two pieces of the wheel design I needed to finalise were the insulation from the axle and the crank pin.

Let's start with the insulation first. It's difficult to see in the photos but what I've done is to simply take the test axle from a few posts back and fit this to one of the wheels. This involved opening out the axle hole in the wheel to 2.8mm which is a nice tight fit for the insulating bush I took from a pair of hornby disc wheels. I'm not sure this is the final way I'll go (I might try turning my own insulating bushes) but it is nice and straightforward and seems to adequately insulate the wheels from the axle at little effort or expense. Obviously on the real wheel I'd trim the axle back to the face of the wheel.

When I was originally working on the 3D model for the wheels my plan was to use a 14BA screw as the crankpin with a hole through the wheel tapped for 14BA so the screw would actually screw into the wheel. I had wanted to cast a recess into the back of the wheel to seat the cheesehead bolt but the wall thickness requirements meant that wasn't possible. So my plan was to screw the bolt into the wheel and then cut the head flush with the back. A little drop of loctite helping to hold the bolt in place. Unfortunately while I managed to open out the hole big enough to tap, I then broke one of my 14BA taps and stripped the cutting threads from another. With no taps left I opened the hole up slightly further so that the bolt was a tight sliding fit. Rather than holding it in place just with loctite on the body of the bolt I decided to drill a recess for the bolt head anyway as there seemed to be enough material. With that done the bolt sits nicely in the back of the wheel and the bolt head helps to keep the bolt perpendicular to the wheel while also providing more surface area for loctite to hold it in place. Once the loctite had set I did try pushing the crankpin out and couldn't do it by hand. Even with a set of pliers it took a lot of force to break the seal, so this definitely looks like a workable solution.