otira miniatures

2010-10-16T19:06:00.000-07:00

hi all, i have been doing some drawings lately. I have found some better motors and gears. This will improve running.

there both 12v and allow room for a flywheel. The garratt drawing is new, it is based on the NA mech parameters. As there is starting to be more wheels here i am tempted to get them made outside by an engineering firm. The garrets drawing is not finished, but most of the overall structure is done.

2010-06-09T16:32:00.000-07:00

hi all, more pics. this is the first coat of paint. is just so i can put the glazing in and glue on the roof.

2010-06-08T16:21:00.000-07:00

hi all, a few more images. its starting to look like a NA now. the chimney was turned on my lathe,

as was the air compressor. handrails and pipes are various sizes of brass wire. the filler caps (i think there filler caps? ) are heads of pins.

2010-02-17T14:43:00.000-08:00

hi all, well i had a go at casting the boiler/side tanks. they turned out quite good. plenty of weight. the truck is a model tt truck, it is by micron art, http://www.micronart.com/index.html

2010-02-14T14:08:00.000-08:00

hi all, been a while i know. here are a few recent pics. the new boiler section i have made is out of styrene. i will reproduce this in whitemetal. two reasons for this. i need the weight and i have multiple NA's on the go. so i only have to make one master.

2009-09-08T15:55:00.000-07:00

not much added to the NA but i have had a go at some trackwork. the points are 5mm gauge.

there made by hand using code 40 micro-engineering rail and nn3 pcb sleepers from fast tracks.

2009-07-23T15:43:00.000-07:00

Hi all, i have reworked the shaft. There is another support and a universal joint. Its hard to see but these are uni joints supplied by hollywood foundry. The mechinism still needs a good run in. need to build track. there is a piece of lead on top for traction. this will be replaced by the boiler and side tanks.

2009-07-13T23:04:00.000-07:00

i finished the drive to the spur gear. runs well. I was a bit worried that the reduction on the g15 motor was going to bo to slow, but it looks ok to me. sorry the video is a bit blurry.

2009-07-12T21:02:00.000-07:00

a few more images so far, the cylinders need to redone as there isn't enough clearence for the rods. i will increase the spacing by 0.7 mm from the centreline.

2009-07-12T20:49:00.000-07:00

hi all, i have reworked the design of the rods and cranks to improve the assembly. the centre photo shows the jigs to press the wheels onto the axle muffs.

2009-05-10T15:43:00.000-07:00

latest revision of a hon30 NA loco.

2009-05-08T17:42:00.000-07:00

something else in the works,

a hon30 version of below. just a rough drawing to see the suitability of off the shelf motors and gearboxes.

2009-04-30T17:19:00.000-07:00

hi all, a few more recent shots of the Na. the last photo shows the motor in the background.

the chassis is free rolling at this point. This design is far neater than the earlier one, assembly is simpler too.

cab

2008-12-09T16:50:00.000-08:00

hi all, a few more recent pics. the white parts are cnc machined styrene. the 3rd pic i hadn't trimed the windows.

2008-11-02T17:05:00.000-08:00

hi all. just a few more pics. the workshop is a bit full at the moment so have been working on the computer. the na i have changed, it now has a split chassie and solid drivers. both the na and the harman have there parts cut on a cnc mill. parts are either brass or plastic. in hindsight it is far more productive i think to design the locomotive completely. But i guess i can do a better job of it now as from the earlier i have a good idea of what can be machined and what cannot be.

2008-10-16T16:26:00.000-07:00

hi all. well above is a machined cylinder set for the na. i made them in two halves which i will solder together. I used a 1mm cutter on the cnc. for scale the outside of the cylinders are 1/8" diametre.

further drawings

2008-09-14T06:55:00.000-07:00

hi all, i have started to work on the boiler design. Shown is the overall dimensions. I will add the finer details as i go along.

2008-09-11T06:16:00.000-07:00

hi all, have built the improved chassis. It goes together with far less effort. I had an idea to use pc board as the cover underneath as i can use it to attact the pick-ups.
regards

redesign

2008-09-10T01:01:00.000-07:00

hi all, well after some thought i decided to re-design. I can say that the current design can lead to a working model. I felt however that the design must be so the kit goes together with ease. i found with the current design it was an effort to build requiring the redoing of solder joints etc.
i figure that as soon as i get one design right i will be able to transfer to simular loco's.
So you can see i have added two internal frames and more rigid cross members, these fit into recesses i cut into the outside frames. the frame will be soldered in once piece. Most importantly the axles are now removable, the bearing surface for the axles are only the top half of the journals alowing them to be removed from underneath. A cover keeps them in place. I figure that the wieght of the loco will keep them in place. This i hope will enable a more accurate assembly of the axles and the valve gear.

rolling chassie

2008-09-01T19:51:00.000-07:00

hi all, have assembled the rolling chassie. was most tricky with the small pins, they were 0.8mm diameter and were rivited.

valve gear

2008-08-30T06:07:00.000-07:00

hi all, well i have assembled the valve gear on one of the chassies. i made the pins, they were either rivithed or soldered in place. i am still experimenting.

rolling chassie

2008-08-22T06:48:00.000-07:00

hi all, well i can say the first stage of construction is over. pics show the rolling chassie. the only modification is i some washers/spaces to go between the frames and the wheel centres as the tires would foul the frame and cause a short.
regards

na axles

2008-08-21T04:43:00.000-07:00

hi all, i have been making axles these week. they are turned from brass. For those that need it a gear pressed on and soldered in place. the gear is cut from spur gear stock. hope to have a rolling chassie soon.

wheels

2008-08-17T22:47:00.001-07:00

hi all, well after lots of thought i decided that one should always do the best job one can, so here they are. spoked wheels 22 scale inches in diameter. The tire is machined brass, and the centre is styrene as per last post.
they look even better in real life :-)
the gunk still attached gets collected when they are handled, a blow with the air cleans them quite nice.

more bits

2008-08-17T16:09:00.000-07:00

hi all, a few more pics.
i re-worked the cam program so better toolpaths were followed this gave a much better shape to the cranks.
Second pic shows the spokes being cut. this in in .040" styrene.

2008-08-13T21:25:00.000-07:00

hi all, another pic. this time the cod rods and cranks. again made on the mill. this time the brass is 15 thou, needed a sprue so i could hold it. if you look close the rod show a little relief showing the differences in thinkness.

nbh wagon

2008-08-13T04:52:00.000-07:00

i tried something new for the nbh kit. i had a master sprue printed on a 3-d printer, the resolution is down to around 15 micros, i have included pics showing the printed master.

this master can be used to make a mould in silicone rubber. I'll post cad drawings of above soon.

nm wagon

2008-08-12T02:44:00.000-07:00

well i thought i better add some more pics of other rollingstock, firstly a nm wagon. i etched the bodies of these some time ago.

NA frames

2008-08-12T02:04:00.000-07:00

Well the first parts have come out quite nicely, good old k&s brass can't go wrong.

the frames were cut out on a cnc mill using a high speed head. i used a .029" slot drill at 20 000 rpm.

intro

2008-08-11T20:05:00.000-07:00

hello world :-) i thought i would invite everyone on a little (tiny) journey of sorts. the task is the construction of a nn30 (yep 5mm gauge and 1:160 scale) na class locomotive. Why a na you might ask, well they dont have a complicated valve gear and look good.
plans i found in a recent issue of narrow gauge downunder.

the na's are famous as they are the mainstay of the fleet for the puffing billy railway.

go to http://www.puffingbilly.com.au/fan/fleet/NA_photo_gallery.htm for a look.

i have started a 3-d drawing of the model using alibre design.

the frames are the first thing i will make.