My Beaut Aussie Cent

[Kevin Hunter]

Hi Robin
Im not sure of the right diameter but there may be a danger piano (or any) wire could bend and or kink? I bought some thin carbon fibre rods of various diameters with a view to possibly using that rather than wire.
It strikes me that probably the most important consideration re aerials is to watch your eyes as you bend over the model! A suitably placed pennant would be a useful safety feature although I dont think they were ever flown from the very tip?
I'm sure you saw Mick Whittingham's Cent turret at the open day - his aerial was bent over and strapped down in what I would call "landrover style". Again, not sure if they did - but it makes the model safer.
Regards
Kevin

[Stephen White]

Good debate. Paul, Kevin Here's my contribution.

Firstly size - the standard whip antennae for Larkspur were 8ft (two four foot sections which screwed into each other). They were made of copper. That;s about 16 inches or 40 odd cms. The two sections were of constant diameter apart from the last two inches which were flared to accommodate the threaded join.

I would think carbon fibre might be the ideal answer. Piano wire could be too heavy for the anttenna bases if you've made them in silicone (or used Mike Stannard's). The other option would be aluminium tube.

As for safety, Kevin, you've got a point. Pennants were used by troop leaders and squadron leaders during the Cent's life but they went out of fashion and were rarely used on operations for obvious reasons. They were flown near the top of the antenna. Raking the antenna backwards also became very fashionable and there was a fitting available to allow it (see below):

http://www.ebay.co.uk/itm/Clansman-Lark ... 1230909198

Again, it was a pretty stupid idea because it dramatically affected range of communication. It did look cool though. The Australians used them in Vietnam where the issue was antenna fouling the overhead vegetation. You can see it over Bob Ferrari's left shoulder in this pic:

https://www.dropbox.com/s/l4o35u1gbyi0b ... 5B1%5D.jpg

Incidentally, the HF radio equipped command vehicles used 12 ft anteannae, which provided endless entertainment when someone forgot to take them down when crossing railway lines with overhaed electric power.

Regards

Stephen

[Kevin Hunter]

[mick whittingham]

Hi Stephen,

I am currently working on the water tank covers which you completed some time ago. What diameter did you use for the actual lid? I am working with 1" steel bar and it looks about right. Also the actual fixed hinge pieces on the hull, in some photo's they appear to have a sloping outward face like the track link brackets. I was going to make mine from square bar with a turned shank but that would not allow enough size to make a sloped face. Is it just another quirk where some vehicles had one style and others a slightly different one.

Your work is looking fabulous as the paint goes on, are you spraying in your work area?

Regards Mick

[Stephen White]

John - the piano wire I used was 18 SWG (1.20mm).

Mick

- The water tank cover by the driver's cab is 23.25mm for scale. The two fuel tank covers are 23.50mm (yes, bizarrely they were different). Note the fuel tank covers have a flat at the rear end.

- I made the hinge posts as you suggest, from square section with a turned shank. All the ones I've seen have a rounded top.

- I've set up a spray booth in the garage and I try to get most of the major surfaces done there but I'll then use a fine airbrush for detailed work in my so called workshop (also known to some as the garden shed. Somehow, the same person also thinks my workshop is a place to story muddy garden tools........

Regards

Stephen

[mick whittingham]

Hi Stephen,

many thanks for the information on the cover dimensions, who knew they would vary.

I am going to play with different methods of making the hinge pieces and will post pics when done.

I sprayed the big bits away from my shop but will try not to make a mess when I start the detail stuff with my air brush.

Regards,

Mick

[Stephen White]

Now for the outer halves of the final drive cases. Care is needed here to preserve the structural strength but there was enough meat to allow the surface to be lowered by 5mm without compromising the strength of the gear housings. The surface needs to be lowered to achieve the correct thickness and to form the housings for the two removable inspection panels, which are such a prominent feature of the final drives and very visible between the sprockets and the top rollers. I also decided to decrease the pitch between the securing bolts for the two halves to represent the scale number of bolts and the correct pitch. So, (very) rough marking out:



It was too difficult to set up the rotary table to cut the circular patterns so I decided on a rough milling cut and hand finishing:







The top profile of the gear cases needs to be altered to mirror the inspection panel housing:



Finally, a fillet needs adding to the forward edge to give a straighter profile - I just had time to add the fillet and will shape next time:



There was some comment a while back about the close tolerance between the rear suspension unit radius arm and the final drive housing. Interesting to see that on the real thing, some relief was cut into the final drive housing to allow a full swing of the radius arm:



Hope this is of interest.

Stephen

[John Fitzsimons]

Thanks for the details on piano wire. I will try to get some.

John

[Stephen White]

Not a lot to report this time, preparing the blanks for the final drive inspection plates seemed to take forever.

Finished the reprofiling of the front of the final drive casing:



Final drive inspection plates. I'm really impressed with using the old engineers hand tools, the scrapers. I surface scraped the plate on the right to remove the turning marks. Very easy to use and much more accurate than filing. Cheap too:



I also had some good advice from Paul Scott about machining aluminium - to use WD40 instead of cutting oil to prevent chips clogging the cutter and using a roughing cutter with serrated splines to reduce galling (adhesive wear due to alu chips sticking to the cutters):



've tried both today and they both make a lot of difference. Thanks Paul.

Rough layout of the plates on the final drives:





Regards

Stephen

[Steve Stuart]

Hi Stephen
Using WD 40 is a tip I will try as well! Someone else told me years ago that paraffin is also useful for wetting hacksaw blades to do the same thing.
Steve

[Stephen White]

Continuing with detailing the final drive casing. Two rebates milled in the hub casing and the inspection panels fitted:





Filler cap:



and drain plug:



Final:







Comparison with original:



Now for the other side.......

Regards

Stephen

[simon_manning]

whats going on, my sunday night instalment has moved forward a day, anyway very nice stephen, a transformation. regards simon.

[Stephen White]

Sorry to disappoint, Simon......! Today was supposed to be starting the second final drive casing, so I'd intended to post the more interesting stuff last night. But then, just as you thought it was safe to go out.......

I realised I'd missed a few things. Firstly the cast numbers, taken from the Illustrated Parts Catalogue:



The return roller housing had two very obvious mounting flanges, which I've added with brass:





Finally, the recesses for the bolt heads:












Now, it really is complete. I'm enjoying all the good stuff going on over on the 25 Pdr section.

Regards

Stephen

[mick whittingham]

Hi Stephen,

wow the work on those gear casings is spectacular, I would not have had the guts to cut into them and your machining and planning skills are to be applauded.

I have been tidying the hull and spent a little time making a mini sheet metal bending machine for forming the tin work on the mudguards etc. I could not justify buying a machine just to do the job so broke off to build one.

I take it you will work your magic on the other side gear casing and I can't wait to see where you will go next.

Best regards, Mick

[Per Sonnervik]

Hello Stephen,

Excellent and inspiring work - awsome!!!.

Cheers,

Per