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Posted: Fri Jun 11, 2010 5:40 pm
Just finished one of the access panels that is on the lower angled bottom plate at the rear.
I've started to take photographs as I make stuff, starting with the Guard Rail in front of the Driver's Visor.
The Guard Rail needs to be a bit longer than the supplied part and can be in one of two variations. Both variations need to be milled, on both sides, at an angle along it's length. I left extra material at each end for when I milled the side and top. You might noticed that I wrote 'TOP' on one surface, this was to make sure I machined the angles on the right edge. Which I didn't the first time
, another lesson learnt!
More to come.
Posted: Sun Jun 13, 2010 2:16 am
Thanks for the pics of the machinery you are using. All new to this newbie.
Posted: Tue Jun 15, 2010 4:42 pm
The Guard Rail is finished and has come out okay. It's the first time I've tried setting the milling machine at an angle, but it went without any problems. On another bit of aluminium I tried making 3.5mm milled circular marks in the top, to represent the fixings on top of the Guard Rail, but I couldn't get them central and accurate enough. So I went the same way as Stephen did with his and drilled/countersunk/tapped in the top instead. Leaving a bit extra material on the ends did make all this easier.
After that, the ends were cut off and machined at an angle. The top edges were rounded off slightly and then a couple of holes drilled through into the Front Lower Deck.
Posted: Tue Jun 15, 2010 11:56 pm
Very nice job. Impressed by the care you too took in clamping the work and protecting the alu from bruising.
Check and recheck that the milling head has actually returned to the perpendicular, even if the scale says 0 degrees! I once got a nice ribbed surface on a flat plate by forgetting to clock it first.
Keep the photos coming.
Posted: Wed Jun 16, 2010 10:04 pm
Thanks for the advice about aligning the milling head. I tried it out on a scrap piece of aluminium and I ended up with groves in the surface. Took a couple of goes to get it right but it's doing flat milling again.
The scale is not that accurate.
So I can end up with the simulated welds relatively flat I've milled a recess along the front edge of the Front Lower Deck and also across of the top edge of thick sloping armour at the front (the bit immediately below the Brake Vents.
It's about 1mm deep, so should be big enough to give the weld/filler something to grip on to.
Posted: Thu Jun 17, 2010 12:08 am
Good idea, but Milliput might stick just as well to an edge roughened with a dremel. The anecdotal evidence seems to point to Milliput cracking off smooth surfaces under shock loads. You might want to experiment with some scrap.
Machining off part of the thickness of a butt joint reduces the load bearing surface. The thinner the material the more pronounced this weakening will be. I elected to reinforce the edges of the upper hull joints of my Sherman with GRP putty. Not an approved mod but it allows me to separate the upper and lower halves of the Sherman (it will have some interior detailing).
Much of this decorative work has to be guided by practicalities. I hve used Milliput, Liquid Metal Adhesive, thick Cyano glue and flexible 3D acrylic paint. All have a place, depending on strength, versus shock resistance ,versus appearence/ease of application.
Posted: Mon Jun 28, 2010 4:39 pm
All the lower hull has has the additional holes drilled, old holes filled and painted with etch primer. The inside has been painted an off white and I'm checking that all the detail parts fit before I assemble the lower hull.
I had forgotten about the hex/cone bolts that fit on the small access panel which is on the rear lower hull plate. These were made up from brass rounded screws, with no slots. They were filed to a hexagonal shape and then a taper was put on with the lathe. I'm now just waiting for some 5BA nuts to go underneath.
I hope that most of the hull will be assembled by the end of the week.
Posted: Sun Jul 04, 2010 8:44 pm
While I'm waiting for some bits and paint to dry I swapped out the M6 Cap Head bolt for a M6 hex head bolt. I filed off the raised lettering on the top of the bolt and also used a centre drill to put a little detent into the bolt head like on the full size Panzer III.
I made two sets with different size detents and I'll see which is best when I darken the detent a little like on the Panzer III photo's.
Posted: Sun Jul 04, 2010 8:55 pm
Looks very nice Sarah.
I assume you can get a socket head in there to adjust the tack tension.
Posted: Sun Jul 04, 2010 10:12 pm
I went away and checked
I've got a box spanner that fits in fine.
Posted: Sun Jul 04, 2010 10:37 pm
Looking good Sarah!
It is those little details....
Posted: Mon Jul 05, 2010 9:59 pm
The domed fan cover is secured with castle nuts, but they are smaller than the ones which Steve Winston makes. I did try Steve's (M3 size), but when compared with a photograph of the full size Panzer III domed fan cover, they do look a bit too big. I had a go at making some M2 size castle nuts and after a few different attempts came up with a method which makes quite reasonable castle nuts. Below are the M2 castle nuts on the domed cover, if any one is interested then I can do a few pictures and notes how to make them. Two of them, on the right hand side, do need to be replaced as I'm not quite happy with them.
Posted: Mon Jul 05, 2010 10:07 pm
Excellent Sarah and yes please do share your technique for making them.
Posted: Tue Jul 06, 2010 1:28 am
Posted: Tue Jul 06, 2010 5:10 pm
To make the M3 Castellated Nuts. Start with some hexagonal brass rod 4mm across the flats. First face off the hexagonal rod to get a good surface to work from, use a centre drill to mark the centre and drill 1.6mm (1/16"), through for about 10mm. Use a carriage stop on the lathe saddle and ensure that the lathe bit is touching the hexagonal face (I skim the face to get a good reference). Set the compound slide DRO/graduated scale to zero. Then using the compound slide, without the lathe bit touching, move the lathe bit in 1.2mm towards the chuck.
Then move the cross slide in until it is just touching the hexagonal bar and set the cross slide DRO/graduated scale to zero. Use the hand wheel on the saddle to move the lathe bit off the hexagonal bar. Adjust the cross slide in ,by 0.05mm, then using the hand wheel on the saddle move the saddle towards the chuck until the saddle touches the carriage stop. Move it back off the work and again adjust the cross slide in by 0.05mm. Again move the saddle towards the chuck until the saddle touches the carriage stop. (This method of using the carriage stop is good as it gives you a consistent point to cut to) Repeat this method until all the hexagonal surface has been taken away, for me that was a total of 0.3mm cut into the hexagonal bar. This should give you the same as in the photo below:
Then using a parting tool cut off a 3mm section
which leaves the Castellated Nut blank, as shown below.
I made a jig to help locate the cuts to form the castellations. This was made from a small piece of tubing, which had a dot punch tapped into it to flare it out than a section of hexagonal bar (4mm AF) tapped into it to form a hex shaped hole inside. Then a slit was carefully cut to act as a guide when cutting in to the top of the castellated nuts. A smaller piece of tube was used to push the castellated nut out afterwards.
The castellated nuts were then tapped M2 and all the sharp corners removed.
You will be able to make two castellated nuts before having to re drill the centre hole. If the centre hole is made any longer, then the drill bit can start to wander and there is more chance of snapping the drill bit in the work.
Hope this is useful