I am building to Treaty rules which does have the no barbette modification rule. The cutout is level with the bottom of the turret, while the raised part will be where the turret connects. Actually, the cutout really doesn't let me change the down angle of the guns - I can point them down far enough to shoot off the fantail right now. What I really need to do is increase the height of the barbette, but I don't think the rule allows that either. I should still have a little clearance beneath the turret on the inside, so I'll start by raising the gun a little farther in the turret and see what I get. But that will have to wait until I get a turret made.
Yep, it's a little tight around the barrel nuts. I can turn them, but raising the guns a little and relieving the the barbette a little should make it a little easier to adjust them.
To change the angle of the guns I just need to adjust the nylon screw in the back of the mounting plate. After loosening the two hold down screws, I turn the elevation screw in to lower the guns and turn the screw out to raise them. The straight part at the front of the mounting plate acts just like gun trunions, forming the center of rotation. Backing the screw all the way out means the gun plate rests flat on the mounting plate inside the barbette, ensure that the guns cannot be raised above horizontal. When I got it where I want it, I just tighten down the hold down screws. My current disadvantage is that I have less than 5 degrees depression to work with before I start hitting my own deck. The CNC has been a lot of fun, even after having it several years I still love to to just sit and watch it cut out parts.
I finished making two molds for the turrets. While I thought I had plenty of draft built into the plug, when I tried to take them out I couldn't budge them. So I had to use a chisel to remove the plug from the mold. The molds still came out pretty good, far from perfect, but very useable. I have made 5 turrets so far, and the 6th and 7th are curing right now. Here's the first one that came out of the mold. Molding in the line to define the barrel openings worked out very well - it made it very easy to cut out the slots. Here's there rear three turrets with the guns mounted. It's really starting to look like a ship now.
looking very nice. your taig can quite easily mill those molds directly for you, if you are so inclined to code it (I particularly like machinists wax for molds, if it doesn't turn out well, melt it down and try again).
If you're going to mill plugs and then make molds, I highly recommend Smooth-On's Mold-Max material... takes overnight to fully set, but it's firm, yet has enough give to pop the pieces out by hand.
I had not thought about milling the molds directly, but I have thought about trying the machinable wax. The wax always seemed expensive to me, but I guess if you can melt it down and reuse it, it might not be so bad.
I'll have to look into that material. I was also talking to Buddy about alumilite, which uses a flexible mold material that I would like to try. However for the turrets this time, I though I would stick which what I knew.
the wax is far cheaper when testing code than broken bits and wasted metal.... but beyond that, while you still need to put release agent on it, you can get a part out that sticks. you may also want to invest in some tapered end mills. they make quick work of draft angles in molds. The hard part with directly milling the molds is that the thinking is backwards from milling the parts... suddenly sharp inside corners on your finished part are ok and sharp outside corners are not (generally speaking). Also, often you can do incredible things if you just think about the mold for a bit and make it a two or three piece mold
Thanks Greg - I didn't know they made tapered end mills. That makes creating a mold on a 3 axis machine possible. I checked out the mills and I'll put them on my wish list. Unfortunately, the tooling list is always much bigger than the budget.
http://www.carbideselect.com/TaperEndmills.php?PHPSESSID=1f5aaf1ce60cfb20b09538f7a21db1d1 check out those. I like these fellows, the price is reasonable and the tools cut well enough. I've also created the taper using a ball end mill, and rather than a taper, you get discrete steps. it also works quite well. The single biggest problem with the taig is the ER-16 collet choice. because you can not get up to 1/2" diameter shanks (screw on tool holders suck) you can not get standard keyway, slot, slitting, and undercutting bits. It is possible to upgrade to an ER-32 spindle but to do it you would need access to bigger precision equipment as the bearings that would fit around available tool holder are bigger than the er-16 holder _Greg
I finally finished the water channeling in the Roanoke. I started with a can of door foam, expecting to use it as the final water channeling. Having used cans of foam for various house projects, I know it is not easy to apply evenly. So I experimented with the foam a little and thought I had the problem under control. However, it didn't work out near as well in the ship as it did in my experimental tries, so it looked pretty bad and also had a lot of holes. So I sanded the foam down and bought a tube of Quikrete self-leveling polyurethane concrete sealant. I put the sealant over the top of the foam, applying it in five separate sessions - left side, right side, back left, back right, and back center. I was very pleased with both how easy it was to use the sealant and the nice appearance of the finished work. Overall I used about 2/3 of a 10oz tube, so it did not add excess weight either. Finished water channels
Indeed. Nicest cruiser build I've seen in a while, the fact that it's your first combat model makes it even more impressive.
just wait, soon enough you will be using that mill of yours to make all manner of things for your combat boats, to the point that the only things you really buy anymore are the co2 tank, pressure regulator, and misc. little things
I would like to be able to make my own regulator, given the expense and weight of the commercial models. However, I have worked with high pressure systems in my professional life and I have a healthy respect for them. Requiring commercial tanks and regulators is a very wise rule in this hobby. The rest of the stuff is fair game however. I have a pump design on paper as well as a gun modification drawn up, I'll work on them for my second model. And of course the stuff from Clippard is so nice I wouldn't waste my time making any of that. I've mocked up my CO2 system. I was hoping for a test fire today, but the day was consumed with honey-do lists lain:. I made a manifold to attach my two MAV2s to, and it also acts as a T to bring in the 1/8 supply line and put out the pilot valve supply through a 1/16 line. The valves will be actuated by MPA-3s, which in turn are driven by 10mm pilot valves. I'll use a radio switch to operate the 10mm valves, both together for now, but with the option to operate them separately if I move a gun to the front.
I'd be interested in what you come up with as far as pumps are concerned (I've made quite a few odd/different ones, and still enjoy it). Are you using any particular approach? I've used "Centrifugal pumps design and application" for some rather successful pumps... if you can find a copy, it is worth a read.
I am a bit surprised that you did the water channel this early in the build. I prefer to fill the water channel sides only after I've skinned the ship and performed initial ballast tests, since that allows me to place lead inside the areas that otherwise would be filled with foam, epoxy, cement sealer, or other stuff.
He could always drill holes for putting weights in and epoxy over them... I do at least the central water channelling (with the attendant battery racks and other large objects) before I get too far into the build. Especially if I'm using the rails forming the channel proper as stressed members in a wooden hull. Not saying that Mark is with this build, but I can see some logical reasons for doing the channels early.
