Drilling holes for metal barrels

[GarethChai]

I am currently building the 1/700 Fuso which has blast bags molded on the guns but separate from the turret itself. I have a tendency to drill slanted, resulting in metal barrels which do not align properly. Is there anyway t fix this problem without puttying the hole and drilling again? A friend of mine suggested using cement to melt plastic within the hole and adjusting the metal barrel, then using thick CA to fill in any gaps between the plastic and the barrel. I have not tried this before for fear of permanently destroying my ships. Has anyone tried this method before, does it work and is there anything. Should pay attention to?

[EJFoeth]

You could use a small drill press?

[hawkeye3d]

You could use a small drill press?

That's obvious, however many of us do not have a small drill press, the means to acquire one, or a place to put it. I would love nothing better than to have all this but it just won't happen. Any suggestions as the OP requested ??

Bob

[Timmy C]

You may find it useful to shorten the brass barrel's "plug" so that you can wriggle the barrel a bit, allowing you to more easily align it.

[GarethChai]

Thank you for the advice. However, it's not the barrel that is the problem. The problem is with the drilling. Is there any way to drill the holes so that the barrels when inserted are aligned?

[Timmy C]

Not unless you have two things that keep both the blastbag/turret face and the drill stationary. Best you can do is use a pin to poke a centrepoint in the surface and then placing the drill bit in that centrepoint, and do your best to keep the drilling straight. Better to drill a hole that's slightly larger than the barrel's plug, because that'll give you room to center the barrel as the glue dries.

[EJFoeth]

Oh, something like a drill press. Did I mention a drill press before? A drill press would probably work, but so would a drill press.



Alternatively, you can insert two/three mountingtubes onto the turret glacis plate in which your barrels would just fit (inner diameter tube ~= outer diameter barrel). Make a small jig of 2/3 rods (depending on the number of barrels) with rods spaced out just right as a guide for the tubes in the turret. Remove jig, sand tubes flush with the turret face and insert barrels. This does depend on the type of turret though.I added an example of a jig I made to align the barrels with drying but then you need to use it for the mounting tubes as well. This might avoid any problems you have with not entirely straight drilling. This turret has the mounting tubes cleverly disguised as that part that later became a blast bag (turrets later replaced by improved versions though).

[GarethChai]

Thanks, but now I have another problem. I can't drill holes for small metal barrels, like those for 1/700 5 inch guns. I tried doing it for my IJN heavy cruiser, and those 8-inchers already broke 3 of my drill bits just for 1 kit. I cannot imagine doing it for anything smaller.

[EJFoeth]

If you use flexible HSS drills (i.e., not the very rigid ones), you do have some room to maneuver for hand drilling (the smallest I use are 0.2mm / 0.008" drills; still, some do break from time to time.) A 1:700 5" guns should have a 0.4/0.5mm end, so those drills shouldn't break. Anyway, one of the reason I've been calling out for a drill press all the time (only $50 for a drill stand) is that you drill in a straight line with a reduced chance of a breaking drill. When the part is really small you can hold it between finger tips and drill really carefully using the pin vice.

[djandj]

Thank you for the advice. However, it's not the barrel that is the problem. The problem is with the drilling. Is there any way to drill the holes so that the barrels when inserted are aligned?

Short answer - no. Use a hand drill and a bit just large than the diameter of the brass barrel stub. This way you have a bit of room to move the barrel into the right position. Also shortening the brass barrel stem as previously suggested will help.

[djandj]

Thanks, but now I have another problem. I can't drill holes for small metal barrels, like those for 1/700 5 inch guns. I tried doing it for my IJN heavy cruiser, and those 8-inchers already broke 3 of my drill bits just for 1 kit. I cannot imagine doing it for anything smaller.

For the smaller stuff, I actually heat up the brass barrel in a candle and if the model is plastic, I can seat the now hot barrel directly into the blast bag and the barrel melts its way into the plastic part and after fuses itself in w/o any glue. If not you can always glue it later, but the heated barrel works w/o drilling.

[Bogey]

I am about to tackle the very same problem on 1/600 Hood 15" barrels. I intend to use is what are known as "center drills". They look like a very short stub of a drill bit attached the a larger diameter shaft. They are used with lathes to accurately position holes for boring etc. Because the shaft diameter is larger, there is a lot less tendency for the bit to wander off, and far less chance of snapping the bit. While they are more expensive than standard drill bits they are readily available on eBay etc cheaply enough in sizes to suit our purposes. Hope this helps.