Saturday, September 26, 2009

This Weekend's Project: Sniper Rifle V2

Decided to redo the TF2 Sniper Rifle. It's not August 1st, but we'll have to settle for a late celebration. I'm building this rifle to the G-43 standard, and adding an addendum to the standard:

**Rifle grip firearms will have a distance from middle of trigger curvature to grip of 10mm. **

The rifle is larger by a small margin compared to the older model. We'll see how those compare in a bit. First, it's time to show you how the rifle gets made.

The rifle can be broken up into two part types: revolves and extrudes. Revolves are objects that can be made by rotating a 2D view around an axis of rotation to form a solid. In this case, the scope, laser aiming module (LAM) and barrel are revolves. These are made from using the Excel sheet mentioned in this explanation. Extrudes are 2D objects that are made 3D by making them thicker by adding the 3rd dimension, the width. Extrudes in this model include the frame, scope cover, and scope mount. Preparing Magic: the Gathering cards for making extruded solids is covered here.

From the schematic, I've scaled it 1:1 in relation to the final object, and traced out patterns of the frame. I've traced this pattern onto four copies of laminated magic cards, four layers thick. This gives us 16 layers, approximately 5mm thick. The four layers can be seen on the left of the above image.

The scope will be made of several tubes linked together to form the scope. I went for as exact of dimensions as possible for a good fit. The barrel was made from rolling printer paper around a 3.175mm diameter bamboo rod. I suggest using printer paper for rolled objects of little consequential structural stiffness and small wall thicknesses since the final part will have less of a noticeable seam to need to sand down.

This is the scope, assembled. The cylinders connect by overlapping anywhere from 3 to 5mm. I made the cylinders as thin as possible (1mm thick walls) so I could have a hollow, unobstructed scope. I cut some discs out of a CD jewel case for lenses and inserted them into the cylinders.

The scope mount was made in a similar manner to the frame: tracing a 1:1 scale final part pattern, then cutting out the appropriate number of layers to get the desired thickness. When making curved elements, you need to glue the layers together as they're in the desired final curvature. Bending a laminate is not suggested.

The two parts of the scope mount were connected by a small 2mm diameter rod. I decided to enhance the structural stiffness by running a paperclip rod through the tube and the scope mounts.

The frame needs a 3mm deep recess to accept the barrel. I made one prior to gluing the laminates together, so I have less machining to do.

One of this model's gimmicks is the moving bolt/receiver mechanism. I cut out a slot in the barrel for the bullet ejection port. I carved a 1mm deep groove into the side of a bamboo stick and bent a paper clip into the appropriate shape of the bolt handle. The handle was glued in place with Loc-tite. Things glued to metal using Loc-tite shears easily, but the level of shearing needed is much higher than what this part will see. I'll be using a bead for the handle knob. This part was glued into place.

Bolt completed. Next item of action: heavy Dremel action. Since I've made the frame from multiple cards' worth of length due to it exceeding the length of one card, I have an unsightly gap between cards. I covered the sides with one sheet of 110lb cardstock before proceeding to the sanding sequence. I gave all the lower parts a gentle 1mm radius round, then hacked off more material at the stock and handle regions.

Here's the result of some merciless Dremel action, followed by some light hand sanding.

The second functional part of this model is the front lens cap. I've glued a "U" shaped strip around a circular plate, 3 cards thick. The U part will rotate around the hinge, made of a paper clip. The holes were made from a 1/16" hand drill. I drilled the holes first, then cut the material around it. Otherwise, the material will deform and twist during drilling.

This is the scope lens, attached. The gun is largely completed at this stage.

Here's the final result. The top rifle is the newly crafted "high poly" model of the sniper rifle. It improves from the previous model featured below with added structural stiffness, enhanced scope features and rounder frame edges.

Here's a photo of the bolt action lever. Much better than the previous model which used just a tube.

1 comment:

Isabela said...

HI! Your Team Fortress set is fantastic, it's exactly what I'm looking for. (Can't believe they haven't done figures yet) Could you make a custom order of the Heavy with the sandwich? I'd like to order one (or you could sell me that one). Even the Medic or Engineer would do (Engineer's my favorite). If you'll accept an order, my email is Either way, if you can find the time, please tell me whether or not you can make one. Thanks! Wish I had your skill but I don't ;P