Saturday, December 26, 2009

This Week's Project: Crafting a Chair

You can only build so many firearms and bladed weapons before you need to sit down and think of more to build. This week, I've opted to go ahead and build a chair than my original plan of a sniper rifle. I can use the chair more than the rifle will ever be.

Chair has a padded seat. The inside is comprised of layers of somewhat thick cloth unfit for doll clothesmaking. I haven't perfected the method yet of making chair cushions. Once I finalize it, I'll share.

For this project, I needed thick, but workable stacks of card. I started off with 4-card thick stacks cut in the shape of the chair part template. By combining five of these stacks (I wanted a 6mm thick leg, so 20 cards ~6mm, in case you're wondering how I pulled that number) and bending them before they dried, I could achieve a gradual curve for the parts. Worked out well, but cutting out the pieces was tedious. I need to perfect the system first.

The chair back was done with a single 4-card layer, glued into place with Loc-tite adhesive. I didn't go fancy this time and put proper joints to assemble the chair like for 1:1 scale furniture, something I rather regret not doing. I'll be sharing what other things I learned from making more furniture in the future.

Tuesday, December 15, 2009

Sewing Some Ushankas

First off, all credit goes to the boys over at The Sixth Division for their in depth tutorial on sewing a 1:6 scale ushanka. If you follow their guide, you'll get some cheap and decent looking ushankas. I'd just like to add that you might want to consider browsing the kid's hat section instead of looking for fleece gloves. I found a kid's fleece baclava for $6 that has enough material for about ten ushankas. Gloves were priced at $9 with enough material for about 3. Of course, there's always thrift.

They kinda look like bad afros. No wonder why it's not supposed to be solid black.

On a side note, I'd suggest making a star and gluing it to the cap. Embroidering one might be a bit tricky since the thread sinks in if you pull the thread taught. Mine look like crap. But hey, not bad for about 10 minute's work apiece. I might try painting the outer cap grey to better resemble the in-game model for the Officer's Ushanka, since the guide does mention painting it to get the right look. A solid black appearance makes identifying the flaps difficult.

Maybe after crafting a few of these things, I'll finally get one in game.

Sunday, December 06, 2009

J.Norad Makes Paper Ball Joints

This post is more for personal reference than of possible use to any of you. Today, I'll be covering some parameters for designing a ball joint. A ball and socket joint provides excellent movement capabilities but isn't an easy element to build with paper.

The key to building a robust ball joint with paper is to have the appropriate materials needed. A good ball joint should provide adequate joint stiffness, but it may vary on your application.

Designing the Ball and Socket
You'll need to know a few things first:
  • Figure out how big your joint is going to be.
  • Figure out how much mobility you want.
Here's some calculations to help assist you in figuring out the dimensions of your ball and socket joint.

Figure 1: The Ball Joint Schematic

There's four design parameters that dictate the performance of your ball joint:
  1. Ball radius (r1 in Figure 1) (You'll hopefully know this value first)
  2. Socket depth (Hl in Figure 1) (somewhat adjustable, has a lower limit)
  3. Support rod diameter (2P in Figure 1) (adjustable, has a lower limit)
  4. Range of motion (phi in Figure 1) (defined by values 1-3)
For a given set of construction variables, r1, Hl and 2p, you can figure out how much motion your ball joint will provide. We'll use some trigonometry to solve for the angle phi, and use this to determine the total angle your joint will provide.

First, we must acknowledge that the support rod diameter 2P and the lower socket height Hl limit our angle. This is because the rod hits the edge of the socket, defined by how deep (Hl) the socket is. Second, we'll define the angle the joint provides as the angle that the center of the support rod makes with the line parallel to the bottom of the socket. This angle will be phi.

From Figure 1:
  1. The red angle Beta formed from the point of contact with the socket edge (Hl) and the support rod walls is less than our desired angle, phi. Since it's a right triangle, we know from the pythagorean theorem that the length of from the center to the tip of Hl is the square root of r1^2 + Hl^2.
  2. The angle formed from the line OP to the support rod centerline is the difference between angles phi and Beta. We know the thickness is 2P, and that OP forms the hypotenuse, and half the rod thickness P forms the opposite wall. Therefore, the angle Phi- Beta = arcsin(P/sqrt(r1^2 +Hl^2)).
  3. From trigoneometry, the angle Beta =arctan(Hl/r1)
Solving for the angle phi, we get Phi = arctan(Hl/r1) + arcsin(p/sqrt(r1^2 +Hl^2)).

The angle we actually want is the complimentary angle to Phi, since that determines the angle relative to the null position. So we take twice the compliment to Phi (two directions) to find the angle of our joint.
Total angle range for the ball and socket joint = 2(90° - Phi)

Where Phi = arctan(Hl/r1) + arcsin(p/sqrt(r1^2 +Hl^2))

This equation tells us some obvious relations, which help support the validity of the result:
  1. If Hl is longer than r1, the angle decreases
  2. if p increases, the angle decreases
  3. increasing r1 increases the angle.
Now for the actual construction!

The Socket
The socket should ideally consist of a durable material. 110lb cardstock will not work, as it wears out fast and easily over a few cycles. The smooth varnished surface of a Magic: the Gathering card is an excellent material. It will withstand more cycles and is fairly strong. Since paper (and Magic cards) does not have "negligible" thickness anymore (you're now working with a system that will requires a few thousandths of an inch in terms of tolerance to work well), you need to account for the overlap of paper. Magic cards have a thickness of 0.30988 mm (experimentally measured), which translates to 0.0122 in. This is enough to make your cylinder a slight oval if there's overlap. (If you consider that the accuracy of hand building has a tolerance in the range of half a millimeter anyways, it might not matter in the long run. And you can always correct for it later...)

Figure 2: The socket.

By acknowledging paper overlap, we form our socket by cutting out a strip of Magic card of a length equal to our projected ball diameter so that when we curl it up, both ends sit flush with each other, thereby eliminating the overlap. Once you have your cylinder, you can freely complete the cylinder with additional layer of Magic card without worrying as much about overlap. Removing overlap helps reduce wear of the ball and socket over time, since the raised edge is most likely to wear first.

Remember: paper is not incompressible. You'll lose a few thousandths over time. Adjust accordingly.

The Ball
The ball part is perhaps the most difficult part to build. Not also do you need to have the dimensions as close as possible for a tight fit, it needs to be built well and uniform.

First, you'll need a decent support rod to use. 1/8" (3.175 mm) diameter bamboo sticks are a good choice. They're usually $2 for a pack of 100. Pick one with low eccentricity if possible, and look for non-slivering/splintering ones. Those will snap first over time.

Next, you'll need to use the excel sheet for making cylinders. I suggest using 110lb cardstock for the ball, since it's easier to work with and tears less than printer paper. However, printer paper glued together with superglue will provide a nice solid sphere. I like to sand the ball after it's made, so I use 110lb.

Figure 3: Tapering the strip. Note the 5cm allowance before tapering.

To make the spherical shape, you need to taper the strip to a triangular shape. If using the 1/8" rod method, start the taper from 5cm from the starting edge and taper it linearly to 3mm to the other side.

Roll the paper around the rod as tight as possible. Any gaps or loosely bonded sections will result in failure in the rod axial direction, meaning it will start to deform and separate as you push it in the socket.

After you've finished, your sphere will be somewhat octagonal in cross section. Break out those calipers and sand that sphere down to as best as you can to a uniform diameter throughout. Irregularities will result in uneven performance, where certain positions are looser than others. You ideally want the ball to be a few thousandths (0.003-0.010 in) larger than the socket for a nice snug fit.

Adjusting the Fit
Your ball and socket joint may be loose or come loose over time due to thermal expansion, humidity, wear or other factors. You can easily adjust the joint to regain stiffness. Options include:
  1. Adding some additional material to pad out the socket to reduce the inner diameter. I suggest using a small section of paper (printer or 110lb works, depending on the looseness) inserted into the joint
  2. Thickening the ball with superglue. Make sure the ball is dried completely before re-inserting.
If there are any other adjustments or updates, I'll add them as necessary to this page.

Friday, November 27, 2009

Wednesday, November 25, 2009

Nothing Says Thanksgiving Like Killing Tools

It's good to be back into the ranks of obscurity again. This week's completely random and forgettable weapon is the Lovekeeper axe from Drakengard 1 for the Playstation2. I liked the weapon for the flavor behind it:
"A young couple, blessed by fortune, were to be wed. But on the night before
the wedding, a small, shining spirit appeared before the young bride.
The ghost whispered in her ear, speaking straight to the weakness in her heart
: "Do you wish to make him all yours? Do you wish to ensure his heart is yours
for all eternity?"
When the girl recovered her senses, she found this gore-splattered axe in her
hand, and before her, the bloody head of her beloved. "Now he is yours
Even now, the ghost of the young bride can be seen wandering the village,
garbed in a blood-splattered dress and clutching the sightless head of the
man she was to marry."

-Drakengard Weapon History for the Lovekeeper Axe
Pretty messed up stuff. Glad I have a blog post tag for decapitations. Now, onto the weapon!

I've scaled the axe to 1:6 scale, based on the handle width. It's quite unwieldy for a girl, based on the size of it.
Luckily, the blade fit the face of one Magic card. The axe blade was made by laminating two 2-card-thick outer layers with the decorative bits drawn and cut out onto a 4-card-thick stack. The spike was made from a simple cone, used from my cone maker. The axe-head block was made from many laminated layers of Magic cards, making it a solid piece. Unfortunately, I forgot to cover the blade edge with a layer of printer quality paper to hide the rough layers made visible by sanding.

However, the Lovekeeper isn't this week's highlight. The actual piece of interest is a more-popular weapon, the Bloodberry from No More Heroes. First, I present the schematic for the major portions of the Bloodberry.

The detailing for the Bloodberry is sparse, made sparser by scaling it to 1:6. It's personally not a very challenging item to make, since it's mostly revolved objects. If you're going to use this drawing, keep in mind it's scaled according to a game screenshot, and NOT the concept art floating around. The concept art has a shorter overall length.

Right now, unpainted and devoid of the blade, it's a very unexciting model.

The Bloodberry is held together by a bamboo stick running through the hilt. The only issue so far is rolling a 2mm diameter tube for the Bloodberry's extension rod that extends the tip. That was constructed by straightening out a paper clip, then rolling printer paper around the paperclip rod until it reached 2mm in outer diameter.

Here is the painted and completed Bloodberry. For the blade, I had spent a good deal of time looking for a blue drinking straw to use to create the glow effect. Somewhat worked. I had to use a clear drinking straw covered with a layer of 3M Polyester 8992 heat resistant tape. Except mine was blue. Great what you can find at your workplace, eh? Some elements required some thin sections, best remedied by bending and painting paper clips. Strong, and versatile! The paper clips were attached with some Loc-Tite adhesive. The small point of contact made gluing a tricky ordeal.

The project was fairly simple, but the biggest problem was finding the right way to convey the beam without actually having a blue plastic rod. That alone stalled this project a good month.

Maybe tomorrow, I'll find some winged animals to slice in half with my new toys.

Sunday, November 08, 2009

This Weekend's Project: The Ambassador

Still trying to procure parts for another project, but in the meanwhile, here's something that's been on the drafting stage since late August: The Ambassador revolver. With the revolver, I bring forth some additions to the G-43 standard I've been using.

  1. The distance from the trigger to the rear of the stock is 55+/- 1 mm.
  2. The trigger guard is around 10mm long from front to back.
  3. The handle width (in the plane of the barrel hole) is a nominal 5mm wide.
  4. The grip thickness (in the plane of a side profile) is around 7mm to be "wieldable" by a 1:6 scale figure. Larger sizes render the model un-wieldable, and smaller ones necessitate special features from the user's hand (spring loaded fingers) or extra tooling (rounding of the grip) of the handle.
  5. Rifle grip firearm distance from middle of trigger curvature to inner grip shall be 10mm.
  6. Pistol grip firearm distance from middle of trigger curvature to the back of pistol grip (where the web of the hand sits) shall be 12±0.5mm
I haven't made any pistol grip based weapons with the standard, and this will help make things convenient for future endeavors.

I had to re-scale the original draft done in August down by 85% in order to comply with the G-43 standard. The widths depicted on the upper right are still applicable.

Here's some diagrams of the finalized structure, and some idea of how it was assembled. Pretty sure if you're going to make your own, you'll buy a toy revolver, paint it silver and extend the front anyways. Otherwise, the dimensions aren't too relevant for you for this project.

With the size comparison, the revolver is quite massive. It's about 6.5 cm long, making it a monstrous 39 cm long at 1:1 scale.

This piece implements some small components that I was skeptical on successfully implementing. The cylinder swings out and spins. This is made possible by ample Loc-Tite to plastinate the paper and using paper clips to function as axles.

The cylinder is made of seven hollow tubes. Drilling holes into a semi-solid cylinder laminate was not an option. Making pivoting mechanisms using paper clips as an axle requires a bit of knowledge that is easily overlooked: paper clips are rarely round. The smaller ones usually have rectangular cross sections around a 16:19 aspect ratio. This results in a inner cylinder diameter that doesn't fit as tightly around the axle as a cylinder does, and if it does fit tightly, it doesn't spin easily. Also, paper clips are not always uniform in dimensions across multiple brands, so you may need to specially use one supplier source.

I took advantage of the size difference to make cylinders using smaller rods, resulting in a tighter fit when using a slightly larger rod. The bottom of the cylinder arm uses this to prevent it from swinging out freely.

Here's a detail of the individual components. The frame, held together with Loc-Tite, is a bit more sturdy than using regular Elmer's alone. The thin nature of the frame makes it vulnerable to deformation.

Here is the completed Ambassador revolver. Engraving was not a feasible option due to the fine width needed and lack of a solid substrate to implement it on. Printer paper doesn't quite work. The next best thing was to use a 0.30mm art pen and draw lightly. The small size allowed me to approximate the details since it would look quite dark and cluttered if every detail and line was inked in.

Saturday, October 24, 2009

Miscellaneous Artifacts, October 2009

This month's planned projects are on hold due to development and procurement issues. Meanwhile, I took care of some local gift requests. Sometimes, it helps to do something different in order to get some insights on your current and future projects.

This week's artifacts includes a rose. I opted to try to take advantage of the colors of the card itself than paint. Luckily, Magic cards have art that usually fits the color of the card frame. In this case, we have a lot of Rock Jockeys and Enslaved Dwarves. I was contemplating making the sepals green on both sides, but it still worked out fine. The rose was fun to build, and a good simple hour's worth of work. Loc-tite made gluing and assembling the petals faster, as the curvature worked against me during construction.

The other artifact of interest is a rough model of a Spanish galleon. My third ever boat. My first was made out of school handbooks and masking tape. My second was a blocky destroyer made from 110 lb cardstock and lots of geometry. I've learned a bit from those attempts, but still need some more knowledge on shipbuilding. I opted to use the natural brown of the card backings to color the hull, but coloring other sections proved to be not as fun. I ended up making as much of the card as brown as possible rather than have a prismatic ship.

I didn't add any rigging, since I'd have to plan out all the mounting locations and glue lots of thread down. The deck's quite bare, since most of the time was spent on hull construction. I added some cannons to make the hull less bland.

For the ship, I gave in and started to use land cards. There were a lot of played land cards that just had to go. I also wanted to get some white color for the sails and plains were the best alternative. I figure land art is better to look at than a zombie gnawing on a guy. There's a couple Italian Mirage forests here and there.

Sunday, October 11, 2009

Would You Like A Second Opinion? You Are Also Ugly!

Sometimes, you get unexpected things that make you laugh. Sometimes, you get this while eating gummy bears:

Figure 1: Regular healthy gummy bear on the left, and what appears to be a cancerous blob on the right.

I brought the specimen to the resident doctor and game warden. Hopefully, they can shed some light on the mysterious specimen. By the time I transported the specimen, I had found that there were some other abnormal bears being analyzed at the sample room.

The red bear on the left was likely formed prematurely. The one on the right lost a limb and had lots of red discoloration on the region. None of them seemed to interact with the green blob.

Medic: I haf never seen anyzing like zat in my life.
Sniper: I wonder if it's hostile to humans. Mind if I take a closer look?

Sniper: It's quite squishy, mate. I can't tell which side is the head. Or what it's supposed to be. Is Norad sure that this originally was supposed to be a gummy bear?

The specimen was agitated and grew hostile. Defensive action was needed.

I think I'm looking at its bum...

You can tell by the subtle shifting of mass towards the Sniper that the blob was acting aggressive. There was no other means of subduing the organism peacefully. The Sniper took aim and put it down. After that, it was dissected and sacrificed for a few bits of health.

I'll be back to normal posts once I procure the proper materials needed for this week's project.

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.

Friday, September 25, 2009

J.Norad's Random Sewing Technique

A quick technique I came across in a sewing book for tying off thread ends. Most of you might find this useful if you're learning to sew and are sick of making knots to tie off your thread.

First, you need to thread your needle through an existing stitch where you want to put the knot at.
Follow the needle paths as depicted in the image

After you thread that through the last loop, just pull the needle out and the loops will close in and form a knot.

Whee. Precise knots where you want them!