# How hard would it be to forge a d20? **URL:** \ **Category:** Factual Questions\ **Created:** [December 15, 2015, 1:45pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528 "2015-12-15T13:45:31Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [December 15, 2015, 1:45pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/1 "2015-12-15T13:45:31Z")
I sometimes do blacksmithing with a couple of my friends. Since we also play D&D together, I think it would be awesome if we could make our own D20s out of steel. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [December 15, 2015, 1:50pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/2 "2015-12-15T13:50:31Z")
[You mean like this guy?](https://www.youtube.com/watch?v=7-rkPI_6DqU) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 15, 2015, 2:09pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/3 "2015-12-15T14:09:10Z")
How precise can you be? With a modern milling machine, homogenous modern materials, good micrometers, and enough patience getting a statistically reliable die would be doable. With some homebrew wrought iron, an anvil, a hammer, and a Mark-1 eyeball you’re going to make an awesomely loaded die. Each subsequent whack will give it a new and exciting probability distribution. Hey, there’s an idea … Keep it hot while in use. After each roll, each player gives it a whack on a random side with their hammer to alter the probability distro for the next roll. Statistically this fails for the same reason that randomly selecting a random number generator algorithm fails. But at least it becomes a lot more unpredictable so one can’t base their game play on knowledge of the die’s bias. Yes, I’m kidding. But it would be a fun experiment. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 15, 2015, 2:12pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/4 "2015-12-15T14:12:12Z")
Alternately: Can plaster of paris withstand molten steel? If so, you could use a lost wax method. Either sculpt a die out of wax or 3D print one, encase it in plaster to make a mold, melt the wax out, pour molten metal in. ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [December 15, 2015, 2:28pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/5 "2015-12-15T14:28:05Z")
There’s also sandcasting, or various techniques that combine sandcasting with investment casting. Alternatively, casting aluminum is a lot easier for the hobbyist since you don’t need to invest in expensive crucibles and furnaces capable of melting steel. Aluminum is also more suitable for easier and more precise DIY lost wax casting. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [December 15, 2015, 2:31pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/6 "2015-12-15T14:31:06Z")
> [@LSLGuy](#): > > With some homebrew wrought iron, an anvil, a hammer, and a Mark-1 eyeball you’re going to make an awesomely loaded die. Make six of them loaded in different ways. Pull one out of a bag at random and roll for each roll you want to make. We’re talking about d and d here, true randomness isn’t needed. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [December 15, 2015, 2:43pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/7 "2015-12-15T14:43:08Z")
> [@lazybratsche](#): > > There’s also sandcasting, or various techniques that combine sandcasting with investment casting. > > Alternatively, casting aluminum is a lot easier for the hobbyist since you don’t need to invest in expensive crucibles and furnaces capable of melting steel. Aluminum is also more suitable for easier and more precise DIY lost wax casting. I’d imagine that the hardest thing would be to get the thing exact enough to not be loaded; a combination of investment casting along with some sort of balancing apparatus and a grinding wheel could probably let you get there with a minimum of effort. I’m imagining you’d cast your die, balance it by grinding it in specified spots to get it even, then probably tumble it in some sort of rock tumbler to even out the surface finish. I’d think the easiest and most accurate way though, would be to use some sort of CNC mill (5 axis?) and CAD model of the die. Not exactly blacksmithing, but what you’d need to actually have a decent d20. I’d think you could probably pound out a passable d6 with an anvil, hammer and grinder though. ---
**Author:** ![sweeteviljesus](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@sweeteviljesus](https://boards.straightdope.com/u/sweeteviljesus)\ **Post date:** [December 15, 2015, 3:41pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/8 "2015-12-15T15:41:44Z")
> [@](#): > > The most common sound in an 18th century gunsmith’s shop was the sound of filing. From the Gunsmith of Williamsburg. I suspect that the file and infinite patience will be your friend. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 15, 2015, 4:02pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/9 "2015-12-15T16:02:13Z")
The OP will have to tell us what he means by “blacksmithing”. 16th century blacksmithing, 18th century gunsmithing, and 20th (or 21st) century metalworking are three very different beasts. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [December 15, 2015, 4:53pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/10 "2015-12-15T16:53:15Z")
For some reason, I interpreted “forging” a bit differently when reading the thread title, and wondered why on earth you would want to make a counterfeit d20 die. ("I fail to understand why I should care to induce my mother to purchase falsified patents. ") ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 15, 2015, 5:03pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/11 "2015-12-15T17:03:41Z")
> [@](#): > > Quoth **bump** : > > I’m imagining you’d cast your die, balance it by grinding it in specified spots to get it even, then probably tumble it in some sort of rock tumbler to even out the surface finish. And then you’d have to re-grind it to balance out the imbalances introduced by tumbling. The tumbled die is probably worse than the original fresh from the cast. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [December 15, 2015, 5:21pm UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/12 "2015-12-15T17:21:02Z")
> [@Chronos](#): > > Alternately: Can plaster of paris withstand molten steel? If so, you could use a lost wax method. Either sculpt a die out of wax or 3D print one, encase it in plaster to make a mold, melt the wax out, pour molten metal in. You can 3D print in steel. [http://www.shapeways.com/materials/steel](http://www.shapeways.com/materials/steel) ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [December 16, 2015, 2:55am UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/13 "2015-12-16T02:55:29Z")
> [@Chronos](#): > > And then you’d have to re-grind it to balance out the imbalances introduced by tumbling. The tumbled die is probably worse than the original fresh from the cast. Really? I figured that a fine enough media would pretty much polish the entire thing evenly. ---
**Author:** ![Scumpup](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@Scumpup](https://boards.straightdope.com/u/Scumpup)\ **Post date:** [December 16, 2015, 3:03am UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/14 "2015-12-16T03:03:10Z")
Paint a plastic one silver. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [December 16, 2015, 4:19am UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/15 "2015-12-16T04:19:36Z")
Try casting. You can try your hand at casting brass. You could then cast a brass mould for a cast iron object. slow speed casting creates a rough surface, basically a blank you’d need to polish up … a lot… the bias , the loading… Drop casting refers to the idea of slamming a slug of molten iron into the mould, so that the hole in the mould can be smaller, and the surface sets solid with a smooth surface. You aren’t worried about the poor mechanical properties (brittle) of a drop cast , cast iron object… Just don’t throw it from the 10th floor to the footpath below. ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [December 16, 2015, 5:17am UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/16 "2015-12-16T05:17:55Z")
> [@puzzlegal](#): > > You can 3D print in steel. > > [http://www.shapeways.com/materials/steel](http://www.shapeways.com/materials/steel) Castable wax, too, from the same site. It’s really not that difficult an art to get into, either, with the right tools and a little practice—I’ve certainly [had a lot of fun with it](https://www.shapeways.com/product/pricing/7KA4R5YRU). ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 16, 2015, 8:01am UTC](https://boards.straightdope.com/t/how-hard-would-it-be-to-forge-a-d20/740528/17 "2015-12-16T08:01:21Z")
> [@Chronos](#): > > Alternately: Can plaster of paris withstand molten steel? If so, you could use a lost wax method. Either sculpt a die out of wax or 3D print one, encase it in plaster to make a mold, melt the wax out, pour molten metal in. I don’t think plaster will withstand the heat of molten steel or even aluminium. You could cast it in pewter using the lost wax method though. Pewter is quite a soft metal when rolled into thin sheets, but when cast into solid objects, it’s quite a lot harder and tougher. Difficult to make (and keep) it totally fair, but it would be an impressively heavy die to roll.