Ravitz Chess

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Notes | Stacking Chess Pieces

New | Weighted | Resin | FDM | Old Files | Storage Tube


Notes

This page is for distribution of my chess pieces via 3D print file (STL). The files are free for printing for personal use.

contact - caryravitz_at_gmail.com (replace _at_ with @)

www.ravitz.us

Last modified 5:02 PM, 12 Apr 2024 - File size 15K - Count 5077
 
 

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Stacking / Nesting Chess Pieces

These chess pieces were designed by Cary Ravitz, 2021, 2022. The pieces stack in any order. Stacking on top of the king or queen takes extra space.

I am currently publishing only STL 3D print files (generated by OpenSCAD from a SCAD file). There are designs optimized for resin printers and FDM (thermoplastic filament) printers. No supports are needed - horizontal overhangs max .5mm, angled overhangs minimum of 45 degrees, no bridges. The ZIP files include STL files with just the models and the models with my rafts.

Since I took these photos, I have revised the pieces a bit.

stacking chess pieces stacking chess pieces stacking chess pieces

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New

stacking chess pieces

resin, small - 2024-04-11

resin, large - 2024-04-11

resin, weighted - 2024-04-11

FDM, small - 2024-04-11

FDM, large - 2024-04-11

FDM, weighted - 2024-04-11

2024-04-11 - Tweaks to improve printing.

2024-04-08 - The knight nose is slightly narrower at the front to accomodate possible future changes. I removed the two piece models - the weighted models work well instead.

2024-04-03 - I changed the screw threads on the weighted pieces to improve the appearance. Unfortunately you cannot mix old and new tops and bottoms.

This update is to introduce FDM weighting and revised resin weighting. The only cost effective weighting concept that I can find is cavities that hold lead shot. Specifically, use #7.5 shot (slightly under 2.5 mm), I prefer copper plated. Tungsten shot is a lot heavier, but very expensive. Print the base and the top of each piece, fill the cavities, staying below the threads, then screw on the top. Some of the shot will be a bit oversized but will fit into the cavity at the notch in the threads. I suggest doing this in a bowl to catch stray shot.

The weight cavities are nominally 3 mm wide so #6 shot fits. But in my experience, the #7.5 shot is easier to work with and gives the same weight. Smaller might be better but I have not been able any.

All of the large bases are 1 mm larger diameter to match the new weighted bases, but identical heights, and the pieces are still stacking compatible with the old pieces.

I removed the separate king's crosses. The weighted pieces are shorter than before because they do not include the base. So there is less need for the complexity of the separate crosses.

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Weighted Resin Pieces (3.75 inch king)

stacking chess pieces

resin, large, weighted - 2024-03-10, includes shortpawn, separate cross

The Pieces

You need to print a cap for each piece. This screws into the base to contain the weights. It can be hard to unscrew once it is tightened, so don't tighten it until the weights are in place.

You can choose to print the king's cross as a separate piece that screws in. This takes about 15% off the height which is a significant amount of printing time. The model has six crosses, each with a different screw angle (5 degree steps). Choose the one that gives the best alignment.

The short pawn is the same height as the regular pawn but the base is 3.3mm thinner. This makes a 16 piece stack almost an inch shorter. It has slightly thinner walls and less nominal clearance from piece to piece when stacked. I have not had any printing or stacking problems with this. The weight cavities lose 3.3mm height, 9 mm length rod or likely one less shot.

The model is oversize by 0.9% to account for cure shrinkage.

The four point star cutouts and holes at the bottom of the weight cavities are there to drain uncured resin and allow alchohol to flow through the interior.

I use Uniformation plant based white and black, and Siraya Tenacious clear. White pieces - 75% white, 5% black, 20% clear. Black pieces - 5% white, 75% black, 20% clear. I think that the resulting light gray and dark gray shows the pieces better than black and white. (The black pieces could use more white than I noted here - maybe 10%?)

The Weights

You have to print a cap for each piece, fill the cavities, and screw on the cap.

The weights are implemented with weight cavities in a band around the base. You will have to fill the cavities. They take 30 steel dowel pins 3mm x 12mm (look for M3 dowel pin on ebay), which is .7 ounce per piece. You need 960 to completely fill a 32 piece set. Compare prices carefully on the dowel pins. I have found them as low as $50 for 1000 on ebay. The short pawns have a reduced cavity, by 3.3 mm, 9 mm rods should work.

Or they can take #6 spherical shot. Ballistic Products has SpheroTungsten Original-15, .73 ounce per piece, $85 for 2 pounds. And SpheroTungsten Super Max-18, .87 ounce, $107 for 2 pounds.

I have used Lawrence #6 copper plated lead shot, .55 ounce per piece, $60 for 10 pounds on Amazon. I won't use unplated lead because I don't want to handle it.

You could also cut your own 3mm x 12mm rods of brass or steel. BUT that's 960 pieces. Even 10 at a time in a chop saw would be 96 cuts. And you need burr free pieces, which I could not get from brass (I haven't tried steel).

The Rafts

My rafts were developed to be easy to remove by hand (with glove). This reduces the uncured resin that gets into the wash.

I use a flex plate. The rafts come off easily by hand when the plate is flexed. I remove the rafts, use a prewash bucket of alcohol, and wipe the excess resin by hand. Then on to the automatic alcohol wash.

For the cross, leave the raft on until curing so that it doesn't fall through the washing basket.

full size full size

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Resin Pieces (3.75, 2.25 inch king)

full size

resin, large - 2024-03-10, includes shortpawn, includes separate cross

resin, large, separate base - 2024-03-10, includes shortpawn, includes separate cross

resin, small - 2024-03-10

full size full size

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FDM Pieces (3.75, 2.25 inch king)

stacking chess pieces

fdm, large - 2024-03-24, includes shortpawn

fdm, large, separate base - 2024-03-24, includes shortpawn

fdm, small - 2024-03-24

I find working with resin to be a very unpleasant job. It stinks, it's hard to clean up, it requires protective equipment, nasty chemicals, and when you finally have good models, it's not clear how long they will last due to UV aging. So I modified the design to aim at FDM printers. FDM cannot handle the detail needed for the weights or screw threads. The drain hole stars are repurposed to hide seams.

The small models do not fit the old small storage tube. 1 inch inner diameter is needed.

The separate base models lets a you print black and white tops and combine them with metal filled plastic (heavy) or different color bases. Depending on the overprint, the fit might be tight or it might need a bit of glue. I have not tried the metal filled filament - watch out for metal content and density, and get an appropriate nozzle.

Setup (mostly default) -
Creality Ender 3 V3 KE
.4 mm nozzle
Hyper PLA (that's Creality's high speed PLA)
.2 mm layers. .3 mm first layer
no brim, no supports
15 perimeters, that gives 100% solid with no "infill"
seam position aligned
perimeter generator classic
perimeters 100 mm/s (so I can use high speed or regular PLA)
small perimeters 100 mm/s
nozzle 205, build plate first layer 65, other layers 62
no raft

A knight takes 34 minutes to print. The result is not bad. The pieces stack nicely and look decent - much better than my old Lulzbot Mini. It appears that FDM printers have improved quite a bit since my first printer.

stacking chess pieces

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Old Files

weighted, with raft
weighted
large, with raft
large
small, with raft
small
resin, large, weighted - 2024-02
resin, large - 2024-02
resin, large, separate base - 2024-02
resin, small - 2024-02
fdm, large - 2024-02
fdm, large, separate base - 2024-02
fdm, small - 2024-02
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Storage Tube

endcaps

endcap for tube outer diameters 1.125 inch, zip file
endcap for tube outer diameters 1.250 inch, zip file
endcap for tube outer diameters 1.600 inch, zip file
endcap for tube outer diameters 1.700 inch, zip file
endcap for tube outer diameters 1.750 inch, zip file

These are designed for FDM printers and do not need any support or rafts. The extra cuts in the threads let the slicer minimize seams - this is important to make the caps work well.

Inner diameters are 1 inch for the small models and 1.5 for the larger models. You can scale in the slicer to accommodate variations in tube outer diameter.

The latest models include four glue insertion spots at the bottom of the tube piece, for liquid glue. There is a band at other end that ensures that the contact point with the tube is completely on the tube even if the top is cut slightly off square. It also limits liquid glue wicking. Slide the pieces onto the tube, square them by ensuring that the tube stands vertically, then apply the liquid glue.

When storing the chess pieces, stack them with a bishop on top of the king and a pawn on top of that bishop - this minimizes the total stack height.

There are four cap lengths with extra length 0, .25, .5, .75 inch. For a 12 inch tube, large or weighted pieces, short pawn, use the .25 longer cap (cap1). For a 12 inch tube, large or weighted pieces, regular pawn, use the .75 longer cap (cap3).

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