https://www.appropedia.org/Open-Source_Grinding_Machine_for_Compression_Screw_Manufacturing
Design Files: https://osf.io/ev6ta/
We build our own!
Status: build in progress
Changes to original design:
- Wood thickness: 12.2mm
- Conduit_OD: 20mm (we use stainless steel rods)
- Threaded rod for linear motion:
- M10 instead of 3/8"-16
- pulleys need to be adjusted due to different pitch (see below)
- 6mm GT2 belt (instead of 8mm), easier to source (not printed)
Github repository with adapted design: https://github.com/ProjectFabMX/ExtruderScrewGrinder
Materials
| Item | Amount | Who takes care? | Status | Purpose | Comment |
|---|---|---|---|---|---|
| Wooden pieces | Blue0cean | done | |||
| 3D printed PLA pieces | In Progress | ||||
| Belt GT2 2mm, 225 teeth, 6mm width | 1 | Andreas Kahler | arrived | belt to connect threaded rod and chuck pulleys | |
| Steel rods 20mm | 140cm | arrived | Rails for the X and Y sliders to move on | ||
| Fastener: M8 x 30mm hex head bolt | 28 | arrived | Axle and secures M8 Bearings | ||
| Fastener: M8 Nylon Insert Locknut | 28 | arrived | Secures M8 Bearings | ||
| Fastener: M7 x 16mm Hex head bolt | 8 | arrived | Mounting the flange bearings | ||
| Fastener: M7 Hex nut | 8 | arrived | Mounting the flange bearings | ||
| Fastener: M3 x 12mm | 36 | arrived | Fasten 3D-Printed parts | ||
| Fastener: M3 Hex Nut | 36 | arrived | Fasten 3D-Printed parts | ||
| Fastener: 5/16"-18 x 1-1/4" Grade 5 hex head bolt ??? | 1 | Mounting angle grinder (dependent on angle grinder used) | Need to decide on angle grinder | ||
| Linear Motion: M10 threaded rod | 100cm | arrived | Moves X-slider for right-hand thread compression screws | ||
| Linear Motion: M10 nuts | 9 | arrived | Moves X-slider for right-hand hex nu compression screws | ||
| --- | Moves X-slider for left-hand thread compression screws | ignore for now (only do right handed crews) | |||
| --- | Moves X-slider for left-hand thread compression screws | ignore for now (only do right handed crews) | |||
| Hardware: 10mm Self Aligning Pillow Block Flange Bearing | 4 | Andreas Kahler | arrived | Secures threaded rod and chuck | https://www.amazon.de/dp/B073L2LWN4/ |
| Hardware: 3-16mm Drill Chuck with SDS-Plus Shank | 1 | Blue0cean | in progress | Holds the stock material being machined | |
| Hardware: 608 ZZ Bearings | 24 | arrived | Linear motion, stock support | https://www.amazon.de//dp/B07RZ651J7/ | |
| Fastener: Flat Head Wood screws 3x20mm | 36 | arrived | Secure individual pieces of plywood together | ||
| Fastener: Flat Head Wood screws 3x25mm | 4 | arrived | Secures the plywood sub-assemblies | ||
| Angle Grinder | 1 | arrived | see below |
Calculation of teeth count
- Extruder screw pitch: 8mm
- Threaded rod pitch: 1.5mm (M10)
- Gear ratio: 8/1.5 = 16/3 = 144/27
- Chuck pulley: 144 teeth
- Threaded rod pulley: 27 teeth
Angle Grinder
The original design uses this 4-1/2" battery-powered angle grinder: https://www.milwaukeetool.com/Products/Power-Tools/Metalworking/Grinders/2680-20
The metric equivalent is a 115mm angle grinder
We decided to use this one: Bosch GWS 18 V-LI
Grinding Wheels
The paper recommends "Type 27 Ceramic 4-1/2", 1/4" thickness" grinding wheels:
- Type 27: these are not flat, but have a raised hub
- Ceramic: ceramic cutting material, e.g. aluminum oxide
- 4-1/2": 115mm diameter
- 1/4" thickness: 6.25mm
These discs may be suitable:
| Type | Buy | for which materials |
|---|---|---|
| Metabo FLEXIAMANT SUPER 115X6,0X22,23 INOX, SF 27 | Metabo Shop No. 616739000 | steel, stainless steel |
| Metabo FLEXIAMANT SUPER 115X6,0X22,23 STAHL, SF 27 | Metabo Shop No. 616275000 | steel |
