instructables Ratchet Screwdriver User manual

Brand: instructables

Model: Ratchet Screwdriver

Category: 3D printers

Type: User manual

The instructables Ratchet Screwdriver is a unique tool that utilizes an overrunning clutch mechanism instead of a traditional ratchet. This allows for smooth and efficient operation, as the clutch engages when turning clockwise but allows the screwdriver to rotate freely when turning counterclockwise. The screwdriver is highly customizable, with adjustable parameters such as shaft diameter, stopper diameter, and stopper spacer, enabling you to tailor it to your specific needs.

instructables

Ratchet Screwdriver Without Ratchet With Overrunning Clutch

by ukman

Ratchet is a mechanism that permits the tool to apply turning force only in one direction while moving freely in the

opposite. There is another mechanism that does the same- overrunning clutch. I created a 3D-printed version of the

clutch and integrated it with a screwdriver.

Overrunning clutch does not require strong small parts so it's possible to create it on a 3D printer furthermore, it does

not crack, unlike ratchet.

The main idea of the clutch is to wedge a shaft in one direction and release it in another by metal cylinders placed into

special slots. It is widely used on bicycles.

Supplies:

You can use dierent parts that can be found in your workshop: hex bits, a tube, nails, screws, washers, and nuts. Also,

you need to print some parts on your 3d printer.

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Step 1: Prepare Wedging Cylinders From Nails

Overrunning clutch is a bearing with cylinders so you can use any metal cylinder. I made it from nails.

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Step 2: Prepare STL Files and Plastic Parts

All parts for the screwdriver are in the Fusion360 model le attached to the post. Download the le and open it in

Fusion360. There are 4 bodies for each part.

This is one of the most important steps. You have to nd the best dimensions of the overrunning clutch for your tube and

nails. The clutch, the tube, and the nails have to work together as a single mechanism. That is why I would recommend

printing 5-10 small cases of the clutch with dierent parameters and testing which one is the best for your purposes.

There are 6 main parameters in the Fusion360 model for tests:

1. Shaft DiameterShaft Diameter - the tube diameter

2. Stopper DiameterStopper Diameter- the nail diameter

3. Stopper SpacerStopper Spacer- the space between the released and blocked position in the stopper slots. It denes the

tightness rotation of the tube in the clutch.

4. Stopper HeightStopper Height- the height of the clutch, for the tests you can print a 20 mm version to save plastic.

5. Shaft Inner DiameterShaft Inner Diameter - it is used for printing screwdriver shank xer

6. Screw Shank DiameterScrew Shank Diameter - it is used for printing screwdriver shank xer

Measure the dimensions of your parts and play with these parameters in +- 0.1, 0.2, 0.3 mm. I printed at least 10 cases of

the clutch and tested how they work. Try how they work in both directions (blocking and releasing). After that print the

"big" version of the clutch 40-100 mm in height.

In order to change parameters open the model in Fusion360, menu

Modify

Change Parameters

. After that make

overrunning clutch visible in browser view and export STL les in menu

File

Export

STL Files (*.stl)

When the best params are found, ll the following params

Press Washer Diameter - diameter of washers that are used as press bearing (see following)

Press Washer Height

You can play with the rest parameters, and watch what is changed on the 3D view after editing parameters.

When you nd the best parameters for the clutch select the

Cover1

Cove2

ShankFixer

in Fusion360 browser and export

them. As a result, you have STL les to be printed. I use PLA plastic and 1.2 - 3mm for walls, top, and bottom in CURA.

At the end of the step, you have the following 3D printed parts

1. Overrunning clutch

2. Top/Bottom Covers

3. Shank Fixer 2 pieces

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Step 3: Prepare the Tube

https://www.instructables.com/ORIG/FTK/HKPK/L6RWTTVP/FTKHKPKL6RWTTVP.f3d

Download

The tube is a rotating part of the clutch. I would recommend using a steel tube 10-20 mm in diameter (diameter must be

bigger than shank diameter) and 1.5 - 3 mm in thickness. The surface of the tube should be a little bit rough, so use sand

if it's polished.

The tube is used to rotate a screw shank that is why you need to put a special 3D printed xer into the tube with some

glue.

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Step 4: Prepare Clutch Covers

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Step 5: Assembly

Use M3-M5 screws with nuts to assemble the clutch with the covers and place a screw shank into the clutch. Sometimes

you need to use a special 3D printed plastic spacer for keeping the shank on one side of the clutch.

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Step 6: Test

The screwdriver works pretty well without any noise. I did not expect it but I do really like this cool tool.

https://youtu.be/OxrA5HIZR_U

Ratchet Screwdriver Without Ratchet With Overrunning Clutch: Page 19

instructables Ratchet Screwdriver User manual

Brand: instructables

Model: Ratchet Screwdriver

Category: 3D printers

Type: User manual

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instructables Ratchet Screwdriver User manual

instructables Ratchet Screwdriver User manual

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