instructables Ratchet Screwdriver Without Ratchet With Overrunning Clutch Instruction Manual
- June 4, 2024
- instructables
Table of Contents
Instructables Ratchet Screwdriver Without Ratchet With Overrunning Clutch
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 different 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.
Preparing
Prepare Wedging Cylinders From Nails
Overrunning clutch is a bearing with cylinders so you can use any metal
cylinder. I made it from nails.
Prepare STL Files and Plastic Parts
All parts for the screwdriver are in the Fusion360 model file attached to the
post. Download the file and open it in Fusion360. There are 4 bodies for each
part.
This is one of the most important steps. You have to find 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 different parameters
and testing which one is the best for your purposes.
There are 6 main parameters in the Fusion360 model for tests:
-
1. Shaft Diameter- the tube diameter - Stopper Diameter- the nail diameter
- Stopper Spacer- the space between the released and blocked position in the stopper slots. It defines the tightness rotation of the tube in the clutch.
- Stopper Height- the height of the clutch, for the tests you can print a 20 mm version to save plastic.
- Shaft Inner Diameter- it is used for printing screwdriver shank fixer
- Screw Shank Diameter- it is used for printing screwdriver shank fixer
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 Modity-> Change Parameters. After that make overrunning clutch visible in browser view and export STL files in menu File-> Eport-> STl Files (“st)
When the best params are found, fill 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 find the best parameters for the clutch select the Cover1, Cove2,
ShankFixer in Fusion360 browser and export them. As a result, you have STL
files 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
- Overrunning clutch
- Top/Bottom Covers
- Shank Fixer 2 pieces
https://www.instructables.com/ORIG/FTK/HKPK/L6RWTTVP/FTKHKPKL6RWTTVP.f3d
Prepare the Tube
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 fixer into the tube with some glue.
Prepare Clutch Covers
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
.
Test
The screwdriver works pretty well without any noise. I did not expect it but I do really like this cool tool.
References
- Yours for the making - Instructables
- Ukman's Activity - Instructables
- Ratchet Screwdriver Without Ratchet With Overrunning Clutch : 6 Steps (with Pictures) - Instructables
- content.instructables.com/ORIG/FTK/HKPK/L6RWTTVP/FTKHKPKL6RWTTVP.f3d
- instructables.com/ORIG/FTK/HKPK/L6RWTTVP/FTKHKPKL6RWTTVP.f3d
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