Instructables
Picture of Bike Crank Removal Tool
This Instructable will show you how to build/ machine your own bike crank removal tool from SCRATCH and for under 3.00 $!!

I know that Park Tool has their own crank removal tool but, WHAT IF you want to make your own??
 
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Step 1: Materials & Tools

Picture of Materials & Tools
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Materials
•1.375 inch x 1" Dia   6061 aluminum solid round 
•.125 inch x .5 Dia      1045 mild steel solid round
•2 inch x 5/16 - 18       Grade 8 bolt

Tools
•Metal lathe (thread cutting ability)
•Metal files
•Hacksaw
•Round End mill - (5/8)

Step 2: Machining!

Picture of Machining!
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•Cut your 1.375 inch long by 1" Dia of 6061 aluminum with a hacksaw or horizontal bandsaw.

•Place the stock Al in the lathe and face off both sides of the piece with a facing tool.

•Turn down .75 inches to .8661 (22mm)

•Drill and tap a 5/16 x 18 inch hole .5-.75 inches from "necked down" end.

•Cut "wrenching" flats



Step 3: Threading!

Picture of Threading!
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•Make sure you present a 60º single point cutter perpendicular to the work piece!!  Also make sure the tool is on center height.

•Set up your machine for 1mm threads.  The Major diameter is 22mm or .8661 inches.  Thread for about .375-.5 inches .

Step 4: Filing!

Picture of Filing!
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•Use a hacksaw and square or rectangle files to make the wrenching flats.  OR you could use an end mill in a milling machine!

Step 5: Machining the Plug

Picture of Machining the Plug
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•Since this plug piece is what the screw must push against (so that you don't wreck your BB threads) it must be make out of a high carbon steel so that it won't deform or "mushroom" under pressure. 

•It needs to be .5" x .125" with a "dish" cut using a ball end mill. 
notingkool1 year ago
Nice work. I also made a couple ones. I remember that my first one, had a M22x1 thread, and i doens't fit into the crank, the i made anotherone, but making a 21,6x1 thread,
Also, why did you use aluminum for the body? and why a 5/16 screw?
Most of comecial pullers are made with steel and use a 10mm screw.
sw.machinist (author)  notingkool7 months ago

The reason I used aluminum was because there are plenty of complete threads on the puller that engage with the crank threads, so steel is unnecessarily strong. Plus aluminum is easier to work with for prototyping - it's softer than steel, but plenty strong enough.

The screw size (5/16-18) was because I'm in the USA and I deal mostly with standard SAE. And course threads are less likely to strip out.

Yeah, aluminum it's quite easy to work. If it's an aluminum alloy like 7075 it will work. When i made my owns crank pullers i use steel just because i need it for steel cranks (i made it for me and a friend who is a bicycle mechanic in a bike shop). What i realize is that the screw must have a fine thread, because you need less torque to extract the crank.
Maybe a 24tpi screw will work better for your tool ( I use a 3/8"x24tpi screw once and work like the M10x1)

This is so cool! Thank you for sharing this.