Intro: Chainsaw Blender
Make the most extreme margaritas, daiquiris, and other blended drinks with a gasoline powered chainsaw blender. No one will question your mixology authority with this 37cc two-stroke chainsaw engine, all controlled with real motorcycle handlebars, throttle, and kill switch.
I decided to keep the chain bar and replace the sharp chain teeth with a smooth bicycle chain, even up close you can't really tell the difference. This dangerous blender is sure to delight and excite your party guests.
Ready to terrify the neighborhood? Let's make!
Step 1: Supplies
This Frankenstein's creation mashes up a chainsaw, a blender, and motorcycle throttle assembly. This will work with just about any standard blender, so if you have an old one lying around this would make a fun reuse for it.
Here's the materials I used to make my chainsaw blender:
- 37cc 2-stroke chainsaw
- inexpensive blender
- motorbike handlebars
- motorcycle throttle grip
- motorcycle throttle cable
- left-handed threaded hex nut
- silver bicycle chain
Coincidentally, both blenders and chainsaws have a clockwise spinning rotation and both motor shafts are left-hand threaded (the opposite of typical threading). The interface between the chainsaw and blender was surprisingly painless, but did require an uncommon left-handed threaded nut.
Step 2: Disassemble Chainsaw - Chain Cover
Chainsaws have a removable cover to gain access to the chain blade, this is typically a few bolts in a conspicuous location.
Using a wrench I removed the chain cover screws and then removed the chain cover, revealing the clutch assembly.
Step 3: Disassemble Chainsaw - Chain and Arm Removal
The chain is held taught by a tightening screw near the chain arm. Unscrewing the chain tension screw releases the chain from the arm allowing it to be removed. The chain arm can also be removed.
Step 4: Disassemble Chainsaw
The chainsaw may have a few other covers and support sections that may be taken off to allow greater access to the motor.
To make the attachment to the blender the chainsaw clutch needs to be removed. The clutch is the spring loaded cylinder that uses centrifugal force to overcome the tension of the springs and engage the outer edge of the cylinder which in turn will turn the chain blade; this allows the chainsaw engine to run without moving the chainsaw blade, only spinning the chain when the engine is revved.
I considered using the chainsaw clutch as part of my blender, but found it was much easier to remove the clutch and interface to the chainsaw motor shaft directly. Removing the clutch allows greater access and and easier interface, but also means that the blender will start spinning immediately the chainsaw engine starts.
Step 5: Clutch Removal - Locate Piston
Removing the clutch from the chainsaw isn't difficult, but does require a few setup steps.
The clutch is screwed to the chainsaw motor shaft and can be unscrewed, however since rotating the clutch also spins the motor shaft we'll need to stop the motor from moving. The easiest way to do this is by arresting the engine piston, which will stop the engine shaft from spinning.
The easiest way to gain access to the piston without taking the entire engine apart is through the spark plug. The spark plug for this chainsaw was located under the air filter cover. Find and unplug the spark plug cap and gently unscrew the spark plug, use care when removing spark plugs as the porcelain insulator of the spark plug is fragile and can shatter if knocked or torqued too tight.
Once the spark plug is removed you can peer inside the opening and see the engine piston. Grab the clutch and rotate, you should be able to see the piston rise and fall (it's dark in there, so make sure you've got a flashlight). Rotate the clutch until the piston is all the way at the bottom.
Step 6: Clutch Removal - Arrest Piston
To stop the piston from moving up and down we'll fill the piston chamber with synthetic rope which will be fed through the spark plug opening. When the piston chamber is filled, the piston will compress the rope and be unable to reach the apex of the stroke, arresting the piston and allowing the clutch to be unscrewed from the engine shaft.
It's best to use a clean and smooth rope, thin enough to be inserted through the opening of the spark plug. Depending on the bore of the piston, the model of your chainsaw, and the diameter of the rope you're using, you're going to need between 5-8 feet of rope.
Insert the rope into the piston chamber and continue stuffing until no more rope will fit. I used a pencil to help the rope along when it started to get full to help compact the rope and get more inside.
Step 7: Clutch Removal - Unscrew
Rotate the clutch clockwise until you feel it stop. The clutch is now ready to be unscrewed from the engine shaft. Clutches vary depending on manufacturer, typically they have two or three shoes that push against the outer cylinder, but all look generally the same and are removed the same way.
You can buy a generic clutch holding tool, which can be used to fit most applications. Luckily this tool doesn't have to be very precise, as it's only function is to grip against the unusual shape of the clutch. You can probably get away with appropriating another tool to achieve the same effect, or you can weld together some ugly creation like I did.
To make my own clutch holding tool I welded 3 beefy machine screws to a small section of steel rod, then welded on a 1/2 nut on the back of the steel rob which allowed a ratchet to be attached, giving enough leverage to unscrew the clutch.
The engine shaft is threaded left-handed, reverse of what's typical for most applications. Remember to unscrew the clutch by going clockwise, this is because the engine spins clockwise, which tightens the clutch when spinning.
Step 8: Disassembled Chainsaw
The clutch is unscrewed clockwise and removed. Remove any other components or accessories attached to the clutch assembly so that just the engine shaft is left exposed.
Step 9: Disassemble Blender
The components we needs from the blender are the toothed cap attached to the blender base that spins the blades in the jug, and the top of the base that holds the blender jug. The toothed cap was easily pulled off the base, showing that it was attached by a shaped nut that holds it in place. We'll need to save this toothed cap for later.
Under the toothed cap there are a few screws that hold the electric motor in place, these will need to be unscrewed. There's several more screws on the underside of the blender that once unscrewed will allow the blender to be opened completely.
Rest the chainsaw on its side with the engine shaft pointing up. Place the blender jug on the chainsaw, centering the base over the chainsaw engine shaft.
Using calipers, measure the distance between the face of the chainsaw housing to the upper edge of the blender jug base. This measurement will dictate how much of the blender base we will need to remove and install on top of the chainsaw to hold the blender jug in place.
Transfer the measurement to the blender base and scribe a line to indicate where you'll need to cut.
Step 11: Cut Blender Base
Cut through the blender base along the marked line to separate the portion of the blender base you need. Take care to cut as straight as possible, this will make attachment to the chainsaw body easier later.
Clean up any burrs and smooth the edge with fine grit sandpaper or a deburring tool.
Step 12: Mark Indentations on Blender Base
The interface between the blender base and the chainsaw body likely has small bumps and indentations that need to be accounted for to ensure a good fit.
Place the separated blender base onto the chainsaw, centering the opening in the center of the base over the engine shaft. Scribe on the blender base around the areas which will need to removed. Carefully remove the marked areas with a rotary tool, bringing the blender base back to the chainsaw body regularly to ensure a good fit.
Step 13: Mount Blender Base to Chainsaw
To attach the blender base to the chainsaw body we'll need to find mounting openings in the chainsaw body. You should be able to find a suitable screw hole or two near the engine shaft that would work to mount to.
This chainsaw had two screws on either side of the engine shaft that were perfect to mount to. After finding the correct size and thread of screws needed, the blender base opening was centered over the chainsaw engine shaft and new holes were drilled into the blender base to match the openings on the chainsaw. Long screws were then screwed through the blender base and into the chainsaw body, attaching the two together.
Your measurements should leave a small section of the chainsaw engine housing protruding from the center of the blender base, ready to accept the toothed cap that will spin the blender.
Step 14: Modify Toothed Blender Cap
The original blender shaft used a 1/4" contoured threaded nut and our chainsaw engine shaft uses a 5/16" nut, to get the toothed blender cap to fit onto the chainsaw nut we'll need to enlarge the opening in the underside of the cap.
The 5/16" left-hand threaded nut is 1/2" wide. Place it over the existing opening on the toothed cap and carefully trace around the nut, leaving an outline that you'll need to carve out. It's important to center the nut on the toothed cap to minimize vibration when it's spinning super fast on the chainsaw, taking the time to ensure a centered trace will result in safer performance later.
Step 15: Enlarge Opening + Install Nut
Clamping the toothed cap securely, I used a small carving bit on a rotary tool to enlarge the opening, making sure to stay within the traced lines.
By removing slightly less than the trace I could ensure a tight fit. The nut was carefully placed into the opening and pressed to fit inside, my fit was so tight I needed to give it a few heavy taps from a hammer to have it seat completely.
Once inserted the new toothed cap can be screwed onto the chainsaw engine shaft, counterclockwise. The chainsaw blender is effectively complete at this stage, the blender jug can be placed on top and the chainsaw fired up, however to make things easier to manage we'll build a base.
Step 16: Blender Base - Trim Bottom
I wanted to reuse the existing blender bottom to hold my chainsaw blender and planned on adding bike handlebars, too. Knowing that the base would be holding a heavy chainsaw and be vibrating around I decided it would also require a counterweight.
Knowing all this, I trimmed down the blender base to remove all excess plastic that wouldn't be needed anymore.
Step 17: Blender Base - Counterweight + Handlebar
I found a thick piece of scrap steel which would serve as the counterweight to help keep my new blender sturdy, but also act as an anchor point to attach the motorcycle handlebars to.
I trimmed down the steel plate to fit inside the blender base, then drilled holes into the plate to match up with the openings I drilled into the motorcycle handlebars. Using long bolts i attached the handlebars to the plate, then I used epoxy to affix the plate assembly to the blender base.
Step 18: Blender Base - Measure Handlebar Height
At the edge of the blender base where the handlebars protruded I measured how high the handlebars were from the base. This measurement was transferred over to the top part of the blender base and small cuts were made in the top of the blender base to allow the top to be placed over the handlebars and attached to the bottom.
Step 19: Blender Base - Top Contours
Just like with the top, the interface between the blender base and the underside of the chainsaw has contours that can be notched out to make a more snug fit. Specifically, the pull cord to start the chainsaw needed clearance.
The areas to be notched were scribed and then cut out using a rotary tool.
Step 20: Blender Base - Buttons
Since I was using the blender base I wanted to keep the old blender buttons. Even though the buttons wouldn't be functional, they are an enjoyable and tactile element that I wanted as part of my blender.
I snipped the electronics from the buttons, then used epoxy to glue the button array into the blender body.
Step 21: Blender Base - Attachment to Chainsaw
With the majority of the components prepared we can concentrate on a sturdy connection to mount the blender base to the chainsaw.
I identified three screw locations on the cover for the pull cord starter coil, these screw locations would provide the location where new longer screws will be used to connect a new wooden brace to hold the blender to the chainsaw.
Using a scrap piece of wood I sketched out an approximate shape that would span to all 3 screw holes. I shaped the piece to have a slim appearance, then drilled the holes.
After, the wood and screws were all painted black to match the blender base.
Step 22: Blender Base - Bringing It All Together
The handlebars were fed through small slits in the plastic blender base housing, and the painted wood block was inserted through discreet openings I carved into the blender base. The screws were then tightened into the chainsaw pull cord housing securing the blender base to the chainsaw.
Step 23: Motorcycle Throttle
I chose to have the chainsaw operated mechanically with a motorcycle throttle cable. This throttle assembly is easily assembled: the knuckled end of the throttle cable is inserted through the mounting assembly and into the notched portion of the hand grip. The hand grip with the throttle cable can be installed onto the right-hand side of the handlebar, and then the throttle mount installed around the throttle hand grip.
After, the left-hand side grip can be pushed onto the handlebar.
Step 24: Throttle Cable Trim
The throttle cable is meant for a motorcycle and is about 4 feet long, much too long for our short distance.
The throttle cable is covered inside a flexible steel sheath. The end of the throttle cable was cut using a rotary tool and the throttle cable was removed from the mounting hardware at the other end of the throttle cable assembly.
The new throttle distance was measured to be about 10 inches of cable. To be save I cut the throttle cable longer than this and would trim it down later as needed. The new shorter throttle cable was now fed back into the cable assembly.
Step 25: Throttle to Trigger
A small hope was drilled through the chainsaw handle and through the trigger. The mounting hardware for the end of the throttle was threaded into the chainsaw handle. The throttle cable was carefully fished through the handle and through the trigger, then wound around a small bolt with a nut tightened onto the end securing the throttle cable.
The throttle action was tested and small adjustments were made to tighten the throttle cable to ensure smooth action.
This chainsaw also has a safety that requires your hand to depress a lever with the palm of your hand in order to pull on the trigger. This safety was overcome with a zip tie around the handle that keeps the safety permanently off.
Step 26: Kill Switch
Motorcycles have a kill switch next to the throttle that cuts power to the engine immediately, I wanted the same effect for my chainsaw.
I removed the electric switch that came with my motorcycle throttle and replaced it with the kill switch from the chainsaw. The small electric rocker style kill switch on the chainsaw was easily popped out, the electrical leads were cut and new longer wires were soldered on. The kill switch was pushed into the cavity where the old motorcycle kill switch was located, and glued in place with epoxy.
Step 27: Add Bike Chain
To really sell the chainsaw portion of this project I decided to keep the blade arm on the chainsaw. Using the original chain would have been dangerously sharp, so I decided to use a silver bicycle chain for aesthetics. This chain does not spin and is not attached to the engine shaft in any way.
The bicycle chain was severed and about 6 inches were removed to fit around the chainsaw arm. The chain was glued in place with strong epoxy and the ends were hidden under the blender top.
Step 28: Install Blender Mixer
All that's left is to put the blender mixing jug on top of your new chainsaw blender and mix up a few drinks!
Step 29: Fire It Up!
Grab some friends, some hearing protection, and let the good times roll!
Remember, without a clutch the toothed blender cap will start spinning as soon as the chainsaw engine ignites. Prepare your drink mix in the blender mixing jug before starting the chainsaw engine. Start this chainsaw engine without the mixing jug on top, then add the mixing jug when the chainsaw is at a stead idle. The mixing jug should start blending the moment it makes contact with the spinning toothed cap, twist the throttle to really kick things into high gear.