Blower fan (working)

I wanted a small blower for my firepit. This is a printed and tested model, everything fits an works as currently designed and uploaded. You will need to print the shaft spacer last so you can measure its height, and scale it vertically accordingly. This is due to minor printer tolerances to keep the rotating assembly tight. It may fit as is, or it may need to be slightly taller. 

There are 2 seals that need to be printed for this assembly, they should be printed in TPU for best results. If you do not have access to TPU, omit the intake seal and use a small amount of silicone caulk or similar to seal the casing body to the top assembly to prevent air leaks. 

NOTE: the included motor mount file is not the most compact design it could be due the shaft an couplers i had on hand. If you have shorter 8mm ground shaft available you can shorten that part significantly. In my build the 8mm shaft is 100mm long if you want to use the motor mount included without modification. 

I included a screen shot of the amazon listing for the motor used in this project. you will also need an 8mm shaft and a coupler to connect the motor to it. 

Assembly note. The slot in the motor mount is there to allow you to tighten the grub screws on the shaft coupler. build the whole blower assembly, with the shaft sticking out the bottom before assembling the motor and motor mount. Depending on the diameter of your coupler you might have to get a bit creative with lining up the shafts but it is doable. 

Recommended assembly steps:

the screw lengths for this model are very forgiving with the exception of the screws that connect the motor mount into the blower body, these should be 18-20mm , for everything else use what you have that makes sense. All screws used (besides the ones that come on the motor) are M3 in this design. 

mount impeller on shaft with about 7-8mm of shaft sticking out for the bearing. Install grub screws in the impeller holes if needed. For me the fit it tight enough where it wont slip. If you do need to use the grub screws it might be best to file a flat on the shaft for better bite. 

install the 608 bearing in the top cover 

install608 bearing in blower case bottom

mount square m3 nuts in blower housing, use a drop of CA to retain them if they are loose, but they should be a snug fit. 

install top gasket on intake, attach top cover to the other side of the gasket and screw on with m3 screws. This should give you to top assembly of the blower with a bearing exposed in the bottom. 

screw the top assembly to the case body with the impeller installed. Do not over tighten, it will be taken apart again before it is complete. 

turn the assembly over so its sitting on the opening of the intake. Then using calipers measure the distance from the back of the impeller to the top of the bearing minus half a mm for clearance. then print the shaft spacer adjusted for this measured height. 

take blower case off, install shaft spacer, and reassemble. 

mount back cover adapter, and the motor mount tube and screw down to the internal square nuts in the blower case. 

slide the shaft coupler onto the shaft, leaving the grub screws very loose for now to make aliment easier. 

attach motor to the bottom of the mount using the included hardware that came with the motor, then tighten all grub screws to lock the motor to the shaft. 

Power motor as you see fit, its rated for 12-24V. you should be able to test the assembly off a standard 9V battery, if it does not spin freely under that power you need to disassemble and asses where the friction is coming from. When running there should be no scraping or rubbing noise, test model the images were taken with runs extremely quietly and smoothly with no vibration. 

possible sources of noise and vibration to look at if you have it:

some times the shaft couplers are over sized, and you have to use the grub screws on either side to center it on the shaft. If one screw is maxed out and the others at its minimum it can cause an off balance shaft, or cause rubbing inside the motor mount tube. The solution is the adjust the screws to center the shafts and coupler in the tube. 

if the shaft spacer is too short, it will allow the impeller to ride on the case bottom causing noise. If this happens print a taller spacer. It will cause excessive heat, wear and noise. 

if the shaft spacer is too tall it may wedge the impeller into the top cover or bearing causing excessive friction, remeasure, or sand down the spacer and reassemble. 

make sure your top seal is fully seated in the blower case grove all the way around. If not, it may cause the top and bottom covers to sit at an angle kinking the through shaft in the bearings, or it may extrude the seal into the body causing rubbing.