- Joined
- Apr 22, 2016
- Messages
- 979
For the past 7 or 8 years I've been renting a parking lot blower to blow leaves out of the yard in the fall. There are/were about 40 maple trees dropping lots of leaves and there are no neighbors within seeing distance of our yard so blowing them out of the yard was the quickest way to get rid of them.
This year when I was done, for the 1st time since using this thing, I had a very sore thigh muscle that lasted several days. That thing is heavy! Another drawback to renting is that in order to get it all done at once and avoid having to rent more than once, I have to wait till the oak leaves drop which are 3 – 4 weeks later that the maples. By that time some of the earliest ones to drop are getting matted and hard to remove cleanly as they would when freshly down and dry.
Solution, build my own blower that can be used anytime I want and before the leaves are matted and stubborn. Cost should be about 5 times the yearly rental fee as most of the stock is on hand. Found a new close-out 10HP Tecumseh engine online and bought one flange bearing. I expect those will be the only out of pocket expenditures.
One other plus is that it will be self-propelled with an old snow blower power unit that is used for such things. It was given to me by my cousin and had not been used that much. Since I already had a good snow blower, this one was converted to a power drive unit (something like the old Gravely tractors). So far, this one is used to power a wood hauler in the spring true fall seasons. In the winter a power broom (made from the blower part) is put on it to keep the sidewalk clear of snow (especially when there's ice under). If the sun can get at the ice w/o snow on top it melts easily even when it's quite cold.
There will also be a set of wheels to attach to it for quick clean-ups with manual push power and to make it movable and facilitate storage when the power unit is otherwise busy.
When the motor arrived, I realized that the output shaft was going to need more support than the bushing that was in the engine. The only way would be to support the hub of the impeller and that was going to be 1 1/2” diameter. So, although the flange bearing looks like overkill, it had to be that big.
I took as much care as I could in building the impeller to keep it balanced and concentric. That was not easy because it's made of 14-, 16- & 18-gauge sheet metal (not to mention honing my thin metal welding skills). The impeller is 17” diameter x 3” thick.
The motor shaft is 4+” long with a taper on the end and a shoulder next to the engine, so a hub shaft was made to fit it and a ~7” x 1/4” flange welded to it. This was then put back in the lathe and turned true and concentric to maintain balance, then the bolt holes drilled on the mill with DRO bolt circle function. Only 2 of the impeller holes were drilled 1st and a little over sized so the assembly could be balanced by physical positioning of the impeller to hub. A setup was made on the floor with 2 CRS rods leveled both ways.
Also made conical bushings for both ends of the hub that fit on a 1/2” CRS rod for a balance shaft. Then I would find the heavy spot and adjust the impeller on the hub flange and try again. Took a lot of tries and about an hour to get it in balance. Then the remainder of the holes were drilled to size and bolted tight. I put the assembly in the mill and spun it (very slowly at first) to check for concentricity and wobble. It looked pretty good.
Because the mounting holes on the shaft end of the aluminum motor crankcase are not very far apart and only 5/16” fine thread, the bearing support plate was allowed to extend below the base of the engine. 1/8 x 1 1/2” angle was bolted to the engine base the ends of which were welded to the bearing support plate. That should make attachment to the engine strong and stable.
Next was to make a lightweight impeller housing from sheet. Using approximate shape and dimensions from pics of commercial unit, the back, band and front w/ inlet were cut with plasma, cleaned and welded. This was probably the most time-consuming part so far. The back piece was gusseted to the bearing spacer.
The front plate has a large enough opening that the impeller can be removed.
Construction of the front plate involved starting the flange bend on the bottom of a 15-gallon drum then shrinking it and final shaping on a short piece of heavy DOM tubing
The opening was then covered with a bolted-on cover that has the air inlet in it. There will be a grating over the inlet to keep junk and hands out.
The outlet unit was made from 12-gauge metal, partly welded and partly bolted to the sheet metal housing. Because I did not like the design or control of the rented model's directional door and the deflector paddle would not stay put for long, I came up with my own. Most of the time air blast is out the left side of the machine but there is a door which closes off the side outlet and opens one to the front. This is useful for blowing out around trees and along the edge of a building. I made a spring-loaded pin detent to control this. The deflector (for directing air flow higher or lower) is controlled by an aviation push-pull cable w/ fine adjustment via twisting the knob or pushing a center button for large movements.
Since this engine was originally made for generator power, it had a fixed speed governor. I simply disconnected the governor and made a new wire link to the carb and a thumb wheel.
Still to do will be to mount it to the power head, put a front wheel on it and make the manual push setup. And a little tidying up painting and testing.
Thanks for looking.
Aaron
This year when I was done, for the 1st time since using this thing, I had a very sore thigh muscle that lasted several days. That thing is heavy! Another drawback to renting is that in order to get it all done at once and avoid having to rent more than once, I have to wait till the oak leaves drop which are 3 – 4 weeks later that the maples. By that time some of the earliest ones to drop are getting matted and hard to remove cleanly as they would when freshly down and dry.
Solution, build my own blower that can be used anytime I want and before the leaves are matted and stubborn. Cost should be about 5 times the yearly rental fee as most of the stock is on hand. Found a new close-out 10HP Tecumseh engine online and bought one flange bearing. I expect those will be the only out of pocket expenditures.
One other plus is that it will be self-propelled with an old snow blower power unit that is used for such things. It was given to me by my cousin and had not been used that much. Since I already had a good snow blower, this one was converted to a power drive unit (something like the old Gravely tractors). So far, this one is used to power a wood hauler in the spring true fall seasons. In the winter a power broom (made from the blower part) is put on it to keep the sidewalk clear of snow (especially when there's ice under). If the sun can get at the ice w/o snow on top it melts easily even when it's quite cold.
There will also be a set of wheels to attach to it for quick clean-ups with manual push power and to make it movable and facilitate storage when the power unit is otherwise busy.
When the motor arrived, I realized that the output shaft was going to need more support than the bushing that was in the engine. The only way would be to support the hub of the impeller and that was going to be 1 1/2” diameter. So, although the flange bearing looks like overkill, it had to be that big.
I took as much care as I could in building the impeller to keep it balanced and concentric. That was not easy because it's made of 14-, 16- & 18-gauge sheet metal (not to mention honing my thin metal welding skills). The impeller is 17” diameter x 3” thick.
The motor shaft is 4+” long with a taper on the end and a shoulder next to the engine, so a hub shaft was made to fit it and a ~7” x 1/4” flange welded to it. This was then put back in the lathe and turned true and concentric to maintain balance, then the bolt holes drilled on the mill with DRO bolt circle function. Only 2 of the impeller holes were drilled 1st and a little over sized so the assembly could be balanced by physical positioning of the impeller to hub. A setup was made on the floor with 2 CRS rods leveled both ways.
Also made conical bushings for both ends of the hub that fit on a 1/2” CRS rod for a balance shaft. Then I would find the heavy spot and adjust the impeller on the hub flange and try again. Took a lot of tries and about an hour to get it in balance. Then the remainder of the holes were drilled to size and bolted tight. I put the assembly in the mill and spun it (very slowly at first) to check for concentricity and wobble. It looked pretty good.
Because the mounting holes on the shaft end of the aluminum motor crankcase are not very far apart and only 5/16” fine thread, the bearing support plate was allowed to extend below the base of the engine. 1/8 x 1 1/2” angle was bolted to the engine base the ends of which were welded to the bearing support plate. That should make attachment to the engine strong and stable.
Next was to make a lightweight impeller housing from sheet. Using approximate shape and dimensions from pics of commercial unit, the back, band and front w/ inlet were cut with plasma, cleaned and welded. This was probably the most time-consuming part so far. The back piece was gusseted to the bearing spacer.
The front plate has a large enough opening that the impeller can be removed.
Construction of the front plate involved starting the flange bend on the bottom of a 15-gallon drum then shrinking it and final shaping on a short piece of heavy DOM tubing
The opening was then covered with a bolted-on cover that has the air inlet in it. There will be a grating over the inlet to keep junk and hands out.
The outlet unit was made from 12-gauge metal, partly welded and partly bolted to the sheet metal housing. Because I did not like the design or control of the rented model's directional door and the deflector paddle would not stay put for long, I came up with my own. Most of the time air blast is out the left side of the machine but there is a door which closes off the side outlet and opens one to the front. This is useful for blowing out around trees and along the edge of a building. I made a spring-loaded pin detent to control this. The deflector (for directing air flow higher or lower) is controlled by an aviation push-pull cable w/ fine adjustment via twisting the knob or pushing a center button for large movements.
Since this engine was originally made for generator power, it had a fixed speed governor. I simply disconnected the governor and made a new wire link to the carb and a thumb wheel.
Still to do will be to mount it to the power head, put a front wheel on it and make the manual push setup. And a little tidying up painting and testing.
Thanks for looking.
Aaron
