Mower Deck Spindle Reinforcement
My uncle commissioned me to make a reinforcement ring for one of the blade spindles on his mower deck. The spindle has a pulley on top (above the deck) that is driven by the belt coming from the engine and the blade mounts on the bottom (below the deck). This unit is installed from the top of the deck and is fastened to the sheet metal with 4 bolts and lock nuts. From years of use and probably hitting rocks and tree roots on the uneven ground, the sheet metal has bent and started cracking around the bolt holes. He has had the deck straightened and the cracks welded, but the welds never seem to hold up. I made a ring to help distribute the bolts' clamping force to a larger area of sheet metal. From the top down, you will have 4 bolts with washers passing through the spindle housing, the mower deck, the new ring and secured with 4 washers and lock nuts. Over the cutting season the nuts had loosened up, which was probably caused by the weakened sheet metal of the mower deck flexing. Hopefully this ring will eliminate the flex and provide a solid clamping surface for the nuts so they won't come loose.
I used a scrap piece of 1/4" steel plate from my late grandfather's stock. I cut out a very rough circle using an angle grinder with a cutoff wheel and smoothed the corners a bit with a grinding wheel. The steel had a pattern of small holes drilled in, so I made an aluminum faceplate for the lathe and attached the steel with the existing holes. After turning the outer diameter and boring the inner diameter, I unmounted it and took measurements. I didn't want to remove the pulley from the spindle, and I couldn't get transfer punches in the bolt holes with the pulley in place, so I took measurements of the bolt pattern. I drew the ring and superimposed bolt pattern in AutoCad and printed out a 1:1 template. I taped the template to the ring, center punched and drilled the bolt holes. I sized the holes for a relatively tight fit to lessen the chance of the ring moving and loosening the nuts, but the tolerances were not so tight that I felt uncomfortable using measurements and a paper template. Click on the pictures for larger images.
I used a scrap piece of 1/4" steel plate from my late grandfather's stock. I cut out a very rough circle using an angle grinder with a cutoff wheel and smoothed the corners a bit with a grinding wheel. The steel had a pattern of small holes drilled in, so I made an aluminum faceplate for the lathe and attached the steel with the existing holes. After turning the outer diameter and boring the inner diameter, I unmounted it and took measurements. I didn't want to remove the pulley from the spindle, and I couldn't get transfer punches in the bolt holes with the pulley in place, so I took measurements of the bolt pattern. I drew the ring and superimposed bolt pattern in AutoCad and printed out a 1:1 template. I taped the template to the ring, center punched and drilled the bolt holes. I sized the holes for a relatively tight fit to lessen the chance of the ring moving and loosening the nuts, but the tolerances were not so tight that I felt uncomfortable using measurements and a paper template. Click on the pictures for larger images.