Trimmer Bump Head Knob. Homelite.

thingiverse

I replaced the old bump head on my trusty Homelite trimmer with this brand new one, made from the original red printed design. This is actually a redesign I came up with after using the same machine for an impressive 15 years - it still runs smoothly as ever. About two or three years ago, I completely replaced the trimmer head, but the bump head wore out once more. Now you can clearly see where it has become entirely worn through in this picture of the black plastic part. To fit it into place properly, the bolt recess required some resizing during my initial attempt - and I made sure to design it that way! If I had left it injection-molded, the same thing might have happened when it came out of the mold - plus, the parts tend to wear down more quickly too. As a test project for myself, this is one of my early 3D printing endeavors. It's an ABS part printed at seven different layers with about fifty percent fill rate, and with each layer set to 0.3mm. I went with red plastic for the trimmer because if you drop it in some tall grass or somewhere where you can't see well, you'll still be able to tell that you've lost it pretty easily - this new design is going extremely well and actually lasts long!