Jos thank you that is a good idea and we were thinking along the same path but only square lifters.
I wanted to change the valve lifter design from the plans to one that had roller bearing ends. The original 1/8" lifter holes were enlarged to 3/8" for some brass bushings to fit in. I was concerned that if I used round lifters with a bearing they would try and turn sideways and bind up. (not good)
1/4" square brass stock with the roller in the end was my favorite style but how do I make a square hole in the brass bushings?
I could buy a square broach but that was too expensive and the brass rod varied in thickness so it would be a sloppy fit if I went that route.
I tried making a broach twice but that didn't turn out too well either.
I decided to machine the inside of the bushings on my CNC using a 1/8" end mill instead but that left material in the four corners of the square because the end mill is round. I could have removed the four corners with a file but decided to just cut the corners off the square rod instead.
![IMG_1538.JPG IMG_1538.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99871-a920edf57572ad5c497c145ee2229cad.jpg)
Ten bushings and ten lifters.
![IMG_1540.JPG IMG_1540.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99872-afecae867ddc5d875681596e84ca2f23.jpg)
Closeup of the lifters.
![IMG_1544.JPG IMG_1544.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99873-e9abcd43d428eb9a1834706b3c0887bf.jpg)
With the bushings installed in the housing
![IMG_1546.JPG IMG_1546.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99874-dfcc603dd0249d80195ba99b55e25904.jpg)
Thanks for looking
Ray
I wanted to change the valve lifter design from the plans to one that had roller bearing ends. The original 1/8" lifter holes were enlarged to 3/8" for some brass bushings to fit in. I was concerned that if I used round lifters with a bearing they would try and turn sideways and bind up. (not good)
1/4" square brass stock with the roller in the end was my favorite style but how do I make a square hole in the brass bushings?
I could buy a square broach but that was too expensive and the brass rod varied in thickness so it would be a sloppy fit if I went that route.
I tried making a broach twice but that didn't turn out too well either.
I decided to machine the inside of the bushings on my CNC using a 1/8" end mill instead but that left material in the four corners of the square because the end mill is round. I could have removed the four corners with a file but decided to just cut the corners off the square rod instead.
![IMG_1538.JPG IMG_1538.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99871-a920edf57572ad5c497c145ee2229cad.jpg)
Ten bushings and ten lifters.
![IMG_1540.JPG IMG_1540.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99872-afecae867ddc5d875681596e84ca2f23.jpg)
Closeup of the lifters.
![IMG_1544.JPG IMG_1544.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99873-e9abcd43d428eb9a1834706b3c0887bf.jpg)
With the bushings installed in the housing
![IMG_1546.JPG IMG_1546.JPG](https://cdn.imagearchive.com/homemodelenginemachinist/data/attachments/99/99874-dfcc603dd0249d80195ba99b55e25904.jpg)
Thanks for looking
Ray