I have been having fun making tools and motors from casting kits. My latest is a die filer.
As usual for me I end up with a project that stretches the limits of my shop. I have a South Bend 9A and a column mill. The guide that came with the kit indicated that you could use the lathe to hold the casting and true up the base. There was no chance that it was going to work for me. I would have thrown the casting across the shop. I decided to use the mill. After some creative use fixturing I was able to get a good base that acts as the reference for most of the remaining work.
My biggest concern was the alignment of the file shaft. There are two bushings, upper and lower, about three inches apart. The possibility of binds was keeping me up at night. I drilled the pilot holes with no way to center drill the bottom hole. Of course, the drill walked and ended up way off center. I used a boring bar to clean it up.
A keen observer will notice that I am WAY over the recommended stick out for this diameter bar. I didn't have a choice. Balance was an issue so I used the back gear to keep the RPM down and made many light passes. In the end the bottom bore is a few thousands smaller than the top due to deflection in the bar. Not an issue because I made the bushings. It was YAHOO!! time when I did the dry fit and there were no binds.
The main drive shaft was bored on them mill with a boring head.
There were lots of bits to machine. The biggest issue was the fit of the parts of the scotch yoke. It took two tries to get it correct with tight fits and running quietly.
The other issue was leaking. The mechanism runs in an oil bath. The design had no seals and the oil came out everywhere. I created an O-ring seal for the file shaft and installed a automotive style shaft seal on the drive shaft. No more leaks.
The drive motor is a repurposed tread mill motor. My brother Chris (active in the gas motor forums) gets bored and buys used tread mills to part out. They are powerful and variable speed.
I hope that this is interesting.
Will
As usual for me I end up with a project that stretches the limits of my shop. I have a South Bend 9A and a column mill. The guide that came with the kit indicated that you could use the lathe to hold the casting and true up the base. There was no chance that it was going to work for me. I would have thrown the casting across the shop. I decided to use the mill. After some creative use fixturing I was able to get a good base that acts as the reference for most of the remaining work.
My biggest concern was the alignment of the file shaft. There are two bushings, upper and lower, about three inches apart. The possibility of binds was keeping me up at night. I drilled the pilot holes with no way to center drill the bottom hole. Of course, the drill walked and ended up way off center. I used a boring bar to clean it up.
A keen observer will notice that I am WAY over the recommended stick out for this diameter bar. I didn't have a choice. Balance was an issue so I used the back gear to keep the RPM down and made many light passes. In the end the bottom bore is a few thousands smaller than the top due to deflection in the bar. Not an issue because I made the bushings. It was YAHOO!! time when I did the dry fit and there were no binds.
The main drive shaft was bored on them mill with a boring head.
There were lots of bits to machine. The biggest issue was the fit of the parts of the scotch yoke. It took two tries to get it correct with tight fits and running quietly.
The other issue was leaking. The mechanism runs in an oil bath. The design had no seals and the oil came out everywhere. I created an O-ring seal for the file shaft and installed a automotive style shaft seal on the drive shaft. No more leaks.
The drive motor is a repurposed tread mill motor. My brother Chris (active in the gas motor forums) gets bored and buys used tread mills to part out. They are powerful and variable speed.
I hope that this is interesting.
Will
