Thursday, April 29, 2010

Power and a new toolpost for the Lathe

I have been slowly restoring an abused Atlas/Craftsman 12" lathe to service. I've posted about the trials and tribulations over the last few years.

Recently I had an electrician install a new sub-panel for my basement shop. The electrician wired in a VFD, an amazing device that converts single phase power to 3-phase power. It lets me control almost anything related to the motor. For example, I configured the VFD so it starts the motor smoothly and will spin up to full speed in about 5 seconds. However, I configured it to stop the motor in 2 seconds. The VFD allows variable speed control without a loss of torque [1/27/13 - probably need a fact-check on this.] It also lets me reverse the motor. Good stuff. Further, the VFD supports a remote control panel so I can control the motor from the front of the lathe and not have to reach my hands in the sub-panel.

Here's the electrical work. The subpanel has breakers for outlets and the VFD. The white device is the VFD. It's about 4" x 4" x 6" and weighs nothing. The control pendant is sitting on the VFD's box. It has a potentiometer for the motor RPMs, an on/off toggle, and a forward/reverse toggle. Underneath the VFD's box, partially seen, is the 3-phase outlet for the motor.

Another advantage of 3-phase motors is that normal people don't want them. The nice Rockwell 1/2hp motor on my lathe was a Craigslist freebie. Gotta love that!

Here's the motor in all it's link-belt glory.

Moving on, the lathe's olde-school (circa 1936) lantern tool post has been "modified" and doesn't function properly. While it's fixable, I only have 2 of the special holders this tool post needs and they're expensive. So I replaced it entirely with a modern quick change tool post. It's a lovely thing. A quick change tool post set includes one toolpost and numerous holders. Cutting bits are secured in holders by Allen screws. The holders slide onto dovetails milled into the tool post and are locked in place when a lever is turned. It takes about 3 seconds to put a new tool in the tool post. Here's a picture of the new toolpost and an inaugural 5-foot long shaving.

The Patch Knife

I repurposed a battered Old Hickory paring knife into a patch knife for black powder shooting. The lead ball is wrapped in a piece of fabric (the patch) which serves as a gasket. The fabric is cut to size using the patch knife.

Here's the original knife.

Why salvage it? Because Old Hickory knives have very good steel in them. They're worth saving.

The handle was splintery and helpfully said, "Vegetable" on the side. I removed it. Then I scribed onto the blade a 'roach belly' profile and took the blade to the grinder. Here are before and after pics. The deep blue layout dye allows me to see the scribed line.

I made a new handle out of some cherry I found in the shop. The handle is held to the blade by two brass rivets. I made the rivet burrs out of some brass strip stock and the rivets themselves from 1/8" brass round. I cut the diamond-shaped inlays into the handle using an X-Acto knife and a 1/8" chisel I made out of some bar stock.

Finally, I peened the rivets down, filed them smooth, and sanded one last time. The cherry was finished with oil and wax. Here's the result.

This is my first knife. I'm proud of it. Hopefully it will provide decades of service.