Tom Utley is doing a detailed restoration of a WWII-era South Bend 16″ x 60″ metal lathe, which is about 9 feet long and weighs 2,700 pounds fully loaded. It was originally delivered to the US Army in June of 1943 with the Crossed Cannons logo of the Army Ordnance Corp stamped into the bed. Tom bought the lathe a few years ago and has been working on a complete factory quality restoration ever since. These parts are his attempt at packaging modern electrical controls inside original Art Deco design cues found elsewhere on the machine. He used Precision Board HDU to make detailed foundry patterns for cast iron parts.
Tom used PBLT-48 for his casting patterns, but you can also use higher densities like PBLT-70 and PBLT-75. Precision Board is easy to work with and cost effective. It has excellent dimensional stability to create accurate casting parts. If you’re not sure what density of Precision Board to use for your project, take a look at our Material Selection Guide for reference.
In addition to having the machine reground and hand-scraped (a technique to restore precision sliding surfaces to very high tolerances), Utley added a few bells and whistles to make it easier and safer to use for himself and his young son.
“I added modern electronics, including a variable frequency motor drive and safety switches that weren’t commonplace on old machines like this. I also worked out a means of adding a custom analog (dial face) tachometer that indicates spindle RPM. It’s actually an aftermarket diesel automotive tach from Speedhut, but with a little custom artwork on the dial it could pass for an original factory option if you don’t look too closely. A tachometer would have been found on high end machine tools of the day, but was never offered by South Bend back then.”
All these new electrical items needed an enclosure to keep them dry and out of the way of flying hot metal chips. Tom could have picked up aftermarket electrical enclosures and bolted them on, but after all the work to restore the machine it didn’t feel right to him to get so far away from the Art Deco styling found on War-era machines like this. So, after lots of hand sketching and cardboard templates, he came up with a design that felt like something South Bend might have offered in the 40s if tachs and safety switches and variable speed knobs had been factory options.
“I decided early on that I wanted these new parts to be made from cast iron just like the rest of the machine'” says Utley. “Castings require patterns, so I set about learning everything I could about the process, mainly via the Web and YouTube. I received a lot of help from the Maker and YouTube machinist community throughout this project.”
A few months ago, Tom was fortunate to meet John Saunders who runs the NYC CNC YouTube channel. John was enthusiastic about the project and offered to cut a casting pattern for him once he had a CAD model.
“I had to teach myself how to use Autodesk Fusion360 for modeling the parts, but after a few weeks I had a usable 3D CAD model of what had been bouncing around in my head,” said Utley.
To compensate for any dimensional and structural changes which will happen during the casting or patterning process, allowances for shrinkage are usually made in the pattern. Talking to Emmanuel King, owner of Cattail Foundry in Pennsylvania, Tom was advised to scale the casting pattern up by 1/8″ per foot of finished part dimension to offset shrinkage in the cooling iron.
“This is a snap to do in Fusion360, all I had to do was tell the software to scale my model by 1% and it was ready for the CNC. The CAD model was then shared with John directly from my PC and he set about carving the two patterns.”
[Swipe] In case you’re curious…comparison of the @coastalenterprises HDU pattern vs. CAD (scaled up by 1%) vs. the finished gray iron part with shrinkage. If you ignore the deviations from my hand sanding of the pattern, it came in pretty close to as-designed dimensions. #foundry #casting #castiron #shrinkage #moltenmetal
Being used to cutting metal, John had to go through a bit of a learning curve with feeds and speeds and workholding, but ultimately found Precision Board to be easily machinable.
After a little bit of hand sanding by Tom, the casting patterns went off to the foundry.
Earlier this month, Utley received the castings back and they turned out great. The foundry owner said the material is great for casting short run parts like this and complimented him for having draft angles in all the right places and for making it so smooth for his foundry team.
Tom is doing final machining on the castings now. Once that’s done and the castings are painted, he will add custom acid-etched brass legend plates for each switch and get the wiring all buttoned up. The two year project will finally be to a point Utley can call it done and move on to his next machine tool, which he hopes will be a milling machine.
“Thanks so much for sharing the story of this old machine–she’s 74 years old now with a lot of history, but she’s just about ready to debut as a brand new beautiful girl with at least another 74 years of making chips ahead. Publicity like this is great because it gives people the confidence to take on bigger restoration projects like this and save good machines from the scrap yard,” he adds.
You can read a more detailed journal of Tom’s restoration efforts, including photos of the lathe in its original condition here. He can be found on Instagram where he shares photos of this and other projects he’s working on.
UPDATE: You can read an article in the December print issue of Production Machining about Tom Utley and his restoration project or read the online version HERE.