At one time in my past, I worked at a factory that forged brass and aluminum parts for many companies. Most of those parts were small parts, like store door handle pulls, and heads for hand held fire extinguishers. Even doing small parts, the machines were huge, around 15' high, with 100 + ton capacities (I could describe the forge press if you wanted to hear about them). Most of the small aluminum parts had to go through the furnace, the forge, the trim press, the acid dip, then back to the furnace to start the process again a few times to provide a starting point for final machining. The 1" diameter x 2.5" long aluminum extinguisher heads were forged from a piece of bar stock which made 4 pieces at a time, that bar stock had to go through the furnace 2 times before even being trimmed, and then each 4 piece had to be trimmed and ran through a 3rd time before they were split into the 4 pieces. The biggest pieces we made were the brass manhole covers that are used on public streets. Those 80 lbs covers start life as a 6" long chunk of 6" diameter round brass slug. they are run through the furnace at 1900 degrees, set in the center of a hammer drop forge. The forge had a 1500lbs head with a 200 lbs die bolted in to it, that was pulled up 10' in the air by rollers squeezing a set of 18 hard rock maple 2" x 4" boards (this is special wood that only lasts a few years) that were wedged into the head. The anvil was a 2400lbs chunk of steel with a 200lbs die bolted to it. The company only had 2 guys that could operate it back at that time. When the drop head was lifted, the brass slug was removed from the furnace and loaded into the center of the bottom die, and the rollers released the grip on the boards and it dropped the head the 10 feet. Then the rollers squeezed the boards and lifted the head back up the 10' and it was dropped again. Two strikes complete the 1st round. Then the pieces were trimmed, and loaded back into the furnace, then the second two drop cycled happened again. Each round took a day to complete (80 slugs a day, the furnace heating the slugs was the limiting factor), and each part went 4 rounds of the two drop hits. The final product was a 2" thick 24" diameter hunk of solid brass. Each time that hammer dropped and the head met the anvil, the entire building shook! You could be in the front office and you knew what was going on! I can not imagine the process of forging a wheel (I would love to watch the process once), but I suspect the chunk of aluminum that the wheel forging starts with could be pretty big, depending on the size of the wheel. Its run through a very large machine with multiple process steps, all of which have to be carefully watched. Once the forged blank has been formed, everything else is likely machined. I suspect most of today's aluminum wheels are cast rather then being forged, metallurgy has come a long way in the last 20 years. If you really have the desire to make aluminum wheels, I suspect you would start by buying the rough forged (or cast) blanks from a forge (or casting) company, then machine the wheels from there. I'm sure the quantity of wheel blanks you buy will have a huge impact on the price per wheel, most forge companies don't do small quantities. The cost of creating the dies is huge, the machine up keep is huge, and the equipment and skilled labor in making the rough forging would be huge. I suspect a web search for a wheel forging (or casting) process could be an eye opening experience.
The Great ,,Li’l John Buttera made completely new wheels on his machine. He was one of the first to make billet wheels,,,,,,,maybe even the first . A master machinist knows no bounds ! Tommy
A lot of the cast aluminum wheels in the 60's-70's were made from recycled aluminum scrap. Heated up and melted into a liquid, scraped the gunk off the top and simply poured into a cast mold. No forging at all. You could look into Motorcycle wheel hoops as they come in 16", 19", & 21", and are narrow.
The expensive stuff is forged, but most are cast. Different methods on this, try searching for aluminum casting. All require a forge to melt the metal. During the billet era, hoops and centers were made for people to turn out their own centers. Look into BBS and 3 piece wheels for creating different widths and backspacing. As with most things, there are videos. www.youtube.com/watch?v=nqOlM6-YIIs Lathes that have more than 12" centers to machine those centers start getting pretty expensive and most will not do spokes and other radial details. Milling machines are able to do this, but the time to program then run a CNC mill starts getting pretty high.
The big thing with wheels is the material used and forces expected all designed to exceed any possible forces. Look at how Bugatti built a wire and solid wheel in the 30s. https://crosthwaiteandgardiner.tumblr.com/image/99303940043 Here's another. There are many others. www.youtube.com/watch?v=4llzm8pAnv0
Most of the aluminum and magnesium wheels from the past that are "hamb friendly" were cast. Nothing wrong with that at all, of course quality varied. Some aluminum forgings existed back then but were less common (interestingly the aluminum centers of the circa '65 composite Hurst wheels were forged; I even had a set of Cal-Nevar Cyclones with forged Alcoa centers). Forged are much more common now, there are cold forged (the original Centerline Auto-Drags were cold forged, some of their ads referred to them as 'cold stamped' IIRC) and hot forged (some of Mickey Thompson off road wheels - pretty amazingly light). Surprisingly aluminum wheel blanks (solid complete wheels intended to be CNC customized), centers, weld-on and bolt together rims are pretty readily available. Steel parts are harder to come by. https://www.specialtyrim.com/products https://americanrim.com/spun-aluminum-wheel-rim-specs/ https://www.mwdepot.com/forgings https://www.msiwheelblanks.com/wheels.html I'm an huge admirer of Little John's work, while I'm sure he could have machined entire wheels out of giant blocks of forged aluminum, instead he used available outers and machined his own centers from forgings. Some bolt-together, some welded two piece. If you look at the wheels he did for his 32 3 window, (BBS outer rims, custom machined center by John from Cragar rough machined plates) you can see the design origins of what became the Centerline Champ 500 wheel. Little John ran Centerlines on his Indy car; they were a sponsor of his Indy car one year too I believe. Caption and pic from the Gray Baskerville Hot Rod article on his 3 window: There are literally thousands of pages written on wheel design and engineering. This is a great in-depth resource, unfortunately the animations are done in Flash so they aren't viewable unless you have an old browser: https://www.euromotor.org/mod/resource/view.php?id=21039 https://www.euromotor.org/mod/resource/view.php?id=21020 I'm no engineer, but it seems that a wheel rolling forward would have less force on the center than the rim; start turning that wheel and lateral force on the center will increase greatly. That's one reason that some wheels (the old Cragar Super Trick for example) were only rated for drag racing and not road racing. Anyway go for it!
@Phillips, great content. If you look at the details needed for design and use, from tire retention to lug seating, to brake clearance, there is a lot of nuance. Add to that the shrinkage issue when casting, and it's something that is not a weekend project. SAMPLE https://image.slidesharecdn.com/p-rim-nf-06april20173-170513025308/75/CAR-RIM-1-2048.jpg
The pics I saw of Lil Johns work was from large round billets . He had them on pallets in his shop . I’m sure he made different wheels,,,,but the ones I saw were 1 piece ,,,,at least I think I saw that ,,,,it was over 40 years ago when I read the book . There was a massive pile of chips laying around . Tommy
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