Atlas lathe for sale
I've seen ads on eBay for "repaired" gear boxes where the mounting ears were cracked, so I suspect there's a bit of a design issue with the gear box. One of these years I'll remake the box and reuse the guts, but will make the mounting ears more robust (thicker).
#ATLAS LATHE FOR SALE CRACKED#
The mounting ears were unbeknownst to me cracked when I bought the mill. My first thought was "I sure wish they'd have made that part out of steel"! However, looking at the material charts, it wouldn't have made a difference. The mounting ears snapped off the box itself. I have an Atlas MFB mill with a broken power feed gear box for the table. If you see a broken Zamak part, theoretically it's not a problem with the Zamak but a design/use problem. You'll see many posts here about broken gears (especially in the back gears) on lathes that are most likely steel, so no material is indestructible. As Robert and others have noted, lots of Altas/Craftsman lathes and mills out there with Zamak gears that have held up really well. It's a lot easier and cheaper to make a steel die and cast gears instead of cutting them individually. I suspect Atlas used a lot of Zamak in strategic parts because of the melting point of 734 F instead of 2200 F for iron. But the point where they start to permanently deform could be the same depending on the type of cast iron. That means a Zamak part will deflect about twice as the same part in steel or iron under the same load. Young's modulus for Zamak is 14,000,000 psi. It's the slope of the line when you plot stress vs. Depending on the cast iron, the yield strength (really the number we care about) - anywhere from 25,000 psi to 105,000 psi.Īnother property is modulus of elasticity. Ultimate tensile strength (when it breaks under load) - 58,000 psi. Yield strength (put a load on the part and it starts to permanently deform) - 52,000 psi. Cast iron from Wikapedia:Ĭhart is for Zamak 2 which added some copper to the alloy (primarily zinc) to make it stronger. The particular alloy used by Atlas is somewhat stronger than cast iron and most batches have held up well considering the age and operating hours on them. Zamak is a die-cast Zinc alloy but contains no lead. The person who wrote that Zamak gears are pot metal was incorrect. I bought mine new in 1981 and still have it. It is a 16-speed machine and has a Quick Change Gear Box and power cross feed.
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The machine has Timken tapered roller bearings on the spindle.
#ATLAS LATHE FOR SALE SERIAL NUMBER#
From the serial number I would guess made late 1970 or early 1971.
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The 3996 was made from late 1967 through March of 1981. An Atlas 10" with a 48" bed would be a 10x30. And the person who said that he had an Atlas 10x48 lathe about the same age as the 3996 was wrong on two counts. The nominal bed length measured along the front or rear way is 54". Assuming that the subject is still open, the lathe that you are looking at is an Atlas model 3996 which is a 12x36 size lathe (12" swing over the ways and a nominal 36" center to center distance (that means that if you put a dead center in the headstock spindle and one in the tailstock ram, and back the tailstock up to the end of the bed, the distance between the two points will be about 36".