Zamak Parts and Magnetism

As an aside, it is amazing how strong some of the rare earth magnets are. I just bought a phone holder that actually sticks to my granite counter top. I assume there is some iron in the granite. You would never notice this except with very strong magnet.
Robert
 
You guys have hit on a very good point. When the part is well designed, Zamack is a viable choice. It is commonly used to cast precision tolerance parts and, if it is heavy enough to handle the load, it does just fine. The cross slide and compound leadscrew nuts on my Emco Super 11 are made from Zamack and they are adjustable for backlash and smooth as silk - ZERO backlash - and have stood the test of time on many Emco lathes. Some CNC ballscrew nuts are also cast from Zamack because they can be made with great precision. Not a bad material; just sub-optimal design and/or application.
 
Zinc, Aluminium, Magnesium, Kupher (?, German for copper) Many products were made with Zamak. I have numerous models made of it. Depending on the manufacturer, meaning quality of the alloy and cleanliness of the molds, it is a solid and reliable alloy.

As stated above, there are several factors involved in the longevity. One not covered by younger readers is that Trichloroethane, 1,1,1, Tech was used for many years as a replacement for carbon tetrachloride. It has been outlawed for a long time. The issue is that when used on Zamak, it turns the metal to dust. Quite literaly... ... This applies to any aluminium compound, not just zamak. Ask any Navy pilot (especially A-10s) from the post Viet Nam period what happens. It clouds plexiglas too.(acrylics)

I have a Craftsman 12X36, which is the same as an Atlas 10" machine. The gears are all zamak, and in very good condition. The lathe dates from the (early?) '50s and the gears seem original. I did replace a couple, but they were from abuse of the QC threading box, not decomposition.

I also have had three (3) UniMat DB-200s. They date from the late '50s, at best. Two have held up well, one was a basket case. They have been passed on, no threading gears... ... The entire machine was cast of zamak. Well, the ways and handwheel knobs were steel. The rest was zamak. I recognized what had happened to the rotton one and eventually took it off the guy's hands, for very little.

In answer to the original question, Zamak has -no- magnetic properties. It is almost as strong as grey iron castings. If the section is increased. For gears it's a perfect solution. For a headstock and the like, not so much unless it is redisigned. The big advantage, in Atlas' case, was that when the gear was extracted from the mold, it was, quite literaly, ready to use. During the WW-2 era, it was very useful for instruments where magnetic deviation was critical. Both in aircraft and in ships. Ever seen "minesweeper" tools, of bronze?

I have, somewhere, a detailed chemical analysis of the material. But it is rather long and I see no need to post a "filler" unless asked. Many older machines that have been "serviced" with chlorinated solvents look good on the showroom /photographs but fall apart a year or two later. Carbon Tet does the same, just not as quickly.

I use a carburator cleaner that is isopropyl based to clean my castings. If it is safe for carburators (zamak) it should be safe for my models.
Bill Hudson​
 
Thanks for the info abut Trich 1,1,1 .
I never knew about the degradation angle, we had it in the refrigerated lip degreasing bath .
 
Here's another comment on the Zamak subject. The Zamak headstock and legs that doomed the 10100 and 10200 were not made in the same mold as the cast iron predecessor. Because none existed. Cast iron is normally cast in sand from a male pattern. The mold is usable only once. The molds used to cast Zamak and other die-cast materials are high pressure molds probably made of some steel alloy. Had the late lamented Zamak headstocks been made to the same dimensions as the cast iron ones, they may well have held up. But they were not.
 
Mazak.zamak was used for the carbys on millions of cars...........an Amal GP carby made of mazak sells for upwards of $400 ..........................some years ago,I "obtained " a large quantity of 1,1,1 trichlorethane from the local electricity generator..........it wasnt banned at that stage,but the elec co was disposing of it..........I sold it for parts washing at $1 per liter......one car repairer who bought the solvent had a pair of Weber carbys disappear ...........all that was left was the brass parts...........I believe its ok provided no water is present..........with water you get a hydrochloric acid reaction that destroys steel drums and light metals.
 
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