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Atlas. 12 inch leadscrew bearing
- Thread starter Selbyrk
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- Dec 9, 2021
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The Zamak bearing was designed to break before overloading anything else in the system. Sometimes they break too easily. I had a brand new one break while taking a very light cut.
If you use a stronger bearing, be very careful not to overload the lead screw/half nut system. It could break something costly.
If you use a stronger bearing, be very careful not to overload the lead screw/half nut system. It could break something costly.
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- Dec 25, 2011
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Nutfarmer, do you have an Atlas/Craftsman 3/8 " bed 12" or the later Atlas or Craftsman 1/2" bed 12"? Provincial's comments only apply to the former.
Provincial, if your new one came from Clausing, they probably will or would have replaced it under warranty.
Provincial, if your new one came from Clausing, they probably will or would have replaced it under warranty.
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- Dec 9, 2021
- Messages
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That was almost forty years ago. I doubt a warranty claim would be appropriate.
Greetings Folks,
Looking for the right direction....The title of the post is Atlas 12 inch..... I am new to the site and am attempting to find information on working on my Atlas, 12 inch Pedestal Lathe, mod # 3996 to replace the two drive belts....
Have fun,
buckshot
Looking for the right direction....The title of the post is Atlas 12 inch..... I am new to the site and am attempting to find information on working on my Atlas, 12 inch Pedestal Lathe, mod # 3996 to replace the two drive belts....
Have fun,
buckshot
- Joined
- Dec 25, 2011
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- 10,552
Provincial,
The actual 1/2" bed Atlas 12" as opposed to the earlier 3/8" bed Craftsman 12" wasn't first made until mid-1957, not 1937. The new 12" (both Atlas and Craftsman) lathes made between 1957 and 1967 were the first version of the 1/2" bed 12". And they used the same lead screws and frangible right hand bearings as the earlier Atlas 9", 10" and Craftsman 12". Rather than being made of "cheap Zamak junk", they were deliberately designed to break and disengage the lead screw in case of a crash. The final 12" versions of course had the lead screw slip clutch to perform the same function. And the right lead screw bearing for those was was made of aluminum and had needle bearing thrust bearings.
Although there were two well known cases where they miscalculated and used Zamak when they shouldn't have, in general the use if Zamak for gears and other small parts allowed Atlas to make and sell around 250,000 6", 9", 10" and 12" lathes over about half a Century. Zamak's supposed bad reputation is traceable to about three cases where the factory was supplied with contaminated feed stocks. Use of such derogatory terms is expressly forbidden by site policy and may be cause for permanent banning without warning.
The actual 1/2" bed Atlas 12" as opposed to the earlier 3/8" bed Craftsman 12" wasn't first made until mid-1957, not 1937. The new 12" (both Atlas and Craftsman) lathes made between 1957 and 1967 were the first version of the 1/2" bed 12". And they used the same lead screws and frangible right hand bearings as the earlier Atlas 9", 10" and Craftsman 12". Rather than being made of "cheap Zamak junk", they were deliberately designed to break and disengage the lead screw in case of a crash. The final 12" versions of course had the lead screw slip clutch to perform the same function. And the right lead screw bearing for those was was made of aluminum and had needle bearing thrust bearings.
Although there were two well known cases where they miscalculated and used Zamak when they shouldn't have, in general the use if Zamak for gears and other small parts allowed Atlas to make and sell around 250,000 6", 9", 10" and 12" lathes over about half a Century. Zamak's supposed bad reputation is traceable to about three cases where the factory was supplied with contaminated feed stocks. Use of such derogatory terms is expressly forbidden by site policy and may be cause for permanent banning without warning.
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- Dec 25, 2011
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- 10,552
Buckshot,
Under Downloads, we have among many other things PDF scans of factory Technical Bulletins that cover disassembly, reassembly and adjustment of all of the various size head stocks. Full access to Downloads requires Donor status (any level).
Under Downloads, we have among many other things PDF scans of factory Technical Bulletins that cover disassembly, reassembly and adjustment of all of the various size head stocks. Full access to Downloads requires Donor status (any level).
- Joined
- Dec 25, 2011
- Messages
- 10,552
I also have a 3996 that was bought new in early 1981 about two months before Clausing quit making them. What is the serial number of yours?
The 3985 and 3986 (12 x 24 and 12 x 36) bench or floor stand models and 3995 and 3996 (12 x 24 and 12 x 36) cabinet models came out in about 1967 and were the final revision. The 3996 was the final model being made up until March of 1981.
The 3985 - 3996 have a different right lead screw bearing that consists of an aluminum block and two needle thrust bearings. Plus a self-locking nut and various flat washers. The other two differences were the addition of a lever to engage the half-nuts and a slip clutch on the left end of the lead screw that functionally took the place of the frangible right lead screw bearing.
What is wrong with your right lead screw bearing? Clausing may still have those available. I know that we do not have the drawings in Downloads, We do however have scans of almost all of the owners manuals and parts lists including the 3996. In the past, Clausing has been willing to supply scans of the drawings for most parts that they no longer have on the shelf.
The 3985 and 3986 (12 x 24 and 12 x 36) bench or floor stand models and 3995 and 3996 (12 x 24 and 12 x 36) cabinet models came out in about 1967 and were the final revision. The 3996 was the final model being made up until March of 1981.
The 3985 - 3996 have a different right lead screw bearing that consists of an aluminum block and two needle thrust bearings. Plus a self-locking nut and various flat washers. The other two differences were the addition of a lever to engage the half-nuts and a slip clutch on the left end of the lead screw that functionally took the place of the frangible right lead screw bearing.
What is wrong with your right lead screw bearing? Clausing may still have those available. I know that we do not have the drawings in Downloads, We do however have scans of almost all of the owners manuals and parts lists including the 3996. In the past, Clausing has been willing to supply scans of the drawings for most parts that they no longer have on the shelf.
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