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101 change gears
- Thread starter bluedxj
- Start date
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- Dec 25, 2011
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- 10,552
Bluedxj,
Regardless of model, there are 10 gears in the standard Atlas or Craftsman 12" lathe Change Gear set. Two of which are 32 tooth. This count does not include 5 gears in or on the headstock/spindle, 2 gears and a compound gear on the tumbler (reversing selector) or 4 gears (two are on one shaft) on the banjo.
As far as age goes, what is your model number? "12" sears/atlas 101" plus asking about change gears tells us that it's a lathe, isn't a 6" and isn't a band saw or drill press but not much else. If the model number is 101.27440 or lower, it was made between 1934 and 1958. The only dates known to be on the machines are engraved into the spindle bearings. Knowing the actual model number will narrow the possible age range somewhat.
If the model number is higher, it was made between 1958 and 1981. A date is still to be found on the bearings plus the casting date of the bed should appear in raised numerals on the back side of the bed. However, on my Atlas 3996, which I happen to know was made in 1980, the casting date is illegible.
There is also some uncertainty as to whether the date on the bearings was engraved while the machine was being assembled or is the bearing inspection date because of the fact that at least a couple of lathes have turned up with the two bearing dates several months apart.
Robert D.
Regardless of model, there are 10 gears in the standard Atlas or Craftsman 12" lathe Change Gear set. Two of which are 32 tooth. This count does not include 5 gears in or on the headstock/spindle, 2 gears and a compound gear on the tumbler (reversing selector) or 4 gears (two are on one shaft) on the banjo.
As far as age goes, what is your model number? "12" sears/atlas 101" plus asking about change gears tells us that it's a lathe, isn't a 6" and isn't a band saw or drill press but not much else. If the model number is 101.27440 or lower, it was made between 1934 and 1958. The only dates known to be on the machines are engraved into the spindle bearings. Knowing the actual model number will narrow the possible age range somewhat.
If the model number is higher, it was made between 1958 and 1981. A date is still to be found on the bearings plus the casting date of the bed should appear in raised numerals on the back side of the bed. However, on my Atlas 3996, which I happen to know was made in 1980, the casting date is illegible.
There is also some uncertainty as to whether the date on the bearings was engraved while the machine was being assembled or is the bearing inspection date because of the fact that at least a couple of lathes have turned up with the two bearing dates several months apart.
Robert D.
- Joined
- Dec 25, 2011
- Messages
- 10,552
Well, it depends upon how you define "really old". Be careful how you answer as some of us on here may be older than your definition! 
I have to look something up first but after dinner, I'll give you the approximate range. I can say without the lookup, though, that Sears changed their catalog and model number assignment system in late 1950 and production of 101.07403 overlapped production of 101.27430 and 101.27440,
Robert D.
I have to look something up first but after dinner, I'll give you the approximate range. I can say without the lookup, though, that Sears changed their catalog and model number assignment system in late 1950 and production of 101.07403 overlapped production of 101.27430 and 101.27440, Robert D.
- Joined
- Dec 25, 2012
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When I got it from a co worker ( fellow machinist ), I didn't know what "brand" it was. A couple guys on other forums identified it and I sent a couple pictures to Tony who has the UK based lathes website.
I ended up taking more pictures.
http://www.lathes.co.uk/atlas/page2.html
My lathe is half way down this page ( the painted blue one in the pictures )
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- Dec 25, 2011
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Jeff,
OK. That qualifies as pretty old. But what you have is an Atlas 918, not 818. I can send you a photo from the 1932 Sears catalog. Your machine has the optional compound rest cross slide (cost $15.50 extra). And is missing the ON-OFF switch that was originally mounted on the headstock above the FWD-REV gearbox. The hole for the wiring is there.
Robert D
OK. That qualifies as pretty old. But what you have is an Atlas 918, not 818. I can send you a photo from the 1932 Sears catalog. Your machine has the optional compound rest cross slide (cost $15.50 extra). And is missing the ON-OFF switch that was originally mounted on the headstock above the FWD-REV gearbox. The hole for the wiring is there.
Robert D
- Joined
- Dec 25, 2011
- Messages
- 10,552
bluedxj,
Based mostly on Sears catalog dates, it appears that the 101.07403 was in production from 1939 until 1957 or early 1958. +/- 6 months on each end. Atlas (and Craftsman) came out with a Quick Change Gear Box in late 1950 (first appeared in the 1951 Sears catalog). Prior to 1951, the Sears Model Number did not specify the bed length. So absent additional information from you, we don't know whether your bed length is 36", 42", 48" or 54" (bed lengths correspond to 18", 24". 30" or 36" between centers). Production of the 36" and 48" (18" and 30" centers) machines ceased sometime in 1947. The most common model produced overall seems to have been the 12X36 (54" bed length). The QCGB was also sold as an accessory to retrofit to the older models back to about 1936. So a few more details may or may not narrow the date range on your machine.
Robert D.
Based mostly on Sears catalog dates, it appears that the 101.07403 was in production from 1939 until 1957 or early 1958. +/- 6 months on each end. Atlas (and Craftsman) came out with a Quick Change Gear Box in late 1950 (first appeared in the 1951 Sears catalog). Prior to 1951, the Sears Model Number did not specify the bed length. So absent additional information from you, we don't know whether your bed length is 36", 42", 48" or 54" (bed lengths correspond to 18", 24". 30" or 36" between centers). Production of the 36" and 48" (18" and 30" centers) machines ceased sometime in 1947. The most common model produced overall seems to have been the 12X36 (54" bed length). The QCGB was also sold as an accessory to retrofit to the older models back to about 1936. So a few more details may or may not narrow the date range on your machine.
Robert D.
sorry mines a 12x36 with no quick change infact its missing most of the change gears for threading and im looking to pick up a set on ebay just wanted to make sure the set was complete most sets ive seen on ebay were 9 or 10 gears.