# Info on Sears Roebuck 101.27440 or 101.07403 + QCGB lathe



## better-lathe-than-never (Sep 22, 2021)

I'm evaluating this machine for possible purchase so I'm trying to find out the approximate year this machine was made as well as any relevant information.  Looks like it maybe a UK model...


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## better-lathe-than-never (Sep 22, 2021)

Here is a pic of this model.


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## pontiac428 (Sep 22, 2021)

Sure looks clean from here!  I'd kill to have a QCGB at this point.  Good looking Atlas Lathe you've found.  Is the price right?


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## better-lathe-than-never (Sep 22, 2021)

Thx - he's asking $1800, which includes the bench, 3 and 4-jaw chuck, live center and some HSS bits, which for around here is about right, a bit above my budget, but I think we can stretch it (or negotiate it down).  Just hope the ways, screw, or bearings aren't worn out.   Plan on seeing it in person tomorrow (if it lasts).


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## pdentrem (Sep 22, 2021)

Good luck! Looks to be 36” CtoC!
make sure to find all the gears, tools and gadgets that you will need.


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## wa5cab (Sep 25, 2021)

First off, that is not the correct model number for that machine.  If it is, as it appears to be, a 12x36 (bed LOA is 54"), the model number is probably 101.27440 made between 1950 and mid-1957.  Or it could be a 101.07403 with a 54" bed (so still a 12x36) with the QCGB kit installed.  If the latter, squirreled away somewhere may be a stack of 10 to 15 loose change gears.  If it is a 101.27440 it was made between 1950 and mid 1957.  If it started life as a 101.07403, then it could be as old as 1940 or as new as 1957 with the QCGB made between 1950 and up into the 1970's or 1980's.  I'm not sure just when they quit making the GB.  The drum switch is hiding the front of the headstock so I can't tell whether the headstock is the early type with an oval hole or a late type with a rectangular hole in the front of the headstock casting for the original motor switch.

If it started life as a 101.07403, it may have the original serial number and some letters stamped into the top right end of the front way and the model number stamped on a name plate on the rear of the bed.  Or both serial number and original model number stamped into a plate riveted to the right end of the bed.

Whether it is an original 101.27440 or was originally a 101,07403 doesn't much matter except that if the latter  it could be up to a decade older and could have more wear on the bed and lead screw if it was originally sold as a 101.07403 or could have been made as late as 1957 regardless of which it originally was.

In any case, the presence of the QCGB is a definite plus.  However, $1800 may be a bit much unless it has a few more accessories than you listed.
Having the AXA QCTP is a plus, especially if he has a good assortment of tool holders.  But I would offer him $1200 cash and unless the bed and lead screw are badly worn, take whatever he counters with.

To evaluate bed wear, with a 0-1 micrometer measure the thickness of the front way near the right bearing (for the original thickness) and 6" to 12" from the face of the three jaw chuck.  To evaluate lead screw wear, compare the thread width right next to the right bearing to that near the headstock.

Anyway, post the serial number and correct model number.


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## pdentrem (Sep 25, 2021)

Excellent suggestions. Tooling cost more than the lathe almost 100% of the time!
Exactly the reasoning that I suggested looking around for anything that belongs to the lathe.
Pierre


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## JPMacG (Sep 25, 2021)

That looks like a longer version of my lathe, 101.27430


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## better-lathe-than-never (Sep 25, 2021)

I went out and looked that Atlas machine Thursday night with a friend. The machine looked pretty good at first glance (though he didn't make any effort to clean it up prior to the buyer coming over.... which makes a bad impression for me from the start).  Second impression, the drum switch was wired on backwards and it fell off the machine when I tried to use it.  He then showed me the tooling he had in a drawer:  rusty mismatched set of odds and ends with maybe one live end to keep, the rest were junk.  The chucks were 4'' and looked tiny, there was some poorly made chuck key, no base plate, no face plate, some old rusty dogs, and cheap Chinese bits. Worst thing was that he didn't know how to make the lead screw run - he never used it and couldn't show me the power feed. I had to assume that it wasn't working.  We mounted a piece of 5/8'' mild steel rod in the chuck that I brought with me and tried to run a basic facing operation..... the machine produced somewhat of a radius cut around the face of the rod.... we could not get a straight cut with what he had setup...  We tightened the gibbs on the side - they were very loose.  Still, it made no difference in the quality of the cuts.

It's entirely possible someone who knows what they are doing would have been able to troubleshoot and make proper adjustments on this thing and probably get it to go right, but I don't have any experience with a lathe yet, so dismayed with what I saw I walked away.

He texted me later to tell me he got the lead screw to run, but I told him I need something with more precision than what I saw there. Disappointing.


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## wa5cab (Sep 26, 2021)

FWIW, 101.20140 is the Sears model number of the QCGB.  Did you by any chance happen to note the Model Number stamped on the lathe's nameplate?

For future reference, assuming that the change gears are more or less correctly set up and that both of the selection levers on the front of the QCGB are engaged, to make the lead screw turn under power , with the motor stopped, move the lever located toward the upper left end of the headstock either up or down.  That lever is called the Tumbler.  To get it to move, first pull out on the knurled sleeve and then lift or lower the sleeve.  Start the motor and the lead screw should start turning.  Then note the threading dial on the right end of the carriage.  If it is not rotating, stop the motor, loosen the square head bolt attaching the dial to the carriage (saddle), swing the dial toward the bed to engage the gear on the bottom with the threads on the lead screw, and tighten the bolt.  Restart the motor and when one of the lines engraved in the top of the rotating disk on the dial lines up with the fixed mark, smartly snap down the lever (called the carriage drive or Half-Nut lever) in front of and below  the threading dial.  The carriage should start moving either toward or away from the headstock.  Stop the motor or lift the lever before the carriage runs into anything.  To engage power cross-feed, pull out on the rotating knob sorta up underneath the cross feed crank or screw.


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## better-lathe-than-never (Sep 27, 2021)

>>>Move the lever located toward the upper left end of the headstock either up or down. That lever is called the Tumbler. To get it to move, first pull out on the knurled sleeve and then lift or lower the sleeve. Start the motor and the lead screw should start turning. <<<
We tried messing with that Tumbler (Up and Down), but the lead screw never moved.... that was the frustrating part....


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## wa5cab (Sep 27, 2021)

OK.  When properly set up, all Atlas and Atlas-Craftsman lathes that are fitted with a QCGB have a 16T/32T Compound Gear set up on the left end of the headstock and a 40T and two 48T change gears installed on the Change Gear Bracket (AKA Quadrant AKA Banjo).  Some of those either weren't present or were incorrectly installed or the Banjo wasn't in the correct lifted position.

I take it that you didn't notice the model or serial number.


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## better-lathe-than-never (Sep 27, 2021)

wa5cab said:


> engaged,





wa5cab said:


> OK.  When properly set up, all Atlas and Atlas-Craftsman lathes that are fitted with a QCGB have a 16T/32T Compound Gear set up on the left end of the headstock and a 40T and two 48T change gears installed on the Change Gear Bracket (AKA Quadrant AKA Banjo).  Some of those either weren't present or were incorrectly installed or the Banjo wasn't in the correct lifted position.
> 
> I take it that you didn't notice the model or serial number.


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## better-lathe-than-never (Sep 27, 2021)

>>>I take it that you didn't notice the model or serial number.<<<

Sorry, I didn't get the serial number....  It was too cluttered to get to it anyway...


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## wa5cab (Sep 27, 2021)

OK.  

However, for future reference, the serial number would have been either stamped into the top right end of the front way or on a nameplate on the right end of the bed.  The only thing that might have been on a nameplate on the rear of the bed and probably inaccessible would have been the model number and only if the basic lathe had been an early 101.07403.  Which with the front view photo would have ID'd the model number anyway.


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