Information needed regarding "Carriage Feed"

Jack,

Look at the chart on the front of your QC box. Just left of center is a column headed "SLIDE GEAR". From top to bottom, it reads IN, OUT, OUT, OUT, OUT. This is the column that tells you where the sliding gear should be. The IN position is only used when you need to cut threads between 4 and 7.5 TPI. So 99% of the time, the gear should be OUT. There is a drawing of the chart in the earliest 12" GB manual but not the latest and not in the 10" box manual. I'm not sure about the middle 12" one as although I have a hard copy, I can't lay my hands on it right now and we don't have a scan of it.

The Yahoo Atlas_Craftsman Group Files section has manuals on the ATLAS 1500 and 1570 10" boxes and the first and third version Craftsman 12" boxes. This site (H-M) had the same files in Downloads but I haven't yet had time to check whether they survived the crash and the several month hiatus. We are slowly getting it back up and running with new software (previous provider went out of business).

Robert D.
 
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Robert:
Thanks for the post.
Leaving the slide gear in the "out" position, will make my life much more simple. I like simple.
Jack
 
I'm very new to this. Would it be correct to assume that I can use a compound gear from a pre quick change atlas 10" machine to accomplish the slower feed speed?
 
DennisV said:
I'm very new to this. Would it be correct to assume that I can use a compound gear from a pre quick change atlas 10" machine to accomplish the slower feed speed?
Click to expand...

You certainly can Dennis, you can also cut metric threads by changing one of the twin gears next to the g/box, I've done both and it works fine for me.

However, there is a simple way (cleverly worked out by Atlas-owner Carvel Webb) to generate a limited range of the more common metric pitches. Because the 30 t.p.i., 24 t.p.i and 20 t.p.i positions represented the same ratio intervals as 1 mm, 1.25 mm and 1.5 mm pitch if one could convert the 30 t.p.i. position to 1 mm pitch, then the 24 t.p.i and 20 t.p.i positions would correspond to 1.25m and 1.5 mm. Now, 30 t.p.i = 25.4/30 = 0.8467 mm. Close, but not close enough, so how to get this closer to 1 mm ? Using 52 and 44-tooth gears gives 0.8467 x 52/44 = 1.0006 mm - which is almost spot-on. The tumbler gears in the Atlas set include a 32/16 shielded gear driving a 40 tooth sliding gear which in turn drives the box through a back-to-back pair of 48-tooth idlers. Because the 52/44 combination fits neatly in place of the 48/48 idler the job can be done. With the 40-tooth sliding gear engaging the 52-tooth gear to the box, the 52-tooth gear is acting as an idler (with the 44-tooth gear as its spacer) and the gearbox operates in its normal `Imperial Mode' - but with the exception of the coarsest (seldom-used) range. However, with the 40-tooth sliding gear in the other position, it engages the 44-tooth gear of the 52/44 combination and introduces the 52/44 ratio into the train. The 30, 24 and 20 positions, or 60, 48 and 40 positions, become the desired 1 mm, 1.25 mm and 1.5 mm pitches, depending upon whether the 52-tooth gear of the 52/44 pair has been placed closest to, or away from, the headstock. However, placing it away from the headstock maintains the bulk of the t.p.i. and feed settings (as per the chart on the gearbox). It also means that it's not necessary to remember to double everything - as would be the case if the sliding gear was driving off the 32-tooth part of the shielded tumbler gear. All that is now required to switch between the normal "Imperial Mode" and the "Basic Metric Mode" is the few seconds it takes to loosen the yoke and to move the sliding gear in or out.

This was taken from this excellent site: http://www.lathes.co.uk/atlas/page11.html

Bernard
 
Thanks Bernard, for the help. I'll start looking for the gears and stud as time permits. thanks again
 
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