From: "Scott S. Logan" <ssl@l****.com>
Date: Tue Apr 18, 2000 7:53 am
Subject: Logan Lathe Back Gears
I recently posted the following on rec.crafts.metalworking, and thought
here might find it useful.
There is obviously a lot of confusion here and elsewhere on the Back
Gear engagement for Logan Lathes, so I will try to explain. BTW,
don't anyone feel bad, I get phone calls like this about every week.
On ALL Logan 10" and 11" Lathes, as well as Montgomery Wards
Power-Kraft Lathes, there is a rod (called the Shifter Rack) on the
front of the Headstock which engages the Back Gears. This rod has a
rack cut into the underside, not visible from outside in normal
The Shifter Rack also has a spring-loaded latch on the underside, just
behind the knob. See
To engage the Back Gears, this rod is PULLED OUT, after pulling out
the pin on the Bull Gear (800 Series lathes prior to s/n 37063 have a
lever on the Bull Gear).
If the Shifter Rack is "out of synch" and requires adjustment, the
procedure is as follows:
1. Remove LA-243 collar from back end of Shifter Rack
2. Pull Shifter Rack Assembly forward, completely out of the
3. Roll the eccentric shaft so that Back Gears are in mesh with the
Bull Gear and Cone Pinion. This part can be difficult. Sometimes you
can reach around the Cone Pulley and cause the eccentric to roll
around, otherwise you need to push on the gear that is engaged by the
4. Slide the Shifter Rack into the Headstock, and it will engage the
gear, causing the eccentric to roll around to the disengaged position.
5. Reassemble the collar on the back side of the Shifter Rack.
6. Pull the Shifter Rack out, and check for proper engagement of the
Back Gears. If there is excessive backlash, repeat the entire
procedure, trying to "catch" a different tooth with the Shifter Rack.
The design of the Back Gear arrangement on these lathes provides for
positive lock in of the Back Gears, and allows cuts to be made up to
full capacity either in forward or reverse spindle directions. I have
taken cuts on an 11" Logan on 8" diameter Cast Iron at 0.06" deep,