23
PM-1228VF v3 2021-05
Copyright © 2021 Quality Machine Tools, LLC
Section 4 SERVICING THE LATHE
Disconnect power before any maintenance operation!
Remove all machining debris and foreign objects before lubricating ANYTHING! Use the
recommended lubricants or similar. Any oil is better than no oil – but only as a stop gap.
LUBRICATION — GEARBOX DRAIN & REFILL
How often? Every 12 months, recommended.
GENERAL
Aside from abrasive particles and machining debris, lack of
proper lubrication is the main cause of premature wear. Ro-
tating parts are easy to lubricate, sliding parts are not. Gibs
are tightened for the best compromise between rigidity and
slideability, which means practically zero gap between the
ways. It is not obvious which are the bearing surfaces on the
various dovetail surfaces — some of the interfaces look like
bearing surfaces, but are simply narrow gaps.
Every few hours of operation: 1. Apply the recommended
way-oil with a dedicated short-bristle brush such as the type
used for applying flux; 2. Use a similar brush to apply oil to the
leadscrews; 3. Apply oil to the ball oilers, see below.
The spindle runs on sealed, pre-lubricated roller bearings re-
quiring no routine attention.
Recommended lubricants
Gearbox
: ISO 68, such as Mobil DTE Heavy/Medium circulat-
ing oil. Alternative: 75W90 gear oil (auto parts store). Approxi
-
mate quantity required is 1/2 pint.
Ball oilers
: ISO 68 way oil, such as Mobil Vactra No. 2, or
equivalent.
Machine ways
(dovetails): ISO 68 way oil, such as Mobil
Vactra No. 2, or equivalent.
External change gears
: light general purpose grease, NLGI
No. 2, or equivalent.
Leadscrews
: ISO 68 way oil, such as Mobil Vactra No. 2, or
equivalent.
BALL OILERS
Use a pump-type oil can, pr
eferably with a flexible spout tipped
with a soft tube. The ID of the tip should be large enough
to seat on the oiler's brass flange, more than spanning the
spring-loaded steel ball. When the oil can tip is firmly pressed
onto the brass surface oil pressure must displace the ball, al-
lowing oil to flow into the bearing. Before oiling check that the
ball is not stuck – press it lightly with a probe.
Figure 4-1
Gearbox fill plug & sight glass
1. Run the lathe for a few minutes to warm the oil if neces-
sary.
2.
With an 8 mm hex key remove the fill plug, Figure 4-1.
3. Locate the drain plug under the gearbox, right hand end
(not shown). Some paint removal may be needed for
access to the hex socket, also 8 mm. Loosen the plug so
it can be removed with the fingers.
4. Place a drain pan under the drain plug, Figure 4-2.
5. Remove the drain plug.
6. Allow the oil to drain completely, then replace the drain
plug and O-ring seal.
7.
Attach a short length of 1/4" ID flexible tube (e.g., clear
PVC) to a small funnel. If using a squeezable bottle of
75W90 gear oil with the usual pointed tip, attach the
flexible tubing directly to the tip, pre-cut to suit the tube on
hand.
8.
Insert the tube into the fill hole, then add just an ounce or
two of oil.
9.
When satisfied that the gearbox is oil-tight, add oil to the
halfway mark on the sight glass (about 1/2 pint).
10.
Replace the fill plug.
Figure 4-2
Drain pan
This example was made from a thin-wall 64 oz
polyethylene box, easily cut with scissors.
LUBRICATION — LEADSCREW
Maintain a light film of oil on both the leadscrew and feed shaft
at all times.
