Model Engineers’ Workshop – July 2019

July 2019 21

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Denford Synchro

the cover which would have prevented
the lathe being started when the cover
was open, but this had been disabled by
a previous owner. To get the full range of
pitches/ speeds a set of 7 stud gears is
supplied, from 16T to 35T, stamped ‘A’ to ‘G’,
and in addition to manipulating the levers
on the box, it is necessary to check that the
correct stud gear is in place. My spare gears
are stored on a spindle inside the gear cover
door, retained by a large wing nut, photo 6.
It sounds quite complicated but is in reality
pretty quick to operate once you have the
hang of it.

Apron and Saddle
The apron (Photo 7) is a delight to use. On
the right-hand side is the lever controlling
half nut engagement, and in the middle
another lever, up to engage, down to
disengage fi ne feeds. It is very light to use
and doesn’t lock up under load as so many
do. These two levers are interlocked, so
they can’t be both engaged at the same
time. On the left -hand face of the apron
is a large knurled knob, twist one way to
select longitudinal feed, twist the other
way to select transverse (facing) feed.
There is a moveable collar on the feed
shaft below the leadscrew, which when
it is contacted by the face of the apron,
disengages a dog clutch, and stops
longitudinal feed. Its only a safety device,
because it takes about 1/4” of saddle
movement to fully disengage it and should
not be relied upon for working up to a
shoulder. I believe some machines had a
similar fi tting to automatically disengage
the half nuts when screw cutting, but mine
doesn’t have this. Presumably, when these
machines were used in training workshops,
the instructor would have set these stops
before letting the trainees loose on them.
The saddle lock is a square headed bolt
which hides under the topslide. I found
that one end of an old double ended brake
adjustment spanner fi tted the square
perfectly, and stays permanently in place,
so no groping under the topslide with a
spanner when I want to lock or unlock the

saddle. One surprising omission, given

the size and date of the machine, is that

there are no felt wipers on the saddle nor

is there any sign that there ever were any.

Rectifying this is something I’ve been

meaning to do (I’ve even got the felt to

do it with) but haven’t got around to yet.

There is a suds delivery pipe attached to

the saddle, but I must admit that I’ve never

used the suds pump, because I think it

would splash too much around in a small

workshop. I just use a household plant

sprayer, fi lled with soluble oil at a dilution

of 5:1, rather than the recommended 15:1,

which I fi nd leaves a nice oily deposit on

the machine, and doesn’t seem to cause

corrosion or staining.

Speeds

A single lever on the front of the headstock

engages or disengages the back gear, photo

8. A lever on the top of the headstock adjusts
   the variable speed pullies and can lock at one
   of six available locations, photo 9.
   The original Denford sales brochure
   gave the speed range as 70-260 in back
   gear and 400-1600 in direct drive. This

...I must admit that I’ve

never used the suds pump,

because I think it would

splash too much around in

a small workshop.

7 8

9

The apron and its controls. The large knob on the left selects
transverse or longitudinal feeds, the lever on the right engages the
half nuts and the lever in the middle engages the selected feed.

The single lever control for the back gear

Headstock speed control. The lever controls the variable speed pullies and can only be moved

when the lathe is running.