Hi Joe,

Yes I have built the Gingery Lathe. I didn't have too much trouble
casting the bed. Second try was virtually perfect.

What I've found though is that the deflection at the center of the bed
is so bad that the lathe is almost unusable for fine work. I have yet
to make my tailstock but I mounted a 4" 3jaw chuck and although I can
face off without much chatter, turning down diameters is impossible.
The virbration and flex are the reason.

But, and here's the big but. I've done a survey with my local metal
working mail group and what I've found is that the Gingery bed and
ways are vastly undersized given the diameter and horsepower
available.

Essentially my research has shown that if the center height of the
lathe is 3.5" then the bed casting should be at least 3.5" square with
suitable re-enforcing to transfer the twisting moment to the sides.
i.e. to prevent twisting as much as possible.

Additionally the ways should project out side of the bed casting by
about 20% of the width of the casting. so the CRS bedway should be 4"
wide, not 3".

This holds true for Lathes up to 8" center height. Those have a
bedcasting in the neighborhood of 8" square.

Next, take a look at Myford or any other 3.5" center height lathe and
you'll see that the ways are around 1/2" thick. Once again that
implies that the CRS should be 1/2"x4".

Now I'm nor quite ready to go the box steel route yet although that is
on my do list. I know the basic lathe is quite solid because a 60
degree center on the end of the spindle is beautiful. My faceplate
cuts really nicely. I've made a number of pulleys including a dual
one for my sailboat engine without effort.

Take a look at other lathes again and you'll find that most have the
foot under the spindle equal in length to the width of the spindle
assembly. Some have it even longer. That in itself would strengthen
the bed (towards the center section) and still fit withing the 6 pound
crucible limitation.

So that's one of my projects. A new LHS foot casting.

Also on the list is to anchor the 1/4"x3" CRS bedway onto the casting
closer to the edge with hex flathead head #10 screws. These will be
counter sunk so that they just clear the pads on the carriage and
hopefully will just go into the thickest part of the bed casting.

The reason for the above modification is that the aluminium flows
around the 3/8" bolts holding down the bedway and the bedway develops
a dip where the bolts are. I discovered this when I used a diamond
lapping stone to flatten a bit of the CRS. It touced the edges and a
2" circle around each 3/8" hold down bolt. In retrospect, I believe
that the bedway (and bed) is also being twisted around the 3/8" center
line bolts. A parallel line of screws will do a lot to reduce that
twist.

Finally another major design flaw on the Gingery Lathe is in the
half-nut assembly. Once again, examine the tried and true products
out there and you'll find that the leadscrew is almost exactly
underneath the front ways. Gingery has it forward of the front ways
and that creates a twisting moment. Makes the carriage jam and harder
to move regardless of how well you've set it up.

For some reason, he also designed the half-nut to be offset from the
center of the carriage and cross slide leadscrew and that creates a
second twisting moment to the carriage. What I did was put the
half-nut shaft under the cross slide and had the lever project out to
the right. It could be to the left too for all it matters.

I have my core plate complete and I just need to cast and machine the
top part of the tailstock. The base is on the bed and scraped and
adjusted. I've also bored a nice MT#1 hole into the spindle for a
removable center. Once the tailstock is done, I'll make a D bit and
drill the spindle for a knockout bar since the MT center fits very
nicely.

John


"Joe" wrote:

Hi..
I was wondering if anybody had built the Gingery lathe and if they had
used alternative methods for the lathe bed.
Looking at the plans I was wondering if CRS 2"X1/4" square tubing for the
bed would be ok if filled with concrete to absord vibration?
I was thinking just to mount the ways directly to the bed after scraping
with lock nuts inside.
Some have pointed out that if one needs to take apart the ways you
could'nt. But I see no reason to take off the ways if done right and would
probably outlast me..: P
Main thing I am concerned with is would CRS and concrete would absord
vibration and make a good bed?
Thanks in advance..Joe