Karl,
The original Eureka was said to have been made in four days. My first
longer
version was done over a period of two weeks. The plates were made
using
a rotary table and boring head a lot while following the plans
closely.
Holding the parts is the hardest thing to do.

The main arbor has three offsets that make it tricky. I used extra
length at
the ends so two sets of centers could be milled off and the relieving
centers
then drilled. The offset is only .030" so it must be done later.

The Eureka described in Workshop Series 17 has the curves of Balzer's
1896 reliever that inspired it. My second version with the pattern
thread
just needed still longer parts and used the Eureka mechanism to drive
it. My half nut carrier has no curves at all.

The Balzer has only one ratchet and uses friction washers to keep it
from freewheeling when not being turned by its ratchet. The Eureka has
a second ratchet that seems like an after thought to do this. I have a
cork friction washer and Eureka's ratchet on mine.

I am cutting A2 steel with broad flat topped cutters making my hobs
so I can't take much of a cut. They have a 7/8" bore and a 1/8"
keyway.

Charlie



On Jul 24, 10:24*pm, "Karl Townsend"
wrote:
Very impressive project. I remember reading about the eureka and thinking it
was too big a job for me to take on. Do you know about how many hours you
spent on construction?

Karl