Ok, so the problem is identified... I
need to eliminate both lateral and vertical movement of the tool head
when installed. Unfortunately, the solution was not nearly so easy to
define. With the 550B fully setup to load, I basically began to
"stare" at the machine. I do this a lot when trying to attack
engineering problems, but that is a whole different article.
At first blush, one thinks of simply
shimming the tool head to rail fit such that the vertical movement is
eliminated. While this might certainly work, shimming would only address
the vertical movement. No problem. In addition to shimming, we can add
jig pins (locator pins) that will provide tighter tolerances and thus
less lateral movement. Unfortunately, this "combo-approach"
still doesn't eliminate all lateral movement, and it all but destroys
one of the most attractive features of the machine: "quick change
tool head". OK... so I backed up, had a beer, and started over...
I "auditioned" several other
approaches like tool head set screws and the like, but they all had
short-comings that outweighed their benefit. For instance, while set
screws would definitely eliminate all movement, the thought of
tightening 4 set screws on every caliber change was not so attractive.
Not to mention, the set screw solution would require drilling, tapping,
and other invasive/difficult operations on the machine frame itself.
I finally decided to pursue a
"clamping" solution. This solution had the greatest potential
for solving the "problem", while simultaneously avoiding
most/all of the less attractive features of the other solutions.
My clamping solution:
a. eliminates all vertical
b. eliminates all lateral movement
c. preserves the "quick change" feature
d. avoids modifications to the 550B frame
e. is easily installed/removed.
f. is compatible with Dillon dies/lock rings
g. is compatible with Redding dies/lock rings
h. is compatible with Forster lock rings
i. allows die adjustment with clamp installed
j. does not interfere with powder measure, and
k. can be produced relatively easily as an upgrade to all RL 550B
So enough with the words already, right?
Let me show you where I am with this project right now and a little bit
about how I got here...