Older tech used in the original design.
The plunger and spring were contained within the rod body by a collar that was staked to the body. Dunno how the early staking was done, but I've been told that in recent years it's been done on a machine, controlled by hand, involving pressing the "dimples" into the rod body in 3 steps (turning the rod to spread out the indentations around the body).
Doing this by hand means it may result in spacing differences, as well as depth of the indentation. The particular material for the rod bodies, and their production (heat treating, etc), might also result in differences.
See the different depth/size of the indentations, as well as the different spacing, in this pair of rod assemblies?
If the staking were to become loose, it might result in the collar and rod separating, which could result in the rod coming out the end of the slide. Typically, armorers are told to replace the rod assembly if the collar can be turned by gentle fingertip pressure (while holding the rod body in the other hand).
The solid 1-piece rod body has been around for a long time, but it didn't really become a standard assembly item in most models until in more recent years. The CS45S I bought early in its production came with a rod assembly of the 1-piece design, as did the later production CS9S, but I was still getting spare guide assemblies for the 4566TSW's of
both designs in the last few years. I saw one shipment of 4513TSW's come with staked 2-piece rods, and then the next shipment come with 1-piece rods.
The advantage of the 1-piece unit is that the collar is machined into the body. No staking to work itself loose over time.
Getting the plunger and spring for the 1-piece units isn't easy, though. Don't lose them. It's apparently easier to get the whole 1-piece assembly (including plunger & spring) than the separate plunger & spring ... unless you order the rod assembly and get
only the rod body (lacking the plunger & spring), BTDT.
There have also been 3 types of plungers made for the 1-piece assemblies. One is plastic and the other is steel. The spring snaps onto a specific end of the plunger (small end of spring), and the "assembled" plunger & spring is inserted down into the rod body, large end of the spring into the rod body. Twisting the spring during insertion helps compress the spring.
FWIW, I've had to help maintain a fair number of 3rd gen's over the years, including several hundred early production models that saw upwards of 16-20 years of service. I only had to replace a handful of the older rod assemblies for having the staked collars come loose.
Regardless of whether the design is the staked unit or the 1-piece unit, it's prudent to inspect in during normal cleaning, looking for any potential damage, breakage or unusual wear. While I've never encountered it, I was told of some rods bodies in some 4566TSW's that had become peened and somewhat "mushroomed' at the front ends, resulting in some clearance issues between the end of the guide rod and slide. I was told it was felt to have been caused by a production/tempering issue.
That can happen to anyone's metal rod body, though, as I was told by a major well known vendor of it having occured with some metal aftermarket rod bodies they sold for Glocks at one time.
Doesn't matter whether we're talking plastic or metal parts, there may be rare occasions when unexpected things can happen during manufacturing & production.
BTW, I still use both staked and 1-piece units in various models & calibers, depending what's at hand in my parts boxes, and I'm confident and fine with using either of them. Just my thoughts.
Guide rods
) of things I've posted.
Linear Mode
