Improving Tool Alignment: 5 Ways To “Float”

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail
Facebooktwittergoogle_pluspinterestyoutube

“If it’s not perfectly aligned, then it should float…” Here’s a few tips on improving concentricity in the handloading process.


Glen Zediker


Water seeks its own level. Moving parts seek their own centers. Trick is getting the centers to agree. When centers coincide, that’s “concentricity,” and that a prime goal in the process of creating better ammunition. Anything under pressure and moveable, such as a cartridge case being sized or a bullet being seated into a case neck, moves toward a path of least resistance. If all the tooling associated is straight, and the case hisseff is uniform, then the result is “straight.” However! That’s in a perfect world.

In reality, which is accepting existence of tolerances and misalignments, taking steps to help two conflicting centers come close together comes from providing some free-play in the apparatus. I call it “floating.” And it works, and here are a few ways to use it.

Now, free-floating can work two ways. One is to incorporate a float into the mechanism in use, and another is to create float, and then use that to center a piece prior to snugging it down.

1. Shellholder
This first one might seem a tad amount clumsy, but it’s really easy to get used to in operation. Presses with conventional shellholder arrangements use a spring clip to retain the shellholder in its slot atop the press ram. Get this clip gone! It cocks the shellholder askew.

The solution is to incorporate an o-ring to retain the shellholder in its slot. Get one at any real hardware store. Size that works is usually 7/8-inch outside diameter, 11/16 inside diameter, 3/32 thickness. The o-ring fits into the exterior channel previously occupied by the spring clip. To install a shellholder you just roll the ring down a tad, slide in the holder, and let the ring back up to block its exit out the front.

This modification lets the shellholder sit flat, as it should, and also provides some wiggle room so the case can align itself with the die opening. [Photo from Top-Grade Ammo]
This modification lets the shellholder sit flat, as it should, and also provides some wiggle room so the case can align itself with the die opening. [Photo from Top-Grade Ammo]
2. Sizing die lock ring
Speaking of wiggle room, there’s a whopping lot of it in a 7/8-14 thread set. That’s pretty coarse. Taking up the play created by thread-to-thread gaps goes a good ways toward “straight” installation of a die into a press. There are a couple of ways to help this.

One is to always (always) tighten a die locking collar ring when there is a case inside the die, and the ram is fully extended upward (handle all the way down). This bit of pressure helps to bring the die into straight alignment. Problem is that it also makes the daggone die hard to remove. Just get stern with it. After initial removal, subsequent re-fittings are easy. I use a “strap wrench” (plumbing supply and real auto parts stores have one for you) if it’s stubborn to turn loose after being tightened initally. Pliers result in cosmetic, but not real, damage. Lock rings with wrench-flats are dandy.

Always put an index mark from die lock ring to die body to press top. That’s a simple way to verify return to “zero” when a die is installed back into your press. And ALWAYS install and remove the die holding ONLY the locking ring! Never-ever the die body. Any teeny body rotation within the locking ring, which is easily undetectable, requires repeating the process of die adjustment.
Always put an index mark from die lock ring to die body to press top. That’s a simple way to verify return to “zero” when a die is installed back into your press. And ALWAYS install and remove the die holding ONLY the locking ring! Never-ever the die body. Any teeny body rotation within the locking ring, which is easily undetectable, requires repeating the process of die adjustment.
I prefer clamping lock rings, like these from Forster. Those with a set screw can cock when the screw tightens in against the angled threads.
I prefer clamping lock rings, like these from Forster. Those with a set screw can cock when the screw tightens in against the angled threads.

For these tricks, choose a case that represents your best: get one with the most consistent neck wall thickness.


3. Expander/decapping assembly
There’s some “feel” involved in this one, but it is worthwhile. To get the expander in your sizing die sitting on center, run up a case fully and then slowly withdraw it until you feel the expander lodge inside the case neck. Then put a little pressure down on the handle, in the direction of raising the ram, while you tighten the locking apparatus.

When it’s possible, and it almost always is, secure the pieces-parts when they’re doing their jobs. For instance, tightening the locking rings on a decapping stem when the expander is holding inside the case neck helps bring the stem into straight alignment, and the expander along with it.
When it’s possible, and it almost always is, secure the pieces-parts when they’re doing their jobs. For instance, tightening the locking rings on a decapping stem when the expander is holding inside the case neck helps bring the stem into straight alignment, and the expander along with it.

4. Lock-ring o-rings
Here’s one I suggest but don’t usually follow… Lemmesplain: It works but I prefer these other means because they’re more “secure.” However! Installing an o-ring up under the die body locking ring (sizers and seaters) provides a cushioned flexibility that provides for takeup in the amount and “direction” needed when a case is run up into a die. O-ring size is 7/8-inch inside diameter and a thickness of 1/8-inch.

O-ring trick: the flexible ring allows for some “wiggle room” to help case and die centers match. Trick is reinstalling the die to hold the desired setting, and the index mark really helps. Hold only the lock ring when threading the die in and out!!
O-ring trick: the flexible ring allows for some “wiggle room” to help case and die centers match. Trick is reinstalling the die to hold the desired setting, and the index mark really helps. Hold only the lock ring when threading the die in and out!!

5. Bullet seating die stem
This one is pretty simple: tighten the lock on the stem when there’s a seated bullet run up into the die. Threads are finer on stems than on die bodies, but better is a better. This is for a conventional-style seating arrangement. Those that use a spring-loaded sleeve arrangement, like a Redding Competition Seater, are good to go as are.


The preceding is a specially-adapted excerpt from the book Top-Grade Ammo just released by Zediker Publishing.

Facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

7 thoughts on “Improving Tool Alignment: 5 Ways To “Float””

  1. Learned a lot of good, new info from this article. Began reloading in 1963. Kudos!
    Note: Lee has used o-rings on dies for a long time. I cut my teeth on RCBS but I am a Leesman. U S A!!

  2. So what is an acceptable and an ideal amount of run out (thousandths of an inch)? Most of my reloads are running 0.003″ or less. How much improvement can I expect if I use these techniques and tricks?

Comments are closed.