Squaring case head with base

[Mulligan]

Preparing Brass for Match Shooting

www.chuckhawks.com

Step 11 indicates some competition shooters are or have been squaring up the case heads with the base of the cases.

I am still pondering this one, but thought I would toss it out there and see what is gained from this endeavor.
CW

 

[BoydAllen]

Years ago I tried that on some of my .222 cases using my Wilson trimmer. Things were going along fine when I noticed that all of the cutting was taking place on the same side of the case as it sat in the trimmer. This led me to the conclusion that the cutter bearing was not square to the "ways". I called Wilson and they verified what I had found. We both agreed that theirs are very good trimmers but that they are not built for squaring case heads. Any time your turn a cutter rather than the work you can have alignment issues. That is why we turn barrels and not chamber reamers. This is why I favor my trimmer that allows me to spin the case while holding the cutter stationary. It is made by PMA Tool, but there are others that do the same thing.

 

[Mulligan]

Years ago I tried that on some of my .222 cases using my Wilson trimmer. Things were going along fine when I noticed that all of the cutting was taking place on the same side of the case as it sat in the trimmer. This led me to the conclusion that the cutter bearing was not square to the "ways". I called Wilson and they verified what I had found. We both agreed that theirs are very good trimmers but that they are not built for squaring case heads. Any time your turn a cutter rather than the work you can have alignment issues. That is why we turn barrels and not chamber reamers. This is why I favor my trimmer that allows me to spin the case while holding the cutter stationary. It is made by PMA Tool, but there are others that do the same thing.

Boyd,
I read some of the earlier posts including yours on this topic. I didn’t see any tests or ideas guiding a person one way or another. Was it just an idea or are folks doing this and if they are, are the efforts worth the squeeze?
CW

 

[SeabeeKen]

Would it be better to just machine the bolt face square to the bore or some other method of squaring it up to the bore? I had a situation where the sizing die was throwing the case out of square. The maker made it right but the brass was ruined

 

[BoydAllen]

Boyd,
I read some of the earlier posts including yours on this topic. I didn’t see any tests or ideas guiding a person one way or another. Was it just an idea or are folks doing this and if they are, are the efforts worth the squeeze?
CW

I don't know of anyone doing this. If I wanted to give it a serious try I would chuck up a piece of stock and Drill and bore a taper that would hold cases that were tapped into it like a Morse taper works, and remove them using a knock out rod through the spindle. I would face them off advancing the cutter with the cross slide. While I was at it, I might try relieving the head a few thousandths so that the only contact with the bolt face was the part of the head that was inside of the ID of the case wall. I believe that it was Creighton Audette that published work that demonstrated that barrel vibrations are influenced by the orientation of variations in case wall thickness, with differing results happening when the thin side of a case was rotated to different positions in the chamber. If this is because the head is hitting the bolt face sooner where the body is thinner, then reducing the radius of the contact patch may help minimize that effect, but of course this is PURE speculation. The good news is that someone with a mini lathe could do the experiment with what he already owns. Keep in mind that the case holder would only be true while it remained in the chuck.

 

[Mulligan]

I don't know of anyone doing this. If I wanted to give it a serious try I would chuck up a piece of stock and Drill and bore a taper that would hold cases that were tapped into it like a Morse taper works, and remove them using a knock out rod through the spindle. I would face them off advancing the cutter with the cross slide. While I was at it, I might try relieving the head a few thousandths so that the only contact with the bolt face was the part of the head that was inside of the ID of the case wall. I believe that it was Creighton Audette that published work that demonstrated that barrel vibrations are influenced by the orientation of variations in case wall thickness, with differing results happening when the thin side of a case was rotated to different positions in the chamber. If this is because the head is hitting the bolt face sooner where the body is thinner, then reducing the radius of the contact patch may help minimize that effect, but of course this is PURE speculation. The good news is that someone with a mini lathe could do the experiment with what he already owns. Keep in mind that the case holder would only be true while it remained in the chuck.

Yep, it would be easy enough to test. That is why I suspect many have, but where are the results?
Depending on what this thread uncovers, I may have to give it a go.
CW

 

[BoydAllen]

Yep, it would be easy enough to test. That is why I suspect many have, but where are the results?
Depending on what this thread uncovers, I may have to give it a go.
CW

I hope that if someone does post results that he posts including his real name, just as you do.

 

[justinp61]

Years ago I tried that on some of my .222 cases using my Wilson trimmer. Things were going along fine when I noticed that all of the cutting was taking place on the same side of the case as it sat in the trimmer. This led me to the conclusion that the cutter bearing was not square to the "ways". I called Wilson and they verified what I had found. We both agreed that theirs are very good trimmers but that they are not built for squaring case heads. Any time your turn a cutter rather than the work you can have alignment issues. That is why we turn barrels and not chamber reamers. This is why I favor my trimmer that allows me to spin the case while holding the cutter stationary. It is made by PMA Tool, but there are others that do the same thing.

Boyd
If it wasn't cutting the base square was it also not cutting the mouth out of square?

 

[BoydAllen]

Boyd
If it wasn't cutting the base square was it also not cutting the mouth out of square?

Yes. I invite anyone who is curious enough to try squaring case heads exactly as I did. It may be that there is a point of diminishing returns for squareness of case mouths. Here is an article includes very low definition pictures of a gauge that could be used to measure case head flatness runout. The mouth of the case is put on a bearing ball and it is supported near the head by a bent wire V. the case is rotated in that position and runout is measured with a test best type indicator. It looks to me like this rig would not be that hard to duplicate, at least the part that measures head runout. After trying to upload the file: Unfortunately the file was too large, but I found some better pictures in this post. https://forum.accurateshooter.com/threads/creighton-audette-case-inspection-gage.4026237/

 

[Dusty Stevens]

You could probably use a rig like that newer neck turning machine and just have that caseholder in backwards and come up with a different cutter

 

[BoydAllen]

You could probably use a rig like that newer neck turning machine and just have that caseholder in backwards and come up with a different cutter

Which one would that be?

 

[Dusty Stevens]

Which one would that be?

Is it an irod maybe? I cant remember

 

[BoydAllen]

Got it.

 

[STS]

The best way I’ve found to square the case head is to apply about 60,000 psi to it against a square bolt face. Works every time.

 

[jackieschmidt]

If you do not have a engine lathe, and a way to set up the case body with zero runout, you are probably wasting your time, and possibly Making things worse.

Years ago, I did this for a rather bizarre reason. We were finding that our current lot of 220 Russian brass had a fairly prominent convex on the case head face. After several firings, the primer pockets would get so tight you could hardly seat the primers.

Boyd Allen probably remembers this.

I made a fixture that allowed me to single point the faces dead flat.

the problem went away. Subsequent lots of 220 Russian did not have the problem.

 

[Mulligan]

If you do not have a engine lathe, and a way to set up the case body with zero runout, you are probably wasting your time, and possibly Making things worse.

Years ago, I did this for a rather bizarre reason. We were finding that our current lot of 220 Russian brass had a fairly prominent convex on the case head face. After several firings, the primer pockets would get so tight you could hardly seat the primers.

I made a fixture that allowed me to single point the faces dead flat.

the problem went away. Subsequent lots of 220 Russian did not have the problem.

Jackie,
I am looking for feedback from folks that have done this. Your comment is perfect. If I understand you correctly, you had some problem brass and turning the face helped with that problem. Since then, you do not bother with this process. Do I have this correct?
Thanks
CW

 

[257ack]

shoot it 50,000 psi will square it up