Question for Giraud users

GardDog

GardDog

LT
Full Member
Minuteman
Apr 16, 2009
2,199
1
53
New Orleans
#1
I went to trim / chamfer a box of brass and noticed this:

08629ee6.jpg


The two pieces of brass are cut identically, the one on the right is turned 180 degrees from the other piece for reference. If you can see the chamfer, it is deep and defined on one and non-existent on the other side of the case mouth. I checked the Giraud site and they suggest rotating the brass as it is being cut, to prevent scalloping. I tried rotating the case as it was cutting, but had the same result. Can the cutting head get offset? I only trim 30 cal (.308 & .300 wsm), so I've never messed with the cutter.

I guess that I can call Giraud on Monday, but I will be at work and I won't have the machine with me for reference. Any Giraud users have a solution?
 
#2
Re: Question for Giraud users

The case with the much larger chamfer is the result of it traveling further into the cutting head.

The cause of this is an inconsistent shoulder position. Are you full-length sizing before trimming? If so, it appears you missed one, or you need to work on your sizing technique. Leaving the expander ball in the sizing die (for example) is one way to cause inconsistent shoulder positions. Another common cause is not enough lube.

 
#3
Re: Question for Giraud users

Just a thought but was the case on the left shorter before trimming than the case on the right? If the left piece did not grow much, there probably was not enough for the trimmer to cut.
 
#4
Re: Question for Giraud users

Both cases have the same scalloped chamfer. Deep on one side and non-existent on the opposite side of the case mouth. I just rotated the one on the right 180 degrees to show the contrast.

They were both FL sized the proper way.
 
#5
Re: Question for Giraud users

Hmm . . . I still think there may be something going on with the brass dimensions.

The cutting bit rotates about a central axis, therefore even if the cutting bit was loose, and slid one way, it would simply change the relationship of the chamfer on the case. In other words, the chamfer could move from the inside to the outside, but it should not be offset like what you seem to have.

Since the cutting bit rotates about center, it expects the brass case to be indexing off this same center. An off-center case would look like what you have. Is it possible the case holder is loose? It is possible you're somehow torquing the cases one way or the other instead of pushing them straight into the case holder? It is easy to do if the trimmer is setup to trim horizontally instead of vertically.

Also, a 308 Winchester has a 20 degree shoulder, and a 300 WSM has a 35 degree shoulder. Can I assume you're using the correct case holder for each?

 
#6
Re: Question for Giraud users

I am pretty sure you can call or e-mail Doug today.

If not today he takes calls after 6pm CST during the week.
 
#7
Re: Question for Giraud users

I had a few rounds .004-.006 beyond the set length that wouldn't trim and felt 'sticky' in the spring loaded insert that were determined to have shoulder sizing problems. Resizing correctly in the right conditions solved the problem.
 
#8
Re: Question for Giraud users

I verified that I had the correct case holder (the difference between the wsm holder and the 308 is substantially obvious). I also checked and the same scalloped pattern shows up on both the .308 and .300 wsm brass when I trim them. I'll call tomorrow and see if I can get an answer from the source.
 
#9
Re: Question for Giraud users

Don't know all your details, but I will say that brass from the same lot and shot/sized exactly the same will have differences. Some brass grows faster than others and will be trimmed more. Also, brass does not necessarily grow uniformly: which means you will see trimming more on one side than another. I trim my brass every firing: stick it in and the rotate 90-180 degrees. The case can tilt in the caseholder, so it is important to stick it in straight and keep it that way while rotating it. You are not going to find a better case trimmer, but technique does matter so pay attention to it.
 
#10
Re: Question for Giraud users

Speaking of giraud technique:

I used to grasp the case by the casehead, push in, then spin the case a full revolution.

New technique, which is way faster, easier, and produces a better and more uniform chamfer... Drop case into the caseholder, push down with palm of hand, give case a wiggle all the way around the caseholder by *attempting* to move your palm in a circle.
 
#11
Re: Question for Giraud users

The case on the left looks shorter than the one on the left. That is more than a few thou difference. It is more like several hundreths. The cutter is not hitting the brass on the left because the neck is too short to hit the cutter.

It happens. I try to cut the "burr" off of my brass from using SS Media. Some pieces get cut and some don't because of the differences in expansion after each firing.
 
#12
Re: Question for Giraud users

Cannot see the pics (govt.Puter) If you are not using high quality dies you may be sizing the neck a bit crooked. I had a set of RCBS dies and it did the exact same thing, it cut deeper on one side of the case than the other. get a Redding or Forster dies set and this should go away. Mike
 
#13
Re: Question for Giraud users

It's all in the technique. Slightly push down on the case until the case is finished being trimmed, then turn the case with your fingers while pushing down approximately 180 degrees. I don't turn it while trimming. Always works well for me.
 
#15
Re: Question for Giraud users

I trim vertical as well. The key is consistent pressure while rotating the case. There is some wiggle room in the case holder. Moving the base of the case from side to side will cause that.
 
#16
Re: Question for Giraud users

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GardDog</div><div class="ubbcode-body">I usually trim horizontally, but I'll give the veritcal technique a shot. </div></div>

I'm thinking you're going to see some benefit from this.
 
#17
Re: Question for Giraud users

I've experienced this as well. Rotating the case while pressing down into the case holder solved this problem for me. I have always used the trimmer in the vertical position FWIW.
 
#19
Re: Question for Giraud users

I trim with the Giraud Trimmer in the horizontal position so the chips don't fall back into the cutters bearings. I can't imagine brass chips and high speed bearings being a good mix. Not sure if that makes a difference or not.
 
#20
Re: Question for Giraud users

Giraud trimming is a 'feel' process. I have calipers in my right hand and measure my case, then trim. I know before going into the trimmer how much I am taking off. Because resized cases may vary a thousandth or two, it's good to know where you are before you trim. I also rotate my cases while trimming. All of my trimmed cases come out perfect using this technique.
 
#21
Re: Question for Giraud users

I believe the manual states to trim in the vertical position.

From the manual:

Flipping the trimmer vertical allows you to let the brass shavings naturally drop
away from the cutter and shell holder. If you use the trimmer horizontally,
eventually you will get shavings inside the case holder. With shavings in the
case holder, the index for the case shoulder is no longer true. Your cases will
come out longer by the same length the shavings prevent the case from entering
the case holder.

 
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