Giraud trimmer "knife edge" debunked with photos

[ireload2]

The quality of the tool grinding on the cutter is excellent.
However your photo is shown at about 8X to 10X of true size and that tiny root radius really does result in practically a knife edge.
The radius should be large enough to cover at least half the thickness of the brass. At least that is my opinion.
Yes you have a radius. I sat in a meeting where they discussed something similar on a pyrolytic carbon heart valve. The discussion
was about the right size edge radius. The debate was whether to use a .0005" or a .001" edge radius.
In the real world that is not really much of a radius.

Why would I contact them? I see no problem. My post was to show the non-knife edge trim and in no way a complain. The reference case was just not cut all the way around, a small hindsight but like I said it's not a problem if you turn the case (like you are suppose to).

 

[jlow]

The quality of the tool grinding on the cutter is excellent.
However your photo is shown at about 8X to 10X of true size and that tiny root radius really does result in practically a knife edge.
The radius should be large enough to cover at least half the thickness of the brass. At least that is my opinion.
Yes you have a radius. I sat in a meeting where they discussed something similar on a pyrolytic carbon heart valve. The discussion
was about the right size edge radius. The debate was whether to use a .0005" or a .001" edge radius.
In the real world that is not really much of a radius.

The level of OCD on this board as expected is at stratospheric levels

If this was for a fancy knife, I am sure the same people will say it is so dull that it will not cut butter, but since it is on a trimmer...

In the end, and I have asked this question before but never received an answer from those who thinks it is a "knife edge", what is the down side?

 

[R.Morehouse]

The up side is that i can take a plug out of the back of my cigar before lighting........

 

[ireload2]

The thinner the edge the greater the stress concentration at the edge. If the sharp case mouth is dinged the case is a little more likely to split starting at the mouth some time later.
It is not really OCD to some one that is used to working with those small details. I prefer to leave the edge a little flatter and flare it slightly with a Lee universal expander. This rolls the inner edge of the case away from the heel of the bullet so it does not get scraped when seated. The expander works regardless of the case edge or even if it has not been trimmed.
It is a crap edge for a knife. They are two completely different FUNCTIONS.
Get a 40X microscope and look at this stuff and look at the crap under your finger nails, Then look at the sharp edge with a 7X eye loupe. Then use your bare eye. Your perceptions will change with a little practice and training of your eyes. Eventually you can judge how deep a thread is cut by the width of the flats on top of the thread. One of my first bosses was a watch maker and I thought he was nuts too.

The level of OCD on this board as expected is at stratospheric levels

If this was for a fancy knife, I am sure the same people will say it is so dull that it will not cut butter, but since it is on a trimmer...

In the end, and I have asked this question before but never received an answer from those who thinks it is a "knife edge", what is the down side?

 

[jlow]

The thinner the edge the greater the stress concentration at the edge. If the sharp case mouth is dinged the case is a little more likely to split starting at the mouth some time later.
It is not really OCD to some one that is used to working with those small details. I prefer to leave the edge a little flatter and flare it slightly with a Lee universal expander. This rolls the inner edge of the case away from the heel of the bullet so it does not get scraped when seated. The expander works regardless of the case edge or even if it has not been trimmed.
It is a crap edge for a knife. They are two completely different FUNCTIONS.
Get a 40X microscope and look at this stuff and look at the crap under your finger nails, Then look at the sharp edge with a 7X eye loupe. Then use your bare eye. Your perceptions will change with a little practice and training of your eyes. Eventually you can judge how deep a thread is cut by the width of the flats on top of the thread. One of my first bosses was a watch maker and I thought he was nuts too.

Sorry but it still sounds OCD to me. If you are really that worried about the neck possibly splitting, either don't buy one or anneal you case like I do.

I used to be a type AAA and so I know an OCD thing when I see it, resistance if futile....

 

[dcali]

In my experience, a Giraud does not cut anything that a sane person would describe as a knife edge. It *looks* that way because of the angle of the interior chamfer which is steeper than most trimmers cut, but the cases do not come out sharp or anything approaching that. It's just a trimmer, guys. It works as advertised.

 

[pat fulghum]

Here is an old thread I started when I first got mine

http://forum.accurateshooter.com/threads/giraud-trimmer-proper-cut-need-help.3905368/


I have two cutters and they both produce a fairly sharp cut. Sharper than butter knife . ...

but to be quite honest it just doesnt matter. It is very consistent and that is what matters!

 

[Brians356]

Here is an old thread I started when I first got mine

http://forum.accurateshooter.com/threads/giraud-trimmer-proper-cut-need-help.3905368/


I have two cutters and they both produce a fairly sharp cut. Sharper than butter knife . ...

but to be quite honest it just doesnt matter. It is very consistent and that is what matters!

A "sharpish" end on the neck walls renders that case mouth needlessly delicate and more susceptible to damage. That's why I strive to remove as little material as possible when chamfering and deburring, followed by burnishing with 0000 steel wool.

The chamfer only need form a "funnel" wider at the case mouth than the bullet, and if the neck ID is sized only .002" smaller than the bullet, a fairly minimal chamfer is plenty wide enough.
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[Brians356]

I sat in a meeting where they discussed something similar on a pyrolytic carbon heart valve. The discussionwas about the right size edge radius. The debate was whether to use a .0005" or a .001" edge radius. In the real world that is not really much of a radius.

It's all relative, I suppose. A persistent legend about the infamous Lockheed F-104 fighter jet was that its thin wing's leading edge was "razor sharp". They did employ cover strips on the edges to protect ground personnel. In fact the leading edge has a 1/8" radius. Small comfort for anyone who bumped their head on it, though. Yikes!
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[ireload2]

You asked what is the down side. You got an answer. There is theoretically a potential for stress concentration on a thin sharp edge.
I never said I was worried about it but you must be because you are asking the questions.
I have no interest in buying one of these trimmers even it if had an ideal cutter. I regard a lot of case trimming, such as you do, as OCD. It accomplishes nothing except generate warm fuzzies. So I don't trim a lot. If I were to buy one of these trimmers I would just hone the cutter to the shape I wanted. The current case edges can be dulled simply by spinning the edge of the case against a piece of dead 400 grit silicon carbide paper.
I will tell you that I have been involved in the machining of metals and other materials for nearly 50 years. None of this is OCD to me. It is the normal attention to detail required to produce reliable products.

Sorry but it still sounds OCD to me. If you are really that worried about the neck possibly splitting, either don't buy one or anneal you case like I do.

I used to be a type AAA and so I know an OCD thing when I see it, resistance if futile....

 

[jlow]

You asked what is the down side. You got an answer. There is theoretically a potential for stress concentration on a thin sharp edge.
I never said I was worried about it but you must be because you are asking the questions.
I have no interest in buying one of these trimmers even it if had an ideal cutter. I regard a lot of case trimming, such as you do, as OCD. It accomplishes nothing except generate warm fuzzies. So I don't trim a lot. If I were to buy one of these trimmers I would just hone the cutter to the shape I wanted. The current case edges can be dulled simply by spinning the edge of the case against a piece of dead 400 grit silicon carbide paper.
I will tell you that I have been involved in the machining of metals and other materials for nearly 50 years. None of this is OCD to me. It is the normal attention to detail required to produce reliable products.

You are right, I did ask, so you do deserve an answer from me.

If I told you I am an auto mechanic with 50 years experience, you will likely acknowledge that I know more about cars than most. However, if I start giving you conclusions about structural and failure analysis of cars, you will likely be skeptical – and rightfully so.

I am sure you know buckets more than me about machining of metals but I am doubtful of your expertise in metal fatigue and failure. Especially specific to rifle cases.

I asked this question about potential downside of the “sharp knife edge” (my words from impression I got off the web) because I wanted to know. This was posted October 10 but as of today 14 days later, I have not heard any reasonable answer to make me worry the slightest. Of course, being able to see the cutter first hand tells me this urban legend of “sharp knife edge” is just that.

On the potential effect of failure of cases i.e. splits due to weakness from the “sharp edge”, I would think if this was truly the case to any significant extent, others would surely have experienced it and would have chimed in by now, and the sale of used Giraud trimmers would be the opposite of what it is i.e. they would be readily available vs. rarely available.

This is the reason why I find your reason difficult to take seriously.