Chamfering

[millsisland]

Is anyone familiar with the "chamfer" process mentioned in Melissa Iverson's article about USFA Armorers College in this issue of American Fencing? Apparently chamfering is the rounding of edges from foil blades.

Why is it necessary? How does one do it?

Millsisland

[Purple Fencer]

Well...I now you can't have any sharp edges, so the chamfering is probably a safety angle.

Now waiting for Donald Clinton to correct me.

[Mergs]

You are partially correct, Sam. A sharp corner will get knicked and cause two things, first a burr that will be sharp and catch on clothing, fingers, etc and cut. The second thing is that it causes a stress riser, or stress concentration point and crack initiation point that will eventually work into a fracture through either fatigue failure (like bening a coat hanger back and forth until it breaks) or impact fracture.

I'm sure brother Neevel will weigh in on this with more details, but this is the down and dirty version.

[oiuyt]

I haven't received AF yet, but I'm willing to answer anyway. :)

What she's probably talking about is the tip of the blade (that normally is covered by the barrel). The top of the wire groove ends (as does the blade) with an edge (there's groove, then the blade ends, so there's in effect the outside of a corner). Because that edge can be sharp and can cut a wire (especially if the barrel works its way loose) some people chamfer the edge. Chamferring (I have no clue if I conjugating that correctly) is the process of smoothing that edge (typically with a file) into a rounded corner as it were. Now if the wire rubs at least it's rubbing something smooth rather than something sharp. This is, of course, done before the blade is wired.

Does that make sense in the context of the article?

Now let the arguments over whether or not that constitutes a violation of rule m.1 begin. M.1 reads:

There are three types of weapon: foil, epee and saber.
All weapons are authorized providing only that they conform to these regulations and to the safety standards which are appended.
The weapon should be so constructed that it cannot normally injury either the user of the opponent. All methods of treating a blade between the guard and the tip (button), by grinding, filing or other methods, are forbidden.
Sharpening the edges or angles of the point is forbidden.

The argument against filing says that it violates m.1 (duh). The counter-argument is that the tip of the blade is inside the barrel (the button), therefore is not between the guard and the button and therefore CAN be filed without violating the rules. The camfering process was explained at Coaches College and Armorer's College by Dan DeChaine, a member of the FIE SEMI commission. Given that HE suggests doing it I'd have to say that it is legal.

-B :)

[millsisland]

Here's the text (Page 8, Winter 2003 American Fencing, "2002 Armorers College" by Melissa Iverson, under "Postcards from the Strip"):

<<Much of DeChaine's teaching is antecdotal. Anyone interested in the history of fencing- armoring-related or not- would benefit from spending time listening to his stories. And as each story unfolds you begin to realize that nearly every rule relating to equipment has a direct and applicable reason for existing. Why must foil blades be "chamfered" (the edges rounded off)? Chamfering drastically reduces blade breakage, thereby signifi-
cantly increasing the safety of the fencers.>>

????

[sallearmourer]

What it does is to prevent surface cracking froming on the blade therefore reduce blade breakage. That the reason that some of my wife blades were still passing the flex test after 10 to 15 years of use.

Tim

[oiuyt]

K, in that case I retract my statement, based on ANOTHER of Dan's pearls of wisdom. I heartily second Melissa's statement and can't wait until I receive my copy and can read it in full.

-B :)

[millsisland]

Okay, Tim-

How does one "chamfer" a blade? Or is that done at the factory?

Do you need to "re-chamfer" as time moves along? : )

Millsisland

[DHCJr]

This is a good thread. Every body gave good and helpful answers. I haven't seen the article yet also. As far as chamfering the blade, it is done at the factory or it is not done at all. Rule M-1 as told before says, you cannot file the blade, but M-8 states the blade must be chamfered. So you must check before you buy the blade. All the reasons above are good answer for why the blade is chamfered. I have nothing to add to that.

Also if you want to find out more about this and other things to do with armoring and Fencing, come to Duel in the Dessert. Dan, along with Carl Oberg, Matthew Porter and myself will all be there as well as others.

[Purple Fencer]

...And don't forget to bring the beer -- uh -- blood supply!

BTW, Donald...did you ever find a source for that really thin spaghetti tubing? I'd sorta liek to have a supply for when I run out of the handful you gave me.

[millsisland]

Thanks for the replies.

I'll check in with the (impressive) armorers group at DITD. I want to ask about balancing the foil. Art and science, I take it. Now there's a subject....

Millsisland

[sallearmourer]

Don is right its suppose to done at the factory at a 45 degrees angles rounded is even better. And it's is in the rules. I don't have mine handed because I am on the road to Saratoga Springs


TIM

[damianip]

Originally posted by sallearmourer
Don is right its suppose to done at the factory at a 45 degrees angles rounded is even better. And it's is in the rules. I don't have mine handed because I am on the road to Saratoga Springs


TIM

Tim,

Since I'm at home, I'll help you out (and you are quite right):

from the rules (99 edition):

m.8 The blade, which is rectangular in section, must be made of steel complying with the safety standards described in Appendix A to the Rules.

The edges must be smoothed off so that they will not cut, and must be chamfered at an angle of 45° (± 5°), 0.5 mm on each side (± 0.1 mm), so that they will neither cut nor become capable of cutting.

Paolo

[Joe biebel]

A chamfer is a beveled edge as opposed to a filleted (round) edge. Both will give you as safety edge, and I believe both are acceptable (.5mm for the foil tip) in the rules. I have never seen this tested (limited experience?) nor any sort of gauge for this at at a competition.