Chamfering outside case mouth.


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Muddydogs
July 30, 2013, 12:05 AM
I am not happy with the chamfer on the outside of my case mouths. I had been using the original RCBS chamfer tool that came with my prep center many years ago, I have since upgraded to the Lyman tool. It seams that both tools but way to much tapper on the case and even leave a ridge if I don't waller the case around on the tool. If I just push the case straight down on the tool it doesn't get all the burr off especially on cases that needed quite a bit of trimming. Am I over thinking this? Is there a better tool for outside chamfering?

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RPRNY
July 30, 2013, 12:20 AM
I too use the Lyman tool. It seems to work better with smaller case mouths than larger. I trim on a Lee Zip Trim, then chamfer inside an outside with the case still in the zip trim. I finish with a piece of bronze wool around the case mouth and it always leaves them nice and smooth.

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Walkalong
July 30, 2013, 08:33 AM
I use an old RCBS tool and have no problems. Push the brass straight into it and stop when the burrs have been removed. Normally there will be just a little bit of chamfer on the case then. All you need to do is take off any burrs etc from trimming and just knock the edge off the 90 degree case mouth.

GLOOB
July 30, 2013, 03:01 PM
Please don't take this wrong. I don't think anyone is a dummy. Try turning the chamfer tool very slowly.

If you twist the tool as fast as you think you should, the 3 prongs chatter away on the case mouth. It takes multiple passes to remove the burr, cuz any given tooth is skipping more material than it's cutting. Each tooth takes a turn digging/catching too deep while the other teeth are catching air. And where the teeth dig, this is where you are getting a secondary burr. If you look at the case mouth under magnification, you can see this, clearly. After one turn, you will see a series of vertical stripes on the end of the case mouth.

If you do it excruciatingly slow and steady, it takes only one pass (a hair more than 1/3 of a revolution), no chatter, clean edge. And it ends up taking the same amount of time.

When I outside chamfer with a drill, I always use my Lee chamfer tool. It doesn't leave as nice an edge, but it works at higher speeds.

Walkalong
July 30, 2013, 03:13 PM
Yes, very slow. When I use power on mine I run it almost as slow as the machine will go. Concentric necks with no dings help as well. If they are out of round or have dings you will get chattering as well.

joustin
July 30, 2013, 03:15 PM
I didn't like the Lyman one either. Switched to an RCBS trim pro 3way cutter and never looked back.

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cowtownup
July 30, 2013, 04:02 PM
Not trying to hijack this thread but I thought this would be a good place to ask...

Do the chamfer tools wear out? What is the typical lifespan of one of those tools?

lightman
July 30, 2013, 04:54 PM
They will eventually get a little dull. It will take forever however, as you are cutting brass with a steel tool. Rust usually hurts them before they can get dull. Lightman

ironworkerwill
July 30, 2013, 05:07 PM
Nickel plated brass wore out my outside of my Lee tool at the .257 area. It still works for everything else tho.

Muddydogs
July 30, 2013, 05:20 PM
I didn't like the Lyman one either. Switched to an RCBS trim pro 3way cutter and never looked back.

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I use one of these for 223 brass and they do work good. Most of my other calibers don't warrent spending the money on a dedicated 3 way but I might buy another 3 way and just switch out the pilots for different calibers.

gamestalker
July 30, 2013, 05:49 PM
I have the RCBS tool, and I also have the Lee, and prefer the RCBS hands down. But I learned that either tool will do a good job with the right amount of pressure and rate of rotation. If you apply to much pressure, and too fast of rotation, it will chatter, leave a ridge, and also take off too much material. I do mine while they are still in the Lee shell holder after trimming with the drill. Slow down the rotation, and apply only a minimal degree of pressure and they will come out fine.

GS

Hondo 60
July 30, 2013, 10:53 PM
When I bought a Lyman Power Trimmer, I also bought an attachment that chamfers.
http://www.lymanproducts.com/lyman/case-prep/chamfer-deburr-accessory.php

Does a great job on the inside & outside of the case mouth.
Not so great on a primer crimp though

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