Case prep question for aircraft assemblers/maintenance

[CarlMc]

I used to build airplanes a long, long time ago. We used these stainless steel brushes, called bonding brushes, for removing paint around a hole before we made an electrical connection to that surface. They had pilots and a few different ways to connect to your drill motor. If you were too aggressive, you could easily spotface into the metal surface.

Now that some of you know what I'm talking about, could any of you give some thought to how well these would work for smoothing the inner and outer edges of a trimmed case? I could go get a new brush from Amazon, but that's a $40 experiment. If someone happens to have one with a close sized pilot just floating around your garage and could test the theory, it would be greatly appreciated.

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[Capn Jack]

I not only remember them, I have a few in the tool box.

There is no way I would use one on any of my cases. The stainless brush is hard enough to put severely wear the brass. There are hand champhering tools made by Wilson, or Lyman that work just fine. I always use one on inner and outer edges of the case throat. I also use a hand primer pocket cleaner. Either of these tools only take a quick swipe and your done.

 

[bellarum]

I not only remember them, I have a few in the tool box.

There is no way I would use one on any of my cases. The stainless brush is hard enough to put severely wear the brass. There are hand champhering tools made by Wilson, or Lyman that work just fine. I always use one on inner and outer edges of the case throat. I also use a hand primer pocket cleaner. Either of these tools only take a quick swipe and your done.

+1

 

[AMProducts]

Try a case deburring tool and call us back. Try the Lee first, I think it's $3, I've settled on the RCBS tool ~20.

 

[CarlMc]

I get what everyone is saying, and I have the usual tools already and wanted to see if this idea had any merit. Like any deburring tool with brass, a brief pass with the brush could be the single step that two tools (inner and outer edge deburr) normally take, or acquire the more expensive 3 way trim tool out there.

Never mind. I'll go get a tool myself and not tell anyone the results.

 

[RVTECH]

Personally I would like to hear your results as I too like experimenting with ways to make ANYTHING easier and quicker - including reloading procedures. My only concern is the brush SCRATCHING the case mouth as opposed to the 'cutting' action of a deburring tool. Like I said as one who experiments also I nearly burned myself out trying to improve (more like re-invent) a quick release case holder FOR the procedure of spinning cases to trim and deburr. I finally settled on a prospective idea but have not yet put tooling to metal yet.

 

[thorborg]

I do not know this tool, so don't know if it abrades finely or coarsely. If it is coarsely; I suggest you inspect the inside closely after you try it and when your ready to load, load a little lite, record any visual surface variances and add that to your batch and shot record data, as you may find it useful later. ( hopefully you have a chronometer)
As my thoughts are:
A scratched up case mouth could equate to knurling, this could produce a wide batch deviation of "grip" on the bullets. This might cause difficulties controlling pressures, or at least standardizing batch performance.
Just theory no actual experience. I would like to know the results, not as an alternative prep, but on performance if the scratching is significant.

 

[CarlMc]

I do not know this tool, so don't know if it abrades finely or coarsely.

Here's one with a 5/32 (0.156") pilot, but they come in a variety of sizes:
http://www.browntool.com/Default.aspx?tabid=344&ProductID=1548

The wires are individually fine and soft, and they should only abrade on the face of the case mouth, just enough to take burrs off, and my curiosity is whether or not they will actually round off the square edge slightly, which is ideal.

 

[SinisterSouthpaw]

I thought it might be helpful to look at this subject from a couple of perspectives that may not have occurred to the OP

The use of a steel brush to chamfer (inside) or even deburr (outside) a brass cartridge casemouth is counterproductive. No matter how fine the bristles, you will end up with a mass of scratches running perpendicular to the bullet's bearing surface and path of travel. This is not so much of a problem on the deburr side as it is on the chamfer side.

For brass used in a factory, off the shelf rifle the uneven chamfer will probably not show up as a problem, except that it could possibly shorten the life of the brass to some extent. On the other hand, there is a group of obsessive compulsive, anal retentive, nit picking, detail obsessed, control freaks who would recoil in horror at your suggestion that a case mouth be...gulp....brushed. These people are widely known as 1000 yard BR shooters. I personally know 4 that examine their casemouths with a magnifying glass after every chamfer. They all use this tool: https://www.precisionreloading.com/cart.php#!l=KM&i=TMRL

If you take the time to study ALL the tools offered to do this job by all the manufacturers, who are people in the shooting biz mainly or even exclusively for decades, you will soon notice that these tools are more akin to potato peelers than brushes. Making a good electrical connection is one thing, chamfering brass is another. BTW, chamfer/deburr tools are among the least expensive shooting accessories you can buy, so there is really no incentive to go off on a tangent about preping casemouths..

 

[thorborg]

my curiosity is whether or not they will actually round off the square edge slightly, which is ideal.

Best guess; yes, with a light touch. Does not look likely to penetrate far enough to do damage with a light touch. The pilot though..., a non metallic bushing or Teflon tape couldn't hurt. If I had one in my tool box, I'd give it a try. Even if it was the slickest thing on earth though, I could buy a lot of trditional case prep tools for 40 bucks. It doesn't really take much time, effort or strength alter brass minutely.