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Post by EOsteam » Fri Dec 29, 2017 4:20 pm

The journal box covers for my Northern trailing truck are brass and have 12 holes for the retaining screws. After drilling the holes, a raised edge was noted on the entrance side of the hole and a more pronounced flashing on the exit side. The first cover did not have any flashing on the exit since it was backed by the Aluminum custom holder that was made to allow indexing of the holes. However, the remaining three covers did due to the drill holes made in the aluminum when the first cover was drilled. Since there is a flange on back side that is close to the holes, how does one debur the hole without making a mess of things? An aircraft mechanic friend was observed spinning a drill bit by hand in holes he had just drilled but the brass is so grabby that it does not work well. Here are a couple of pics.
Journal Box cover
Flashing on exit of drill holes

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Re: Deburring

Post by spro » Fri Dec 29, 2017 4:51 pm

I think the name is counter bore. This is and end mill sort with and interchangeable pilot. The center pilot fits the holes and spun by any means (including a brace) cuts the flash off evenly.

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Re: Deburring

Post by tornitore45 » Fri Dec 29, 2017 5:56 pm

I have 4 sizes drill bits (1/16; 1/8; 1/4 and 1/2) mounted on handles. All are stoned with zero rake. A quick turn of the wrist and the burr is out, A bit more pressure and you have a tiny chamfer. For straight edges I scored a small 3 corner scraper.
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Re: Deburring

Post by SteveHGraham » Fri Dec 29, 2017 6:03 pm

I wonder why people don't use abrasives for this. Sometimes a cutting tool really wants to leave a burr.
Every hard-fried egg began life sunny-side up.

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Re: Deburring

Post by GlennW » Fri Dec 29, 2017 8:14 pm

I use Noga Rotodrive tools for hand deburring small holes. ... t_-_RD2010

I already had the handle for other deburring blades so i just buy the countersinks.

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Re: Deburring

Post by Rick » Fri Dec 29, 2017 8:49 pm

I have always used fluteless countersinks in a cordless drill or by hand

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Re: Deburring

Post by Magicniner » Mon Jan 01, 2018 7:34 am

For non-grabby deburring I have Noga, drill bit with the edge stoned, woodworking countersinks for screwdrivers, proper HSS countersinks, and a nice countersinking and chamfering milling tool from Daishowa, the name of which escapes me ;-)

(EDIT - Daishowa Center Boy, I made my own holder)

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Re: Deburring

Post by earlgo » Mon Jan 01, 2018 11:14 am

I have always used a carbide ball burr of the appropriate size, mounted in a handle. It makes a nice small chamfer and is easy to turn.
Long ago and far away I had a room-mate that apprenticed at Bausch and Lomb in Rochester, NY and that is a trick he learned there.
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