Deburring the back side of a hole

[Vern Smith]

I have a situation where I drill through 2 layers of 6061 with a .400 gap between them. It's a pain deburring them by hand and I was hoping I could deburr them with a reverse boring cycle. My first question is what type of boring bar would you get for this job? I thought an internal threading tool for lathe applications might work OK.

My second question, is there a better way to do this?

Vern

[dertsap]

interpolate it
its pretty easy to do it with a lolypop mill .
if the hole is big enough then a double angled mill works well on flat surfaces .
or its easy to hand grind an old endmill if your in a pinch

[GeorgeRace]

I wonder if the holes you are drilling are large enough to be milled with a small tool. That would probably stop the need for any deburring.
Just a thought.
George

[beege]

Also look into Cogsdill back chamfering tools

[HelicopterJohn]

Hi Vern,
I second Beege's suggestion.

What size hole are you drilling? I saw a guy on e-bay that offered a bunch of used ones in various sizes.


http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT


My friend Francesco used them on his project on 1 inch square tubing 1/16 wall thickness and they worked really nice.

We used them in my HAAS TM-1P.

[Delw]

Vern
the back chamfering tools are nice, but they dont repeat very well, the ones that close when going into the hole then open when spindle is in reverse. sometimes they stick open if chips get in the way and ruin your bore as well as pill the part out along with tool.

I use 45º cutters from harvey tool or a tool grinder cuts them for me. there fast and rigid. solid carbide. thet are like a threading tool but with a 45 degree angle on them.

IN a pinch I have used a solid carbide lathe threading bar(micro 100) to just break the burrs off were the angle wasnt a big deal. its a single sided cutter and runs off center so you need to be carful and not crank the rpms up

[Vern Smith]

I appreciate all the suggestions, I should be able to get it done with this selection Is there another name for lolly pop mills?

[djr76]

http://www.ezburr.com/index.php

just bought one for the first time and it worked great

[Matt@RFR]

Originally Posted by Vern Smith Is there another name for lolly pop mills?

Undercutting endmills.

http://www.harveytool.com/products/i...&category_id=1

And here is what DelW is talking about I think:

http://www.harveytool.com/products/i...&category_id=1

Lakeshore Carbide is a distributor for Harvey Tool.

[Vern Smith]

Thanks, I'll call Carl at Lakeshore.

[offsetxyz]

If the reach is not too long and the hole not too small (smaller than .308 inches) a P H Horn boring bar can the programmed to drop in and go around the bottom. It can also go in between the two inside the gap. PH Horn makes two sizes of boring bars in 3 different lengths. The inserts are on 45 degrees. They also make 3 and 6 pointed tools for chamfering with circular iterpolation. Of course you can make a bar to fit your jobs.

[Delw]

not a bad idea but the problem with lathe boring bars is they are not balance for a mill. slow RPMS should be no problem.