FLUMMOXED: Milling thru leaves sharp edge. Fix how?

[Frogblender]

Howdy... The picture shows the cross-section of my setup for cutting parts. 6061 stock and 6061 sacrificial plate are held down with screws (not shown). My tooling sequence is:

1) Slot with EM. The slot extends about .015" into the blue sacrificial plate (see pic).
2) Use 45° chamfer to give a nice edge on the top.

The problem: the bottom edge of the finished parts is very sharp. How do I take the edge off a little? .003" would be plenty.

Here's some things to consider:
- the top of the part is already cosmetically finished, so I don't want to tumble the part.
- flipping over the part and running the chamfer tool: problems with registration, and marring the cosmetic side.
- Would like the bottomside edge removal repeatable over hundreds of parts.

Any ideas would be greatly appreciated!

[Kipper]

What is the first cut into the sacrificial plate like? If good can you chamfer the underside while still in the fixture....

[Frogblender]

Originally Posted by Kipper What is the first cut into the sacrificial plate like?

Not sure what exactly you're asking. The cuts are nice and clean. When the EM cuts the sacplate, DOC totals about .040" (.015" is the sacplate, .025" is the stock).

Originally Posted by Kipper If good can you chamfer the underside while still in the fixture....

What kind of bit would be used?

[djr76]

a dovetail cutter would do the trick

[Kipper]

Originally Posted by djr76 a dovetail cutter would do the trick

Thats the ticket!

[Frogblender]

[QUOTE=djr76;771132]a dovetail cutter would do the trick[QUOTE]

Hmmm.... the dovetail does look pretty.

FYI: here are some I found small enough to fit down my 1/8" slot. Not particularly cheap, though:

http://www.harveytool.com/products/p...vetail+Cutters

[ctate2000]

Try a simple burr knife. $12 from MSC.

[djr76]

oi, I didnt realize it was an .125 slot, that can be a bit of a pickle. A small file, lightly buff it on a pedestal buffer, or with what ctate2000 said.