Machining Cross Drilled Barrel Port

[m1chaelw]

Evening

Been thinking about machining up a blank and wondered if anyone had any tips / tricks for machining the barrel port.

I'm planning to use an undersize drill suitable for cross holes then open out , but it got me thinking about how to minimise the burr / how to debur ?
Got a couple of ideas on how to do this but thought I'd ask.

Any tricks that won't risk damage to the lands.

Cheers
Mike

[Ca_Varminter]

Well for me...
I don't use a drill bit..
I use a sharp EndMill....
This will minimize burrs...
Take your time, Not a lot of down force needed..
Also Peck drill it... Drop the cutter down a small amount and back out...clear the chips

Then for the final check,
I also use a tapered diamond burr in a pin-vise.
To clean up the edges....


Good Luck,
Stuart

[Bigal.]

Drop thing down that blocks the barrel up.metal/wood,
Measure the depth needed,
Then u no you got a back up on drilling.
Push pellets through on de-burring to show how your going,
Mark the pellet b4, eg at 12oclock, u slowly push in and look where it is when u push it back out, if any marks on the pellets, 12 o'clock mark will show where a burr is, eg 5 o'clock.
Just push the pellets over the port hole, then back.

Leave a pellet in over the port hole after pushed in more, Then  back over the hole, mark the pellet small screwdriver etc,
Then pushed out 100% u see again any trouble. 

Watch the English.  Lol. Al

[m1chaelw]

Many thanks for the advice , on the endmill / slot drill , have you gone straight to size ? I was thinking about leaving 0.5mm on dia and opening it out with a Final Cut at size.
Also like the idea about plugging the barrel with something 👍

Cheers
Mike

[Ca_Varminter]

If you are Using a Quality Center-Cutting Endmill...
Take your time, clear the chips as you go...
You don't really need to...

But..It wouldn't Hurt anything if you did!!

Good Luck!!
Stuart