long reach 82 degree countersink

[kendo]

I need an 82 degree c-sink but the only ones I find in the books are between 1and 2 inches long
we usually use the "zero flute" type with a single hole through the body of the cutter and no pilot

Im doing holes that are next to a 3" wall of an aluminum part, and the diameter cant be any more than 3/8" since the holes are so close to the wall

[Konrad]

Perhaps make one up, turn down shank and sliver solder a piece of drill rod with a hole in it.
Have made some, up to 2 foot long.

Konrad

[gsrmmeza]

This is a link to Rutland Tool. It is a combined drill countersink. The tool is a number 4 1/2 which is a 3/8 diameter shank. The drill part of the tip is 9/64. The angle is 82 degree. I hope this helps.


https://www.shoprutlandtool.com/weba...atalogId=10001

[Boots]

Buy the length of tool you need then grind down the OD for your clearence.

[DareBee]

McMaster Carr sells them.
They are uniflute type C-Sink tip that threads onto a long shank.
Almost an exact match to your spec.
I thought it was pricey but worked well for me.

[kendo]

OK I got this extension with the 1/2 and 3/8 "general purpose" heads

so... how the heck do I run these?
I'm drilling a .201 hole, then countersinking it for a #10 screw
in aluminum, with coolant (squirt per peck, not flood)

I'm running it at 4 IPM and 1250 RPM and the holes look like garbage
I'm peck it once, leaving a .015 finish peck

this is a LOT slower than I've ever run a countersink
the tool is making a large ridge at the top of the hole, the finish looks melted,
and I can see the tool wobble as it makes the finish peck

the page says these are for steel, brass, and bronze, but I use a c-sink just like the fast-cut single flute all the time
the general purpose heads have very shallow flutes and I think the aluminum is packing them up, even at such low feeds

any help out there?
I still need an extended c-sink for aluminum!
I guess Im off to mke my own for now
thanks