Countersink


I am trying to machine some aluminum and it involves countersinking some holes. I have tried a variety of 3/4" countersinks and so far they all suck rocks. I tried the Vermont American single flute and it didn't want to cut. I next tried a Bosch and it chattered so badly even in wood as to be unusable. I have a Stanley 1/2" that works great but cannot find anyone that carries Stanley countersinks. Any suggestions for a multi flute countersink?
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suck
cut.
that
countersink?
http://www.leevalley.com/hardware/page.aspx?c=3&pA012&cat=3,41306,41328
No longer available on LV, but you maybe able to find another source. http://www.leevalley.com/wood/page.aspx?c=3&p2270&cat=1,180,42240
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Upscale wrote:

Upscale has the pricier ones, and I have the cheaper model:
http://www.leevalley.com/hardware/page.aspx?c=3&p2308&cat=3,41306,41328
That's the best c'sink I've ever used, and I'm sure it would cut nice countersinks in aluminum too.
Tanus
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This is not really a sig.

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not big enough.
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Get a bigger one.

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R. Pierce Butler wrote:

That's what an ex girlfriend once said.
Tanus
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This is not really a sig.

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Pilot essential, speed slow, work held fast, most any HSS design will yield acceptable results, Ford better than others if chamfer precut with piloted cutter. Sample in the http://patwarner.com/new_pix.html link done this way in 2 stages.
http://www.patwarner.com (Routing & drilling) _____________________________________________ R. Pierce Butler wrote:

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Agreed. Use oil or something similar as a lubricant in aluminum ALWAYS. Aluminum becomes gummy on just about any tool at just about any speed sooner or later.
Run the RPMs as slow as possible... "Play with" your downward pressure to minimize chatter as needed. Pilot hole is absolutely necessary.
Ask in rec.crafts.metalworking for a more professional-soundign answer. :)
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com
V8013-R
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I have used my Stanley 1/2" countersink in wood and brass with no issues. Even starting to countersink a hole in soft pine using the Bosch CS resulted in horrible amounts of chatter.
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What RPM are you running when this happens? Is the tool new or at least sharp?
I don't have the RPMs for countersinks memorized, but I'd guess that if I had to simply walk up to a drill press (you are using a drill press and not a hand drill, right?) and make a counersunk hole, I'd run it at 1/2 the speed of drilling to start.
Rough, ver conservative drilling RPMs can be found on my site at: http://www.multi-drill.com/drill-speed-chart.htm
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com
V8013-R
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I chucked the Bosch bit in my drill press at the lowest speed and it chattered very badly. I decided to try a variable speed hand drill and no matter what speed i tried, it chattered. Wood, Brass, it doesn't matter. I think I will have to order a set to get a good countersink that I can use in my drillpress. I wish I could find a Stanley 3/4" countersink. BTW, I clamped the pieces to the drill press using c clamps.
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You are on the right track. Sounds like the Bosch bit may either be dull, a specialty bit for something else, or simply doesn't like you.
Much success.
Also, final thought on RPM... Some folks countresink up to 3X the diameter of the inside hole... In that case, you may want to drop the RPMs even further... i.e. a 1/4" hole with a 1/2" ctrsink will have the ctrsink run at 40-50% of the hole drilling rpm. But... a 1/4" hole with a 3/4" ctrsink will run at 33% or less the speed of the drilling rpm, etc.
When in wood, it usually doesn't matter as much unless you want a clean hole and/or no burnt wood. I haven't met a wood worker yet who uses coolant other than air...
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com
V8013-R
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"R. Pierce Butler" wrote...

suck
I've had good luck with this style countersink in wood, aluminum, and plastic:
<http://www.woodcraft.com/family.aspx?familyidQ54
-- Timothy Juvenal www.tjwoodworking.com
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Too small. I need a 3/4" countersink.
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R. Pierce Butler skrev:

http://www.leevalley.com/hardware/page.aspx?c=3&pA012&cat=3,41306,41328
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that could work. I will have to get one the next time I order from Lee Valley.
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"R. Pierce Butler" wrote...

Countersinks are for sissies. Real men use a plug cutter and recess the screws, welding the plug in place.
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Hard to do that with 3/8" thick aluminum plus make the screw removable.
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R. Pierce Butler wrote:

G'day, I gather the holes are already drilled ??. If not, drill the countersink first with a drill bit the right size for the screw heads, than drill the hole through the centre for the screw shank. The smaller bit will self centre in the larger, countersink holes.
Regards John
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ORDER A GOOD SINBLE FLUTE FROM http://www.kbctools.com / I HAVE SEVERAL THAT I USE ON ALL METALS, WOOD AND PLASTIC. I USE THEM ON THE DRILL PRESS, HAND HELD, AND SOMETIMES IN AN OLD HAND CRANK, BREAST DRILL. WORKS JUST AS GOOD WET OR DRY. DON'T GET THE CHEAP ONE YOU WILL HAVE THE SAME RESULTS YOU ARE HAVING NOW.
GOOD LUCK WOODWORM

suck
cut.
that
countersink?
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