Counter sinks

[Dphariss]

Awhile back there was a topic about chattering countersinks.
Multi flute countersinks are generally meant for rigid setups in machines. I.E. work piece clamped and countersink in the machine chuck.
Single flute countersinks are suitable for hand held tools.
This from making up an order and finding this info in my MSC catalog.

Considering a topic on barrel crowns.
Also MSC sells countersinks in 60-82-90-100 and 120 degree angles.
I am wondering if the single flute 120 would make a good cutter for cutting crowns by hand or if it would grab on the lands?
MSC part number for a single flute 3/4" 120 degree by Cleveland is 63778484. Catalog show 30.82. But prices now are generally higher than shown in the book...

Dan

[Acer Saccharum]

Anytime I ever tried a countersink in the muzzle, I got chatter. Maybe Taylor's trick of a piece of cardstock under the bit would have helped.

Now I use a lathe, so all this is out the window. Don't need no stinkin countersinks.

Nor any chatter either.

Acer

[George F.]

I haven't done this but why can't one of those stones shaped like a cherry with a arbor mounted in it be chucked in an electric drill used for crowning the muzzle?   ...Just asking...    Geo.

[t.caster]

Mounted stones with a 60 degree included angle cone work fine in a hand crank or a slow variable speed drill. You can even do a multiple angle job if needed with 90-60-45.  30 degrees is approaching a cone job and goes pretty deep, I wouldn't recommend it. I wrap strips of emory cloth around the stone & turn slowly with light pressure to get a bright, smooth finish. All the rifles I've finished this way report excellent accuracy & easier loading without tearing patches. The round ball stones still leave an edge to cut patches, unless you get down near bore diameter of ball. Care has to be taken to keep the bit inline with the bore, so you get the same depth all around, but no need to get anal about it. Yes, a big lathe is the professional way to do it, but how many can afford or have room for one.

[volatpluvia]

Acer,
I have a 1 inch thick single flute countersink that works really well in a handheld drill running on slow speed for the muzzle.
volatpluvia

[Jim Filipski]

I haven't done this but why can't one of those stones shaped like a cherry with a arbor mounted in it be chucked in an electric drill used for crowning the muzzle?   ...Just asking...    Geo.

George I use these on barrels I don't cone ( cone most now days) I wouldn't use it in an electric drill however. I put it in a brace. Plum the barrel vertical in my vice lube the stone and do a random walk around the barrel while slowly turning the brace and sway it to and fro. I have different size ball stones for the different calibers ...makes a nice small working crown.
Jim

[Dphariss]

Anytime I ever tried a countersink in the muzzle, I got chatter. Maybe Taylor's trick of a piece of cardstock under the bit would have helped.

Now I use a lathe, so all this is out the window. Don't need no stinkin countersinks.

Nor any chatter either.

Acer

I have a lathe too, a pretty good one actually. However, it takes a lot of time to *properly* set up a barrel. So for ML crowns I tend to use the lathe to MAKE tools to do the crowns. I still think that a 100-120 degree single flute will do a good job of roughing in a crown with hand tools.
I just upgraded my lathe from a rather down in the mouth Clausing to a much better LeBlond.


Using the lathe to make tools that require no machine set up saves a lot of time in the long run.



This was made to do a crown in my 16 bore hunting rifle. The cutting agent is wet or dry paper applied with double stick carpet tape. It can be a pain if you work it too hard but but does a nice job and can be used with an electric drill if one feels the need. Removable pilot is aluminum.
I am going to make one for the smaller bores next.

Don't get me wrong, I like using a lathe to cut crowns, works great, very precise. But its time consuming.
I did a lot of BPCR crowns in the lathe and still would. But to do it right needs dial indicators and plug gauges at BOTH ENDS with a "cats head" at the far end of the spindle bore to get the bore running true. All this just to break the lands to an angle at the muzzle but it looks really precise, is precise and I was doing work for finicky BPCR match shooters, national champions etc.
A ML crown really needs to be more complex to work well and I generally use more than one tool. Shoot the rifle then go back and change if needed. I could spend an hour(s?) in just in setups.
I have used stones in the past as well and they will work well. I have polished crowns with wet or dry on a countersink. I have made them with a large flat head screw for a countersunk hole with lapping compound. I have tried lots of stuff over the years and it will ALL WORK if done carefully.
But a tool like that above will do a good grown that is square with the bore and with 600 grit as a final cut makes a very smooth surface.
Using this then another similar tool to put about 1/8" long shallower angle "funnel" on the lands greatly eases loading. This has allowed me to shoot a significantly thicker patch in the 16. Its been crowned about 3 times now as I keep fine tuning it.

Dan