Author Topic: Barrel Crowning ??  (Read 4838 times)

Offline Majorjoel

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Barrel Crowning ??
« on: April 17, 2009, 01:09:29 AM »
How do you guys go about crowning the muzzle of a sharply cut barrel? I don't want to cone it, just a nice crown to keep the patches from shredding.
Joel Hall

Offline D. Taylor Sapergia

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Re: Barrel Crowning ??
« Reply #1 on: April 17, 2009, 01:10:57 AM »
I'll ask my brother.  He may have an opinion on this.
D. Taylor Sapergia
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Offline Roger Fisher

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Re: Barrel Crowning ??
« Reply #2 on: April 17, 2009, 04:49:25 AM »
I'm not too scientific -this is the way I do it: Barrel in padded vise vertical. Can do with barrel in stock if careful.  I use a hand brace/bit with a round ball cutter not too aggressive mind you and kinda walk around the job as I slowly cut don't take much.
Then a brass ball (did I say I have some? :D) mounted in the brace with compound to smooth the campher, then 400 or 600 paper or cloth on the brass ball to further polish = done.    Simple

Daryl

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Re: Barrel Crowning ??
« Reply #3 on: April 17, 2009, 05:18:03 PM »
Roger's method sounds just about perfect - I would finish off with my thumb and 320, then 400 to crocus cloth with oil for a nice polish.  The smoother the transition from beneath groove depth to tops of the lands, the easier it is to swage the ball and patch into the bore.
I might add, the first part of the job can be done with an electric drill and one of the tapered grinding stones with the shaft sticking out the large end.  Chuck it up, barrel in a padded vice, put a wrap of 320 Emery around the stone, then insert with some oil on the emery and grind away, moderate speed- rotating the drill slightly will help with a perfectly centered angle. Finish with your thumb as previously described.  It's easier in a lathe - wish the barrel companies would do this - it's fast and would take only 23 seconds longer than the simple cut they already do with a lathe tool - holding 400grit wet or dry against the spinning barrel for 10 - 15 seconds will give a perfectly polished and nicely radiused crown.  This one was done that way.  Simple and fast.


Offline Dphariss

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Re: Barrel Crowning ??
« Reply #4 on: April 17, 2009, 06:00:16 PM »
How do you guys go about crowning the muzzle of a sharply cut barrel? I don't want to cone it, just a nice crown to keep the patches from shredding.

"Low tech" will make excellent crowns. You can file in a crown with needle files. But I would do as below.
If you lack other tools you can start it with a large counter sink, preferably a single flute. Don't go too deep when you start to cut groove depth stop. SLOW speed if you use power tool.

Now wrap the countersink with 220-320 grit wet or dry and smooth the cut since its usually chattered with a multi-flute tool.
Do the same with 400 grit and 600. Fine grit polishing is done with the tool hand held in most cases.

This will produce a usable crown. You can further polish it with some 600 simply pressed against the muzzle with a finger or thumb and rotate your hand. You can also cut/polish with a large flathead wood or machine screw and lapping compound.
As Daryl mentions hardware stores often have shaped grindstones to be used with a brace or electric drill. Rough with the stone then wrap with wet or dry to clean and polish.
It need not be terribly deep.
The crown pictured in the "No Cone" thread in BP shooting is deeper than needed but this rifle suffered some crown damage a few years back and I cleaned it up in the lathe so now its deeper than it was.
Using a coning tool can give just a slight relief at the top of the lands if used to put about 1/8" long cut on the lands.

The tool below works very well but requires a lathe to make. But sized right would work on 45-54 calibers perhaps even a wider range. This was made to do a crown on my 16 bore. The pilot keeps everything true with the bore. It is made of aluminum and removable. This one will do bores down to about 54 I suppose. But if you make or have one made remember that the paper and double stick tape adds to the diameter so the diameters have to be adjusted to allow for this.

Dan
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Offline Acer Saccharum

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Re: Barrel Crowning ??
« Reply #5 on: April 17, 2009, 06:27:08 PM »
I'll ask my brother.  He may have an opinion on this.

Ya think?
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Offline Brian

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Re: Barrel Crowning ??
« Reply #6 on: April 17, 2009, 07:33:03 PM »
Very neat gadget Dan.  Even I couldn't mess up too badly with one of those!  Alas, I don't have a lathe.

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Offline Stophel

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Re: Barrel Crowning ??
« Reply #7 on: April 17, 2009, 09:09:11 PM »
I do the same, but with a round ball grinder.  I just turn it in my hands.  I put just a very slight bevel on them.
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Offline Majorjoel

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Re: Barrel Crowning ??
« Reply #8 on: April 19, 2009, 12:00:01 AM »
Thanks all for your great ideas on this little proceedure. I will go about it very carefully and try to keep things centered with the bore. A good polishing when I'm satisfied with the crown.  All the best....Joel
Joel Hall

Offline longcruise

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Re: Barrel Crowning ??
« Reply #9 on: April 19, 2009, 05:13:32 AM »
How do you guys go about crowning the muzzle of a sharply cut barrel? I don't want to cone it, just a nice crown to keep the patches from shredding.

I do it like this:

http://www.mikeswillowlake.com/barrel_conditioning.htm
Mike Lee