how often do you cut a perfect muzzle crown?

[shawnba67]

I have cut 4 on my lathe and it doesnt seem that i am doing something right? The term perfect is used to describe the crown where every land and groove comes out distinct and sharp. mine are coming out nice but often do not have that distinct sharpness im after.
Side not does any one know how to sharpen a .250 radius crowning tool? mine is from ptg

[shawnba67]

172322
This is my fuzzy looking job

[44man]

I didn't have a lathe back then but I cut with a hacksaw, filed the end flat and used abrasive with a bearing silver soldered on a rod. Used like a valve lap tool, I got perfect crowns. Never had chatter or burrs to clean up.

[Der Gebirgsjager]

There are several different styles of crowns. Yours appears to be a recessed target crown. Looks just fine from what I can see in the photo, but of course the proof is in the shooting. What kind of a tool bit are you using for the job? An ordinary lathe bit can be used, but there are specially ground tools for the job depending on the style of crown you want.

[izzyjoe]

I have also cut a few off with a hacksaw, filled flat, and used a large carriage bolt in a drill with valve grinding compound to recess the crown. The trick is a slow speed drill, and work it in a circular motion. I wish I had a large ball bearing mounted on an arbor for this process, but the carriage bolt works well. The main thing is to have the muzzle flat to start with, and then it will be centered. Don't get hung up on resseced target crowns, though they look nice they offer no advantage over a flat crowns that have been used for many years!

[shawnba67]

I did the recess solely because I like the way they look. It is 11degrees after the recess I did not break the edge with emery cloth at all that is exactly as the lathe left it. I just wish it had the razor edge that let you see all of tge rifling standing proud.might not shoot better but would look awesome.
Im not currently lapping the crown at all fearful ill get it cock eyed even if only slightly

[country gent]

I work th crown in with the lathe and a square HSS cobalt tool ground for that purpose. First to getting the true crown is set up Indicate both ends of barrel with a snucg fitting pin into zero in a 4 jaw chuck and spider on the back. This insures that the crown will be cut true to the bore. Th tool is ground by hand to cut Similar to a boring bar. It is then honed by hand to a razor edge with thepoint broken by a .010-.015 radious. I set the compound to the face angle wanted and zero crossfeed and compound at outside dia - .010 os so. I cut the crown to what isdesired running at fairly high rpm feeding slowly out to zero. When to depth I take a very light polish cut and feed out to + .010 on the compound. Last is to remove any burrs sharp edges left with a brass ball and diamond compound. This is donewith the ball lightly coated with yellow diamond and the stem on the ball worked in a figure 8 pattern. I make 4-5 figure 8s then rotate barrel 1/4 turn and repeat thru a full rotation. Crowns are clean, tru, and Sharp with no burrs or imperfections.

[Ballistics in Scotland]

I have cut 4 on my lathe and it doesnt seem that i am doing something right? The term perfect is used to describe the crown where every land and groove comes out distinct and sharp. mine are coming out nice but often do not have that distinct sharpness im after.
Side not does any one know how to sharpen a .250 radius crowning tool? mine is from ptg

Have you fired the one in your picture yet? It might be that the edges are very slightly burred over, and a few shots will clean them up very nicely. It doesn't, in any case, look functionally defective in any way.

You mean the Pacific Tool and Gauge tool? If it is only a little blunt, I would use a stone on the flat side of the edges, and do nothing with the rather complicated shape of the part that faces the muzzle. But it takes a lot of work, or some unusual material, to blunten one of those. I would have crowned the barrel by rotating it by hand against a ball shaped tungsten carbide burr, held stationery in a vice, and most especially if it was a chromed bore.

[B R Shooter]

I don't believe in using any kind of ball and lapping compound, because you are applying pressure against the crown which can push metal towards the bore. Cutting a crown isn't difficult in a lathe, which is the only proper way to get it square with the bore. A sharp positive rake small radius tool with plenty of relief underneath is all you need. The type of crown makes no difference accuracy wise. Two things are important, square to the bore, free of burrs. What the end of the barrel is beyond the bore edge is mute. Use plenty of rpms and make the cuts from inside the bore and pull out to the barrel edge. Never cut back towards the bore. Light cuts, sharp tool, will leave a burr free crown.

[KCSO]

Can't add anything to that.

nuff said

[DougGuy]

I use a 20° carbide cutter from NeWay it is actually a small engine valve seat cutter that I sleeved and made it center on a Manson mandrel. This centers off the rifling and the 20° is about perfect. I looked at slowed down film or video footage of the pressure waves as they exited the muzzle, and measured this angle on my computer monitor and it comes out right at 20° for an included angle of 40° so this I chose as the optimum angle to set the crown to. It cuts precision crowns in some cases better than a lathe can cut them.

I also use the lathe when I can as I have learned the tricks of using a carbide insert on a toolholder and setting the compound on 20° works a champ. The insert must have rake in it, and the height above centerline is critical. You only want a few thousandths of offset. I set the toolholder so the side of the insert is also on 20° and parallel to the compound. I can get beautiful sharply defined crowns with both methods.

Handful of lathe cut crowns:

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/1911%20Crowning/DSC03604crop_zpsdkrr9vk5.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/1911%20Crowning/DSC03604crop_zpsdkrr9vk5.jpg.html)

Factory on left (SA Range Officer), Cut with NeWay cutter center, polished on right.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/1911%20Crowning/CrownPasted1_zpseoewbwua.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/1911%20Crowning/CrownPasted1_zpseoewbwua.jpg.html)

[Blackwater]

I'm not much of a machinist, but when you get unsharp cuts like that, isn't it ususally due to either a cutter that needs resharpening, or the particular type of metal being cut? Or am I all wet in that?