use this screw for crowning...

[captain concrete]

its called a TAPCON screw. we use them in concrete work for fastening boards to concrete. they are extremely hard and strong. i used one this time on a para project and unlike using a regular wood screw, this did not get deformed in the crowning process. it barely scratched the paint on the screw. the one i used was about  1 1/2" long. any hardware store carries these for about .35 each. pic is not the best but you can see what they are. im sure most of you have seen them before.

[buckmeister]

I don't think you want anything in the bore. A brass carriage bolt or bound head bolt an grinding compound are what is recommended.

buckmeister

[panoz77]

I'd be scared of using a tapcon, if it wobbled it would F up the barrel.

[captain concrete]

worked fine for me. nice bright un damaged bore with a nice even crown. use what you like but this works just fine.

[Prince50]

So you used a Phillips head screwdriver, and put the shank of the screw in the bore?

I've never seen that, but it should work and will give a true 45 degree crown.

Not bad. Perhaps tape on the screw threads to protect the bore just in case.

Nice work.

Darin

[jbanzai]

or how about just completely cutting the threaded part off so you only have the head in contact with the crown

[captain concrete]

or how about just completely cutting the threaded part off so you only have the head in contact with the crown

yes... thats what i should have put in my first post. if you have a careful grip you can do it with the screw as is. if not, just cut it. these screws are HARD. the one i used only had the paint scratched on it after doing 1 crown. i would expect 6 uses out of one screw... maybe more.

[captain concrete]

So you used a Phillips head screwdriver, and put the shank of the screw in the bore?

I've never seen that, but it should work and will give a true 45 degree crown.

Not bad. Perhaps tape on the screw threads to protect the bore just in case.

Nice work.

Darin

i used my BOSCH lithium cordless drill to do the work... and some cutting fluid as i didnt have any lapping compound.
it worked great. you know how screws have a taper to them... it gave me a very uniform crown. cant say if its a true 45 angle, but that shouldnt matter as long as is uniform i would think???