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useful method for turning crowns on octagons
Posted: Fri Jun 18, 2021 4:03 pm
by mdeland
I genuinely dislike all the fiddle farting around setting up spiders or collar bearings for turning an octagon to crown or chamber so I got this idea to mold a gob of epoxy putty near the end of a barrel and turn a bearing in it for crown or chamber work. I'm sure it is not original thinking but it is to me and might be of help to some one else.
I turn a brass button for the dead center then mount the barrel between centers in the lathe and turn the bearing surface in the cured putty. This simple bearing surface is now directly centered to the muzzle center and is almost always more accurate then will be a spider or collar mounting.
When done a simple whack with a wood chisel will split the epoxy, pull the duct tape and your done.
Re: useful method for turning crowns on octagons
Posted: Fri Jun 18, 2021 6:18 pm
by John Bly
Why not just put in a 4 jaw and indicate the bore true? You need a lathe that will take the barrel through the spindle.
Re: useful method for turning crowns on octagons
Posted: Fri Jun 18, 2021 6:44 pm
by mdeland
My spindle is .750 John so I have to do it all between centers. Plus four jaws don't work so well on tapered octagons without a lot of shimming.
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 6:27 am
by DeadEye
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 9:27 am
by Shadow 4
I know this tool, very handy, tis
Very quick, easy. 5 guns, less than 30 minutes, with a bullshit session
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 10:21 am
by Red River Rick
John Bly wrote: ↑Fri Jun 18, 2021 6:18 pm
Why not just put in a 4 jaw and indicate the bore true? You need a lathe that will take the barrel through the spindle.
That doesn't work worth poo with a tapered octagon barrel.
The chuck jaws are only touching at a small point.
RRR
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 1:17 pm
by mdeland
Yeah,they work fine for a crown trim if the pilot is a good fit but have no ability to turn the barrel shoulder or breech back a thread on the other end for set back. Even in crown work their only made for trim and truing to remove nicks and dents not for crown profile establishment .
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 1:26 pm
by DeadEye
Not true Mike, we changed the profile of my Winchester/Browning from the deep recess to the 11 degree profile with no trouble. Just took a few more turns. I suspect you do not own one and have not used one.
Paul
Re: useful method for turning crowns on octagons
Posted: Sat Jun 19, 2021 1:50 pm
by mdeland
True, as I have the lathe but do have a close friend that has one and uses it on a couple of his rifles. The problem as I see it is the pilot turning on the land tops and the handle cantilever orbit to turn the crown cutter . A few turns to true it up no issue but turning the crown back say .250 after cutting it off would be more pilot wear on the land top ends then I would care for.
Yeah it can be used to cut a full crown but it's main purpose is to trim a crown of nicks and dents and keep it true.
A typical chamber reamer pilot should have a clearance of no more than .0005 and closer is better. The reamer should be held in a floating holder to follow bore snake or taper and not bind. It also does not stay in the same place as does a crown pilot and there is no cantilever effect on pilot from the handle orbit. One mans opinion.
Re: useful method for turning crowns on octagons
Posted: Wed Jun 23, 2021 2:03 pm
by MikeT
According to the video I watched, the pilot is locked in the bore so that the pilot does not turn.
Keep on hav'n fun!
MikeT
Re: useful method for turning crowns on octagons
Posted: Wed Jun 23, 2021 2:13 pm
by DeadEye
Re: useful method for turning crowns on octagons
Posted: Wed Jun 23, 2021 2:35 pm
by mdeland
That is true the one I saw demonstrated had the pilot revolving in the barrel and a solid pilot if anchored true would be a better method.
As far as the prophecies there will be no need for you to apologies when they happen as we will all be to busy celebrating to even consider such.
Re: useful method for turning crowns on octagons
Posted: Wed Jun 23, 2021 2:43 pm
by DeadEye
Whew! That's a relief.
p
Re: useful method for turning crowns on octagons
Posted: Thu Jun 24, 2021 4:25 pm
by mdeland
That makes me chuckle. I can see your really in a lather over the comment ................... buuuuuuuuuuuuuuuuut your in for a surprise ! If you love Yeshua it will be a good one!
Re: useful method for turning crowns on octagons
Posted: Thu Jun 24, 2021 10:12 pm
by Shadow 4