Question about smoothing out a new barrel

[webradbury]

I've started my second build and have a new Octagon to round swamped 62 caliber smoothbore barrel. Very nice barrel at a good price! Sighting down the barrel, one can see slight undulations or waves. My first build barrel was the same way. On that build, I draw filed the barrel and thought this removed the waves until I polished it, and there they were again.  So is there a way to smooth it all out, perhaps a very wide file? I'm asking before I do anything else. Don't want to mess up anything.

[Sidelock]

I'll take a stab at this - seems like you have the draw filing procedure down - that is the first step.  I assume it is in the rounded section of the barrel that you are seeing the problem.  Try this - using strips of progressively finer grits of abrasive papers (say 280, 320 then 400) tear the paper into strips about 1 1/2" wide from the long side of the sheet.  Use these strips in a "shoe shine" fashion on that round section, buffing each section.  Change out paper frequently as it doesn't last very long at all before it is dull.  Once you have buffed out all of the file marks from the draw file process, continue onto the next finer grit - utilize the same process - then do the same with 400.  After that is complete, switch to 1/3 sheets of paper and scrub the round section along it's length holding the paper fast in your palm.  Work the barrel down with the 400 for a few minutes then buff it out with single 0 wool.  I hate polishing out metal but, the job will go better once you just make peace with the fact that it is going to take you about double the time you think it should. 

[rich pierce]

I’ve broken a mill file off near the base and used the handle-less file to file round barrels lengthwise to remove undulations.

[Ky-Flinter]

webradbury,

Could the waves be an optical illusion?  Have you checked with a straight edge?  If the waves are actually high and low spots, I would either file or use sandpaper on a long backer board, working lengthwise.  I'd be careful using the "shoe-shine" method with sandpaper lest you put waves back in.

-Ron

[James Wilson Everett]

Guys,

Really, such variations are most often evident on an original forged barrel.  Perfect straightness is the sign of the modern machine made barrels.  I often have folks sight down my barrels to notice the variations as evidence that the barrels are not "store bought".  My advice, leave these in!  It will result in a more historically correct gun.

Jim

[longcruise]

I do something similar to what Rich does when building a bow.  The edges often have barely perceptible dips but yet the overall length of the edge has a gentle curve to it as with a swamped barrel.  I true them with a long stiff yet flexible sanding stick with the appropriate grit paper glued to it.  Needs to be stiff enough not to follow into the dips but flexible enough to follow the swamp.

Sorry for the non ML simile.

[Robby]

I lightly use a fine 10" file holding it slightly askew and run it longitudinally the length of the rounded portion of the barrel taking down the high spots, then put a 2" strip of packing tape on some 220-320 emery paper slice it off and polish it like you would a shoe. If you monitor your progress you can leave some undulations like Mr. Everett suggests. It goes fast.
Robby

[Bob Roller]

Forget about sand PAPER or any other abrasive PAPER.Get  different'grades of
abrasive CLOTH,It's a lot stronger and as it wears it does a better job.

Bob Roller

[flehto]

Used a .54 Colerain oct/rd bbl for an early Virginia LR and didn't notice any waviness  and even if I missed it, the etched, matte finish of the brown covered it up.

But the question arises....if the round part of the bbl was turned in a lathe between centers, there shouldn't be any waviness....unless the final cut was too coarse and the person filing the bbl didn't knpw what he was doing?.....Fred

[webradbury]

Used a .54 Colerain oct/rd bbl for an early Virginia LR and didn't notice any waviness  and even if I missed it, the etched, matte finish of the brown covered it up.

But the question arises....if the round part of the bbl was turned in a lathe between centers, there shouldn't be any waviness....unless the final cut was too coarse and the person filing the bbl didn't knpw what he was doing?.....Fred

This barrel of mine was made by a maker that is very highly regarded. It was pretty smooth when I got it but there were the slight aforementioned undulations, first noticed when I gripped the barrel and ran it through my grasp. I could feel them. Really not a big issue, I’ll smooth them out a little more. I’ve used the above mentioned long sanding block and already see a difference. I didn’t expect the barrel to arrive perfect. Thanks to all! Will