SUNNEN HONEING GUN BARRELS

[clowdis]

I do not believe for one minute that a hone with a stone 1 1/2 inches long is going to straighten out a hole that is 28 inches long. Yes it will flatten the high spots and impart a uniform finish from one end to the other but in fact that's about it. If the bore curves .010 from one end to the other it will still curve .010 after it's honed. Another problem is that after the bore is rifled the only thing that is honed is the top of the lands and in fact that is probably the thing that matters least. The land cuts into the jacket of the bullet while the bottom of the groove (actual bore diameter) is what holds the bullet and normally comprises the most surface area of the bore. If you gotta polish something you need to polish the grooves! That's the reason barrels get hand lapped! An exception to this might be the Benchmark 2 groove smallbore barrels that only have the 2 narrow grroves. I understand that they do shoot well.

 

[David Sengelaub]

Barlow: The abrasives are metal bond CBN bonded to a steel holder.

Clowdis: You bring up a point that was not clarified. The honing operation is meant to go before rifling. You are correct, honing a 28" barrel with a 1.500" stone will not remove any curve. It will remove the waves and leave a consistent size and finish from end to end.

 

[acloco]

Actually....from somebody that HAS operated a Sunnen CK10 (cylinder hone), Sunnen line bore hone, and Sunnen connecting rod hone (that is also used for other purposes), a LOT depends on the operator AND the material you are working with.

Besides the grit of stones, condition of stones, raw material metal properties, amount of pressure applied to mandrel, stroke distance the mandrel is moving, and the operator's "feel" (which is LEARNED), you might be surprised how near perfect metal can be....and how far OUT most machined components are.

 

[BoydAllen]

https://www.youtube.com/watch?v=MtBL2if7aac
Watch it work.

 

[OIF/OEF]

Anyone want to go halves on one of these Just out of curiosity what does one cost.

 

[Turbo900rr]

Anyone want to go halves on one of these Just out of curiosity what does one cost.

No idea on price, I bet you better find a few more business partners.

 

[jbarnwell]

As always, thanks Boyd. Very interesting machinery.

 

[BoydAllen]

I think somewhere in the neighborhood of 100k and 5-6K for each caliber.

 

[butchlambert]

Banana bore?? You're kidding I hope. Boyd, I think you are light on the price. I believe you can double the investment on the stones for the more popular calibers. If you mess one up, you need a spare right now.

 

[BoydAllen]

Butch,
I was referring to caliber specific tooling, not the ongoing cost of consumables.

 

[David Sengelaub]

Boyd you’re in the neighborhood the machine is under 100K the tools under 4K, and you are right the tools are caliber specific.

The heart of the machine is the computer and the servo drives. They can interpret what the tool feels and make corrections.

 

[dmoran]

One of my best shooting barrels ever was not straight. You could really see how much when spinning it in a lathe.
Won a lot of matches with that "bent bore"......

Jerry Siminson once told me one of the best 100/200-BR barrels he ever owned/used was a customer reject because it was bent, that after laying around for a couple years, he finally chambered it up with intent to be a "fire-forming" barrel, that he then discovered was a true "hummer". Guess we'd call that a "bent hummer" !.!.!
Donovan