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How would one impart a taper to a CHF bore without the mandrel being tapered?
Note: I already know the answer.
EDIT: For clarity, not all CHF barrels have a taper, but the ones that do, receive that slight bore taper from the actual CHF process, and not afterward. See Centurion's website:
"Cold Hammer Forged Barrels
Hammer forging is a process in which a drilled, reamed and honed blank has the rifling formed into it by placing the barrel blank on a mandrel that has the rifling ground into its outer surface. The blank and mandrel are then placed between two opposing power hammers and the blank is beaten around the mandrel leaving the rifling pattern in the barrel. This process leaves an extremely smooth and consistent surface on the inside of the barrel, that lends itself to excellent accuracy. The forging process also work hardens the barrel steel causing a very durable and much longer lasting barrel. Our barrels have a slight taper to the bore during the hammer forging process to ensure better accuracy."
More info, from a professor at Purdue University.
http://www.vsms.org/Forum/Seite_34_forget-barrels/S34.htm
Last edited by BufordTJustice; 11-21-16 at 08:55.
"That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892
"The body cannot go where the mind has not already been."
Interesting that Centurion claims that, as I know where they get their barrels, and that's not when the tapering happens. Watch this video and you tell me if a mandrel is physically capable of creating a taper in this bore:
Ask yourself how the @3" long mandrel (shown at 1:17) could POSSIBLY create a taper in a 16" barrel...
Last edited by WS6; 11-21-16 at 08:59.
You're serious? That's a chamber mandrel.
In the video below, 2:46 in shows ACTUAL full bore mandrels.
Notice their length.
https://www.youtube.com/watch?v=oALJDh43K3I
AND see the mandrel at 1:22 in this video....note also the lack of a chamber and how one might be able to alter the number of hammer strikes per barrel location within the hammer machine to create a tighter bore-to-mandrel fit or a LOOSER bore to mandrel fit.
https://www.youtube.com/watch?v=8pzL5h2cl80
Additionally, at 3:38, this states that the barrel blank is "roughly .2 millimeters larger than the mandrel", and "the cross sectional area reduction going from blank to mandrel is about 25%-40%."
https://www.youtube.com/watch?v=dC7pWfM3ngU
Last edited by BufordTJustice; 11-21-16 at 09:28.
"That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892
"The body cannot go where the mind has not already been."
Why does the chamber mandrel I showed you a video of have grooves and lands? (yes it's a chamber mandrel, I'm curious about why it's rifled as well)
Why did the video you link me to also show mandrels with only 2-3" of grooves and lands (please watch your own video at 3:17)?
Do you think that the mandrel is at/over the length of the barrel, and this whole length contains rifling, which the barrel is pounded around? If so, you're mistaken. Only a small section of the mandrel has rifling, and this section is traversed by the bore while hammers strike it around said small section. This is why it is literally impossible to hammer forge a taper into a bore. The actual rifled part of the mandrel is only a few inches long. In both your video, and mine...
Last edited by WS6; 11-21-16 at 09:30.
Requote:
Additionally, at 3:38, this states that the barrel blank is "roughly .2 millimeters larger than the mandrel", and "the cross sectional area reduction going from blank to mandrel is about 25%-40%."
https://www.youtube.com/watch?v=dC7pWfM3ngU
"That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892
"The body cannot go where the mind has not already been."
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