Author Topic: Vent liner  (Read 3187 times)

Offline Dphariss

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Vent liner
« on: April 07, 2010, 04:41:37 AM »
While shop built this is essentially a White Lightning liner.
The photo shows a good installation. It also illustrates why this type liner is reliable when properly installed.
Dan
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Offline Acer Saccharum

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Re: Vent liner
« Reply #1 on: April 07, 2010, 04:59:45 AM »
Gotta love it. Powder grains sittin' right up at the inside of the touch hole. Perfect install, Dan.

Since you made your own liner, does it bottom on a shoulder?

Tom
« Last Edit: April 07, 2010, 04:59:56 AM by Acer Saccharum »
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Offline Larry Pletcher

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Re: Vent liner
« Reply #2 on: April 07, 2010, 05:53:10 AM »
Dan, Acer,
I think this pic supports my idea of one charge instead of two - at least when the prime is against the barrel.
Regards,
Pletch
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Offline Dphariss

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Re: Vent liner
« Reply #3 on: April 07, 2010, 05:20:40 PM »
Gotta love it. Powder grains sittin' right up at the inside of the touch hole. Perfect install, Dan.

Since you made your own liner, does it bottom on a shoulder?

Tom


Digital cameras are wonderful things. I take all sorts of photos now that would never occur to me back in the film era.

Yes its on a shoulder. I make a thicker wall than the WL usually has and this one is simply drilled as a counter bore not coned as the WL is. Since I have many feet of left over or scrap 5/16" 303-304 stainless rod I have lots of material to make liners from.



The light down the bore shows the web before the bore. This is a 1" pistol barrel tapered to 7/8".
of the breech plug.



I drill for the counterbore pilot, then counterbore, then drill just a few thousandths over the counterbore in the liner so there is no fouling trap. Fit using magic marker to get a seal at the bottom and at the slight countersink at the barrel flat. If not countersunk here the threads will show when filed flush.


I thread these with a die after making everything to size. By using a split die it it possible to make it slightly oversize for a tighter fit in the barrel than if simply threaded to standard size.


Fitting. The hole appears off center since the part is threaded and has partial depth on one side and full depth on the other.



Larry timed a vent similar to this but drilled as I do for #10 x32 (this is 12x32) and IIRC is just marginally slower in Larry's tests than the ones with the larger cavity and its far simpler to make.
10x32 allows a counterbore that works well with fff powder the 12x32 may be better with ff.

It does take a few measurements and head scratching to get the web right.
I start with a vent in the .055-.060 range.
On larger diameter vents like the one in the Nock breech I made it is possible to use a lathe tool and copy the English/White lightning internal cone.
Or I could make a smaller lathe tool for the #12 liners ;D

Dan
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Offline Dr. Tim-Boone

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Re: Vent liner
« Reply #4 on: April 07, 2010, 11:32:43 PM »
I like the deeep pan opening !!!...... and your engraved golf clobs on the gun!!   ;D ;D
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