Post by: Sabotloader on March 27, 2018, 07:36:30 PM
For something to do I decided I would tackle the replacement of a Knight Vent Liner in the breech plug. I had collected the bits needed - I just did not have lathe to do it on! A fellow ML shooter here in Moscow has one and I was planning on him and I doing the project together, but his lathe was on the fritz! So I decided I would use my drill press in the wood shop.
Heated the shop up and began the project. The first step in the project was to insure the drill press table was perpendicular to the chuck. Use a long drill in the chuck and a square to the table to 90*
Also - I felt it was important to slow the drill press to it lowest speed to reduce heat and provide more control. So I move it down to 640rpm.
Next I inserted a the 3/8" mill end bit in the chuck and the Breech plug in the table vice. Then I centered the drill on the hole in the vent liner. Pulled the bit down to the hole and turned the chuck by hand to confirm the etching on the vent line was equal.
(https://s26.postimg.org/wokv10rg9/3-8_Inch_Carbide_Jobber_bit.jpg)
After the operation began.
Placed the 3/8" Carbide Jobbers bit in the chuck and started the drilling operation. I would only drill for a few seconds and lif the bit up and out. Using compressed air I would blow the BP out and observe my progress. The observations were to insure that I was only drill Vent Liner - I did not want to drill in to the BP metal. Repeated the drill and observe steps several time. Finally I thought I could feel the bit touch the BP metal as the bit turned easier and more smooth.
Remove the Carbide bit and insterted the 3/8 x 82* bevel Mill end and cut the seat for the new Vent Liner.
Remove the Mill bit and Install a #21 Carbide Wire bit to drill out the old Vent Liner Stem to the BP flash Channel
Remove the #21 bit and install the 10x32 Tap in the chuck. Lower the Tap to the hole insert the tap and turn the chuck by hand to clean out the old existing threads and to cut a few additional threads in the BP.
Remove move bit from BP and BP from vice. Install a new Lehigh Savage Vent Liner and test for fit... All is good
He is a composite pic of the operation
(https://s26.postimg.org/mr9u7xwp5/Drilling_Composite.jpg)
Some additional pictures that might be hard to see in the Composite
(https://s26.postimg.org/ntk0qipt5/Bits_Used.jpg)
(https://s26.postimg.org/5qqxzbh3t/Completed_Project.jpg)
(https://s26.postimg.org/k9y30qhyh/Drilled_-_New_Plug.jpg)
Project BP on the Left a new Lehigh Breech Plug on the right.
This whole operation turned out to be much easier than I expected.
Post by: whacker1 on March 28, 2018, 05:11:14 AM
Post by: Skyvalhunter on March 28, 2018, 05:16:42 AM
Post by: Sabotloader on March 28, 2018, 07:48:07 AM
The current Knight breech plug with a installed vent liner is subject to eroding out after a given number of shots. The problem is the vent liner is sealed into the breech plug. So instead of just replacing the vent liner by unscrewing it you have to replace the whole breech plug. A replacement vent liner is $7/8. A breech plug is more expensive. Savage owns the patent to a removable vent liner so Knight has to assure that the vent liner is not removable.
So it is an effort to save a little money and replace the contract vent liner with a real Lehigh Savage vent liner hardened to survive shooting smokeless powder. The new vent liner will survive about 4 times longer than the BP vent liner.
Hope that explains it...
Post by: whacker1 on March 28, 2018, 08:57:02 AM
Really good question guys...
The current Knight breech plug with a installed vent liner is subject to eroding out after a given number of shots. The problem is the vent liner is sealed into the breech plug. So instead of just replacing the vent liner by unscrewing it you have to replace the whole breech plug. A replacement vent liner is $7/8. A breech plug is more expensive. Savage owns the patent to a removable vent liner so Knight has to assure that the vent liner is not removable.
So it is an effort to save a little money and replace the contract vent liner with a real Lehigh Savage vent liner hardened to survive shooting smokeless powder. The new vent liner will survive about 4 times longer than the BP vent liner.
Hope that explains it...
What lifespan are you getting out of a knight breech plug / liner? 100 rounds? more or less? trying to ascertain what 4 times the life looks like in practical terms
Post by: Sabotloader on March 28, 2018, 09:26:05 AM
Really good question guys...
The current Knight breech plug with a installed vent liner is subject to eroding out after a given number of shots. The problem is the vent liner is sealed into the breech plug. So instead of just replacing the vent liner by unscrewing it you have to replace the whole breech plug. A replacement vent liner is $7/8. A breech plug is more expensive. Savage owns the patent to a removable vent liner so Knight has to assure that the vent liner is not removable.
So it is an effort to save a little money and replace the contract vent liner with a real Lehigh Savage vent liner hardened to survive shooting smokeless powder. The new vent liner will survive about 4 times longer than the BP vent liner.
Hope that explains it...
What lifespan are you getting out of a knight breech plug / liner? 100 rounds? more or less? trying to ascertain what 4 times the life looks like in practical terms
Some people are reporting 100 with 120 grain loads of BH - T7 is not quite as erosive so I would say 150 ish or slightly more. With the new Savage liner I would be surprised if it only lasted 400 shots. I have one I know I have 500+ shots of T7 on.
Both the Knight Liner and the Savage liner far outlast the flash hole in a regular breech plug.
Post by: elkboy on March 30, 2018, 04:55:32 PM
Post by: Sabotloader on March 30, 2018, 06:19:21 PM
I thought shooting smokeless powder from a muzzy was not recommended or unsafe! Are new muzzleloaders designed differently?
No - do not shoot smokeless from a conventional ML!!! I hope I did not give you the impression I was shooting smokeless. What I was trying to say is that the current Lehigh Vent Liner is built for the use in a smokeless ML. Shooting smokeless through a flash hole in a BP is way more erosive than either T7 or BH.
The BP I was working on was the one out of my Mountaineer..