Donation

All Springer/NP/PCP Air Gun Discussion General > Machine Shop Talk & AG Parts Machining

Barrel blank prep questions

(1/9) > >>

Taso1000:
Hey All!

I am getting ready to machine my first barrel with my new mini lathe.  My barrels are Lothar Walther, .177 caliber, unchoked, polygonal rifling, stainless steel, 23.8" long and .63" diameter.

I'd like to do what I can for the best accuracy within my machining and assembly limits.  I've never used a lathe before and I am starting to accumulate tooling so I don't have much.  I've also just started trying to resolve some binding issues in the carriage and compound rest.  I took it all apart last weekend and this weekend I hope to clean up mating surfaces with 500 grit sandpaper and fix some not straight gibs. 

What is the best way to indicate off the bore of the barrel?  Are Lothar Walther bores concentric with the od?

I am aware of the 80%- 20% rule of effort versus performance so I don't want to spend too much effort trying to achieve the last 20% if the benefit isn't there.  My goal is 100 yard accuracy with lead bullets. 

I intend to support the barrel with a live center at the right end and I have a "spider" to support the left end of the barrel out of the spindle.

I have not decided if I want to clean up the exterior surface of the barrel yet.

I am also a little confused at what would be the most efficient order of operations.  I have attached pictures of the original receiver end of the first barrel I intend to duplicate.  I also want to crown the muzzle. 

If I clean up the exterior of the barrel, concentric to the bore, I guess I could indicate off that (od) for later operations.

I know my 7 x 14 lathe is weak so I intend to go slow and make many light passes.

Thank you all in advance for your suggestions!

Taso

WhatUPSbox?:
Taso
Are the pictures of what you need to create on the new barrel?

From your other post "I will have to turn down the diameter to fit into the receiver, cut an o-ring groove in the face of the breech, a ring around the diameter of the barrel for the retaining screw and a crown at the muzzle."

I would get some aluminum round stock and go through all the machining steps as a test case.

For indicating the bore, I would make some aluminum plugs but there may be a more legit way.

ShakySarge:
I would agree that doing some test runs on cheap material would be highly advisable. Taking steel off is easy. Putting it back is a whole other story!

Privateer:
You might want to look into a steady rest.
https://littlemachineshop.com/products/product_view.php?ProductID=2418

The 0 to 1" will probably be all you need for the mini lathes.
I have that and the 1 - 2" version

For practice? Get a steel bar. Cutting Aluminium is different from cutting steel.

Taso1000:

--- Quote from: WhatUPSbox? on December 13, 2018, 06:39:55 PM ---Taso
Are the pictures of what you need to create on the new barrel?

From your other post "I will have to turn down the diameter to fit into the receiver, cut an o-ring groove in the face of the breech, a ring around the diameter of the barrel for the retaining screw and a crown at the muzzle."

I would get some aluminum round stock and go through all the machining steps as a test case.

For indicating the bore, I would make some aluminum plugs but there may be a more legit way.

--- End quote ---

Hey Stan!

Yes, that is the barrel I was trying to describe. 

Thanks!

Matt and Jeff,

I will check out the local home improvement stores and see what steel rod stock they have and practice with that to get a feel for the lathe.

Thank you!

Taso

Navigation

[0] Message Index

[#] Next page