(1 of 2) How to machine a barrel blank on hobby equipment (new .22 for my BRK Ghost)

[SniperX]

Very good.
Why not a 4 jaw chuck and the spider only on the outboard?

"Muzzle done. Onto the breech end. First I chucked it up in the spider to cut the OD to match the factory Ghost barrel.
The surface finish was just OK. My cheap chinese carbide inserts are spec'd more for aluminum, so I used a green scotch-bright pad to cover up the evidence.
I think another factor was the "stick out." The barrel was held in a "spyder" in a chuck and still had a few inches of stick out. The super light cuts necessary generally arent well suited for carbide tooling."

Part is not hanging out too far for light cuts at all. Just stop and invest some time in making HSS tool bits. The best investment a hobbiest can make. Few ever do. Then you'll start getting a decent finish. Not to brag or cut up. Trying to help you. And here is proof. And why I never use carbide.
Examples. None of these steel parts were ever polished. Mostly all made from scrap steel.
View attachment 436798View attachment 436789View attachment 436790View attachment 436791View attachment 436794View attachment 436796
Above. The bolt above was single pointed and then case hardened. Replaced a missing carriage lock bolt on a South Bend lathe. Not hardened yet.
Below. A small 60 degree HSS bit for making little screws. Threads up to a shoulder. I make a lot of small screws. Gotta focus and time the half nuts right. I don't thread in back gear, it's too slow. These are proprietary threads and there are no dies. For prewar BSA. I dial in DOC with the compound set over at 29.5 degrees for a reason and you probably already know why.
View attachment 436845
When I learned to operate a lathe HSS was what we were taught to use. A few bits and an Elk Tool tool holder
View attachment 436867
I hope you find this useful

Good advice. I did switch to HSS at the end but found the finish wasnt a whole lot better; so I went back to the carbide.

The reason for the spider with 2 sets of bolts is to bring the barrel into concentricity along two points. With a 4 jaw, the bore can be dialed in on one point. For example, think about when a rod is chucked up. Sometimes its necessary to tap the end to eliminate wobble even though the jaws may be centered properly.

Nice work your doing!

 

[KWK]

Hello @SniperX

Beautiful photos and work, looking forward to part #2.

I use reverse to thread, starting at the "relief area" and threading outward.

ThomasT

You have to place your bit on the back side upside down and then you are cutting towards the tailstock. Spindle in reverse.. Thrust bearings are not set up to handle as much load in that direction on many lathes. It's still commonly done. Especially for internal threading.
Here I have a left hand Acme thread set up so I can turn toward the headstock. LH thread doesn't have to be upside down tool bit but reverse spindle. HSS Acme profile bit I ground. Yielded .002 backlash in the nut. I think the compound slide was offset 11 degrees.
Caution! when turning in reverse with a threaded spindle mount!
Hope you don't mind me throwing this in.

I use lantern tool posts to prove I don't know what I'm doing

 

[bucketboy]

Very nice work fella

 

[KWK]

Good advice. I did switch to HSS at the end but found the finish wasnt a whole lot better; so I went back to the carbide.

The reason for the spider with 2 sets of bolts is to bring the barrel into concentricity along two points. With a 4 jaw, the bore can be dialed in on one point. For example, think about when a rod is chucked up. Sometimes its necessary to tap the end to eliminate wobble even though the jaws may be centered properly.

Nice work your doing!

HSS is a whole nother skill set. Master it and you'll not go back. Brass and aluminum are child's play. And delrin. Steel is another story. Your angles have to be right or it tears and doesn't shear cleanly. That's the secret. Play with it until you get it working on scraps. Invest the time. Not even making anything. Experiment with it. That's how I did it 40 years ago. Most Youtubers don't have a clue with it. Their profiles usually look crude to me.

Dial in the 4 jaw and then dial an outboard spider. Then recheck the 4 jaw. I'm sure you had to go through those motions anyway. An outboard spider would be all you need because you normally already have a 4 jaw. An outboard spider is always useful and versatile.
My friend has a lathe with an 8 inch spindle bore that has a huge 4 jaw chuck on the outboard side. An old salvaged machine that still makes good money threading pipes for sewage plants on occasion. His machine shop is out in the sticks and every small town has a sewage plant. Much shorter travel to haul it to him and back.

 

[Privateer]

Good thread just as I'm about to do the 1/2 20 work on my .22 Evanix project.

 

[MrP]

Some of my favorite post here are when people with some kind of advanced skills describe the process they use to achieve some end on an accessible level. Gives a little glimpse of what things look like through their eyes

 

[Privateer]

It also helps one figure out how much more cash they need to spend to get the proper tooling.

Had to order the stuff to cut threads as I don't have a few things yet.

 

[heavy-impact]

Hello @SniperX

I use reverse to thread, starting at the "relief area" and threading outward.

ThomasT

I do the same and learned the trick from Joe Pie.

 

[heavy-impact]

Very good.
Why not a 4 jaw chuck and the spider only on the outboard?

"Muzzle done. Onto the breech end. First I chucked it up in the spider to cut the OD to match the factory Ghost barrel.
The surface finish was just OK. My cheap chinese carbide inserts are spec'd more for aluminum, so I used a green scotch-bright pad to cover up the evidence.
I think another factor was the "stick out." The barrel was held in a "spyder" in a chuck and still had a few inches of stick out. The super light cuts necessary generally arent well suited for carbide tooling."

Part is not hanging out too far for light cuts at all. Just stop and invest some time in making HSS tool bits. The best investment a hobbiest can make. Few ever do. Then you'll start getting a decent finish. Not to brag or cut up. Trying to help you. And here is proof. And why I never use carbide.
Examples. None of these steel parts were ever polished. Mostly all made from scrap steel.

Above. The bolt above was single pointed and then case hardened. Replaced a missing carriage lock bolt on a South Bend lathe. Not hardened yet.
Below. A small 60 degree HSS bit for making little screws. Threads up to a shoulder. I make a lot of small screws. Gotta focus and time the half nuts right. I don't thread in back gear, it's too slow. These are proprietary threads and there are no dies. For prewar BSA. I dial in DOC with the compound set over at 29.5 degrees for a reason and you probably already know why.

When I learned to operate a lathe HSS was what we were taught to use. A few bits and an Elk Tool tool holder

I hope you find this useful

I need to start grinding HSS cutters myself. I've been using the cheep chinese carbide for years with mixed results.
Made a spider nut for my G0602 spindle and use the 4 jaw chuck for barrel work. I need to make a good solid tool post riser to replace my flexing compound.

 

[SniperX]

Quick write up on the first shots/accuracy is here: https://www.airgunnation.com/threads/22-ghost-lw-barrel-blank-first-test.1307049/