Order of Operations?

M

MattM

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I have a 1.25x26'' .30 caliber rifled barrel blank.

Want to make a .30-06 24" barrel .

Here is want I want to do: thread the tang, chamber, cut to length, thread the muzzle to 5/8 24, taper the barrel, and flute it. I have all the machines (no CNC) and tooling to do it. Not so sure about the skill level though I have done all operations before.

How do I proceed? Your guidance is welcome.---Matt
 
1. OD diameter for the first 6" around the chamber. Face, shoulder, and thread for receiver.
2. On centers -- overall taper. Do this rough, about .100 over, let it set for a week or more to see if you've relieved any stresses and if it moved.
3. Chamber area... chamber plus any ramps or counterbores that might be required. Effectively finish the aft end.
4. Cut to length
5. Back on centers - finish overall contour/taper.
5. Thread muzzle.
6. Fluting (I'm assuming straight flutes)

That's more or less arranged in a descending order of precision.
But some guys are heartfelt about saving the chambering for last. Others want to profile the overall taper first thing. Each has some merit, or at least some plausible reason.
Some guys will advise fluting first to keep the final product "more stable" and they might be right. However, I think early fluting just provides more impact and possible movement during final contouring. So I save it for last. I've not had the inclination to try spiral fluting just yet.
In reality, the exact order probably hardly matters. Any of these steps can be done in any order as any gunsmith will tell you they've had to do each of these to a finished barrel somewhere along the line ;-)

Wrat
 
Agree with the above it most likely matters not the exact order you perform the machining ops as long as it fits your methods and machinery and achieves the desired level of precision. Since you asked however if it was me I would do all the exterior profiling and get the blank whittled down to the final form. Consider leaving it long as possible if this helps later in indicating and chambering. IDK if you have ever profiled a barrel, it is not one of my favorite tasks. Mitigating chatter is a balancing act of tool geometry and speed and feed. Some experimentation will be required. Once the blank is done thread and chamber the breach end flip it cut to length and crown it..
Couple tips on turning that I have found to work for ME. If you are not cutting a taper use a follow rest if you have one. I use a hs steel cutter with a small radius tip. I turn the blank slow 100 -200 rpm and feed the tool on the fast side. I have used a lead hammer laid on the barrel while turning to quell chatter, it can be a pia to get a decent surface finish.
 
Thank you both.

I tapered a piece of scrap barrel yesterday. Offset the tailstock and rough cut at fast speed and feed with a carbide insert. Then for two finish cuts used the same speed but took very fine cuts at my slowest feed rate with a new carbide insert. Each pass took 20 minutes but the finish was excellent and no chatter. I used 240 grit and fine Scotchbrite to pretty it up.

The Wife says it is "Beautiful".

Today I might try to straight flute it. I tried fluting a piece of scrap the other day and it went OK. I have no idea of how to do spiral flutes.

I'll never make money as a "Smith" but what the hell, I'm having fun.
 
wrat said:
Don't feel bad. Most Smiths don't make money as a Smith, either! :p
Click to expand...

Fortunately I don't have to. I'm a "amateur" amateur machinist enjoying a fascinating hobby in my declining years. I have three old retired machinists who give me hands on advice and rap my knuckles when I make a mistake. Also the wisdom on this forum is of great value.

When I was turning that barrel yesterday I was thinking it would take me at least 20 hours to do the complete job. Makes a finished Pac-Nor barrel with action installed for $625.00 seem a bargain.
 
Barrel contouring takes time and patience, especially with a small machine. I've had people ask why I don't try to turn my hobby into a living. My reply is that I like to be able to eat..................

Matt- I'm 58 and just got back into machining and started hobby-smithing 2 years ago.

I'd encourage you to read through some of the threads here in the Gunsmithing forum for a boatload of good advice.

Good luck with all of your projects!
 
Spiral flutes will require a cnc machine with a 4th axis. They could be cut on a manual milling machine if it was equipped with a differential milling attachment. Some of the older horizontal mills had gearing that would drive a dividing head causing it to rotate as the table travels. I have pondered how I might accomplish differential milling on a bridgeport style mill and came to the conclusion that the juice wasnt worth the squeeze
 
Tried cutting some flutes on my beautifully tapered barrel. Came out looking like a squirrel's tail blowing in the wind.

Back to the drawing board...

Started tapering a 26" barrel tonight between centers with tailstock offset same as the other one. Using same method: high speed (860 rpm) and feed for roughing, then same speed and very low feed with a new insert for finish, lots of hand applied Tap Free.

This will take some time.
 
wrat said:
Don't feel bad. Most Smiths don't make money as a Smith, either! :p
Click to expand...
After a long career as a gunsmith, let me say: Damn right brother! Ain't Makin any money as a "semi-retired, burnt out 'ol gunsmith either! But just like with hot women -- I like it!!!!! A lot!

Squire

Sent Using Tapatalk - Cherokee Nation of Oklahoma
 
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