About to cut my first chamber

[birdiemc]

Just want to see what advice all the experienced guys have before I cut my first chamber.
The reamer has been here for a week but work is crazy right now. I plan to re read the 2 books I have this week.
My shop equipment is far from ideal, grizzly lathe not what the pros have but I'm able to turn parts to zero run out on .0001 indicator. I'm a far cry from a gunsmith or a machinist and don't claim to be. I just love the satisfaction of building something myself. I bought this lathe 3 years ago and have been learning at home with the help of a couple machinst friends and am finally ready to give it a try.
I know plenty of people are going to say take it to a reputable smith and have it cut, but I didnt spend $8,000 on equipment and tooling and 3 years running a lathe in my spare time to just go take it to a Smith. Obviously it's not about saving a buck it's about the pride of building a rifle myself. At least as much of it as I can.
So that said, what advice do you machinists and Smith's have about running a reamer into a pre drilled hole?

It will be a 6.5cm in a shilen 9twist by the way. Planning to build my own stock and put it in a savage SA that I have laying around.

 

[ar10ar15man]

do you have an indicator that will reach where the throat will be ?
do you have an outboard spider to support the muzzle end of the bbl?
predrill is a step, next step is to dial in the throat and then taper bore to match the reamer.
what chuck is on the lathe ?
is there no bending stress on the bbl ?
how is your thread cutting skills ?
look into reverse upside down threading,cutting away from the headstock.

nothing like the feeling when a rifle you built shoots little biddy groups
( well that will not happen you did pick 6.5 cm...lol)

 

[birdiemc]

do you have an indicator that will reach where the throat will be ?
Yes

do you have an outboard spider to support the muzzle end of the bbl?

Yes
predrill is a step, next step is to dial in the throat and then taper bore to match the reamer.
In all my reading about cutting a chamber I've not come across tapering the bore to match the chamber, can you expand on this please?


what chuck is on the lathe ?
Will use 4 jaw

is there no bending stress on the bbl ?
Should be stress free setup

how is your thread cutting skills ?
look into reverse upside down threading,cutting away from the headstock.
Comfortable threading, definitely going to practice cutting a few plugs to thread into my action before threading the bbl, and huge fan of reverse threading away from headstock

nothing like the feeling when a rifle you built shoots little biddy groups
( well that will not happen you did pick 6.5 cm...lol)
What are you talking about....I picked 6.5cm so I dont even have to use the lathe, just wave the reamer around ceremoniously above the barrel and let the magic happen right?

 

[Gregg C]

I find this intriguing. I am by no means a machinist, nor a gunsmith. Once upon a time, tho, I wanted to be an automotive machinist. Was given an old Rottler boring bar that " couldn't be fixed." It wouldn't center in the bore. I had a bunch of engine blocks laying around, so I started trying to figure out what was wrong with it. Wrecked alot of cylinder blocks. Fiinally found the problem, fixed it, and taught myself to machine car engines. Later, I SOLD that bar back to the guy who said it would never be right. I could pull off a bore, and go back and cut .001 out on diameter. That leads me to a suggestion for you: would it be advantageous to get some round stock to practice on? Or would you lose some of the useful life of your reamer ? Just thinking of all those blocks I wrecked....either way, good on you, dude!! Keep posting your progress !

 

[DUSTY NOGGIN]

tagging in

 

[birdiemc]

That leads me to a suggestion for you: would it be advantageous to get some round stock to practice on? Or would you lose some of the useful life of your reamer ? Just thinking of all those blocks I wrecked....either way, good on you, dude!! Keep posting your progress !

I have actually considered doing this. The only downside would be dulling the reamer, the upside would be not ruining a barrel.

 

[NEMTHunter]

If you ream slowly you should get lots of life out of the reamer. I am not a gunsmith. Just going by what my gunsmith told me.

 

[shortgrass]

I have actually considered doing this. The only downside would be dulling the reamer, the upside would be not ruining a barrel.

There are 'lots' of chambers in a reamer that isn't abused. Using a piece of bar stock isn't a bad idea, but you'll need a chucking reamer for your pilot hole, and it's not nearly expensive as a chambering reamer. Use lots of oil and don't crowd the chambering reamer and it'll last for many chambers.

 

[ar10ar15man]

lets start with a pretty well known fact
bbl bores are NOT STRAIGHT, they worm hole
if you use a bushing to follow the bore IT WILL push the reamer around the axis of the bushing..which is following a worm hole. the back of the reamer has a hard time maintaining no run out and correct dia.

jump forward
once the bbl is aligned at the throat.
taper bore to match the reamer.
now WITHOUT A BUSHING, the reamer aligns on the taper, which is pointed at the throat.
if all is done correctly, your chamber will point the bullet squarely into the bore.

 

[shortgrass]

Unless you are an experienced machinist, cut your first chambers the traditional way using the pilot. Hundreds of thousands of accurate chambers/rifles have been built that way. Save the advanced techniques for later, after you have a bit of experience. A reamer with removable pilots is always preferred over a fixed piloted reamers. But, both have been used to cut good chambers making accurate rifles.

 

[birdiemc]

Unless you are an experienced machinist, cut your first chambers the traditional way using the pilot. Hundreds of thousands of accurate chambers/rifles have been built that way. Save the advanced techniques for later, after you have a bit of experience. A reamer with removable pilots is always preferred over a fixed piloted reamers. But, both have been used to cut good chambers making accurate rifles.

Sounds like good advice.

 

[jrock]

If its absolutely your first chambering attempt on anything, I would advise wrapping that Shillen barrel up and putting it on the shelf. Buy a cheap blank from Green Mountain and try all the different techniques you can find in books and online. It was well worth it to try the methods and tooling setups to see which one worked the best for my setup. A reamer will last lots of barrels so don't worry about wearing it out. Doing this can also can tell you a lot about how rigid your setup is and if there are any bending forces in the barrel. Practice makes perfect so I wouldn't expect perfection on the very first time.

 

[tgonza]

I am not an expert machinist by any stretch of the imagination, although my dad was a machinist is for many years for Cummins diesel. Unfortunately he passed away before I started my barrel machining. That being said, I have done a few barrels, some at a Gunsmithing class and some at home on my older Jet lathe. The ones I did at home actually came out pretty well using rented reamers. I used finish reamers for both barrels. My grandson shot an antelope with a 6 mm BR that I built on a sporter barrel at 380 yards. He also shot a a 4x4bull elk with a 284 Winchester I built on a short action. Both of these were Savages which are ears easier than doing a Winchester or a Remington.

 

[birdiemc]

If its absolutely your first chambering attempt on anything, I would advise wrapping that Shillen barrel up and putting it on the shelf. Buy a cheap blank from Green Mountain and try all the different techniques you can find in books and online. It was well worth it to try the methods and tooling setups to see which one worked the best for my setup. A reamer will last lots of barrels so don't worry about wearing it out. Doing this can also can tell you a lot about how rigid your setup is and if there are any bending forces in the barrel. Practice makes perfect so I wouldn't expect perfection on the very first time.

That's exactly what I had planned to do but my spindle bore is only 1" and when i looked all the green mountain blanks were bigger than that. I suppose I could turn between centers, but I have been planning to use an outboard spider.