NEW to CHAMBERING

J

Jdaniel343

Guest
I purchase a lathe about a month ago to do my own gunsmithing.
I have been building tooling during this time.
I want to practice chambering without ruining a good barrel.
I thought I would practice on a piece of 1-3/8" cold rolled round stock.
Drill holes in centers for bore size and begin the process of setting up just as if it was a new unchambered barrel.
Is there any problems with practicing like this?
Thanks
 
New to chambering

No. Practice on barstock is cheap and will go a long way toward making you feel confident when you set up a new $300 blank. As to drilling a bore hole and actually reaming your "practice blank" this would require you to drill a deep hole of close to groove diameter and may be a little more trouble.

If you have anyone near you that fits barrels they may have some Take-off barrels you could practice on. Some guys are always trying to make a buck and I have no problem with that, but it would be worth $30 or so to have an old barrel to practice on.

Scott Roeder
 
There can be. You probably have 1018 cold rolled, it is very grabby when you try to run the reamer in and if your not careful you will snap the reamer. If you havn't seen a barrel chambered before I would recommend getting the Grizzly Machine chambering video by Gordy Gritters. You don't have to use his technique but watching how he does it you will see what needs to be done.
I jumped in with both feet on my first chamber, no practice and it truned out great. Just pay attention to detail and take your time.

James
 
Buy some free machining leaded stock if you must, but I have heard this same response (don't want to ruin a good barrel) so many times...You can't ruin a barrel..only screw up the thread pitch, or run the reamer in too deep...don't cut your barrel to length until it is chambered and headspaced, that way your mistakes will not influence you finished barrel..all of these are easily remedied...I recommend you practice setting up your barrel and indicating it in to near as zero as possible...take your time...make a day of it and insure that you dont have more than a couple of inches sticking out of the chuck (reduces chatter when threading or chambering)... take it slow and measure your tenon length and ad .100" to that to give you some mistake room...then start making cuts on the tenon diameter and measure after each cut to get a feel for how much you are removing each time...until your final diameter is reached...if you measure often you will most likely not cut your tenon undersize...then thread the tenon taking light cuts .003" no reason to get in a hurry..keep the lathe rpm slow so you can avoid hitting the shoulder...but if you hit the shoulder "don't worry" just finish threading and machine the shoulder forward until it cleans up...no harm done...it may take 10+ passes to get the right thread depth, but the thread finish will be nicer...once you have the thread depth about right...try to screw the action on several turns...if it feels tight make another light threading cut until the action will screw on several rotations without binding..now you can concentrate on cutting the tenon to final length...and cutting the counterbore or cone angle...TAKE YOUR TIME...if you are on a schedule...stop and come back when you have several hours and can concentrate...it does't hurt to leave everthing in the lathe setup...even if you have several day delay...when you get to the reaming step...use lots of cutting oil and feed no more than .025" before removing the reamer and cleaning the chips from the reamer flutes and barrel...SLOW and EASY is best...check the depth with a headspace gage and depth micrometer often...until you get within .050" of finished depth then feed about .010" and clean the reamer/chamber and check headspace...if you go in too deep just determine how much "too deep" you are, then move the shoulder and counterbore/cone forward that amount...then check the headspace...and ream as needed...

You can't learn to swim in the wading pool "jump in" and stay confident that you can't ruin a barrel..!;)
 
Last edited by a moderator:
New to Chambering

I have watched Gordy's Video. I will be using his technique.
I will follow his order of doing things since I have the video and can write down his sequence.
I think I will look for a takeoff barrel to practice on.
Your right, if I buy a new barrel at 30", I will have some screwup room.
Thanks for the advise.
Should one use carbide or HSS. I've been using carbide and when threading the threads seem to be rough, as if the material is being torn.
I have sharpened the bit and I have the correct angles.
Maybe I'll try a new bit.
 
What are you sharpening the carbide with?
Try using pre-formed carbide insert tooling, works really well especially if you get comfortable with threading at a higher rpm.
 
You can get some cheap barrels at Numrich Arms (Gun-Parts store) They may be odd length or diameter but that would not hurt for what you are doing. Also Green Mountain Barrels are less that $90.00 for the sizes that they sell. You could practice on one for a few inches and still have enough to make a rifle with when you get your reaming and thread cutting down correctly.
Lowell
 
Get on the phone and call every marquee barrel maker in the states. Ask if they have a scrap bin they want cleaned out. Pay for shipping and maybe a few extra bucks and you'll have all the barrel material you can stand before too long and it'll have a qualified hole that your pilot will center on.

IMO a guy should practice on what he's actually going to be machining. Barrel steels are a little different from other materials due to the heat treat and stress relieving processes.

As for tooling. GET INSERTED carbide and learn to run the RPM and SFM that it likes to operate at. There is no reason a guy has to turn threads at 60rpm. Take a weekend and do nothing but practice "race tracking" your threads and you'll be a pro by Sunday evening. You'll have better finishes and this means better "lock up" and less "squishy feel" when your sucking that barrel onto the receiver. The shoulder on a tennon is nothing to be afraid of. Just call out a cadence when you engage the half nut and keep time with a foot the way a drummer keeps the beat. It's easy I promise!

Good luck.

C
 
Last edited by a moderator:
Sorry to go against the grain here, but I think learning to grind ones own HSS tools from bar stock is a better path here. There will be other operations that come up that will require toolmaking.

Some 3/8" HSS blanks and a starrett thread tool, is all you need to cut excellent threads in 4140 or 416SS.

I do have a few small carbide tipped boring bars on hand for boring after drilling. Thats it.

Just my tuppence.

Ben
 
It's kind of hard ...

... to grind a full profile threading tool on high speed steel by hand. But then I really like full profile inserts. I keep 16, 18 & 20 TPI exterior and 16 TPI interior inserts in inventory. Because of having to go back and forth between threads I have each threading tool with an insert and its appropriate shim in separate Aloris tool holders. Once you go full profile it's hard to go back.

Nic.
 
NesikaChad said:
Get on the phone and call every marquee barrel maker in the states. Ask if they have a scrap bin they want cleaned out. Pay for shipping and maybe a few extra bucks and you'll have all the barrel material you can stand before too long and it'll have a qualified hole that your pilot will center on.C
Click to expand...

I second this recommendation by Chad...the first one I called sent me over a half dozen barrels and I can screw them up all I want. I also purchased three used chamber reamers, coincidently from Chad, and called Midway and got some go-gages and start making mistakes and learning.

The other end of the barrel gives you endless amounts of practice. Call a muzzle brake maker and do the same-same with rejects. Cut threads of a different size and get the reject muzzle brakes to Class III quality fit. Be careful with your threads in the brake and not botch those or your SOL on that practice unit. Don't fret though, you were going to throw it in the garbage anyway...

Stick the threaded muzzle in your band saw, saw it off and start over. Each time your stick it in your headstock you will be practicing indicating the barrel and this is wonderful experience.

Save your pieces parts and mark them with a date or number. After you get three or four barrels chopped up you will have some basis of comparison to see your own improvement. When you get that Barney Fife look of confidence on your face, do your very best and chop several off and send to a trusted smith or machinist to comment on.

HSS vs carbide? I am too new and totally unqualified to help you here. What I did was remove the incorrect grinding wheels on my common bench grinder and really botch two or three, with the fourth coming our "finished" that would give some guys on this forum a heck of a belly laugh, tears, the whole bit.

I was scared or apprehensive to start the grinding part as it was intimidating. So what? I kept after myself and with the correct wheels I can grind a reasonably good form tool or bit. Mind you, I cannot write my own name--I have zero artistic ability. Now, I just think of an excuse to get to the grinder.

It will all come to you in time...be patient and practice!
 
You must log in or register to reply here.
Back
Top