Does a chamber reamer remove only the last few thou from a near-net-shape chamber, or does it remove all the material in the chamber from the caliber-sized drilled hole?

If it's only the last few thou, how is the near-net-shape hole cut? Is the chamber first cut with a twist drill to something close to the smallest dia of the case body? A series of larger drills run in to decreasing depth?

I ask because my experience is with hand reamers putting a final finish on a simple drilled through-hole, where you typically try to stay within a few/several thou of final diameter. I'm wondering how you would go from a .416 diameter bore to a finished 416Rigby chamber using only a reamer.

Thanks

I've seen it done both ways: using a reamer to hog out the entire chamber and at the opposite end cutting the metal first with a piloted twist drill, then with a "roughing" reamer, then with a "finishing" reamer. As far as I am concerned, the latter way is the only way, if you expect superior performance out of the rifle.

I know a smith that starts all of his chambers with a boring bar.

quote:

Originally posted by Fjold:
I know a smith that starts all of his chambers with a boring bar.

That would be me. Actually I use a twist drill and then bring the hole into compliance with a boring bar.

mrjulian_1970, a chamber reamer will remove it all. It's a rather slow way to go, but it will do it.

With a through the bore fluid cooling/lub system I've done several chambers with a steady ~0.005"-0.010"/sec feed with no stopping with a rented reamer. You can go faster probably, but that was fast enough for me. That's about half an inch a minute so it doesn't take too long to cut a chamber.

That's for 223 - '06 size cases...for belted and larger cases I sometimes drill with a carbide stub drill, then boring bar, then reamer...sometimes reamer only. Even then it never takes more than about a hour from beginning to finished chamber including dialing in.

Basically I decide depending on the bore size in relation to the case size. I did my 510 Makatak Rigby cased chamber the old fashioned way...no drilling/boring, reamer only...dip the reamer in DoDrill, cut 0.100", clean, start over...basically 29 cycles and it still took less than an hour including coffee, BS'ing and futzing around.

As always...whatever anyone does and how they do it...it depends...

Luck

quote:

Originally posted by Westpac:

quote:

Originally posted by Fjold:
I know a smith that starts all of his chambers with a boring bar.

That would be me. Actually I use a twist drill and then bring the hole into compliance with a boring bar.

I also do that. Some of my reamers are solid carbide. With those I do the entire chamber & don't look back.

quote:

Originally posted by xausa:
I've seen it done both ways: using a reamer to hog out the entire chamber and at the opposite end cutting the metal first with a piloted twist drill, then with a "roughing" reamer, then with a "finishing" reamer. As far as I am concerned, the latter way is the only way, if you expect superior performance out of the rifle.

X-

I am curious about your post. Why do you feel that the latter way was the only way to get superior performance?

What do you feel will be better performance? Or I guess what would you lose by cutting the whole chamber with just the finish reamer?

I guess I need to add the qualifier that I am in absolutely no way asking this in an argumentative/condescending/whatever way. i am simply asking what you feel you gain/lose depending on which way you go about it.

I am asking for the same reason i ask guys how they are finishing stocks these days-bcause many of us have an evolving way of doing things in the shop. I am always looking for better ways to do things. "Better" can mean several things - faster, more accurate, less wear and tear, or anything else.

In the Fall '09 issue of Gunmaker Michale Ullmaan wrote about and posted a chart showing many popular chamberings, the drill sizes he uses AND how much he feeds each one. i thought it was a pretty helpful chart.

Due to my health I am and will always be an incredibly low volume chamberer. i just cut it all with a finisher. The only thing I stick in the bore before the chamber reamer is a countersink reamer with the proper pilot on it.

i have watched my mentor's chambering methods evolve over the time I have known him and it is now a lot different than when I learned. He does everything through the headstock with a barrel flush system. He said that system makes it go WAY faster. He is healthy, a full time funmaker, and does a lot of barrel jobs.

I am always looking for a better mousetrap. And also always on the lookout for new or different things. It is for the same reason that I like to see other guys' shops-just to see how they have everything arranged and set up.

As Foobar said, if you're just doing one chamber, and are not into production work, it is perfectly feasible to do the entire job by hand, with a finishing reamer. Go slowly, blow out chips OFTEN, keep reamer properly lubed, and voila. That's how the chambers in my .450 #2 NE double were cut and they don't get any bigger than that.

It's wear and tear on tools that's the key.
Yep one chamber who cares.
Production
Drill/bore.
Rough ream
Finish ream

When you drill/bore the hole. Do you bore a straight parallel sided hole or do you bore a tapered hole to match the taper on the reamer?

Speaking for myself only I have cleared out the chamber by boring straight steps.

I drew out the chamber on paper and calculated diameters and depths leaving about .020" in diameter and depth at each step to clean up. .020" is a huge amount if you are keeping good track of where you are in the chamber. I did it this way a while back and felt I should have reduced it to .010" but also it's easier to remove material then put it back. so I just took my sweet time with the reamer.

You could bore the taper but you'd better indicate your compound or taper attachment. I feel it's just too much setup time to bore it on a taper. The reamer will take car of that for you.

Questions to all the eksperts.

Try to tell pros an cons on making a chamber using a tall drillpress. where you clamp the muzzle in a centered 3 jaw.placed at the base of the drill press.
Reamer choise
1: piloted carbide 3 fluted rougher followed by piloted 6 fluted finisher.
Oil should be pumped from the muzzle in large volumes. flushing out chips.

try to ewaluate the build inn self centering process, remowing the need for anny kind of floating reamers.
On the reamer holder there should bee a fine threded stopring for dialing the final debth.

To me this solution just seems to briliant and could reduce chambering to under 5 min, leaving you with a perfectly inline chamber with min dimention

quote:

Originally posted by jørgen:
Questions to all the eksperts.

Try to tell pros an cons on making a chamber using a tall drillpress. where you clamp the muzzle in a centered 3 jaw.placed at the base of the drill press.

What part of the bore would you center the 3 jaw on? And if I read this correctly, you would leave the breech end free to oscillate as the reamer turned?

There ain't no perfect chamber jobs because they ain't no perfect barrel bores.
I only chamber for my self. I do it in the headstock. I wouldn't cut a chamber without a predrill, double check the indication of the throat, taper bore to .050 of the shoulder and .010-.020 of diameter. I finish with a piloted reamer with a loose bushing. I want the reamer to follow my taper bore and not the wandering bore of the barrel in front of the throat.
Butch

quote:

Originally posted by Westpac:

quote:

Originally posted by jørgen:
Questions to all the eksperts.

Try to tell pros an cons on making a chamber using a tall drillpress. where you clamp the muzzle in a centered 3 jaw.placed at the base of the drill press.

What part of the bore would you center the 3 jaw on? And if I read this correctly, you would leave the breech end free to oscillate as the reamer turned?

Asuming the barrel is turned on live centers, fixing the muzzle, leaving the chamberend to alighn with the reamer, should give the smalest amount of missalignment.
The breech would not osillicate, as the reamer runs steadíly. The bore would only be mooved untill perfect alighned.

quote:

Originally posted by butchlambert:
There ain't no perfect chamber jobs because they ain't no perfect barrel bores.
I only chamber for my self. I do it in the headstock. I wouldn't cut a chamber without a predrill, double check the indication of the throat, taper bore to .050 of the shoulder and .010-.020 of diameter. I finish with a piloted reamer with a loose bushing. I want the reamer to follow my taper bore and not the wandering bore of the barrel in front of the throat.
Butch

The general problem with predrilling is that you has a lot of dificulties in making your pilot overrule your predrilled hole, that could easily be excentric to the bore.

My basic idea of chambering is that specially the throat should be perfectly concentric to the bore, to prevent the bullet from entering asymetric, causing the bullet to wobble.

jA rgen
Read my post and method again and pay attention.
Butch

quote:

Originally posted by butchlambert:
jA rgen
Read my post and method again and pay attention.
Butch

I dont know if i got you right.
Do you prefere the chamber to follow your preedrill. giving a shit about if it is concentric to the bore, in the point where the throat enters the bore

When I do pre drill I stop the drill short to where the reamers live pilot is fully supported by the bore. Then I proceed with the finish reamer & finish the chamber.

No, read my post again. After drilling, I reach inside the hole and indicate the groove at the throat. Can't get in there until I drill. I indicate it and taper bore .050 short of the shoulder and .010-.020 less then the finish diameter of the chamber. I do this with a short stiff carbide boring bar. After that I run the reamer in. The bored hole is coaxial to the bore at the throat and the bore is coaxial to the spindle bearings of the lathe.
Butch

Butch-

I presume you would agree that there is not too much problem with wandering bores when one is reaming a short chamber, such as the .30 BR or 6 PPC?

Everyone has their own approach, but I have won a lot of matches with barrels I have chambered for myself with just a good finish reamer.

I do use top quality 4-jaw chuck, floating reamer-holder, and a spyder. I Chamber through the headstock, with the barrel and muzzle both centered using long tapered rods (brain fart prevents me from remembering the official "gunsmith" name for those rods at the moment, but I buy mine from Dave Kiff).

Anyway, as I don't do barrels for others the time required is no significant factor in my work, so I don't mind "slow".

Not trying to argue with you. Just mentioning this because what size cartridge one is cutting achamber for, and for whom, can make a diference in the "best" (most pactical under the circumstances) approach.

Best wishes,

AC

Alberta Canuck:

(brain fart prevents me from remembering the official "gunsmith" name for those rods at the moment, but I buy mine from Dave Kiff).



Range rod

I'll do it my way and you can do it your way. I think that is better than getting worked up about it.
Butch

Butch, didn't we just go through this on another forum? Reminds me of the old saying "there's more than one way to skin a cat. the worst is to stick a straw in either end and suck out his guts". It turns me off when someone claims it's the "ONLY" way to do it. Your right as it not worth getting worked up over so I"m finishing my coffee and head over to the shop to do something wrong. RandyB.

When asked to recommend the "best chambering method", we respond that it is whatever process produces the desired results. We also acknowledge that different 'smiths have used widely varying techniques to produce equally accurate chambers.

The goal, of course, is to cut a chamber that is smooth, on-size, concentric to the bore and headspaced properly to the receiver. Achieving this standard may require different techniques, depending upon the equipment and tooling available to the man doing the job. The number of chambers to be cut also affects which technique is "best". One size doesn't fit all.

Is it better to use a rougher or piloted drill, or chamber from scratch with the finisher? Again, it depends on the equipment available. Utilizing only the finisher is certainly possible--just be sure to clear chips before the flutes are filled so the reamer doesn't bind and possibly twist off. This means that you can run the reamer in quite a ways before clearing chips when cutting the throat and neck sections; once you're cutting the shoulder and body, this will have to be done more frequently.

In my opinion, using a lathe--as opposed to chambering in a mill or drill press--is the preferred method. In a a mill or dril, you're dependant upon the pilot to maintain concentricity with the bore. With the barrel properly centered in the lathe, rotating forces tend to center the reamer about the lathe's axis of rotation, thereby helping the pilot keep the reamer on-center.

Different ways to skin a cat and if it works for you, have at it.

Dave Manson