Chamber Flushing.

C

Curious

New member
My friend has his lathe set up with a pressurised barrel flush system similar to the one used by Greg Tannel, I have used his set up a number of times to build my own rifles and I have been very happy with the accuracy on all of them. Each time Ive set them up in the headstock and dialled the area of the bore where the neck/lands will be to within 0.0002" then worked from there.

I have now acquired my own workshop and lathe but I can't decide exactly what difference the flushing system really made, if any?

Building my own system will be both time consuming and costly, I see lots of guys just wiping the chips away from the reamer and oiling every 0.100" or so. I would expect far more rifles are chambered by home or even professional gunsmiths without the pressure flush system but my question is will they still be as accurate? or in other words does the barrel flush system really make that much difference? I also wonder if just connecting toe suds system to the muzzle would be an acceptable compromise?

I would add that a rifle that shot no better than 1/2" would be considered a bad one, all my others will shoot 1/4" or less in the right conditions with careful reloading. Needless to say my friend says I must go down the pressurised barrel flush route, can I ask you guys your thoughts and experiences of this aspect of chambering and if you saw any real improvements in your chamber finish or rifle accuracy after converting to this method?

Many thanks in advance - Curious :)
 
I THINK doing 0.100 without a flush system COULD lead to chips marking the chamber.
I do not think i have read of anyone here doing 0.100 in a pass.

50 and smaller the closer you get to the end.
 
Flushing

psi. is the dictator in how much plunging you do for clearing chips....... in a production set-up.with high pressure on the lube..... the chamber can be cut in 1 pass........
do a search........ on this site.... subject previously posted...
"Rustystud" aka nate lmbert who posts on here is teaching classes on it at and building your own system at"Trinadad School Of Trades Gunsmithing School".... and a lot of stuff on this site about people using flush systems............. they all seem to prefer it....
 
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Reading on the net youd think a flush system is a must and everybody thats anybody uses one which couldnt be farther from the truth.
 
.100 advance on a pass is too much, with or without a flush. The reamer will clog.

The only time a chamber flush is of use if you are doing multiple barrels at a time, and are on some flat rate production schedule where every minute counts. That holds true for just about any machining operation where drilling and reaming is involved.

For the normal Benchrest Shooter doing his own barrels, If you want to install one, that's fine. But you certainly don't need it.
 
jackie schmidt said:
.100 advance on a pass is too much, with or without a flush. The reamer will clog.
Click to expand...

The above is certainly true if you're not pre-boring the chamber. I wouldn't go more than about 0.050 if i was cutting full material with the reamer. However if you pre-bore the chamber to within about 0.020 of finial dia you can easily cut about 0.300 depth per pass without clogging of the flutes.. I usually pre-bore in two depoth stages so i always have the pilot in contact with the bore.
And for the record i don't use a flush system..

Cheers
leeroy
 
Curious said:
I would add that a rifle that shot no better than 1/2" would be considered a bad one, all my others will shoot 1/4" or less in the right conditions with careful reloading. Needless to say my friend says I must go down the pressurised barrel flush route, can I ask you guys your thoughts and experiences of this aspect of chambering and if you saw any real improvements in your chamber finish or rifle accuracy after converting to this method?

Many thanks in advance - Curious :)
Click to expand...

A properly set up barrel flushing system can speed up chambering a lot and help produce a nice finish, which makes it well worth the trouble and expense for a guy that chambers a lot of barrels. For a do it yourself home gunsmith, it is a lot of expense and extra trouble and especially mess. There is zero relationship between whether a barrel was chambered using a flushing system and how accurate it turns out to be. Did I mention how messy it can be?
 
Flush Systems

There are several methodologies with flush systems. The first flush system I ever saw was Willis Fowlers, he used rigid pipe threading oil and a electric drill pump. The second flush system I ever saw was Greg Tannel's system. He used a gear head pump and heavier cutting fluids. he designed his own barrel coupling system. I believe his system is a very good one. The third system is what I designed. I to use a carborated relief valve gear head pump. I started off using Rustlic 255R cut 5:1 with distilled water, My system flushes with a 4 gpm at 35- 75 psi with a max of 125 psi. I do my chambers from start to finish with a finishing reamer. I ream .100" back out .100" and flush. The last .250" I check the reamer for any chips or chip weld and cut them at .050" The chambers are slicker than when polished with 600 grit. I have reamers with over 3000 chambers cut without a regrind. I use a duff Norton Rotary coupler and heater hose to adapt the barrel to my system. I use a modified bread basket to catch my coolant and return it to the reservoir. It has earth magnets in the bottom to catch the swarf. I have a 2 micron whole house water filter to catch any swarf that gets recirulated. I have magnets in the bottom of my reservoir. I incorporated two extra ball valves and added air to my system to clean out the barrel during the headspace checking. My system cost about $1,400.00 - $2,000.00 to build. It is not cheep and if you do much chambering it will rapidly pay for itself. It take me longer to dial in a barrel than to chamber it. Ten years ago I chambered 300 plus barrels a year. Now I am only doing about 100 per year. I have other fish to fry. for the time and tool wear my system paid for itself in a month.
Nat Lambeth
 
I do not understand going thru the effort of pre-boring and then using a pilot bushing.
The two surfaces are working against each other.

Leeroy said:
The above is certainly true if you're not pre-boring the chamber. I wouldn't go more than about 0.050 if i was cutting full material with the reamer. However if you pre-bore the chamber to within about 0.020 of finial dia you can easily cut about 0.300 depth per pass without clogging of the flutes.. I usually pre-bore in two depoth stages so i always have the pilot in contact with the bore.
And for the record i don't use a flush system..

Cheers
leeroy
Click to expand...
 
jackie schmidt said:
.100 advance on a pass is too much, with or without a flush. The reamer will clog.
Click to expand...

I'll go full depth minus approximately .025" on a single peck. Then again, I'm pre-boring, using water based coolant through the bore, using 4 flute carbide reamers and reaming .025" short of finish depth in less than 45 seconds.
 
Might i ask ,
How many winning bench rest rifles have you chambered with this process ??

Rubicon Prec. said:
I'll go full depth minus approximately .025" on a single peck. Then again, I'm pre-boring, using water based coolant through the bore, using 4 flute carbide reamers and reaming .025" short of finish depth in less than 45 seconds.
Click to expand...
 
Thank you for your opinions guys.

0.100" was just a nominal figure I used as an example, whether we can cut more or less than this in a pass wasn't really the issue for me, it was more about the quality of the finished chamber. Im a former machinist so I understand and have worked with flood/pressurised cooling in that environment, speed of cut and extended tool life being the main advantages in my experience rather than accuracy of work.

I respect the guy who showed me his method of chambering too much to question him hard on his thoughts, hence joining a forum to discuss it.

As I said in my first post, of the rifles I have chambered so far all have been as accurate as I would wish for and I put this down to an accurate set-up of the bore before machining starts and then good attention to detail during the procces and in the rest of the build and into reloading. Considering we are working with tapered reamers it is my opinion that only the final pass will matter when it comes to surface finish as each pass will remove any marks caused by the previous one, if indeed you caused any. Providing the bore is lined up right and the reamer is well piloted and floated then the first 95% or more of material removal weather roughed with a roughing reamer, pre-bored or cut entirely using a finish reamer is just stock removal, the last 0.025" or less will be where avoiding any marks from a clogged reamer matters surely?

I use my lathe for other machining and have seen first hand how messy my friends pressurised system can get when running at 60-80psi so in truth if I can avoid going down this route then I will. My plan is to start building rifles for others and to ultimately turn a hobby into a small business but I wouldn't end up chambering 75 barrels a year so far from a high volume production set-up, I can afford the time of the non flush method if that is all it costs.
 
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I don't make any claims that I am always right but I have a done a lot of chambering over the last forty years. I have used flushing systems and liked it fine but I am perfectly happy blowing out the chips, inspecting the reamer, re-oiling, and going again. On a typical hunting barrel, I rough with a twist drill (about .020 under shoulder diameter) and my first cut with the reamer will be to a depth of about .500"; none of this .050 stuff! As I cut deeper, I will reduce the depth of the plunge as the reamer starts cutting more and starts cutting on the neck. As rule, I ream until the chips are coming out at the back. After each cut, I blow off the reamer and run my finger nail down each cutting edge. If I feel a chip welded on, I stone the face of the flute to remove it then, having blown out the chamber, I give the chamber a squirt, the reamer a splat, then ream some more. On longer cartridges (30/06, 300 Mag etc.) I will have to drill twice since I don't drill so far the the pilot doesn't catch. I generally stop the drill about .06 short of the final headspace measurement so the last bit is cut with the reamer only. I contrive to have the final cut be about .020" and the reamer is cleaned, stoned on each face, and is fed in very slowly for the last few thou.
A couple of caveats, if a cartridge features minimum body taper, much more care nust be taken during initial cuts because any scoring is less likely to be removed as the reamer is fed deeper since the diameter doesn't change much. Also, if the barrel is on the crooked side one has to dial at the throat and bore to get a straight start, even for a hunting rifle. Other wise, you are likely to get an out-of-round chamber or, if the throat runs out significantly, a somewhat eccentric chamber. Neither is desirable, of course.
The first point is why chambering a cartridge like the 30/40 Krag or 303 British is easy at the start. With the generous body taper you can just hog that puppy out in the initial cuts and careful reaming toward the finish will remove any scoring (within reason, of course). I use Rigid NuClear or Rigid dark with equal results and recently cut one chamber using 10-30 (was out of Rigid and didn't feel like driving the forty miles to town to get some) motor oil and it worked out fine.
Although not a high volume shop (especially now that I'm retired!) I have fitted and chambered a half dozen barrels in a day using this technique so it doesn't slow me down that much. Also, I have reamers which have cut dozens of chambers so they seem OK with it too. Regards, Bill
 
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