Notes on Chamber Ing

GT, this happened to me a few years ago. I never figured out why it started to chatter, but I figured the barrel was ruined. It was a #4 stainless Shilen, (not much shank), so I knew I couldn't set back enough to start over. I talked to David Kaiser at Brownell's and then to Dave Manson. Dave K had some good suggestions, but Mr. Manson was specific about what to try. On his recommendation, I took a .30 cal cotton cleaning patch and punched a hole in the center just big enough to slide over the reamer pilot and back to the shoulder, then lubed everything and fed the reamer in .010" and then pulled it out to clean it. Repeated this 3 times with a fresh patch every time. It worked like magic. The reamer flutes cut right through the patch, but it damped the reamer enough to stop it from just deepening the chatter marks. Once the chamber cleaned up, I depth miked it and determined exactly how much I had to set the shoulder and breech back. I was curious enough to shoot the rifle with the chatter marked chamber before pulling the barrel back off. It did not extract, and I had to tap the case out with a cleaning rod. I kept the fired case, and it looks a lot like the .308 hulls out of an H & K. A floating reamer is a great thing especially for those who work in the headstock and use a highspeed flush system. As for comercially available floating reamer holders there is the Clymer, Manson, JGS, Gre-Tan, and the Bald Eagle. Please forgive me if I have left any out. A floating reamer holder is not rocket science. Someone previously posted that they cut chambers within .001. I cut chambers using a JGS floating reamer holder and my chambers have "less than" .0002 tir. The floating reamer holder will allow correction for the spindle bearing runout. If I did not use a floating reamer holder I would do my

chambers like Mike Bryant of Bryant custom guns. I think you will find the better rifle builders are all today using some form of floating reamer holder and piloted reamers. I have talked personally with Dave Kiff, PTG, Dave Manson, Manson Precision Reamers and Don L/N/U at Clymer, the big three reamer makers. All recommend a floating reamer holder and a highspeed flush system. There are two schools of thought about chambering. I would suggest you look at the methodology used by the benchrest and cross the course shooters since they setback, rechamber and rebarrel with the most frequency. I was a little flabergasted at the responses to your post. I would never tell someone else how to do their chambers. There are many ways to skin a cat. I cut several hundred chambers each year. My first concern is precision alignment and concentricity, IE: quality work . My second concern is safety, time, tool wear. I don't know where you live, but in almost every region of the country there is a rifle builder that uses a floating reamer holder and a highspeed flush system that would show you his operation. I have cut chambers every way conceivable. An for the guy who is going to just do one or two barrels a year the best method is having someone else do them for them that does them right. When I did all my chambering in the steady rest center to center I was lucky to do 1 or 2 chambers in a weekend. Doing them with a highspeed flush system I can do 5 or 6 different calibers in a weekend. If I am doing multiples of the same setup I can do maybe 20 chambers in a weekend. If you use a highspeed flush system you don't have to predrill or use a roughing reamer. The whole chamber is done with a finishing reamer. The reamer cuts like it is designed to do and does not grind out the metal. A barrel set up in an alluminum, copper or brass wire band inside a 4 or 6 jaw chuck with a spider on the end of the spindel is much more rigid than a barrel set up in a center with a steady rest. Unless your steady rest is set up with a center bearing and cathead. Most chambers cut using a steady rest have enough flex that the chamber will indicate out or round or cnocentricity on a .0001 indicator. I have cut chambers that it took an electronic guage .000001 to determine the out of round or concentricity. I am not bragging but stating a fact. For hunting rifles being within .ooo5 may be alright. But for target quality rifles they need to be right on the money. .0002 or better. I have the capabilities so I build all my rifles to the tightest specs possible. I set up on deltroic pins or an indicator rod. If you are not familiar with these. I have pins that are cut -.0002, .00000, and +.0002 for each caliber. My Indicator rods were made by Dave Kiff at PTG. They have a removable pilot and I have 5 pilots in .0005 increments above and below the indicated caliber sizes. The rod itself is precision ground 1.5* and they are about 6 inches long. After inserting the rod down the bore one can take two simultanious readings one on top and one on the side using .0001 indicators. I indicate and center both ends of the barrel. I don't start chambering until I get them down to no indicated run out or at least below .0002. The bearings in most lathes have .0002 to .0003 run out. I do my hunting guns the same way I do my target guns. I would not put my self in the same class as Greg Tannel, Mike Bryant, Butch Lambert, Micky Coleman, etc. But I am learning and my customers guns seem to be holding their own when it comes to their shooting. As for floating reamers some people love them and some people cuss them. I have seen floating reamers that were working perfectly but the gunsmith did not understand how they worked and ruined it by modifying it. I still say that the reamer makers know more than the adverage gunsmith because they

see what is being used in the commercial and industrial setting. The majority of old time gunsmiths hated chambering. It was costly both in equipment and time. Only about 1 in 10 licensed gunsmiths chamber barrels. For every 100 gunsmiths who chamber barrels about 1 does more than 100 barrels per year. They are the ones who are equiped, experienced, and have a following of other gunsmiths and target/varmit shooters. Many of the top shooters do their own work. I learned the old school way of chambering. But I had an open mind and saw what was being done by the next generation of rifle builders. The metals, machines, indicators, have all improved dramatically. I choose to use a floating reamer holder others choose not to use a floating reamer holder. We live in a free society and you can do as you please. The logic behind a floating reamer holder is sound. The proof is in the final product. Do you want chambers cut within ten thousants that is . 0001 or do you want chambers cut within thousants that is .001. High speed chip clearance I use a 1/2 hp Sherwood Close coupled Carbonator gear pump with a relief valve (up to 125 PSI). MSC part number 09390774. I have it set up on a 15 gallon tank with a recirculating bypass using two ball valves. It also has a well type 2 micron filter in line after the pump. It goes from black iron pipe to a section of flexible hydrolic line with two swivel couplers, then to a Duff Norton Rotary Coupler. I know of folks who use 100% Molly Dee, Brownells Do Drill, and Black/Dark high Sulfer cutting oil. For the last 4 years I have used Rustlick 255R cut to 5:1. This was the recomendation of the coolant/lubricant manufacture. It is an extreem high pressure coolant/lubricant and is water soluble. Easy to clean up and enviromentally friendly. I experience no heat or chatter problems. I cut at 175 RPMs throught the headstock getting great chambers. Rustystud I have a new Micrometer Adjustable Reamer Stop that is coming out next month. You should get a good floating reamer holder and a Micrometer Adjustable Reamer Stop. These two idems along with a good flush system will make your chamber reaming much better and without any costly mistakes. Where do you purchase your reamer holder and stop? MrGadget: Do you want to learn a trick to cure your spindel and chuck alignment problem? Asuming the distance from in front of your chuck to out your spindel bore is not longer than your barrel. (Then you have to do something else. IE: self aligning center bearing with rigid pipe inside, to a hollow 60 degree taper.) Assuming you are using a 4 jaw or 6 jaw independent chuck on one end and a spider on the other end. Get a piece of 4 gauge copper or aluminum ground wire. Cut a piece long enough for one wrap around the barrel. Then tighten the jaws until you get it centered. Then center the muzzle end using a indexing pin to within .00002 or better. Then center the tendon end .

0002 or better. Adjust both ends until you get them running true. It takes several adjustments. when you get it right you can take two simultanious readings 4 inches appart, off and indexing rod and have no run out. Using the bearing surface of the wire it gives your barrel the ability to flex and not be in a bind of two inches or more of clamping chuck jaws. I credit this discovery to Butch Lambert, and Mike Bryant I learned this and did not come up with it on my own. here are a number of floating reamers on the market. In fact I have one under development. Before you buy a floating reamer holder check out Mike Bryants website "Bryantcustomguns". He uses just a cup on drill chuck. Pretty slick. No particular order. Bald Eagle floating reamer holders are available through Dave Kiff at PT&G Manson Floating Reamer Holder is available from Dave Manson precision Reamers. Clymer Floating reamer holder is available from Clymer tool company. The JGS floating reamer holder is available from JGS tool company. Greg Tannel makes a floating reamer holder. The Micrometer Adjustable Reamer stop will be out hopefully in the next couple of weeks some are being made as this is written. I have about 100 orders. We are going to try and have them available from Brownells, Midway, and Sinclair. Just be patient they will be worth the wait. The floating reamer holder needs to adjust for both co-axial and concentric misalignment. You want the reamer to follow the bore without influence from the reamer holder. All the reamer holder should do is drive the reamer. If the smith takes his time and aligns the barrel bore with two indicators spaced about 4 inches apart to .00002 or better then the floating reamer holder will do the rest. The bigest problem I see is folks who don't use a test bar and align their tailstock with their spindel. I have a 4", 6", 8", 10", 12", 14", 16", 18", 20", 22", 24", 26, 28", 30", 32", and 36" test bars. I don't care how good your lathe is the beds will not remain perfectly aligned. Time, gravity, wear, all take their toll. You can't make a good (accurate) cut on a lathe if the stock is not aligned with the spindel bore. You can use old barrels to make your test bars. ery interesting pictures of your cam bar rifling machine! I can add to those books of interest "Advanced Gunsmithing" by W.F.Vickery. It was first printed in 1940. You can fairly easily find it on the Net. I bought three copies that way. This book I consider one of the most completely covering the subject of gun building AND making the necessary tooling for that. Shows in detail how to build and operate both the scrape cutter and the hook cutter.

Really very instructive! I have used this book very much during all the years I´ve been in the ML gunsmith`s business. (see my homepage) Also see page 204 in the 1968 Gun Digest. It shows the way to build and use the slow-working scrape cutter head. Magnus in Sweden