Floating reamer holders

I have read lots of posts about folks that use floating reamer holders. I have never used one, I drive my reamer with the live center in the tailstock. Since I've never used a floater, I just imagine that it could cause some chatter, since it is not a rigid setup. I would like some opinions. I have spent lots of time aligning my lathe to be dead nuts true, both front to back and height of center. With the tailstock aligned as such, why would someone use a floater? Another point I can't seem to grasp, using a floater, the concept is to let the reamer find it's own way down the bore. But, it is being guided by only the pilot, which is only about 1/2" long. That seems a little short to guide a reamer that is several inches long. Let's discuss this so I can understand why folks use a floater. Is there realy an advantage?

The machine or chucking reamer cuts on the chamfer at the front of the tool.

The flutes don't cut at all, the lands on the flutes act as a bearing surface that rides the I.D. of the reamed hole.

The fluted part of the reamer has a "back taper" of about .0005" in its length.

A machine reamer will follow the path of the previously drilled hole.

Reaming allowances are slight - usually .005" on smaller holes and about 1/64" on holes about 1/2" in. and larger.

These are "basic" machine shop tools, they can be used in the spindles of just about any old machine, especially drill presses. The spindle does not have to rigid or precise like that of a milling machine.

The idea is to allow the reamer it's natural tendency to follow the drilled hole. If the reamer is cramped by holding it too rigidly the flutes may bind in the hole if the spindle holding the reamer isn't in exact alignment with the hole center.

That is one of the reasons that chucking reamer shanks are as long as they are. They can deflect just a bit.

The floating reamer driver solves the alignment problem. The chamfer in the end of the reamer starts automatically in the hole and the floating driver just provides the drive.

Once the reamer is cutting full I.D. it guides itself on the diameter it has just cut.

Since a reamer of this sort provides it's own bearing, machine reamers must always be run with a lubricant.

Reaming speed is from 1/2 to 1/4 the drilling speed. Since there are many cutting edges at work, the feed can be quite aggressive.

It is all right to withdraw a reamer to clear chips, but you should never reverse a reamer.

Reamers hold size nicely and leave a very good finish.

Most reaming troubles start with the drilled hole. Using dull or improperly sharpened drills causes the hole to go out of location and go out of round and leave a bad finish.

to correct for this, reaming allowances are increased and that is where the trouble begins.

When using reamers in the lathe it is customary to take a light boring cut after drilling to true up the hole.

The reamer just provides the finished size and surface finish. Reaming allowances can and should be at the minimum.

All of the above applies only to Chucking and Machine Reamers.

Since this is the Gunsithing Column, I feel I should make this distinction beacuse straight machine reaming techniques don't resemble the techniques used with chambering reamers.

JimK, I don't disagree with anything you wrote, but I do think there is a difference when cutting a chamber. First, when dealing with a rifle barrel, the hole is never perfectly straight. Second, we are creating a chamber, not just performing a finish cut through a bored hole. The reamer is only run in a certain distance, and what it creats must be in line with the bore, and concentric. By holding the reamer rigid with the tailstock, it will cut what it comes in contact with. Thus the reason for proper alignment of the lathe. Your information is first rate.

see no reason for floating hldr if t/stock is truly centered & NOT WORN ,so it is in vertical alignment also.....floating is insurance ...was checking bed wear on 1895 14 in lathe ,indicating on top of test bar ,as carriage traversed towards t/stock ,as approached what shud be wear & carriage drop , indicator showed carriage RISING!!!what the he--.....turns out ,hardly any be wear ,but ended up w/ .024 shims in t/stock to get it back up!.....simplest float is chucking reamer w/ jaws open .010 & driving on a washer against tap wrench .....the one time i used an as new x/y floating holder ( nicely made ), i had a wallowed out o/size hole using a st machine reamer ..still dont know what happened......have mentioned earlier that friend of mine holds some national records ,& chambers w/ hard chucked reamer ,but loose t/stock clamp & SLIDES t/stock to ream ...i have chambered for almost 50 yrs using dead center on reamer center ..have had more than a few sub 1/2 moa rifles , BUT never attempted to create something for serious bench work..reckon when one starts talking tenths ,u startlooking for every edge u can get...........probably the worst thing abt having every available appurtenance is ,when it still wont shoot ,u are completely out of alibis!!.....& remember ,u generally want to beg off a pickup tennis game , when the guy shows up w/ new, clean tennis shoes!..while it certainly is a sign of the times that the rankest neopyte HAS to have the most & best of everything,..accuracy is more a matter of diligent application ,than equipment ......the time vs. economic constraints of professional smithing may require quicker & more fool proof tooling ..on the 3 occasions when i turned an avocation into a vocation , most of the pleasure vaporized....

best wishes
docn8as

For the record, IMHO, these are the ultimate floating reamers -

www.practicalmachinist.com/ubb/Forum10/HTML/000009.html

D.Thomas, these look like first rate tools, but not applicable to chambering a barrel. A chamber reamer is made as a tool in itself, to be held/driven into the bore of a barrel. Chamber reamers are ground with the body taper, neck, throat, etc. all in one tool. They must be held in some manner while being fed into the barrel, somehow. That is the jist of my post, what to hold it with. Thanks for the info though.

I use a floating reamer holder even though my tailstock is indicated in. You would be supprised how much a top quality barrel bore runs out in just the length of the chamber. If you hold your reamer hard in the tailstock you can have an oversize hole at the base of your chamber. If you use factory ammo and it is not a competition rifle it probably won't matter. I am a benchrest shooter and we are a little anal about our barrel work. Thebarrelman

it is not a good picture of them though

[This message has been edited by Schulze (edited 09-24-2003).]

Butch, I too shoot benchrest on the east coast, mostly score, but shoot some group as well. I do my own work, and have chambered many barrels of all manufactures. I have seen straight barrels and pretty crooked ones too. I have posted here about indicating in a barrel, which I believe you agree on my method. So I'm fully aware of the straightness problem when chambering. I use the best reamers money can buy, all piloted, and use a barrel flush system. I have done fairly well with my guns, I think they can shoot with the best of them, but the shooter has to do his part! I can keep my chambers' runout to less than .0005" using the tailstock method. I'm just curious about using the floater. I've used roughing reamers followed by finishers; and I've pre-drilled, cleaned up with boring bar, and finisher reamer for final chamber. I get the same results either way. I was a little uncomfortable about pre-drilling at first, thinking the the finisher pilot was not in the bore until it gets way in there, but it does work.

I was just putting the question out there for opinions, and I respect yours, as well as others, since we play the same game.

I agree with what you just posted and hope you didn't think I said there is only one way to do it. I have seen barrels chambered in what I call a sloppy way that shot, but had brass problems. I do enjoy your and other peoples'post. Butch

I used a floating holder that I think was made by Clymer. It works well and When I use it I make sure that the float is mainly in the up/down direction. The tailstock should be indicated in anyway but some lathes have a little up and down variation and useing the floating holder this way seems to help.

I have done it both ways and I think the only real difference is in the comfort level of the user. For my preference I will use the floating holder and if my tailstock is set right then I shouldnt need it but every little bit helps.

Charles

Regarding My Post:

I thought that when the subject of floating remaer holders was broached that someone was going to use machine reamers.

That is why I went through the explanation.

I am surprised that chamberng reamers are used with floating holders. I had alwas thought they were set up in a spindle truly aligned with the center of the spindle of the lathe.

I have not reamed a chamber, but have done some form reaming and I didn't even think of running it in a Floater.

Since there is considerable reaming done in gunsmithing (pins, etc.) I don't regret putting my post up there for those wo want to know.

I have a question, however.

In Gun Factories, do they sometimes hold the barrels stationary and run the chambering reamer with a rotaing spindle?

Seems to me a good idea especially since the cutting oil can be fed from the muzzle end to flush the chips.

My young friend, Jimmy has a modern Remington 700 in .270 Win. and I have an older Model 700 in .243 Win.

Both guns have nice, snug chambers.

Now Remington makes quite a few of those guns a day. I would love to know how they do such nice work so consistantly.

We might just have to Boogie on up to Ilion!

Oh, by the way, New York is the only State I know that has an "Ilion" and a "Troy".

Greece has only one!

remingtons consistancy is currently up to debatre. When the outfit that own stren bought them their QC went down hill.

JimK, I really can't say how Rem. does their chambers. I have heard that some makers form their chambers by the hammer-forge method, the same as their barrels. But I don't know. I do know that as a factory chmabering, it must be big enough to accept ANY factory loaded round from any maker. This equates to BIG! And, who knows how well they are aligned with the bore. After all, they are in the production business, not accuracy. The barrels are rough, by custom barrel standards, yet some shoot fairly well. Since my interest, as well as Butch's, is in benchrest shooting, we use the best barrels we can get, set them up as close as we can, and make every effort to have everything in perfect alignment when chambering. This, along with the use of custom-made reamers that are held to TIGHT tolerences, have fitted neck diameters, custom actions, etc., is what gives us the abillity to shoot accuratlly beyond what some people can believe. It's a fun game, frustrating sometimes, but fun. I continually look for better ways to do my own work. I realize a great amount of satisfaction when my guns perform with the best, made by top shelf riflesmiths. Thanks for your input.

I have always been a strong believer that tight tolerances can be held with consistancy in quantity production.

I know that all production guns of a certain caliber have to chamber all factory cartridges of that caliber, but that's no excuse for 1 1/2 inch groups at 100 yards.

If Remington is currently having trouble holdng consistant quality, then the problem originates in The Front Office, not the Shop floor.

Of All People, Rem. can afford the best reamers, gauges and tools.

Private and custom rifle makers are not only having a good time meeting the challenges of Precision Shooting, they are doing the Firearms Industry a service by keeping standards of performance high.

Remngton has always been proud of its Model 700V. If this gun gets a reputation of not being as accurate as it once was, then shooters will go directly to custom makers withot giving the gun a chance.

I do not have the eyesight for benchrest shooting, but young Jimmy has.

He is only 21. When he clams down a but I want to try us out on long range precise shooting.

I am good with techniques and proceedure and he is a good "natural" shooter.

When his groups tighten up, I will be inclined to working up a custom target rifle.

I believe that when Jimmy shows me a mastery of my 1960's M700V, it will be time to do so.

I am looking forward to that.

Keep in mind I dont shoot benchrest and probably never will. I shoot LR HP, Palma, Long range tactical.

Tactical is by far the hardest of the 3 I shoot. The target is 1 MOA 10 ring and 2 MOA 5 ring at 600-800-900-1000 yards. Yes we shoot pie plates at over half a mile.

no sighters, and I use a 308 winchester.

.308 Rules!

JimK, You make many good points. Rem. 700 is by far the most used factory action, bar none, when going through the accuracizing for competition. It is inherantly accurate when it is right. But the folks that do the blueprinting for such competition guns can say they have seen good ones and some that are quite bad. I guess that's why some shoot well and others don't. The subject of which factory gun is the most accurate has been hashed about a lot. It seems that nowadays, the Savage holds the edge, out of the box. They do have drawbacks though. The trigger is the most often complaint. But that is falling away too, since they have come out with a good alternative from the factory. And, just as with the Rem., many aftemarket triggers are available for the Savage too. Still, the Rem. remains the most popular among accuracy smiths.

give me a winchester

if it needs aftermarket parts to perform, recoil lug etc, just get a winchester

The Savage is available from the factory now with the good trigger. They are so ugly, but shoot so well. If you are well trained and know your triggers, the Remington are easy to stone and adjust. If you are not really schooled on them they can be dangerous! I have 2 Winchester mod.70 bought the same time from the same wholesaler. They are about 170 numbers apart in serial#. Fireformed brass is .003 different when measured at the base and about the same in headspace. Does not mean that they don't shoot, but there are differences in the chambers. Butch