Picked up these reamers with some tooling (didn't pay much for em) and I'm puzzled a bit by the "pilots".

There's no solid section to ride the lands like in a typical solid pilot reamer- the cutting flutes go all the way to the end (7mm Mag and .45-70)

They're laser engraved, so commercial- but I've not seen flutes run full length before (?)

In all probability someone modified them for some specific purpose. I have had die making reamers with no pilots or throats which I believe were made by Hartford or Guild. But they were always stamped (size) or (sizer).

Yes, such things exist but definitely don't use them for chambering a barrel unless you don't care how it shoots. I have a barrel from Italy that has two steps in it that looks like it was chambered with a rusty drill bit; they are no longer in business.

There was a very logical reason for every reamer manufacturer in the world, making their reamers with pilots. Some going as far to put removable pilots on them to match the bore diameters EGGZACKERY! But I dissremember what that was now? HUMMM!

Someone please tell these guys when a pilot is not needed on a chambering reamer.

OK guys, since we are talking reamers and pilots there is something I have puzzled over for a while ( I have never chambered a rifle bbl). When re-chambering a barrel, say .300h&h to .300 Wby or 7mm Rem to 7mm STW etc. what happens with the pilot? The reamer would start to remove metal before the pilot ever enters the bore, which to me, seems not so good? Do they make reamers with very long pilots for just such purposes or in this case does the pilot serve no real purpose? In fact could the pilot not jam things up in this case if the original chamber is a little eccentric? Just wondering.
C.G.B.

In most cases it's just like using roughing reamers. The reamer is tapered and the old chamber is tapered. Also, very little material has to be removed because of the old chamber so for the first little bit the reamer simply follows the old chamber. After the pilot picks up, if there is any lineal or axial discrepancy the pilot will straighten out the path of the reamer and correct everything. When I do rechambers I always make sure that I have plenty of float in the steady rest posts so that the barrel can move around and let the pilot push the barrel where it needs to so that it can straighten everything out. I also hold the reamers in heavy, ER40s and not ER32s and turn at slow speeds with heavy cuts to help break chatter. Very light cuts, with light, unsupported tooling over the length of tapered reamers is always an invitation for harmonics.

I run the drill real , really fast and hold the barrel real really tight between my legs . That way the reamer doesn't have time to wobble , it runs true all the time ?
OK so you don't believe me .
My real way is ; if the Reamers pilot is long enough to reach the rifling , I simply rechamber ( as said above ) if it doesn't reach I bore the old chamber ( still under new reamer specs ) till I can reach the rifling .

OK another guess . It was owned by the famous bubba that we all heard of , you know ,the one that ground down the pilot on his 30-06 reamer so he could rechamber the 6.5 jap that kicked so hard . Maybe others wanted to take it a step further .
Yes I've had too much sugar .

Seriously; they are for die reamers; where you do not have a bore to pilot off of in the first place. No one would ever chamber a barrel without a pilot, except that Italian company that I have the barrel from, a 45-60 from a 76 Win.

quote:

Originally posted by dpcd:
Seriously; they are for die reamers; where you do not have a bore to pilot off of in the first place. No one would ever chamber a barrel without a pilot, except that Italian company that I have the barrel from, a 45-60 from a 76 Win.

Actually Tom, some of those little-group-guys cut their chambers with no pilots. Or use horribly undersized pilots. They hold the barrels in double cats heads which are held in the 3 or 4 jaw. They then dial the barrel in between the throat and the start of the chamber using range rods, a long rod with a tight fitting pilot on it, or a deep reach indicator. They then cut the chambers with boring bars until they are within about .010 inch on all dimensions and then drive the reamer in, basically unpiloted to clean up the chamber walls and bring everything to EGG-FAWKING-ZACKERY size. The general idea they have is to outfox the bend in the barrel left by the drill helix and get the throat perfectly square to the chamber. Outwardly it all sounds mighty suspicious and hoodoo, but these guys do take home a lot of shiny plastic trinkets when they come home from the range. While not in agreement with their logic and being in no way superstitious, considering their results, I can't help but find myself being, just a LITTLESTITIOUS ! Our very own Papa, Butch Lambert is just one such critter who practices these ancient and mystical practices !



Personally, I believe that Papa is just a master of wind, airbending and an EXTRAORDINARY shot, who could probably still win using an old Topper shotgun with slugs and a little glow bead for his failing eyesight. He just chooses to handicaps himself, so as not to discourage the up and coming kiddies in the game!

Well that sounds like a bad idea. Of course, I won't chamber anything under 33 caliber anyway, the smaller stuff being useless for most any purpose that I can think of. Pest guns and toys they are.
Read more Elmer.

quote:

Originally posted by dpcd:
Well that sounds like a bad idea. Of course, I won't chamber anything under 33 caliber anyway, the smaller stuff being useless for most any purpose that I can think of. Pest guns and toys they are.
Read more Elmer.

Keith is dead. Don't mess with those little-group-people. Most of em are old and cranky. Most of them can out shoot us. Most of them are damned cheap and don't waste ammo on warning shots!

I know; we have a group of them here; they are all very old and very mean and nasty guys; not friendly at all; when they are practicing and I un- limber a 500 Nitro or some other medium bore thing, they all look at me and frown. '
I smile and wave and say, "Put your ears on".

There's also no area ahead of the neck to cut the chamber throat.. which means either they are designed to allow the throat to be cut with a separate reamer, or they are made to cut a sizing die.
I suggest measuring in a few spots like neck diameter, shoulder diameter and so forth, and compare to a standard chamber print. If the same dimensions, then they're made to cut a chamber. If noticeably undersized, they are either roughing reamers, or are made to do a sizing die.. Just my 2 cents worth.
Oh, and I use the indicate, drill and prebore method for most of my chambers, without the pilot attached. Works very well. So that makes me old, grumpy, and unfriendly I guess. Well if you want an ice cream cone and a pat on the head, go visit the fire station.... if you want a straight chamber, come see me....

The one point everyone is ignoring or has missed. If those reamers have a 60 degree center drilled into the nose. It was intentionally made that way. The center is needed to go from the lathe to cut the dimensions, the mill to cut the flutes and the universal grinder to true it after heat treat and sharpen it. Odds are, if it was made that way it's a sizing die reamer and is undersized and useless. To accurately measure reamers ? The best way is with a .0001 indicator and a DRO on a lathe or mill. Put the reamer between centers and zero the indicator on a known diameter like the shank of the reamer. Set that known diameter into the DRO. Then proceed to touch up at differing points on the reamer until the indicator goes to zero. Then read your true dimensions from the DRO. It's accurate +-.001 inch or so and you don't have to worry about nicking the reamer with the hard surfaces on your micrometer. Plus, you can't get an accurate measurement with a micrometer anyway because the flutes are staggered. Measuring it between centers with a DRO and an indicator gives true measurements even though the flutes are staggered.

No center hole in the nose means that it's simply a bastardized reamer.

^^^
Yup. Forgot to mention, nicely cut centers with 60 degree (prox by eyeball) chamfer on the end of the flutes. Must be sizing reamers...



Interesting suggestion putting it between centers and using the DRO. Still a little fuzzy on it...but I guess I'd use the Z axis to map the length, and the X axis readout combined with the indicator at zero if I follow ya. Might try that for shi*** and giggles.

I was talking about the bench rest shooters, not the ones doing the chambering; relax.

You can bet that they didn't drill those holes after heat treatment.

The length is really a non issue. The necks on chamber reamers are always .020 inch (OR SO) to long. The body length measurement is also irrelevant. The body taper can be checked by offsetting the compound the known degrees using a machine protractor against the compound and chuck face and then running your .0001 inch indicator up and down the cutting surface. If the indicator holds zero if you run it up and down, its correct. If not, you can adjust the compound until it does run zero and then recheck the actual taper. You can do the same with the shoulder taper.

The shoulder and base diameters are the important ones and you don't have to be dead on with your Z axis locations on the reamer as the body taper is normally only .010 per inch or less (.005 inch per side). Getting Z withing 1/64th inch is really all that is needed to get the measurements you want.

I guess you can tell I don't belong to the 1/10th of 1 thousandths club. I don't have a temperature controlled environment, my equipment won't measure to a tenth with any reliability and my machines will barely cut to .001 inch first thing in the morning before my second cup of coffee.

quote:

Originally posted by dpcd:
I was talking about the bench rest shooters, not the ones doing the chambering; relax.

Sorry, those little group guys scare me. They're all meanies !

Thanks. Tried Google-fooing the numbers, but came up empty. Thought it odd that they're laser engraved with a product number and date, as sizing reamers aren't a "production" item. They're recent (one being only a few years old) so I was hoping to dig up the source.

515-084
7mm Rem
2/14

515-226
45-70
9/12