Carbide reamers..........

K

kevinnevius

Member
All:

I was wondering if any of you had used solid carbide reamers, and if so, could share your speeds / feeds and technique?

I have been using them recently with good results - always interested in a better way or better ideas!

For what its worth - I run carbide with more speed (540 to 800rpm), flooded with Kimball Midwest 80801 tool coolant. The finish is great, but my tool life is less than I would expect (and frankly extended tool life is why I went with carbide in the first place). I can tell when the reamers life span is close because you will see a very tiny burr at the exit end of each land FYI.

Any thoughts would be appreciated,

kev
 
I run mine at 300 RPMs with oil in a chamber that's been roughed out with a caliber specific core drill. I can feel it starting to get dull after several hundred chambers but it still cuts clean for a lot more. Can't say I have ever taken one completely out of service yet.
 
JerrySharrett said:
Just curious, are these reamers SOLID carbide or cemented carbide?

Dave Kiff makes me wonder.


.
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I have to know..... is this some sort of inside joke? I'm not a machinist, I'm not a gunsmith, I pour concrete. But I DO have a perty firm grasp of how tools work. Did somebody, somewhere actually try this? This seems less practical than the late Harold Vaughn's fixation with bonding lead sheathing to steel rifle barrels. Or wrapping a concrete bond beam with carbon fiber to "strengthen" it.

Or carbon fiber wrapped barrels LOL
 
alinwa said:
I have to know..... is this some sort of inside joke? I'm not a machinist, I'm not a gunsmith, I pour concrete. But I DO have a perty firm grasp of how tools work. Did somebody, somewhere actually try this? This seems less practical than the late Harold Vaughn's fixation with bonding lead sheathing to steel rifle barrels. Or wrapping a concrete bond beam with carbon fiber to "strengthen" it.

Or carbon fiber wrapped barrels LOL
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Al
It is a bit far fetched but. I've done work for with several manufactures and the grind they put on production reamers makes them cut like the cement carbide inserts we use. There's more than one reason factory barrels aren't as accurate. I had a discussion with some engineers once after I couldn't cut a single chamber with their reamers. They referred me to their reamer maker. After many calls he realized the reamers are ground to get under and plow metal. Not cut. I plan on cutting 300 chambers with a carbide reamer. They want 3,000. It takes a lot of HP and big machine to do that. Then there is the discussion about it only takes one tool change and 20 seconds to do it right. That didn't go any where.
 
I do not really see the purpose of solid carbide reamers.

Carbide is at its best taking heavy cuts at higher speeds.
The heavy cuts make sure heat is carried off in the chip.

Maybe if you ran a factory making production quantities of rifles.
Like chambering a rifle every 60 seconds.
It might have an advantage in less down time to change out worn reamers.

HSS can still be sharpened to a smoother (sharper) cutting edge than carbide.
The 'grain size' in a good HSS steel is very very small.
 
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brickeyee said:
I do not really see the purpose of solid carbide reamers.

Carbide is at its best taking heavy cuts at higher speeds.
The heavy cuts make sure heat is carried off in the chip.

Maybe if you ran a factory making production quantities of rifles.
Like chambering a rifle every minute 60 seconds.
It might have an advantage in less down time to change out worn reamers.

HSS can still be sharpened to a smoother (sharper) cutting edge than carbide.
The 'grain size' in a good HSS steel is very very small.
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I respectfully disagree. Having cut maybe several thousand chambers with carbide and probably 5K+ with HSS there is really no comparison between HS and the carbide reamers ground for the custom gunsmith when it comes to finish. Carbide wins hands down. You don't have to cut a chamber. A close inspection of the cutting edge is all that's needed.
 
5-600 RPM, 300psi coolant through the bore and enough feed to ream a 6/6.5 Creedmoor size chamber in about 45 seconds with 4 pecks and substantial dwell for flushing.
 
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Dave Tooley said:
I respectfully disagree. Having cut maybe several thousand chambers with carbide and probably 5K+ with HSS there is really no comparison between HS and the carbide reamers ground for the custom gunsmith when it comes to finish. Carbide wins hands down. You don't have to cut a chamber. A close inspection of the cutting edge is all that's needed.
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Who is sharpening your HSS?

HSS when correctly sharpened has a well earned reputation for cleaner cuts.
 
brickeyee said:
Who is sharpening your HSS?

HSS when correctly sharpened has a well earned reputation for cleaner cuts.
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My apologies, this thread has kind of gone off the rails a bit.

This reply is basically at the heart of my original question.

HSS is (and has been) the material of choice for reamers, and the proper use of it regarding speeds, chip clearing and lubrication are pretty standardized. I originally tried solid carbide to try to get better tool life, which I believe it provides (at some additional wait time and cost for the tooling) - but IMHO carbide requires playing around with the mentioned variables to get the same (or better) results, again in my very humble opinion.

That's where the original question came in - to see if any of you were using carbide reamers, and if so, what were you doing to get exceptional results?

I am self taught, so I am certainly thankful for input - and appreciate the forum for that reason the most.

I initially started using carbide with Kimball Midwest 801 tool coolant (flooding as I chamber, using higher speeds that I typically used with HSS). But I have found that as the reamer wears, it can leave a very small burr at the edge of the leade (even though the chamber walls look absolutely perfect under magnification). HSS in my experience will show some imperfection along the entire surface as it wears - which is a better indicator the reamer should probably be replaced.

Thanks for your reply,

kev
 
We had to use solid carbide drills in some obnoxious grades of aluminum.
But then we still switched to HSS reamers on high precision holes and just put up with the wear.

Some places we could only get about 5 or 6 holes out of the HSS reamer.
7000 series stuff is a real PITA to work.
 
My only carbide reamer experience was one that I borrowed from a high production barrel chambering shop. They only use CNC. I wasn't even aware that it was a carbide reamer until I mentioned to my friend that it cut a beautiful chamber. He said it was a carbide reamer. I usually chamber at around 350rpm. I do drill and taper bore before chambering. Throat and leade looked great and had very little fluff.
 
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I thought carbide was dull until I bought some good carbide. And sliced my finger handling an endmill.
 
Butch Lambert said:
My only carbide reamer experience was one that I borrowed from a high production barrel chambering shop. They only use CNC. I wasn't even aware that it was a carbide reamer until I mentioned to my friend that it cut a beautiful chamber. He said it was a carbide reamer. I usually chamber at around 350rpm. I do drill and taper bore before chambering. Throat and leade looked great and had very fluff.
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"very fluff"?

GsT
 
For all practical purposes we can ignore the finish on the body, shoulder, neck and freebore. They are background noise in this discussion. Having used carbide reamers for 5 years now I can tell you for certain the leade angle cut with carbide is noticeably smoother. Even as they dull they cut a pretty good finish. The throat is one thing I pay very careful attention to. In my chambering routine I inspect every reamer as it's used. With experience you will see the leading edge of the neck and shoulder start to break down. Scalloping on the face of the flute means the edge has also broken down. The same thing is happening to the most important surface on the reamer. The leade. You can cut a lot of chambers with a compromised reamer but you can't cut good chambers/throats. As far as sharpening them. I have had mixed results. I should be able to get detailed pics of cutting edges on new HSS and carbide. If I can I'll post them.
 
Dave Tooley said:
For all practical purposes we can ignore the finish on the body, shoulder, neck and freebore. They are background noise in this discussion. Having used carbide reamers for 5 years now I can tell you for certain the leade angle cut with carbide is noticeably smoother. Even as they dull they cut a pretty good finish. The throat is one thing I pay very careful attention to. In my chambering routine I inspect every reamer as it's used. With experience you will see the leading edge of the neck and shoulder start to break down. Scalloping on the face of the flute means the edge has also broken down. The same thing is happening to the most important surface on the reamer. The leade. You can cut a lot of chambers with a compromised reamer but you can't cut good chambers/throats. As far as sharpening them. I have had mixed results. I should be able to get detailed pics of cutting edges on new HSS and carbide. If I can I'll post them.
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Dave, I have used Marcus at http://mcctooling.com/contact.html to make and or sharpen tools of all kind for about 35 years. He has some really nice CNC grinders as well as the manual tool and cutter grinders. I also use him for wire EDM work.. I will take a reamer for him to look at next week.
 
With insert tooling, carbide usually has a duller edge prep for durability. But with uncoated tooling like a chamber reamer the edge prep is very sharp, like hss. Theres no doubt it leaves a better finish in a chamber, but I do still prefer hss reamers. Handled correctly they last a long time and produce a finish very close to carbide. I do not like coolant for reamers, I think cutting oil will help your tool life. I also chamber about 300 rpm hss or carbide.
 
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