Reamer cutting inconsistent on body.

[Ksracer]

Can anybody help explain why a reamer might cut like this on the body? The neck and shoulder seem to cut fine, but as I progress into the chamber, it will start to drag or "tighten up", until I feel a jerk on the handle, followed by what I can only describe as a "scraping noise" and then chips like the ones pointed to in the pic are flushed out. They are long, and coiled inwards like a spiral pin. After that happens, it turns freely in the chamber for another .100" until it starts over again. This is the 4th reamer I've recently gotten that cut like this. 3 from the same manufacturer, and the 4th from another one. Neither manufacturer is who you are probably thinking. I'm driving the reamers off a center in the tailstock and flushing with a high sulphur threading oil. I've tried rotating the reamers 180* in my holder thinking I had an alignment problem, but the chips seem to appear on random flutes. I've chambered multiple barrels in between these 4 with other reamers I own and had no issue with them.
I'm obviously going to send them back for inspection, but having 4 of them with nearly the same problem makes me wonder if it's not something unique to my setup.
Has anybody else seen a reamer do this?

 

[Dusty Stevens]

To me that seems like chatter. Your setup could possibly be a bit loose somewhere. Those type chips are what i see with chatter. How are you holding the barrel? I see this sometimes with small contact points on the chuck

 

[Ksracer]

To me that seems like chatter. Your setup could possibly be a bit loose somewhere. Those type chips are what i see with chatter. How are you holding the barrel? I see this sometimes with small contact points on the chuck

Interesting. I can see how chatter would produce those types of chips, however I don't feel it in the handle and checking afterwords with a long reach DTI doesn't show any.
I'm holding the barrels in a viper type fixture with 3/8 brass tipped set screws. I've been using the same one for many years and hundreds of barrels. It's a 17" industrial duty machine that's in good shape. The reamer that gave me trouble today was brand new. I needed to make a case holder for a Giraud trimmer so I grabbed it to test out. If you're not familiar, the case holders are about 3/4 inches long and I clamped it directly in the 3 jaw. The new reamer went through a few of the drag/cut long chip cycles before it grabbed so hard it spun the handle out of my hand. I polished down the gouge where the flute bit in, grabbed a different reamer of the same caliber and carefully restarted it in the hole. It cut perfectly normal after I got past the damage from the previous incident.
I feel like it's tool geometry causing the issues, but I'd like to cover my bases before I send them back. I think I'm going to order some Vipers Venom to see if it's a lube issue before I send them in.
Thanks for the feedback!

 

[Dusty Stevens]

Yea try some vipers venom or some rigid dark before you get too far. It may be too sharp and need some break in

 

[Ksracer]

Yea try some vipers venom or some rigid dark before you get too far. It may be too sharp and need some break in

I'm using the Oatey version of that oil in my flush system, but I'll definitely give the Vipers Venom a try.
If anything, I feel like the reamers aren't sharp ENOUGH. They act like the flutes on the body need excess pressure on them to cut, and once they finally penetrate, they try to take the material all at once and produce the long, thick chips. The rest of my reamers cut very freely on the body and don't really produce a visual chip, or very tiny ones. It looks more like a fine black powder when you inspect the cuttings.
Again, thanks for your input.

 

[Tucker65]

Is it possible to chuck up a known good cutting reamer in the lathe and check with an indicator the relief of the cutting flutes and then compare that to your reamers that are giving you trouble. I'm not a tool maker so I don't know what that relief should be but there might be a measurable difference between the two.

John

 

[Ksracer]

I was going to compare them under a magnifying glass, but it wouldn't be hard to put them between centers and run an indicator on them either. Problem is, I'm not a toolmaker either, and don't really know what to look for. It's definitely an area I'm hoping to educate myself in.

 

[Nightraider]

100% chatter

 

[Ksracer]

100% chatter View attachment 1174666

I agree 100% that the chips in your pic are from chatter. Long and stringy from the reamer "ricocheting" back and forth in the bore. My chips are different though. They are rolled inwards and if you unrolled one, would probably equal 45* of uninterrupted cutting action.

 

[Will Henry]

You have a reamer which is ground with insufficient clearance. It is also possible the face of the flutes are sitting a tad behind center in combination with insufficient clearance. The point is, the reamer is incorrectly ground. If the face is behind center, it messes up the clearance angle and the reamer will act a lot like you describe; won't cut then will dig in. Eventually, the reamer might break and the issue will resolve itself but not in a good way. Reamers which don't cut are one maker's stock in trade. WH

 

[Nightraider]

I agree 100% that the chips in your pic are from chatter. Long and stringy from the reamer "ricocheting" back and forth in the bore. My chips are different though. They are rolled inwards and if you unrolled one, would probably equal 45* of uninterrupted cutting action.

Those are 250rpm, I'm guessing you're slower than that.

 

[Ksracer]

Those are 250rpm, I'm guessing you're slower than that.

I start at 75rpm. Once I'm .050 deep, I speed up to 175 or 210, depending.

 

[hogpatrol]

Another vote here for not enough clearance/incorrect grind. Can you post a closeup photo of the reamer in a couple orientations?

 

[gunsandgunsmithing]

Wrap thew reamer with a couple of wraps of wax paper and try it again. It's an old fix that has dug me out of this wood pile more than once.

 

[Ksracer]

Another vote here for not enough clearance/incorrect grind. Can you post a closeup photo of the reamer in a couple orientations?

Here is a pic of the worst offender. If you look close, you can see 3 separate angles on the top of the flute.



Here are a couple more angles, along with a pic of the chip it pulled. This happened a month ago. Covid has them shutdown so I can't contact them.

 

[gunsandgunsmithing]

Lots of factors in why a reamer will chatter. Same relief angle may work in some barrels but not others..Barrel steel, flute spacing, shoulder angle, body angle, pilot fit, speed and feed, for examples.

 

[Ksracer]

Another vote here for not enough clearance/incorrect grind. Can you post a closeup photo of the reamer in a couple orientations?

Here is a pic of a reamer from the second manufacturer that bit hard enough to pull the handle from my grasp. It was turning smoothly, just very tight before it happened. I can't visually see a third angle on this one. If I put these between centers and roll them under a tenth DTI as Tucker65 suggested, will I be able to measure a drop in the relief areas?

 

[Dusty Stevens]

Since theres so many doing the same thing im still betting its your setup. Using a cathead does that on some barrels because of the limited contact points.

 

[Nightraider]

Since theres so many doing the same thing im still betting its your setup. Using a cathead does that on some barrels because of the limited contact points.

I'll second this

 

[Will Henry]

Set-up may cause a reamer to chatter but it won't cause a reamer to not cut then dig in when enough pressure is applied. That comes from a lack of clearance at the cutting edge. WH