Not trying to hijack this, but I'm about to buy some Dewey stainless rods for my 30 and 6br. Please correct me if I'm wrong, but, has anyone actually damaged a barrel with a steel rod or a nylon coated? I find that hard to believe. I understand that the rod makes contact with the barrel, but your mashing a bullet down it at high velocity, should we really be worried about a rod slightly touching the bore? That just seems irrational to me, but I'm usually wrong, so feel free to correct me.
Carbon fiber cleaning rods!
- Thread starter Mark611
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J.D.Erwin
Gold $$ Contributor
Buy what you like and like what you buy has allways service my needs!
JMO
Aim small shoot small
Jerry
Used Tipton CF and Dewey coated for many years. Never an issue with either. I buy them in the length I need and not too much rod sticking out to flex. It will flex some inside the bore but my scope has yet to show any damage to my bores. Never wore off the Dewey coating either. I have seen some scuffing on CF from abrasive cleaners but thats it.
jelenko
Gold $$ Contributor
Cool!
TRSR8
Silver $$ Contributor
Have personally seen and know smiths that have seen Match SS barrels destroyed by rod damage.
JEFFPPC
Gold $$ Contributor
I hear these stories also. But, I never have put much stock in them. It's like, Show me the money. Stories. I have a buddy who is a huge believer in those stories. I don't. I been around this game for many years. Never SAW any examples.
SteveOak
Gold $$ Contributor
Here is a research paper on the topic of the abrasive nature of carbon fiber when sliding across metal.
Handy link to article
Finite element modeling of indentation and adhesive wear in sliding of carbon fiber reinforced thermoplastic polymer against metallic counterpart
Israr Ud Din1,4*, Stéphane Panier1, Pei Hao1, Gérald Franz1, Jayashree Bijwe2, Li Hui31. Laboratoire des Technologies Innovantes, LTI-EA 3899, Université de Picardie Jules Verne, Amiens, 80025, France2.
ABSTRACT
In this work, adhesive wear in uni-directional (UD) reinforced carbon thermoplasticPolyetherimide (PEI) composite laminate caused by the sliding of a metallic counterpart isanalyzed. The study is based on the finite element method (FEM) in various in-plane directionsof sliding relative to fibers. The damage and failure mechanisms induced by the adhesive wearare predicted with 3D Hashin's theory and Puck's theory. These failure theories were implemented in ABAQUS via UMAT in implicit environment. The damage mechanisms predicted by the FEM model showed a better correspondence with the observed damage modes in the wear experiments of fiber reinforced polymers (FRPs). Furthermore, specific failure exposure factors were also compared with the specific wear rates determined experimentally in a qualitative manner.
Keywords: Adhesive wear, 3D Puck’s theory, Finite element modeling, Wear damage mechanisms.
1. Introduction
Fiber reinforced polymers (FRPs), specifically thermoplastics (PEEK, PES, PEI, etc.) reinforcedby carbon fibers (CFs), are used in the elevated temperature applications in tribo-componentswhere harsh operating conditions prevail such as in aircrafts. Previous studies show that CFs inthe tribo-systems offer partial lubricity in addition to higher specific strength, thermal conductivity, resistance to fatigue and damage, etc. [1, 2]. Such material combinations provideother advantages including recyclability in contrary to thermoset polymers as epoxy andunlimited shelf life [1]. It is important to study numerically the damage induced by the contact of two counterparts and the subsequent wear in FRPs. However, this numerical analysis of wear process is a very complex task to accomplish. Different types of fibers, their properties and fiber volume ratio make the numerical analysis of this process further difficult. Wieleba [3] describedthat the dominant wear process during the rubbing of fibrous composites is the adhesion. But depending on the type of fibers and friction conditions, other wear mechanisms may also been countered. Fundamental factors that influence the wear of fibrous composite materials includefiber type, fiber volume ratio in the composite, and the properties of the fiber/matrix interface. This study focuses on the UD based FRPs composite laminates under in-plane wear conditions.
Wear phenomenon in FRPs has been studied experimentally and literature is available for different modes of wear including abrasive wear and adhesive wear [1, 4, 5]. Cirino et al. [5]investigated the dry abrasive-dominant wear in UD composite in which the composite was worn in three principal directions. These three directions were designated as N (Normal), P (Parallel)and AP (Anti-Parallel) with respect to the fiber orientation as shown in Fig.1. P and AP wear directions are in-plane while wear in N-direction is out-of-plane and is not considered in this study.
Fig. 1: Three principal sliding directions with respect to fiber, (a) Parallel (P), (b) Anti-Parallel (AP), (c) Normal (N)[6]
The damage mechanisms encountered in the abrasive and adhesive types of wear were studiedusing scanning electron microscopy (SEM) in each direction of sliding in the experiments [1, 2,7, 8]. In case of wear in direction P, a typical SEM micrograph can be seen in Fig. 2 [7]. Thisfigure shows different failure mechanisms during the wear process in FRPs composite. Thesecomprise fiber/matrix de-bonding, fiber bending, fiber cracking and matrix shear features. It isnoticeable in Fig. 2-a that the polished surface remained in its undamaged state away from the groove scratched by the diamond tip indenter. At higher magnification (see Fig. 2-b), a fibercrack transferring from one fiber to the next is noticeable. In addition, the formation of shear features can also be seen.
Fig. 2: (a) SEM micrograph of P-direction composite surface scratched by a diamond tip indenter, (b) an enlarged view [7]
Similarly, Fig. 3 depicts the damage mechanisms when a FRPs composite is scratched by adiamond tip indenter in AP-direction. Due to the compressive and frictional loads, fiber bendingtakes place in the depth direction (out-of-plane bending) and also in the sliding direction (inplane bending). Both in-plane and out-of-plane bending ultimately contribute to fiber fracture inthe central region of the groove as well as in the transition between the groove and theundamaged area. The damage mechanisms are similar to the P-direction scratch including fiber/matrix de-bonding, shear features of the matrix material between the broken fibers, fibercracking and their removal from the fiber beds. Friedrich et al. [9] emphasized that if the diamond tip indenter is replaced with a small steel ball, the characteristic wear and damagemechanisms are very similar but these are not seen clearly as in case of the damage mechanisms produced by the diamond indenter.
Fig. 3: (a) SEM micrograph of AP-direction composite surface scratched by a diamond tip, (b) a magnified view ofthe groove [7]
Friedrich et al. [7] explained that wear process takes place in a sequence of damage mechanismsand these were termed as wear cycles. Accordingly, the wear cycle initiates from the matrix wearand fiber sliding wear. Fiber sliding wear is also known as fiber thinning in the literature. These are followed by fiber cracking and fiber/matrix de-bonding at the interface. When the wear process reaches the steady state then a so-called compacted wear debris layer (CWDL) coversthe surface which is composed of pulverized fibers and matrix material. During the wear process,this layer is continuously formed and removed by the surfaces sliding against each other. The preceding studies were limited to only three directions comprising P, AP and N. Sharma et al. [2,8] carried out experimental studies in various fiber directions. UD carbon reinforced thermoplastics (PEI) with 80% by volume were tested at range of angles as 0°, 30°, 45°, 60° and 90° during abrasive wear [8] and in dry-adhesive wear [2]. The increase in the coefficient of friction (µ) was reported as the fiber angle with respect to the sliding direction was increased. In addition, very low specific wear rate 30 ( , volume removed per unit of wo K unit mm / : rk require N d = . ) m was determined for the sliding in the fiber direction (P-direction). On the other hand, the specificwear rate in AP-direction (90°) in the experiments was computed as four times higher than the P direction (0°). Ovaert [10] reported similar results by conducting wear experiments on fiberreinforced thermoset epoxy matrix. Sharma et al. concluded that sliding orthogonal to the fiber(AP-direction) leads to higher wear. In addition, they highlighted that in AP-direction, FRPs aremore vulnerable to de-bonding, peel-off the plies and the pulverization of fibers as compared to the P-direction sliding.
Handy link to article
Finite element modeling of indentation and adhesive wear in sliding of carbon fiber reinforced thermoplastic polymer against metallic counterpart
Israr Ud Din1,4*, Stéphane Panier1, Pei Hao1, Gérald Franz1, Jayashree Bijwe2, Li Hui31. Laboratoire des Technologies Innovantes, LTI-EA 3899, Université de Picardie Jules Verne, Amiens, 80025, France2.
ABSTRACT
In this work, adhesive wear in uni-directional (UD) reinforced carbon thermoplasticPolyetherimide (PEI) composite laminate caused by the sliding of a metallic counterpart isanalyzed. The study is based on the finite element method (FEM) in various in-plane directionsof sliding relative to fibers. The damage and failure mechanisms induced by the adhesive wearare predicted with 3D Hashin's theory and Puck's theory. These failure theories were implemented in ABAQUS via UMAT in implicit environment. The damage mechanisms predicted by the FEM model showed a better correspondence with the observed damage modes in the wear experiments of fiber reinforced polymers (FRPs). Furthermore, specific failure exposure factors were also compared with the specific wear rates determined experimentally in a qualitative manner.
Keywords: Adhesive wear, 3D Puck’s theory, Finite element modeling, Wear damage mechanisms.
1. Introduction
Fiber reinforced polymers (FRPs), specifically thermoplastics (PEEK, PES, PEI, etc.) reinforcedby carbon fibers (CFs), are used in the elevated temperature applications in tribo-componentswhere harsh operating conditions prevail such as in aircrafts. Previous studies show that CFs inthe tribo-systems offer partial lubricity in addition to higher specific strength, thermal conductivity, resistance to fatigue and damage, etc. [1, 2]. Such material combinations provideother advantages including recyclability in contrary to thermoset polymers as epoxy andunlimited shelf life [1]. It is important to study numerically the damage induced by the contact of two counterparts and the subsequent wear in FRPs. However, this numerical analysis of wear process is a very complex task to accomplish. Different types of fibers, their properties and fiber volume ratio make the numerical analysis of this process further difficult. Wieleba [3] describedthat the dominant wear process during the rubbing of fibrous composites is the adhesion. But depending on the type of fibers and friction conditions, other wear mechanisms may also been countered. Fundamental factors that influence the wear of fibrous composite materials includefiber type, fiber volume ratio in the composite, and the properties of the fiber/matrix interface. This study focuses on the UD based FRPs composite laminates under in-plane wear conditions.
Wear phenomenon in FRPs has been studied experimentally and literature is available for different modes of wear including abrasive wear and adhesive wear [1, 4, 5]. Cirino et al. [5]investigated the dry abrasive-dominant wear in UD composite in which the composite was worn in three principal directions. These three directions were designated as N (Normal), P (Parallel)and AP (Anti-Parallel) with respect to the fiber orientation as shown in Fig.1. P and AP wear directions are in-plane while wear in N-direction is out-of-plane and is not considered in this study.
Fig. 1: Three principal sliding directions with respect to fiber, (a) Parallel (P), (b) Anti-Parallel (AP), (c) Normal (N)[6]
The damage mechanisms encountered in the abrasive and adhesive types of wear were studiedusing scanning electron microscopy (SEM) in each direction of sliding in the experiments [1, 2,7, 8]. In case of wear in direction P, a typical SEM micrograph can be seen in Fig. 2 [7]. Thisfigure shows different failure mechanisms during the wear process in FRPs composite. Thesecomprise fiber/matrix de-bonding, fiber bending, fiber cracking and matrix shear features. It isnoticeable in Fig. 2-a that the polished surface remained in its undamaged state away from the groove scratched by the diamond tip indenter. At higher magnification (see Fig. 2-b), a fibercrack transferring from one fiber to the next is noticeable. In addition, the formation of shear features can also be seen.
Fig. 2: (a) SEM micrograph of P-direction composite surface scratched by a diamond tip indenter, (b) an enlarged view [7]
Similarly, Fig. 3 depicts the damage mechanisms when a FRPs composite is scratched by adiamond tip indenter in AP-direction. Due to the compressive and frictional loads, fiber bendingtakes place in the depth direction (out-of-plane bending) and also in the sliding direction (inplane bending). Both in-plane and out-of-plane bending ultimately contribute to fiber fracture inthe central region of the groove as well as in the transition between the groove and theundamaged area. The damage mechanisms are similar to the P-direction scratch including fiber/matrix de-bonding, shear features of the matrix material between the broken fibers, fibercracking and their removal from the fiber beds. Friedrich et al. [9] emphasized that if the diamond tip indenter is replaced with a small steel ball, the characteristic wear and damagemechanisms are very similar but these are not seen clearly as in case of the damage mechanisms produced by the diamond indenter.
Fig. 3: (a) SEM micrograph of AP-direction composite surface scratched by a diamond tip, (b) a magnified view ofthe groove [7]
Friedrich et al. [7] explained that wear process takes place in a sequence of damage mechanismsand these were termed as wear cycles. Accordingly, the wear cycle initiates from the matrix wearand fiber sliding wear. Fiber sliding wear is also known as fiber thinning in the literature. These are followed by fiber cracking and fiber/matrix de-bonding at the interface. When the wear process reaches the steady state then a so-called compacted wear debris layer (CWDL) coversthe surface which is composed of pulverized fibers and matrix material. During the wear process,this layer is continuously formed and removed by the surfaces sliding against each other. The preceding studies were limited to only three directions comprising P, AP and N. Sharma et al. [2,8] carried out experimental studies in various fiber directions. UD carbon reinforced thermoplastics (PEI) with 80% by volume were tested at range of angles as 0°, 30°, 45°, 60° and 90° during abrasive wear [8] and in dry-adhesive wear [2]. The increase in the coefficient of friction (µ) was reported as the fiber angle with respect to the sliding direction was increased. In addition, very low specific wear rate 30 ( , volume removed per unit of wo K unit mm / : rk require N d = . ) m was determined for the sliding in the fiber direction (P-direction). On the other hand, the specificwear rate in AP-direction (90°) in the experiments was computed as four times higher than the P direction (0°). Ovaert [10] reported similar results by conducting wear experiments on fiberreinforced thermoset epoxy matrix. Sharma et al. concluded that sliding orthogonal to the fiber(AP-direction) leads to higher wear. In addition, they highlighted that in AP-direction, FRPs aremore vulnerable to de-bonding, peel-off the plies and the pulverization of fibers as compared to the P-direction sliding.
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I've seen ONE that was almost certainly cleaning rod damage. It was a bare ss rod used. The customer had lodged a tight patch in the bore and needed it removed. After all done, bore scoped it and one land was "smeared" flat on one side. Not really smeared but looked more like a smear than a hit..but a hit is what actually did it when he was hitting the handle trying to drive the patch through. He said he only used the palm of his hand so I believe him but the damage was mid way from the patch to the chamber or end of the bore guide used. Basically, the rod flexed when being hit and the rod just hammered on that land very noticeably. I lapped it a bit and the gun shot ok afterward but the damage was still there. Lapping helped a little but did not get all of it. It was probably a bit les than 1/2" long and just in that one place..fwiw.
Like others said, I've heard about galling and such but have never seen what I could attribute to rod damage with any degree of certainty, as they described anyway. Maybe but doubtful and certainly not a true "gall", as I've read Calfee call it. Galling takes speed and pressure..friction. We're just not close to creating a true gall with a cleaning rod. He was adamant about his terminology being correct though.
No doubt that it can scratch but the question is, enough to hurt anything? and as compared to what? You can scratch highly polished ss with your bare skin if ya want get picky enough about it. Also, fwiw, it appears that test was with multi direction lay up of the cf as opposed to parallel. Bottom line, we're splitting a very fine hair. Without getting into the weeds, cf isn't magic. It's soft, fine strands of "cloth" glued together.
SteveOak
Gold $$ Contributor
I posted the portion of this paper I can kind of understand. There is more most of which is well over my head. Additionally, this is not my field, perhaps someone with the proper background can 'translate' it for me. LOL
jelenko
Gold $$ Contributor
Wait.
My reading of that is about damage to the fiber; I didn't see any discussion about effect on the metal.
TRSR8
Silver $$ Contributor
You haven't seen it so it can’t happen???
Here’s my best one.
Back @ the IBS 200-300 nationals I was in line for the doorprize….Hawkeye borescope., which also allowed a free bbl inspection for those less familiar.
Guy in front of me was an established BR shooter, buddy. Put the scope in, looked up startled. I got a chance to look…….about 2”-3” of the barrel just past the chamber, right @ 6 o’clock had zero land showing.
I’ve known others at a well respected RFBR smiths.
you believe what you want….. I’ll believe my eyes.
JEFFPPC
Gold $$ Contributor
So the the conclusion was it came from the cleaning rod. How many thousands of rounds were through it. Your making an assumption or did I miss something. I had a well known national record holding gunsmith tell me what your describing comes from where the bullet is first landing in the rifling. He said it happens quicker with long heavy for caliber bullets. I don't know either way as there is no proof, just their OPINION.
JEFFPPC
Gold $$ Contributor
Abuse is not cleaning. I have stuck a few patches in my day. I have found by turning the gun upside down, putting lots of solvent down the barrel and leaving it sit overnite or longer allows me to push the patch out.Hope this tip helps,
Been there but it only works sometimes. Push, don't beat it out. I've done several I a latĥe
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