Honing cylinder throats vs. reaming cylinder throats

[DougGuy]

Reaming cylinder throats leaves the finish deeply scratched with tool marks and you have to go behind the reamer with abrasive to clean up the tool marks, now your throats gets bigger than what the reamer cut when you use the abrasives so it then becomes a guessing game, exactly what the finished diameter will be by the time the tool marks are gone.

The Sunnen hone is a precision automotive hone designed for fitting wrist pins and pistons to connecting rods allowing the user to achieve extremely precise fits with less than .0001" tolerance. Used with pistol diameter mandrels the way it locates itself in the cylinder throat keeps the tooling square and concentric with the centerline of the hole, it will round egg shaped holes, it will make barreled holes parallel, a lot of cylinders the metal gets flame hardened by the intense heat and then cooling from firing cycles and these throats will turn out belled like a funnel pointing outwards, Not only does the flame harden the area of the throat directly in the path of the flame, the repetitive thermal cycles can also cause the metal to contract over time, making the throat diameter smaller on the entrance than the exit. The Sunnen hone operator can make the hole parallel by riding only the tight portion with the hone, and keep it parallel during honing.

The number one main reason I switched to using the Sunnen hone exclusively is because the heat treatment in the long steel rods Ruger uses to make cylinders is all over the map. It changes hardness in a seemingly random fashion, I have encountered quite a number of Ruger 45 and 44 cylinders with 3 throats that cut easily with the throating reamer, then the 3 remaining throats the reamer will be excessively hard to turn, the reamer will squawk loudly when you turn it, and it will feel like you are about to twist the shank right off the reamer because the metal in this throat is a lot harder than the other throats on the other side of the SAME cylinder.

Other cylinders are much more consistent in temper and with these cylinders, throats will ream much more predictably and the throats will be more of a consistent diameter. The throats that are harder, will finish smaller diameter than the throats that cut normally, so now you have inconsistent finished diameters because the size of the bore the reamer cuts is totally dependent on the hardness of the metal you are cutting with it. Harder metal makes the reamed throat come out smaller than a cylinder with softer metal. Quite common with Ruger SA cylinders.

Enter the Sunnen precision automotive hone. It is a stepless system so there is no defined stops or notches or whatnot, and it will make all the throats the same diameter regardless of metallurgy of the parent metal. And it's nicely polished to 800grit when finished! A reamer just can't do what the Sunnen hone does, you don't have much control with a reamer, you are at the mercy of the temper of the steel in the cylinder. The Sunnen hone is not hampered by changes in temper. It will take longer to hone a harder cyinder throat, it slows the hone down but you would never know in the finished throat because they can be held within +-.0002" of each other, and in many cases +-.0001" throat to throat tolerance can be achieved given a bit more time and patience at the hone.

[contender1]

Great info here!

[DougGuy]

Great info here!

Thank you sir! :bigsmyl2:

[Nueces]

I can testify that Doug's honing work is superb. It's a pleasure to observe a dead smooth finish on my cylinder throats.

[kerplode]

I can testify that Doug's honing work is superb. It's a pleasure to observe a dead smooth finish on my cylinder throats.

Agreed!

That reminds me...I have another cylinder I need to box up and send to him.

[Winger Ed.]

Moved to Wheelguns as per OP's request

[HWooldridge]

Yep. We used to have a Sunnen where I work and I used it to hone all of my revolver cylinder chambers. I checked final fit with .0005 incremental pin gages but we could get really precise and use an air gage (or the bore checker that Sunnen supplied) for a variable measurement. I think the hone is also faster than a reamer because you can hold the cylinder by hand rather than setting up a holder for the reamer. It's just better all the way around for that purpose.

[charlie b]

That's great news.

Does that mean nitrided barrels won't be such a hassle? That may get me off my butt to send a barrel to you (HK with poly rifling).

[challenger_i]

Doug, are you running the hone wet, or dry? If wet, what is your preferred fluid, and is it run in a constant flow or dribbled in during the process?

[HWooldridge]

Doug, are you running the hone wet, or dry? If wet, what is your preferred fluid, and is it run in a constant flow or dribbled in during the process?

I’m not Doug, but we ran our machine with flood coolant, which was a sulfur based oil we bought from Sunnen.

[M-Tecs]

Per Sunnen they claim many/most honing problems are caused by using the wrong oil. Different materials require different honing oil. In my shop I needed to keep three different honing oils on hand.

Honing of this type requires a flood of oil generally high sulfur and chlorine oils with various additives give the best performance. Soft materials like aluminum require a heavier flow. The high sulfur and chlorine oils can't be used in some airspace applications.

https://www.sunnen.com/Catalog/Cutting-Fluids/Cutting-Fluids-Honing-Fluids

This is an example of this type of process.


https://www.youtube.com/watch?v=j5UqmpMME88

[castmiester]

Doug


the heat treatment in the long steel rods Ruger uses to make cylinders is all over the map. It changes hardness in a seemingly random fashion

from the beginning of it's production to date, or when did the QC start to go downhill?

[DougGuy]

Doug



from the beginning of it's production to date, or when did the QC start to go downhill?

It's not a QC issue. It's something that just comes with the territory. S&W doesn't have these random temper changes, their cylinders are much more uniform in metallurgical breakdown, as is Freedom Arms. If you want perfect cylinders with throats suited for cast boolits and blueprinted tensile strength and high quality alloys all the way through the cylinder, add another thousand to fifteen hundred to the price of a Ruger revolver. You think guns are expensive now, hold your breath, cause you ain't seen nothing.

Honing cylinder throats to suit, tailored to the half thou, sized half thou above boolit diameter is a pittance really, typically a one-time expense per gun. You spend more money on revolver grips than most cylinders cost to hone. Be THANKFUL gwasshoppa, that Ruger left us with tune-able cylinder throats, rather than one size fits all and who knows how big throats would be with that mindset?

[DougGuy]

Doug, are you running the hone wet, or dry? If wet, what is your preferred fluid, and is it run in a constant flow or dribbled in during the process?

I use the honing oil sold by Goodson. It's very close to Sunnen honing oil. I run it in a steady stream right on top of the mandrel.


That's great news.

Does that mean nitrided barrels won't be such a hassle? That may get me off my butt to send a barrel to you (HK with poly rifling).

I have not yet seen a viable path to honing a throat with a tapered leade in to the rifling. The Sunnen hone is meant and made for honing parallel bores like cylinder throats, connecting rods, pistons, etc..

I have dreamed about making an abrasive shaped like a boolit nose and with a live pilot to hold the stone centered in the bore, much like a Kwik-Way valve seat grinding machine uses a mandrel tightly fitted in the valve guide.

A segmented CBN stone shaped like a round nose/flat point/WFN boolit that will ride on the mandrel. Manson makes nice mandrels that fit in 9mm/357, 44 and 45 barrels and index off the lands. I have a friend who is in the abrasive business in China, I've gotten CBN (Boron) stones for Sunnen mandrels that are excellent quality and long lasting. I contacted him about this idea of a mounted abrasive, shaped like a boolit, with a hollow core that can ride the mandrel and have the CBN abrasive cemented onto it, he said I would probably have to have it plated on, but that's too thin, won't last so I haven't pursued it any farther than that.

[challenger_i]

Thank you, sir!

[charlie b]

Thanks Doug. I'll just stick with jacketed or plated bullets until I buy a new barrel for it.

[DougGuy]

Thanks Doug. I'll just stick with jacketed or plated bullets until I buy a new barrel for it.

I could have at least asked what caliber the gun?

[castmiester]

It's not a QC issue. It's something that just comes with the territory. S&W doesn't have these random temper changes, their cylinders are much more uniform in metallurgical breakdown, as is Freedom Arms. If you want perfect cylinders with throats suited for cast boolits and blueprinted tensile strength and high quality alloys all the way through the cylinder, add another thousand to fifteen hundred to the price of a Ruger revolver. You think guns are expensive now, hold your breath, cause you ain't seen nothing.

Honing cylinder throats to suit, tailored to the half thou, sized half thou above boolit diameter is a pittance really, typically a one-time expense per gun. You spend more money on revolver grips than most cylinders cost to hone. Be THANKFUL gwasshoppa, that Ruger left us with tune-able cylinder throats, rather than one size fits all and who knows how big throats would be with that mindset?

Freedom arms.... they look like Blackhawks. Guess everything about them are stellar. How do they shoot ?

[lightload]

Did I dream this--that Ruger New Vaqurero cylinders are a notch above the other ones in the Ruger line? I thought Doug had commented on the subject.

I make a point to read everything that Doug writes and wish to thank him for his contribution. Larry too. And Outpost. These guys are scientists.

[DougGuy]

Did I dream this--that Ruger New Vaqurero cylinders are a notch above the other ones in the Ruger line? I thought Doug had commented on the subject.

I make a point to read everything that Doug writes and wish to thank him for his contribution. Larry too. And Outpost. These guys are scientists.

The new models (3 digit prefix serial number, medium frame) that I have seen had an overall much better fitment, the barrels seem to be pretty much free of thread choke for the most part, and the cylinders are much more consistent in throat diameters, although they are still just a tad bit small for optimal cast boolit use, they are made better than the older 2 digit prefix guns. The Lipsey's limited edition guns are the pick of the litter.

[georgerkahn]

The new models (3 digit prefix serial number, medium frame) that I have seen had an overall much better fitment, the barrels seem to be pretty much free of thread choke for the most part, and the cylinders are much more consistent in throat diameters, although they are still just a tad bit small for optimal cast boolit use, they are made better than the older 2 digit prefix guns. The Lipsey's limited edition guns are the pick of the litter.

DougGuy -- you have me a tad confused? You wrote, "The Lipsey's limited edition guns are the pick of the litter". I very recently posted you my
Ruger Blackhawk Lipsey Exclusive 5 ½” Barrel .45LC/.45ACP Bearcat s/n 520-xxxxx Model 5241, which (THANK YOU!!!!!) you did an awesome and then some honing -- but you indicated my cost was at upper end due to the cylinders being out of whack? (Perhaps mine was a "late Friday afternoon" product?) Not by any means a "biggee" -- as soon as some funds free up for me I'm still planning on sending another two cylinders to you for your magic -- but if the "Lipsey Limited edition..." are the pick of the litter... then how bad are the other models?
geo

[nicholst55]

The new models (3 digit prefix serial number, medium frame) that I have seen had an overall much better fitment, the barrels seem to be pretty much free of thread choke for the most part, and the cylinders are much more consistent in throat diameters, although they are still just a tad bit small for optimal cast boolit use, they are made better than the older 2 digit prefix guns. The Lipsey's limited edition guns are the pick of the litter.

I have a .45 Flattop convertible that has a significant thread choke (and also had grossly undersize and varying diameter throats, but I had them reamed). I bought it used, but I think that it's a Lipsey's gun. IMHO, Ruger stainless barrels are not practical to firelap, due to their hardness. Short of refitting (or replacing) the barrel, my understanding is that Taylor Throating is the best solution. Do you offer this service?

[DougGuy]

I have a .45 Flattop convertible that has a significant thread choke (and also had grossly undersize and varying diameter throats, but I had them reamed). I bought it used, but I think that it's a Lipsey's gun. IMHO, Ruger stainless barrels are not practical to firelap, due to their hardness. Short of refitting (or replacing) the barrel, my understanding is that Taylor Throating is the best solution. Do you offer this service?

I do have a taylor throat reamer in 45 caliber but I can't receive a complete firearm, only components.

[DougGuy]

DougGuy -- you have me a tad confused? You wrote, "The Lipsey's limited edition guns are the pick of the litter". I very recently posted you my
Ruger Blackhawk Lipsey Exclusive 5 ½” Barrel .45LC/.45ACP Bearcat s/n 520-xxxxx Model 5241, which (THANK YOU!!!!!) you did an awesome and then some honing -- but you indicated my cost was at upper end due to the cylinders being out of whack? (Perhaps mine was a "late Friday afternoon" product?) Not by any means a "biggee" -- as soon as some funds free up for me I'm still planning on sending another two cylinders to you for your magic -- but if the "Lipsey Limited edition..." are the pick of the litter... then how bad are the other models?
geo

Yours had really tight throats, both smaller than .451" one at .450" so the few Lipsey's that I have had in the shop came with .452" throats, I have honed a few dozen Lipsey's cylinders, I was mainly emphasizing the fit and finish overall, not specifically the cylinder throats.

I own one Lipsey's limited edition 45/45 flattop blackhawk convertible and one 45 vaquero. They all had throats honed and hammer pads reduced, and Wolff 30oz. trigger return springs added, neither has the slightest hint of thread choke. A couple more I have seen in person had zero detectable choke.

Truth be told, they were SO good, the medium frame guns are the best Ruger has turned out to date IMHO! I was jealous, I *had* to have a couple for myself. Mine are great shooters, the cylinders will even interchange between them!

This is not a "Praise Ruger" thread but since you asked georgerkahn, here's the lowdown..

[nicholst55]

I do have a taylor throat reamer in 45 caliber but I can't receive a complete firearm, only components.

Roger that.

[castmiester]

Doug

Do you have spare Redhawk cylinders to sell ?

[DougGuy]

Doug

Do you have spare Redhawk cylinders to sell ?

Where do you come up with these off the wall questions? I can't believe you wasted your time typing this and can't believe I wasted the time to respond. NO I do not have a "spare" RH cylinder hanging around like on my desktop serving as a pencil holder? You must have typed this question in a dream.

[castmiester]

Maybe to you it was, but who knows what you have, figured I'd ask, or you can guide me to a good used one to fit. But I heard there's fitting to my gun, but you did mention, in your previous post, unless it is just with the model you posted, that they are interchangeable. Remember......... I'm a newb.

[DougGuy]

Maybe to you it was, but who knows what you have, figured I'd ask, or you can guide me to a good used one to fit. But I heard there's fitting to my gun, but you did mention, in your previous post, unless it is just with the model you posted, that they are interchangeable. Remember......... I'm a newb.

My throats are .432~5. If l insert the gauge most of the way in the throat/chamber l get a snugger gauging.

The Ruger single action cylinders are interchangeable from one model to another model of the same frames. That does NOT assume they will fit and be usable. Sometimes you buy a used cylinder off ebay and it drops in with .080" or more end shake. Ridiculously wide barrel/cylinder gaps. Sometimes they won't even go in the frame. It's anybody's guess whether they will work. MY medium framed guns could interchange the cylinders with exact fit, not even .001" difference between the flattop and my vaquero. Luck yes. Does it happen often? It could.

A Redhawk, sp101, gp100, all of those double action revolves are meticulously fitted one gun at a time. you have end shake, barrel/cylinder gap, timing, there is a bunch of stuff involved in replacing a double action cylinder. Ruger does not sell these parts. I have never even SEEN a redhawk cylinder listed for sale. EVER.

Now that you have hijacked my thread with a totally unrelated subject matter, you are welcome to butt out and go start your own thread about redhawks or whatever. You have ZERO forum etiquette. Learn some.

[castmiester]

I’d pm you but you ain’t answering me.. LOL

[charlie b]

i could have at least asked what caliber the gun?

lol hk vp9

[alfadan]

David Richards on youtube says his Sunnen hone is the most accurate machine in his shop.

[Forrest r]

I have never even SEEN a redhawk cylinder listed for sale. EVER.

You have ZERO forum etiquette. Learn some.

Interesting!!!
There not that hard to find if you know how to look and what to look for. Heck, ebay has them for sale all the time.

https://www.ebay.com/itm/285057243753?hash=item425ebc5a69:g:-wsAAOSwjP9je9ev&amdata=enc%3AAQAIAAAAwLZ65%2FA6KsL4E72A9VXSJUBjHgC PPJBN5m3FuknWixE99%2FFEieCxt8i8RyLCWSCo4Vt%2BOLySq bYFWEnfsSXR534WR1yWdvA09lH%2FmRR8b2fSd47jqg%2FebR0 terwFHxnZa2mtwlJYZAmXhH%2Br5%2B%2FiFSFHZH%2BdfGW3Z 6FPV4PHp93zNKQI9j4KwLdamdvOdMFRBE3TwK7%2B%2FEEN40X U3gcW2HlC75hvK9rGwXRshJMqruWWWAgPwIq2KDmzCmtepQKvF A%3D%3D%7Ctkp%3ABk9SR7CthOmtYw

And yes the lowly numrich arms has them most of the time also.
https://www.gunpartscorp.com/products/1818180
https://www.gunpartscorp.com/products/559880

[53slf]

I just have to say Doug did a great job on my S&W 63 cylinder. He turned a gun I had stopped shooting because cases would not extract after a few cylinders full to one that now is joy to shoot for hundreds of rounds! Cases come out smoothly regardless of brand.
Luckily my other revolvers are fine the way they came even with cast.

[Bigslug]

Doug, thanks for the explanation of the process. It took a couple of YouTube vids covering the larger Sunnen machines for me to get the gist of what's happening, but I eventually got there.

Truly a better way to do it regardless of the material you're working on. . .but the notion of different hardness levels within the same 2" diameter cylinder (a.) makes the brain ache, and (b.) pretty much closes the deal. I've had a few Ruger chambers that weren't quite there that I selectively shot fire-lapping rounds through while removing frame/barrel crush to equalize with the rest, but I like the sound of your way better.

Would you say that Ruger has recently been taking steps to generally improve this stuff? I recently had an overpressure load blow out one of the cylinder stop notches on my 1990's era GP-100, and I sent it in with a note that I shoot cast where these measurements matter, and I got it back with a new cylinder on which the throats pinned uniformly. Whether that more to do with my request or how they do things currently, you'd be in a better position to say, but by your description of the Lipsey's guns, they certainly can when they want to.

[DougGuy]

Doug, thanks for the explanation of the process. It took a couple of YouTube vids covering the larger Sunnen machines for me to get the gist of what's happening, but I eventually got there.

Truly a better way to do it regardless of the material you're working on. . .but the notion of different hardness levels within the same 2" diameter cylinder (a.) makes the brain ache, and (b.) pretty much closes the deal. I've had a few Ruger chambers that weren't quite there that I selectively shot fire-lapping rounds through while removing frame/barrel crush to equalize with the rest, but I like the sound of your way better.

Would you say that Ruger has recently been taking steps to generally improve this stuff?

I don't know if Ruger is changing the metallurgy in the cylinder rods, they come in on rail cars from what I am told. I have no clue how to explain the variances in the hardness of the steel in those rods, but I have ran into this time and time again when I was reaming cylinders. Even when you do get those harder throats reamed, if you mic them with a dial bore gage or snap gage or even a pin gage, you will find that throats that were easier, more normal to ream are larger than the ones that were harder to ream. I think this variance in temper continued on into the medium frame 3 digit prefix guns.

Afaik, Ruger cylinders are the only ones that have these wide swings in the temper. No other brand of revolver that I have reamed or honed, has been inconsistent from one side to the other side of the same cylinder. Their cylinders are pretty much overbuilt in that it takes a LOT to blow one up. Ruger paid for a study years ago with a private firm to conduct destructive analysis of their guns and if I recall correctly they found that it took at least 60,000 psi to destroy a 45 Colt blackhawk.

Two instances come to mind, one I got a msg from a member here who had bought a reamer from Brownell's and was intending on reaming his 45 Colt cylinder. He reamed 3 throats and then ran into the exact scenario I described numerous times in bunches of my posts, this thread included, he couldn't get the reamer to cut the rest of the throats, and he got scared of forcing it, he contacted me and sent his cylinder and the reamer to me to finish the job. I used his reamer and turned it with vise grips to ream the rest of the throats and sent the cylinder back. I didn't have pin gages in those days, and it never occurred to me that those three throats might be smaller in diameter than the others. I was using ACRO laps then, and I lapped those throats to match.

I mean, you would think that if a .4525" reamer went through the throat and reamed it, that it would be .4525" right? Doesn't work that way. Reamers can and will crush depending on how much resistance the steel puts against the cutting flutes, and the same reamer will cut different sized holes in stainless, hard steel cylinders, softer steel cylinders, they will all be varying diameters. I had one cylinder that the reamer got severely stuck in, and I had no choice but to beat it through with a big nylon hammer. The reamer came through the ordeal okay, sent it to be sharpened later, but the throat that I just FORCED a .4525" reamer through, would NOT allow a .452" pin gage to go into the hole. Go figure. Explain that one.

The other instance of inconsistent temper that sticks out in my memory was with one cylinder that I honed all the throats, and there was one throat that I had to go back through with the 400 grit CBN stone followed with a 400 grit silicon carbide stone, and finish with a 500 grit silicon carbide stone. I had to repeat this process 3 times in total to bring that one throat to match the drag on the pin gage that the other throats had. There is no way possible that a reamer would have cut this throat to match the other 5. Just a weird piece of steel in this one cylinder.

Anybody else would have sent that cylinder back to the customer with 5 good throats and 1 that could not be reamed to match the rest. Stories like this one are why I invested in the Sunnen hone. It does what nothing else can do, despite changes in the hardness of the steel in the cylinder.

[jrayborn]

Having reamed some cylinders myself, I'd love my own Sunnen Hone. Kind of overkill for this kind of work, but certainly makes it easy if you do it for a living. :)

[shooting on a shoestring]

I like overkill. It works!