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Curious
07-02-2016, 08:16 PM
Ive read a couple of comments on forums from guys who ditch the pilot bushing while using this method and they are getting good results, the idea seems to be to stop the pilot from influencing the reamed as it follows the pre-bore and they also dislike the idea of the bush rubbing up the rifling right where the bullet will touch.

Can anyone speak from first hand experience of this?

ndh78
07-02-2016, 10:32 PM
I've done it several times on long cases where the bore is crooked enough that the spot where the pilot will end up runs true but the part where it first enters the rifiling has some run out and I get good results. Sometimes I ream to almost full depth and then put the pilot on.

Curious
07-03-2016, 02:59 AM
I've done it several times on long cases where the bore is crooked enough that the spot where the pilot will end up runs true but the part where it first enters the rifiling has some run out and I get good results. Sometimes I ream to almost full depth and then put the pilot on.

Thats interesting, thanks.

When you say good results, do you measure these and if so how good is good?

JerrySharrett
07-03-2016, 06:31 AM
If you use an accurate dial indicator like an Interapid and a stylus long enough to reach the point in the to-be cut chamber where the bullet will intersect the bore and closely dial in that part, and you prebore the chamber base taking all the curvature out at that point, then use a floating pusher and a snug fitting pilot you will end up with an accurate and to proper size chamber.


,

coyotechet
07-03-2016, 10:37 AM
If you use an accurate dial indicator like an Interapid and a stylus long enough to reach the point in the to-be cut chamber where the bullet will intersect the bore and closely dial in that part, and you prebore the chamber base taking all the curvature out at that point, then use a floating pusher and a snug fitting pilot you will end up with an accurate and to proper size chamber.


,

Well said and very true. :)

Curious
07-03-2016, 11:58 AM
If you use an accurate dial indicator like an Interapid and a stylus long enough to reach the point in the to-be cut chamber where the bullet will intersect the bore and closely dial in that part, and you prebore the chamber base taking all the curvature out at that point, then use a floating pusher and a snug fitting pilot you will end up with an accurate and to proper size chamber.


My question was regarding any advantages or disadvantages in ditching the pilot bush Jerry, have you ever tried this method?

Mike Bryant
07-03-2016, 03:00 PM
My question was regarding any advantages or disadvantages in ditching the pilot bush Jerry, have you ever tried this method?

If the barrel is a 5C type barrel, it's pretty important to use a fairly tight bushing. Something to do with the canted land will sometimes try to induce chatter if the pilot doesn't fit well. I'll go along with what Jerry states. It's worked well for me a long time. Been using basically the same system for chambering barrels since 1991. Tried all the other methods, but always come back to an indicated bore at the throat and boring the body to rough out the chamber.

Butch Lambert
07-04-2016, 02:43 PM
All kinds of opinions on this.

Curious
07-04-2016, 03:04 PM
All kinds of opinions on this.

Has it been discussed at length anywhere I could read?

Or would you like to share your thoughts?

WSnyder
07-04-2016, 05:18 PM
Has it been discussed at length anywhere I could read?

Or would you like to share your thoughts?

Have you read through the article referenced at the top of this sub forum?

http://benchrest.com/showthread.php?95094-BIG-article-concerning-chambering
http://houstontruetens.com/RUGER/chambering.pdf

Butch Lambert
07-04-2016, 05:43 PM
Have you read through the article referenced at the top of this sub forum?

http://benchrest.com/showthread.php?95094-BIG-article-concerning-chambering
http://houstontruetens.com/RUGER/chambering.pdf

Bill, I think he has been directed there earlier. He wants you to school him first hand! Possibly can't comprehend the links.

Curious
07-05-2016, 03:35 AM
Bill, I think he has been directed there earlier. He wants you to school him first hand! Possibly can't comprehend the links.

Wow, I guess forum spirit is dead among some then?

Take some time to think about this Butch.

A guy puts a random compilation of thoughts about chambering into a document and then guys like you just link newbies like me to it because you can't be arsed to talk it through again, your not interested in a way that I get the answer Im looking for in a more direct and efficient manner, you call it 'first hand schooling', I call it being helpful. If you can't be bothered to engage with me then why say anything at all, just let it slide by?

Steering me to a document that Ive looked at a few times is pointless, if I had got the information I wanted in a way I understood then I would not have been asking the question. There may be lots of great info in that compilation but seriously, have you tried reading through it all from the perspective of a novice? - I will assume no is your answer! If your stale in terms of forum contributions the why be a smart arse and spoil it for me? Forums are about sharing information in many different ways, directing to stickies every time is just plain lazy and counter-productive so I end up frustrated and I walk away.

You win big guy.

JerrySharrett
07-05-2016, 06:00 AM
My question was regarding any advantages or disadvantages in ditching the pilot bush Jerry, have you ever tried this method?

I wonder? Why "try" a chamber without using a pilot bushing when I have one available? At best it might give a good chamber but also it might not??? If you use a snug fitting pilot on the reamer the merge point at the freebore and leade will create the best fit and that is what the bullet needs to start its journey down the barrel without any in-bore yaw.

.

Dave Tooley
07-05-2016, 08:15 AM
Ive read a couple of comments on forums from guys who ditch the pilot bushing while using this method and they are getting good results, the idea seems to be to stop the pilot from influencing the reamed as it follows the pre-bore and they also dislike the idea of the bush rubbing up the rifling right where the bullet will touch.

Can anyone speak from first hand experience of this?

The pilot bushing can't follow the prebored hole. If you indicate in the throat area, as I do and use a floating pusher, I want the reamer aligned as quickly as possible, that means using a bushing. I use flush coolant and have never had an issue with marring the finish on the lands.

Butch Lambert
07-05-2016, 09:04 AM
Wow, I guess forum spirit is dead among some then?

Take some time to think about this Butch.

A guy puts a random compilation of thoughts about chambering into a document and then guys like you just link newbies like me to it because you can't be arsed to talk it through again, your not interested in a way that I get the answer Im looking for in a more direct and efficient manner, you call it 'first hand schooling', I call it being helpful. If you can't be bothered to engage with me then why say anything at all, just let it slide by?

Steering me to a document that Ive looked at a few times is pointless, if I had got the information I wanted in a way I understood then I would not have been asking the question. There may be lots of great info in that compilation but seriously, have you tried reading through it all from the perspective of a novice? - I will assume no is your answer! If your stale in terms of forum contributions the why be a smart arse and spoil it for me? Forums are about sharing information in many different ways, directing to stickies every time is just plain lazy and counter-productive so I end up frustrated and I walk away.

You win big guy.

You type a lot, but haven't said anything. Didn't mean to piss in your Post Toasties.

NezRongero
07-05-2016, 04:28 PM
There may be lots of great info in that compilation but seriously, have you tried reading through it all from the perspective of a novice? - I will assume no is your answer! If your stale in terms of forum contributions the why be a smart arse and spoil it for me? Forums are about sharing information in many different ways, directing to stickies every time is just plain lazy and counter-productive so I end up frustrated and I walk away..

Here is a response from a novice.

Besides the tremendous help I got from Butch, I printed and put that compilation in a binder and read it I don't remember how many times, I even took it with everywhere I went and read it any chance I had; in flight, at the airport, break time from the grandkids, at the hotel after shooting in matches, etc. It was overwhelming at first, I am kind of slow, but what was written in the whole binder made more sense later the more I read it. I tried the different approaches others wrote about, turned a bunch of shot out barrels into buckets of chips. Lots of good information, but after testing other procedures, I found out my lathe, my cutters, and my set up are not the same as anyone else's, I better learn how to use what I have to achieve the same results. I suppose I was not afraid to try and fail and just dove right into it, and learned a lot, and still learning. Now, even after cranking over a couple of dozen barrels I still consider my skills to be in the crawl phase compared to the gentlemen on this forum.

I don't know what machining background you have, I started from nothing, l had to learn the very basics of running a lathe and a mill. I spent many hours sometimes almost all night trying different things. Ignorance is bliss.

It is a journey, enjoy the ride.

WSnyder
07-05-2016, 04:38 PM
You asked Butch for anything you might read on the subject. I had no indication you had read the sticky I referenced or that you had been directed there before. That document contains a lot of good information. I see nothing wrong with directing someone to a sticky (that's why it's there). Maybe if you had noted you had read the document and had questions others might find time to discuss your questions.

You might feel the forum participation is somewhat dead which may be true. You have to understand that after many many years of these very questions followed by some of the heated bickering that ensues has taken a bit of the motivation to share out of quite a few.

As to your question: I basically do what Tooley and Sharrett have stated although I doubt I do what either of them do exactly. I indicate the throat, use a bushing and pre-bore. I am confident in my pre-bore method and could probably do without a bushing but I feel why do that if I have a bushing available? I feel the bushing will help to insure the throat is where it is supposed to be as the chamber is nearing completion. Inspecting with a borescope I have yet to have a misaligned throat. I have not experienced bore damage or marking of the bore from using a properly fitted pilot bushing. In the end it all comes out the way I want it so I do what works for me and not necessarily what works for others. I also try to keep an open mind and I'm certainly not above trying something new now and then.

skeetlee
07-05-2016, 04:41 PM
Reamer flex is a real issue and I wouldn't ever ream a bored out chamber without a good fitted bushing.
Mike I have also experienced the chatter issue on a 5c or 5r barrel. I also use a snug bushing, and I use tap majic extra thick cutting oil. the Tap Magic extra thick is like glue. Its kind of a pain to clean up but it works for me. I hate 5r/ 5c barrels, and I always do my best to steer my customers away from them. The 5 grooves are also harder/ if not impossible to indicate directly off the bore like I like to do with a standard 4 groove barrel. For the life of me I have no idea why they are so popular. They are though!! Lee

WSnyder
07-05-2016, 05:15 PM
My experience with 5R barrels is limited to Bartlein .308" and .264" 5R barrels, I have had no issues or difficulties with indicating or chambering them.

CMaier
07-05-2016, 06:55 PM
How many of the responders "taper bore" when they say "pre bore" ?

I see a potential issue with a taper bore and a bushing.,2 surfaces trying to guide the reamer.

jackie schmidt
07-05-2016, 07:01 PM
How many of the responders "taper bore" when they say "pre bore" ?

I see a potential issue with a taper bore and a bushing.,2 surfaces trying to guide the reamer.

If you indicate what will be the throat area properly, you will not have this problem.

That being said, all chambering allows for a little bit of compromise, because regardless of our best efforts, we are still dealing with a barrels ID that does not run truly straight with it's own self.

That is where that all important "common sense" that I am always alluding to comes into play.

Mike Bryant
07-05-2016, 10:41 PM
Reamer flex is a real issue and I wouldn't ever ream a bored out chamber without a good fitted bushing.
Mike I have also experienced the chatter issue on a 5c or 5r barrel. I also use a snug bushing, and I use tap majic extra thick cutting oil. the Tap Magic extra thick is like glue. Its kind of a pain to clean up but it works for me. I hate 5r/ 5c barrels, and I always do my best to steer my customers away from them. The 5 grooves are also harder/ if not impossible to indicate directly off the bore like I like to do with a standard 4 groove barrel. For the life of me I have no idea why they are so popular. They are though!! Lee

Lee, any time I get to pick the rifling pattern, I'll pick a 4 groove. Think the chatter is caused by a six flute reamer in a five groove barrel. When the flute of the reamer hits the land it's not hitting on the opposite side. I've had the best results with 5 groove barrels using a snug fitting bushing, .0002" smaller than what won't go in the bore and pushing the reamer in with a dead center until it starts cutting at the shoulder at the bottom of the pre bored hole. Then switching over to the pusher to make sure the chamber cuts as close to reamer size as possible.

Mike Bryant
07-05-2016, 11:06 PM
Here is a response from a novice.

Besides the tremendous help I got from Butch, I printed and put that compilation in a binder and read it I don't remember how many times, I even took it with everywhere I went and read it any chance I had; in flight, at the airport, break time from the grandkids, at the hotel after shooting in matches, etc. It was overwhelming at first, I am kind of slow, but what was written in the whole binder made more sense later the more I read it. I tried the different approaches others wrote about, turned a bunch of shot out barrels into buckets of chips. Lots of good information, but after testing other procedures, I found out my lathe, my cutters, and my set up are not the same as anyone else's, I better learn how to use what I have to achieve the same results. I suppose I was not afraid to try and fail and just dove right into it, and learned a lot, and still learning. Now, even after cranking over a couple of dozen barrels I still consider my skills to be in the crawl phase compared to the gentlemen on this forum.

I don't know what machining background you have, I started from nothing, l had to learn the very basics of running a lathe and a mill. I spent many hours sometimes almost all night trying different things. Ignorance is bliss.

It is a journey, enjoy the ride.

I think you've hit the nail on the head. What works for one person with their equipment may or may not work with yours. Lathes too long through the headstock, spindle holes too small for the barrels you want to chamber, lathes with short beds, worn spindle bearings, worn lathe beds, all come to mind. You have to figure out what methods will work with your equipment to get the results that you want. We all start somewhere. The benchrest game originally drew a lot of machinists who adapted their skills to building rifles. Still a lot of full time machinists in the sport. If you look at a lot of the equipment lists, you'll find that one of the most frequently listed gunsmiths is self. I was fortunate when I started shooting benchrest that my best friend was a full time machinist. I watched him for hours after work chambering our benchrest barrels. Later bought a lathe and started doing it myself. We have pharmacists, radiologists, retired brick layers, dentists, ranchers, farmers as well as machinists doing their own barrel work. It's just an acquired skill that you'll get better the more you do it. Read everything you can on the subject, figure out what works best with your equipment and make lots of chips. One of the articles compiled in the sticky was an article I wrote for Precision Shooting magazine in '91. At that time, I'd been chambering my own barrels for 5 years. Just be careful when you get the barreling bug or you'll wind up with a shop full of machine tools.

Zebra13
07-06-2016, 11:37 AM
Just be careful when you get the barreling bug or you'll wind up with a shop full of machine tools.

Mike,

Amen, brother. I just bought my 4th lathe. I'm on my second mill. I have a surface grinder under a tarp outside my shop.

I work on rifles for fun.

I think the cheese has slid off of my cracker...


Justin

Greg Walley
07-06-2016, 06:42 PM
One can eliminate the chatter in the 5R or canted rifling barrels by boring 0.010 to 0.015 undersize the neck diameter for the length of the chamber - stopping 0.020 short of the chamber length. This will provide enough support to the cutting edges on the body of the reamer to keep it from chattering. Loading up the flutes with cold lard will also help. I use small carbide boring bars made by Scientific Cutting Tools that use the diamond shaped insert to do the deep hole bore. I use a 0.003 or 0.007 corner radius to keep the boring bar from chattering. I use a 0.002/0.0025 feed at 1600-1800 RPM. I can get about 30-40 chambers out of one corner of a coated insert.

Even if the chatter is eliminated in the body, sometimes the chatter will still be present in the throat. Don't fret over this, because world records have been set with barrels that have this “problem”. The imperfection is usually small enough that it erodes away in 100 rounds or so (with 6.5/7mm cartridges used in F-Class).

I tried to illustrate the profile in CAD of the cross-section of the rifling superimposed over the cross-section of the reamer to show that only one cutting edge and land of the reamer is engaged with the canted rifling, which is why the reamer vibrates. Unfortunately I don't have a good enough optical comparator to show the true profile and draw it accurately. Some barrel makers' canted rifling don't have this problem, because I suspect as one cutting edge is engaged in the cut, the other cutting edge or trailing edge flute 180 degrees opposite is supported enough on the opposite land to keep the reamer from vibrating.

Greg Walley
Kelbly's Inc.

Mike Bryant
07-06-2016, 10:20 PM
Greg, it would be interesting to see how well a 5 flute reamer would work in a 5 groove barrel. When I sold Red Cornelison's reamers for Bonnie after his death, he had a few Red Elliot reamers that were 4 flute reamers. Mostly roughing reamers, but the Eliott reamers had a reputation of cutting very well. Wound up buying one of them, but it's a 7x57 reamer and haven't had anyone want a rifle chambered in that caliber. So never have used it.

CMaier
07-06-2016, 11:26 PM
get it in spiral flute..and no more issue ??

Louis.J
07-07-2016, 12:23 AM
I have learned allot from reading those articles and I am not brightest cookie in town but I have still been able to put it to good use. I am very thankfull for the information, none of them had to take the time to put it down in writing along with pictures or to share it. You had no right to start mouthing off as if someone was beholding to you especially so to Butch.

Greg Walley
07-07-2016, 10:20 AM
Greg, it would be interesting to see how well a 5 flute reamer would work in a 5 groove barrel. When I sold Red Cornelison's reamers for Bonnie after his death, he had a few Red Elliot reamers that were 4 flute reamers. Mostly roughing reamers, but the Eliott reamers had a reputation of cutting very well. Wound up buying one of them, but it's a 7x57 reamer and haven't had anyone want a rifle chambered in that caliber. So never have used it.

It would be an interesting experiment. If you want to verify your theory, I'll see if I can locate a 5R 7mm scrap end of a barrel that's long enough to do the test and I'll send it to you.

We have a few Elliot reamers, but they are all six flute. We also have Eliot roughers to go with the finishers that are four flute. They are remarkable reamers for the finish they give and their longevity. The four flute roughers are quite amazing how easily they remove material and hold their edge. I believe it was one of the reamer makers that told me Elliot used a tool steel that was also used for rock chisels - and Red had a hell of a time grinding them since that was in the days before Borazon grinding wheels.

A spiral flute reamer was mentioned...we have a 7mm/08 spiral flute Clymer reamer. It's one of the older ones that was water honed. It's one of the best reamers I've ever used. I wish the reamer makers would still offer this profile.

Greg Walley
Kelbly's Inc.

Dave Tooley
07-07-2016, 11:36 AM
Greg,

I wish we would of had more time to chat at the SS. Maybe next year. I plan on shooting now that they've brought UL back. Lot of information to exchange.
It's been my experience that 5R rifling can bring out the worst in a reamer nor necessarily the other way around . I say this based on using multiple reamers(6 or more per caliber), over multiple calibers, all chambers roughed in the same way, all reamers made by the same manufacturer at different times. Each reamer has it's own personality. Some cut quietly, dead like a corpse. Others are a bit lively and will leave that ever so fine chatter in the throat. Because of the quantity of barrels for a recent contract I went to carbide for my 308 reamer. Different manufacturer and it's cuts dead quiet. This doesn't apply to this group but I don't have these issues on 338's.

Tim Oltersdorf
07-07-2016, 07:33 PM
Mike,

Amen, brother. I just bought my 4th lathe. I'm on my second mill. I have a surface grinder under a tarp outside my shop.

I work on rifles for fun.

I think the cheese has slid off of my cracker...


Justin

Justin, was that a Haiku? Tim

Greg Walley
07-07-2016, 07:49 PM
Greg,

I wish we would of had more time to chat at the SS. Maybe next year. I plan on shooting now that they've brought UL back. Lot of information to exchange.
It's been my experience that 5R rifling can bring out the worst in a reamer nor necessarily the other way around . I say this based on using multiple reamers(6 or more per caliber), over multiple calibers, all chambers roughed in the same way, all reamers made by the same manufacturer at different times. Each reamer has it's own personality. Some cut quietly, dead like a corpse. Others are a bit lively and will leave that ever so fine chatter in the throat. Because of the quantity of barrels for a recent contract I went to carbide for my 308 reamer. Different manufacturer and it's cuts dead quiet. This doesn't apply to this group but I don't have these issues on 338's.

Dave,

I also use a carbide 308 reamer. I think I've reamed over a hundred chambers with it in the last year, yet it still leaves a finish as if it were new and is spot on dimensionally (verified with gage balls and a Triebel throat gage)...although I'm quite sure I don't really take advantage of its capabilities. I run it at twice the RPM and feed rate over the HSS reamers. We just added a 1000 PSI coolant pump to one of our turning centers, so I'll have to give it a try with that setup and use a higher feed rate and get the chip-load up. I suspect it will give an even better finish, and no chance of picking up swarf around the pilot and scoring up the rifling with the coolant blasting by. Using standard flood coolant, I still must peck away for the last 1/3rd of finish length to keep from scoring up the rifling with the pilot.

I love to hate the canted rifling barrels too. Yet I've been made into a true believer in that style of rifling by some of our customers experiences (mostly F-Class) with the winning aggregates and a number of world records set. They are getting exceptionally good barrel life too, even with 55-60g of medium slow burning propellant. I find it mind boggling to see those 7mm 180g VLD "stretch-limo" bullets go into .3xx groups at 200 yards! I'm finally ready to try one for myself. It's my understanding that ratchet rifling is dominating the rimfire game too, but I'm not involved in that discipline to personally testify to its value over the standard profiles.

I'm sorry I couldn't be more sociable at the FISS this year. I was sick for the entire week (that was incredibly inconvenient!). I'm also looking forward to the UNL match at the FISS. Unfortunately it's hard to garner up enthusiasim in our region to have rail-gun matches. Next year we'll have a great time!

Hopefully Tennessee Jerry's RV won't break down again, because it's always a rip-roarin' good time with Jeff and Jerry...especially when he brings his trusty special "six-pack". :D

JerrySharrett
07-08-2016, 06:30 AM
Dave,

I also use a carbide 308 reamer. .....


Hopefully Tennessee Jerry's RV won't break down again, because it's always a rip-roarin' good time with Jeff and Jerry...especially when he brings his trusty special "six-pack". :D

Well guys, I hopefully have everything back together. Totals so far is in excess of $10,000, but worth it. I now have a new engine from Ford and all related parts, I hope.

Somewhere, maybe Fairchance, maybe 2017 SS, but we will get Brother Jameson and his 5 other Jamesons and talk some treason!! At least plot against that infernal wind that jerks our bullets crosswise!!


.

skeetlee
07-08-2016, 12:49 PM
I feel like I am offering up a pretty good product these days, but I still appreciate folks like Mike Jerry, dave and greg for sharing your knowledge. thanks fellas!! I still learn new ideas from you guys all the time.. Lee

Zebra13
07-08-2016, 01:37 PM
Justin, was that a Haiku? Tim

Doctor,


What is a Haiku

What are you trying to say

Please explain yourself


You know how us Californians are into poetry and such...

Patchouli Oil is my chambering fluid of choice.


Justin

alinwa
07-08-2016, 09:05 PM
Doctor,


What is a Haiku

What are you trying to say

Please explain yourself


You know how us Californians are into poetry and such...

Patchouli Oil is my chambering fluid of choice.


Justin


wow that's like so good

extemporaneous, so

Californian

Zebra13
07-09-2016, 01:32 AM
wow that's like so good

extemporaneous, so

Californian

Al,


Tim-O M-R-I

Cement contractor form board

To hell with haikus


I thought you might be along. How is that new Heavy 10 working out?

Justin

alinwa
07-09-2016, 03:18 AM
Al,

How is that new Heavy 10 working out?

Justin

It tinkles ;)

Seriously it's a very tight machine and so quiet that it does make tinkling noises when not loaded. Machine marks still on the ways.....I think I'm going to really enjoy the back-gear.

Still setting it up, building the collet racks and oiling system, trying to decide if I should open it up or not, oil goes through cleanly so I probably won't. I look forward to using it but haven't really.

It makes me happy thinking about it even though I'm still doing all my work on the Grizzly.

Zebra13
07-09-2016, 03:22 PM
It tinkles ;)

Seriously it's a very tight machine and so quiet that it does make tinkling noises when not loaded. Machine marks still on the ways.....I think I'm going to really enjoy the back-gear.

Still setting it up, building the collet racks and oiling system, trying to decide if I should open it up or not, oil goes through cleanly so I probably won't. I look forward to using it but haven't really.

It makes me happy thinking about it even though I'm still doing all my work on the Grizzly.

Al,

Cool...glad to hear it's working out. Do you have much gear noise?

Justin

Tim Oltersdorf
07-09-2016, 06:57 PM
A Haiku is a Japanese poem usually consisting of three lines (in its modern form). The last line usually seems dissimilar to the first two in meaning. It is popular with American hipsters. This is probably because 3 lines is the extent of their attention span. Tim

CMaier
07-09-2016, 08:23 PM
three lines..hmmmmmm


A Haiku is a Japanese poem usually consisting of three lines (in its modern form).
The last line usually seems dissimilar to the first two in meaning,It is popular with American hipsters.
This is probably because 3 lines is the extent of their attention span.

Tim

alinwa
07-10-2016, 01:16 AM
A Haiku is a Japanese poem usually consisting of three lines (in its modern form). The last line usually seems dissimilar to the first two in meaning. It is popular with American hipsters. This is probably because 3 lines is the extent of their attention span. Tim


L-O-freaking-L Dr O........me, a hipster......

Furthermore it's typically Americanized to three lines of 5 syllabussess, then 7 syllabusses, then 5 again........

kinda' like posts 35, 36 and 37 ;)

alinwa
07-10-2016, 01:21 AM
Al,

Cool...glad to hear it's working out. Do you have much gear noise?

Justin

No, and the gears are wikikid square, still got broaching grooves on them. running it with the end open is scary :) turning it over by HAND is scary, I about cut myself inspecting the gears.....

Zebra13
07-10-2016, 12:12 PM
No, and the gears are wikikid square, still got broaching grooves on them. running it with the end open is scary :) turning it over by HAND is scary, I about cut myself inspecting the gears.....

Al,

Thanks. I've got a few questions about em', so I'm gonna start a new thread. See ya over there.

Justin

Rubicon Prec.
07-10-2016, 06:06 PM
Dave,

I also use a carbide 308 reamer. I think I've reamed over a hundred chambers with it in the last year, yet it still leaves a finish as if it were new and is spot on dimensionally (verified with gage balls and a Triebel throat gage)...although I'm quite sure I don't really take advantage of its capabilities. I run it at twice the RPM and feed rate over the HSS reamers. We just added a 1000 PSI coolant pump to one of our turning centers, so I'll have to give it a try with that setup and use a higher feed rate and get the chip-load up. I suspect it will give an even better finish, and no chance of picking up swarf around the pilot and scoring up the rifling with the coolant blasting by. Using standard flood coolant, I still must peck away for the last 1/3rd of finish length to keep from scoring up the rifling with the pilot.




Greg, I am curious what speeds and feeds you use on the turning center with carbide. I started at 600 rpm/.008" ipr with a 4 flute carbide and 100 psi of water based coolant through the bore. It cut amazing chambers but was a bit noisier than I liked. I slowed down to 450 rpm and it was dead quiet but seemed like I could still fine tune it at a higher speed. I was taper boring the chamber body .010" under sized as deep as I could reach with the small diameter boring bar. I moved my equipment and haven't gotten the new shop powered back up yet so haven't had any time to experiment. I'm always curious to hear how other people how others are chambering with turning centers.

Greg Walley
07-12-2016, 10:31 AM
Greg, I am curious what speeds and feeds you use on the turning center with carbide. I started at 600 rpm/.008" ipr with a 4 flute carbide and 100 psi of water based coolant through the bore. It cut amazing chambers but was a bit noisier than I liked. I slowed down to 450 rpm and it was dead quiet but seemed like I could still fine tune it at a higher speed. I was taper boring the chamber body .010" under sized as deep as I could reach with the small diameter boring bar. I moved my equipment and haven't gotten the new shop powered back up yet so haven't had any time to experiment. I'm always curious to hear how other people how others are chambering with turning centers.

I haven't used the carbide on the CNC, only on the manual machine. I haven't been confident using the carbide with low pressure water-soluble coolant, I don't like the way the carbide reamer performs with water-soluble coolant, even though it cools more efficiently than cutting oil. I've only used them hand feeding using highly chlorinated light viscosity cutting oil. Apparently the lubricity the cutting oil provides is necessary for the carbide reamer to work properly. I'll try using them on the CNC with the high pressure pump and the appropriate water-soluble coolant that will not break down under high pressure (most aren't made to work under high pressure). I typically run the HSS reamers at 35-40 SFM with 0.001" or so chip load, and 0.004-0.006 IPR. I've run the carbide almost double these parameters. These figures are for 416 SS barrels, yet interestingly enough I don't have to vary them much for CrMo barrels.