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Pete Wass
07-29-2016, 09:51 AM
I have been mulling this subject for the past couple of weeks. I am left with the following thought. When we go to all the work of dialing in a barrel to .000" we then use a disjointed device to ream a straight hole. How can that make sense? There has to be enough running clearance for the pilot bushing to rotate plus, with a ball in the back end pushing, shouldn't the running clearance be projected back to the rear of the reamer and magnified by it's length?

That said, for those who don't bore first, Why go to all the work of indicating the barrel bore in to .000? Why wouldn't, say two or three tenths be ok? If we have potential error and, from my experience, errors compound, it wouldn't seem to me that the bore would be terribly critical, within limits, of course. I realize in practical practice, things all works out in the end or we have to live with what we end up with, at least.

It's just nagging to me that we start with a dead nuts hole then use tools with slop in them.

Has anyone tried the reamer holders that are used on Screw machines and production Lathes?

Pete

CMaier
07-29-2016, 11:56 AM
do not use a bushing,
dial in,
drill
check dial in
pre bore,
check dial in ,
taper bore to match reamer,
insert reamer and cut chamber

Pete Wass
07-29-2016, 12:58 PM
do not use a bushing,
dial in,
drill
check dial in
pre bore,
check dial in ,
taper bore to match reamer,
insert reamer and cut chamber

Personally, I don't want to spend the time you have lain out to cut a simple chamber.

Pete

shortgrass
07-29-2016, 01:43 PM
I have been mulling this subject for the past couple of weeks. I am left with the following thought. When we go to all the work of dialing in a barrel to .000" we then use a disjointed device to ream a straight hole. How can that make sense? There has to be enough running clearance for the pilot bushing to rotate plus, with a ball in the back end pushing, shouldn't the running clearance be projected back to the rear of the reamer and magnified by it's length?

That said, for those who don't bore first, Why go to all the work of indicating the barrel bore in to .000? Why wouldn't, say two or three tenths be ok? If we have potential error and, from my experience, errors compound, it wouldn't seem to me that the bore would be terribly critical, within limits, of course. I realize in practical practice, things all works out in the end or we have to live with what we end up with, at least.

It's just nagging to me that we start with a dead nuts hole then use tools with slop in them.

Has anyone tried the reamer holders that are used on Screw machines and production Lathes?

Pete

Yes, you could make a tool holder like was (is?) used on automatic screw machines. Darned near fool proof if careful thought is given to method(s) used to make one.

JerrySharrett
07-29-2016, 04:36 PM
I have been mulling this subject for the past couple of weeks. I am left with the following thought. When we go to all the work of dialing in a barrel to .000" we then use a disjointed device to ream a straight hole. How can that make sense? There has to be enough running clearance for the pilot bushing to rotate plus, with a ball in the back end pushing, shouldn't the running clearance be projected back to the rear of the reamer and magnified by it's length?


It's just nagging to me that we start with a dead nuts hole then use tools with slop in them.


Pete

Easy Pete, the purpose of the flowing holder is to allow the reamer to self align with the chamber center. Your lathe ,my lathe,or Zippy Poos lathe will have the tailstock out of alignment with the headstock.....period....in just a short time. The last lathe I was the Project Enginerr on was a Monarch 85hp, 60" swing and 228" centres. We sat it on a floating foundation that had 128 yards of concrete. We let the foundation cure the traditional 30 days plus an additional 90 days because of the actual lathe delivery.

We sat it on floating hold downs because the concrete foundation will move, probably forever. We used a laser alignment tool that we use for the large steam turbins in our 4 power generating facilities. I had the techs set the laser head in the spindle bore and the sending device in the tailstock center. Just for kicks we left this in place for a couple of weeks. Each day the techs took readings. Each day the tailstock had moved its alignment in relation with the headstock....

As to automatic screw machines tooling, that is how spark plug housings are made.

IF you ream a chamber with the reamer being held firmly in the tailstock that reamer will cut an oversized chamber body.....period!!


.

coyotechet
07-29-2016, 05:18 PM
Thanks Jerry
Very well said and true. Give me the Floating style reamer holder and a taper bore.

Thanks Chet

Pete Wass
07-29-2016, 06:27 PM
Easy Pete, the purpose of the flowing holder is to allow the reamer to self align with the chamber center. Your lathe ,my lathe,or Zippy Poos lathe will have the tailstock out of alignment with the headstock.....period....in just a short time. The last lathe I was the Project Enginerr on was a Monarch 85hp, 60" swing and 228" centres. We sat it on a floating foundation that had 128 yards of concrete. We let the foundation cure the traditional 30 days plus an additional 90 days because of the actual lathe delivery.

We sat it on floating hold downs because the concrete foundation will move, probably forever. We used a laser alignment tool that we use for the large steam turbins in our 4 power generating facilities. I had the techs set the laser head in the spindle bore and the sending device in the tailstock center. Just for kicks we left this in place for a couple of weeks. Each day the techs took readings. Each day the tailstock had moved its alignment in relation with the headstock....

As to automatic screw machines tooling, that is how spark plug housings are made.

IF you ream a chamber with the reamer being held firmly in the tailstock that reamer will cut an oversized chamber body.....period!!


.

Yeh, Yeah, Yeah,

It seems absurd to me to spend all the time to indicate something to .000 and then use something other than absolute precision for the final step. The reamer holder thing; a friend of mine has a Harding Chucker and he showed me a reamer holder that came with it. Looked pretty dern foolproof to me. It resembled the same kind of floating reamer holder I have seen on Ebay for screw machine tooling.

I have seen someone use their tailstock with a reamer held fast in it. The barrels coming out of it always seem to shoot well. I just wondered who's reamer holder and bushing can hold .000 is all.

Pete

JerrySharrett
07-29-2016, 06:30 PM
Yeh, Yeah, Yeah,

It seems absurd to me to spend all the time to indicate something to .000 and then use something other than absolute precision for the final step. The reamer holder thing; a friend of mine has a Harding Chucker and he showed me a realer holder that came with it. Looked pretty dern foolproof to me. It resembled the same kind of floating reamer holder I have seen on Ebay for screw machine tooling.

I have seen someone use their tailstock with a reamer held fast in it. The barrels coming out of it always seem to shoot well.

Pete

Well, why did you ask if you have the answers?



.

alinwa
07-29-2016, 07:45 PM
There are also folks who believe that having a "stiff, straight reloading press" will help produce straight reloads and that "dropping the ram softly, then do a half turn and bring it down hard" (or some variant thereof....all involving twisting the case in the shellholder) will "make straighter cases"........

There are also tools made for "straightening reloaded rounds" and there are people who use them.

And believe in them.

It's impossible to argue with this sort of logic.

In absolute cold reality adding SLOP and PLAY into the system results in the best sized cases. In reality, if your reloaded rounds ARE NOT COMING OUT DEAD TRUE.....you're doing something wrong. And a "stiffer" or "straighter" press won't "fix it."

In reality, whether you're sizing brass or reaming a chamber you must MAKE stuff straight and true and KEEP it straight and true through the final sizing/reaming step.

I consider brass to be modeling clay and equipment to be as flexible as rubber......

And I cain't measure nuttin' so I gener'ly gage it....


makes life easier.


That, and I can't afford Jerry's or Jackie's million dollar/million pound lathes that are "heavy, stiff and straight," ;) and all they'd do is make it more costly to make stuff crookedy....

But I absolutely CAN make straight cases, and I absolutely CAN chamber a line of barrels to shoot them.....50-100 times each if I want to....on cheepo chicom equipment. I can even make the dies which are the critical component to maintain the tolerances.....


SO, I'll say it again.


The REAL TEST of your setup is not "does it shoot"......... it is "can you do it over and over, day in and day out, barrel after barrel and can you wear out a barrel with only 20 cases?"

And then use these same 20 cases in your next barrel if need be??

And never trim them?

And never anneal (unless you want to...)???

Rubicon Prec.
07-29-2016, 11:23 PM
I just wondered who's reamer holder and bushing can hold .000 is all.

Pete

Mine gets checked regularly and holds better than that.

http://img.photobucket.com/albums/v654/300sniper/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg (http://smg.photobucket.com/user/300sniper/media/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg.html)

CMaier
07-30-2016, 01:48 AM
i cannot comply with pete's spec...'cause i do not use bushings

RJM
07-30-2016, 06:58 AM
i cannot comply with pete's spec...'cause i do not use bushings

Why?
Is it because running a pilot will damage the lands?
Or that the lands run out relative to the grooves?

Nothing snarky, I'm just trying to understand your reasoning.

Regards,
Ron

CMaier
07-30-2016, 10:05 AM
Go read the upper post.
Taper bored, reamer follows it
No need to have a bushing trying to move
the reamer from the path i cut.
Bores are not straight.

Pete Wass
07-30-2016, 12:31 PM
Well, why did you ask if you have the answers?



.

Discussion is something that is tough to achieve on these forums. Lots of people have THE answer but very few will enter into an open discussion with discussion in mind. What I was looking for here was something to change my mind and I have yet to see it. Probably I should simply stay off here considering the situation. I'm never offended when someone does not agree with me or questions what I think to be true. I don't see much of that here. What I was looking for is for someone to explain away the potential for error in the question I asked. What I got was several methods of doing the job yet we are left with the bushing and the pusher, which I think many folks use solely.

Pete

skeetlee
07-30-2016, 01:13 PM
Without the bushing, you are going to have more reamer flex. If your sure your set up is nice and true, why not use it??? Ill keep on using mine!! Actually its silly not to. Lee

Pete Wass
07-30-2016, 01:31 PM
Mine gets checked regularly and holds better than that.

http://img.photobucket.com/albums/v654/300sniper/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg (http://smg.photobucket.com/user/300sniper/media/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg.html)

This looks like what I imagine a CNC setup looks like?

Pete

CMaier
07-30-2016, 01:53 PM
imho,
just the opposite.
the reamer is following the taper bore. straight true no stress.
the bushing will try to follow the bore..which is not straight, creating stress and
attempting to pull the reamer off the intended path.


Without the bushing, you are going to have more reamer flex. If your sure your set up is nice and true, why not use it??? Ill keep on using mine!! Actually its silly not to. Lee

coyotechet
07-30-2016, 03:18 PM
What I like about chambering thru the head stock using the cats head:
And why I fill most comfortable using a fitted bushing after indicating two points in the bore then taper bore indicated off the reamer using the tailstock and compound to the nearest .0001.
(How do I know for sure the reamer chucked up in the tail stock is square to the spline bore?)
P.S. I have checked my tail stock every way possible that I know of to be true to the spline bore, but then there is the mores taper and chuck that can be off.

No matter if I chuck the reamer up tight in tailstock or use a pusher or floater holder. I want the reamer to start straight with the two points that I indicated. Without the use of a bushing how do I KNOW FOR SURE the reamer is going to start straight if it only has one contact point ( that being a the very base of the chamber.) I know the reamer SHOULD FOLLOW the tapered bore. But then is my tail stock 100% true to the spline bore is the pusher 100% square the floater is just going to follow how it is started. I fill that starting the reamer with the same two contact points that I had indicated in early is the most surest way of staring the reamer straight and then it will follow the taper bored chamber with the fitted bushing help. What happens between the two indicated points is removed by the prebore. Thatís why I personally like the floater and using the fitted busting. Tried quite a few other ways and this is what giveís me the best results, so myself I am staying with the floater and fitted bushing.

Chet

CMaier
07-30-2016, 03:55 PM
But your second "point" is just that..a single point.
Once you advance the reamer, the bushing is trying to follow the bore,
which we all know is not straight.
The bushing tries to follow the worm hole we call a bore, putting stress on the tapered portion .

Again just my 2 cents worth, spend it well.


If you start with the bushing for 1/4" or so, then go reamer fit in the
taper, it might be better/less stress.
As Pete says, it a conversation of ideas and opinions.


What I like about chambering thru the head stock using the cats head:
And why I fill most comfortable using a fitted bushing after indicating two points in the bore then taper bore indicated off the reamer using the tailstock and compound to the nearest .0001.
(How do I know for sure the reamer chucked up in the tail stock is square to the spline bore?)
P.S. I have checked my tail stock every way possible that I know of to be true to the spline bore, but then there is the mores taper and chuck that can be off.

No matter if I chuck the reamer up tight in tailstock or use a pusher or floater holder. I want the reamer to start straight with the two points that I indicated. Without the use of a bushing how do I KNOW FOR SURE the reamer is going to start straight if it only has one contact point ( that being a the very base of the chamber.) I know the reamer SHOULD FOLLOW the tapered bore. But then is my tail stock 100% true to the spline bore is the pusher 100% square the floater is just going to follow how it is started. I fill that starting the reamer with the same two contact points that I had indicated in early is the most surest way of staring the reamer straight and then it will follow the taper bored chamber with the fitted bushing help. What happens between the two indicated points is removed by the prebore. Thatís why I personally like the floater and using the fitted busting. Tried quite a few other ways and this is what giveís me the best results, so myself I am staying with the floater and fitted bushing.

Chet

Richard
07-30-2016, 07:32 PM
to no bushing is if you use oil through the bbl. Alot more oil goes by the reamer and keeps the chips flushed out.
I can finish the chamber in two "passes" with the reamer doing it this way. If every thing is dialed in perfectly I have seen no difference between bushing vs no bushing. Looking through the the bore scope both methods work equally well.

Richard

Curious
07-30-2016, 08:10 PM
imho,
just the opposite.
the reamer is following the taper bore. straight true no stress.
the bushing will try to follow the bore..which is not straight, creating stress and
attempting to pull the reamer off the intended path.


to no bushing is if you use oil through the bbl. Alot more oil goes by the reamer and keeps the chips flushed out.
I can finish the chamber in two "passes" with the reamer doing it this way. If every thing is dialed in perfectly I have seen no difference between bushing vs no bushing. Looking through the the bore scope both methods work equally well.

Richard

Can I ask if you have successfully chambered 5 grove barrels using a 6 flute reamer without the bushing?

If so what do you consider success in terms of TIR at the throat and chamber mouth?

In theory I agree that if your pre-bore is true and you get the reamer in half way you should have enough contact area to keep everything straight without the bush but so far Ive never had the confidence or spare piece of barrel to try it out myself.

Richard
07-30-2016, 08:43 PM
is 4 and 6 groove, so I can't help with 5 groove bbl's. TIR on the 4 and 6 run from nothing to .0002

Richard

Tim Singleton
07-30-2016, 08:57 PM
is 4 and 6 groove, so I can't help with 5 groove bbl's. TIR on the 4 and 6 run from nothing to .0002

Richard

When you say tir is nothin to .0002 this is reading what and where? Just the chamber itself ?
or neck to aft of chamber? Or throat to aft of chamber?

RJM
07-31-2016, 08:23 AM
to no bushing is if you use oil through the bbl. Alot more oil goes by the reamer and keeps the chips flushed out.
I can finish the chamber in two "passes" with the reamer doing it this way. If every thing is dialed in perfectly I have seen no difference between bushing vs no bushing. Looking through the the bore scope both methods work equally well.

Richard

That's a clear explanation of one reason for "no bushing". However, I have no oil flush but I do use a lot of oil & clean chips frequently.

Why I don't understand the "no bore is straight, so don't use a pilot" argument is simple:

The pilot is maybe 1/8" ahead of the throating portion of the reamer. How much can a match grade barrel run out in that 1/8"?

The pilot, at the closest, is .0002-.0004 smaller than the lands, and the pilot runs on a oil film the lands that takes .0001-.0002 of that space. So the reamer is following the lands pretty true to the lands at the throat, which is the goal of a good chamber.

No doubt you can do a good job either way, but I'll still use a pilot every time until I get an explanation that convinces me otherwise.

Regards,
Ron

CMaier
07-31-2016, 09:34 AM
no,
it depends on how much material is removed behind the throat.
it all influences the stress on the reamer.
some of the posts say get a 1/2 of taper reamer fit....that leaves about
an inch of reaming on the bushing BEFORE the throat
if you pre-bore as close as jackie does, it is a non-issue,
but starting 1/2 into a 1 1/2" chamber is plenty of room for stress.

again just an opinion form my collection of pennies




The pilot is maybe 1/8" ahead of the throating portion of the reamer. How much can a match grade barrel run out in that 1/8"?

The pilot, at the closest, is .0002-.0004 smaller than the lands, and the pilot runs on a oil film the lands that takes .0001-.0002 of that space. So the reamer is following the lands pretty true to the lands at the throat, which is the goal of a good chamber.
Ron

Curious
07-31-2016, 10:51 AM
I guess the indicator is the judge here and rather than opinions we should be able to deal in facts, surely this same principle would also separate out the different chambering methods?.

coyotechet
07-31-2016, 11:15 AM
Need to make my ealier post a little more clear about why I use the bushing and starting the reamer.

All of my chambers are first drilled then taper bored to within .004 to 008 (some Less) wall thickness and as close to the shoulder as I fill comfortable .025 to .050. No matter if 6PPC or 338 Laupa Mag. The reason I say Ĺ inch is when talking about 6PPC, that is the least amount the reamer with a fitted bushing can be started at and make contact with both pre-indicated points. As said earlier ever since I have been using the PTG floater and a close fitted bushing all of my cut chambers (6PPC to 338 Laupa) have TIR of .0001 or less at the base. :rolleyes:

Base TIR checked with a .0001 Brown&Sharpe 7023-3, Mitutoyo 503-504, and Interapid 312-3
Neck throat TIR or as far as I can reach with a Interapid 312-15, Mitutoyo 513-512, and Brown&Sharpe which are all long needle reading at .0005 can see Very little or no movement of the needle.
Way less than .0005.:rolleyes::rolleyes:
Chet

alinwa
07-31-2016, 12:05 PM
From someone who actually DOES this............

The reason we do it this way is to avoid the reamer pilot following and wallowing in "runout ahead of the throat."

That area, from the ogive FORWARD about an inch is specifically the area which is dialed into alignment. From this parallel section, the metal behind it is bored/single-pointed away and the area ahead of it is allowed to run wild.

The way I do it, the pilot enters the bore just before the reamer starts to cut and it's only function is to eliminate chatter generated (IMO) be reamer wrapup. It doesn't "guide" anything nor does it make any marks of any sort.

It works well.

It's repeatable,

and since the amount of barrel runout is generally many times greater than the resolution of the measuring method it becomes an elementary matter to point the barrel wherever you want.

My method is to bring things into a straight-back track with a small muzzle-upward bias.

coyotechet
07-31-2016, 12:42 PM
One last remark as to using the bushing. I have and do check each bore in front of the throat where the bushing is on the reamer with a Hawkeye bore scope and have never seen any kind of a mark indicating that the bushing might be touching the barrels bore. Like a good South Bend heavy 10 spindle bearing it lets the spindle float under a load with a fine film of oil and I believe that is what is happening with the piloted reamer bushing riding on a light film of oil.
Just my point of view. :rolleyes::rolleyes:
Chet

alinwa
07-31-2016, 12:52 PM
One last remark as to using the bushing. I have and do check each bore in front of the throat where the bushing is on the reamer with a Hawkeye bore scope and have never seen any kind of a mark indicating that the bushing might be touching the barrels bore. Like a good South Bend heavy 10 spindle bearing it lets the spindle float under a load with a fine film of oil and I believe that is what is happening with the piloted reamer bushing riding on a light film of oil.
Just my point of view. :rolleyes::rolleyes:
Chet

I've never found any marks either, since I got my Hawkeye about 6yrs ago.....which is AFTER I started using my current method. I went to this method because of chatter I've experienced in the past. With my current method chatter is just a distant memory, as are scratches/ridges/rollups/burrs/eccentricities in the throat/leade area.

In other words...."I couldn't agree more" :)

jackie schmidt
07-31-2016, 01:05 PM
If posters review my thoughts on this subject, I have presented a way to check your work. This is standard practice in machine shops every day.

The customer demands that you have a verified method of checking, and verifying your work. Always be aware that a flawed testing method will produce flawed results.

I have also stated that when presented with an imperfect part in the beginning, (in this case, the straightness of a barrels ID with its self), then you are automatically faced with a compromise. How you deal with this compromise determines the final outcome.

As a professional, (how's that for a high fallutin term :cool:), I have to deal with these problems every day as varied jobs com through the door. It is sometimes difficult to discuss these things with those with limited knowledge of what I call "basic machine shop practice".

Always be cognizant of what you are trying to achieve. Develop a set up that allows you to reach this goal with the machinery you have on hand. And always remember that is just as important, perhaps more important, to be aware as to WHY you do things a certain way as well as knowing HOW to do things.

alinwa
08-01-2016, 04:53 PM
I just wondered who's reamer holder and bushing can hold .000 is all.

Pete





Mine gets checked regularly and holds better than that.

http://img.photobucket.com/albums/v654/300sniper/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg (http://smg.photobucket.com/user/300sniper/media/cnc/B4B8DA12-C4D9-409E-A20F-56A282D6EA5E_zpsjmzcnphq.jpg.html)

Man.... some day I'ma' get me some equipment that holds better than .000

but UNTIL THEN.....I'll jus' keep fightin' fer center....