help boring 4.575 diameter

[rich]

hi everyone,

here is the problem. i have to bore a hole 4.575 +.0005/-0.0 dia thru hole 16.0 long. in 4140 and i have 30 parts to do. i'm running these parts on a niigata hn50c. the rough dia is now at approx 4.23 i'm looking for some input on a good way to rough this hole and how much to leave for a finish pass. and some feed and speed imput for finishing with a kaiser twin boring head mounted to a simultaneous fit bar 17.0 long .

[Tony]

Do you have access to a dial bore gauge?

[rich]

i hope there is somebody that can think of something better then "do you have a dial bore gage" do you always respond to topics just to see yourself talk or maybe you just don't have anything better to do. the last thing i wan't to see is a dumb response to a ? that i post or anybody else might post. hopefully the next post is more helpful!!!

[Philcott]

Rich,

 

I won't be able to help you with your boring problem as I don't know what kind of machine a niigata hn50c is (I would hazard to guess a horizontal mill??), but I can probably give you some friendly advice on trying to get help in this forum. Sometimes a forum member needs to ask what may seem to you "is a dumb response" because they need to get a better idea what you have at your disposal to allow you to do the job complete. To get results in here you need to come in with your hand outstretched not your middle finger pointed up toward the sky. There are an incredible number of folks in here that will help you if they can.

 

What is with this statement?? "do you always respond to topics just to see yourself talk." Cheer up man have a beer.

 

Good luck in here,

Phil

[Tony]

You can't cut -.0005 / + nothing

Without being able to check size's

[mark l]

Philcott is right there a lot of people in here that can help you a lot if you ask the right way, I don't post that much but I do read almost every post becouse of any help it may be in the future. but just as much help I see I also see a lot of snubing and most of the time it is rightfully so.

Mastercam is a very good program but no matter how smart you are you can't learn it on your own, you will always have a question, and now you have just pissed off anyone that will help you FOR FREE.

[Jack Mitchell]

rich,

 

Leave .03" for finishing; If you’re a little nervous then this is a good thing - if you leave .03" then take one finish pass at .01", learn form the result, take another finish pass at .01" learn from the result; you still have .01" left to size the part.

I usually leave .01~.015 for one finish pass only given your bore size - When unsure about rigidity or sizing issues we usually split the difference into two passes - the first one is the learning pass or for lack of the better term "the nervous pass".

 

I know that the insert manufactures recommend a minimal cut of the tool nose radius itself but that’s another storey – they sell tools based upon theoretic – we machine metal based upon reality and results.

 

The learning curve is going to be long for the first and second piece ~ from there you will gain a feel. (Scrapping one of the parts is truly excellent, but only if you learn something from it). (If the supervisor complains about the cost of scrapping a part then offer him the opportunity to show you how to do this). Difficult tasks will always build character.

 

At 16" my concern would be insert wear and how to deal with the sizing issue once the wear factor begins.

 

Niigata is fairly popular around the Toronto area and an excellent horizontal machine tool as well; although a 16" bore would task most of us, you can do this as well as anybody else in here.

 

By the way, Tony always gives very short one liner responses – I believe this to be his way of extracting more information from the source question.

 

Regards, Jack

[Trevor Bailey]

Frm being a long time memeber and knowing Tony thru the forum, I bet if you just answer his simple question, he probably has much more advise to give. Nobody in here is going to be able to give you the golden answer right away.

 

I think all of us has wanted an answer right away at some time or another. I understand your job is either "hot" or getting very frustrating at the thought of boring a part so deep. Bare with the replies you get and inevitably you will get more help than you could imagine. This is one of the greatest places you will ever find to get and share knowledge.

 

It sounds to me that you have the right tools to get the job complete. There are a few different ways that come to my mind to get it done. My question to you is, is the part finshed on the OD already? If not, you are in pretty good shape. Rought the part from both ends. If you machine runs true enough, you will be able to finish the same way. You may want to leave some stock on the ID anyway and then send the part out to have the finished diameter ground being it has such a tight tolerance. If you are able to do this, finishing the OD is no problem. Once ground, you could put the part back on your machine with live centers on both ends to finish the OD. That would ensure a tight TIR.

 

As far as inserts go, I have always had pretty good luck Sandviks 4025 grade.

 

Hope this helps and please keep us posted.

[Jack Mitchell]

rich,

 

I my haste I responded as if you’re using a 1/64th insert; Given the size of the bore I would expect a 1/32nd or 3/64ths finish insert size; if this is the case then double my previous recommendation. IE .06” then .02, .02, .02!

 

A dual insert roughing bar does a great job – finish the size with a single insert only please, even if you need to remove the insert from one side for finishing; If you have a boring bar that is 17” long with a 4” diameter then I actually envy the opportunity to play with such big tools.

 

Regards, Jack

[Jack Mitchell]

It just has to be a pump housing - am I close?

 

Regards, Jack

[Finecut]

A VTL would be perfect for this

Jack is right, it sound like the best way to go

This is a learning experince, stay focused. You can do it

A dial bore gage is needed. You have to find the sweet spot, RPM, Feed, depth of cut for the best finish

 

Finecut

[Catman]

Hi Rich,

 

I am doing a lot of boring of 2"--4" dia (+-0.001)on mild steel. From my experience it's very difficlut and expensive to hold that tolerance (+0.0005-0) to use a twin boring head as a finisher. In my opinion you have to grind them to the required tolerance after machining.

[tfb2000]

jack, this is the kind of help i came to this forum looking for. i was also concerned abut the wear factor. i did not know if a heavier cut then .01 would be in order because of the length of cut. i've been thinking about this for a little while and i would like to run something by the forum to see if it's a good idea. since there is about .170 on a side to be removed i thought i could rough within .025 a side with a 3.0 dia. seco z axis plunge cutter from both ends. then take a semirough boring head thru the bore from both ends to clean up the scallops from the plunge mill leaving .01-.015 as jack said. the finish bore tool is 17.0 long and there is no changing that so i thought i might as well try to finish in one pass without rotating the part. so i don't have to deal with a mismatch problem.

 

trevor, the part has 2.0 wide legs that were cut out to capture 180 deg of the od of the tube then welded on so that it stands up about 4.0 off the table. when i say stands up the tube is still horizontal. i have to mill a flat on the top and mill a 1.25 and a 1.0 slot thru to the thru bore and put some tapped holes in the part also. so the o.d. is not critical. to answer phils earlier ? the machine is a horizontal mill 50 taper.

 

as for tony's one-liner and not to fuel the fire anymore but how else did he suppose someone is going to check a bore like this . i read and chime in on the forum and i know what a valuable tool it is and i do appreciate everyones imput. and if you read my first ? i certainly didn't ask the ? or for anyones help holding my middle finger in the air.

thanks for your responses and i will keep you posted.

[tfb2000]

thanks for the replies i just finished a reply that was pretty long but can't resist replying again. jack the part is an actual machine, that has a bridgeport style head sort a speak with a 5000 rpm spindle and 8.0 of moving spindle stroke. and it is for finishing ends of tubing.

i only have 1/32 inserts but have no problem buying the right tool for the job. i was actually thinking i should use both inserts in the cutter i have had awesome luck boring holes this way in the past but that doesn't mean it will work this time. i use tons of kaiser boring tools. kaiser is to boring as komet is to drilling in my opinion. this new simultaneous fit boring bar is a new one i just bought and the ? always comes up how much so i'll tell you now 3,800 and i'm real excited to use it. i thought i would try it because the bar and head are 55lbs. and i thought having the tool holder actually making face contact w the spindle would add the little extra rigidity to get me through this job. thanks again rich

[Trevor Bailey]

Even with that bar you have and if you still want to finish from one end, I would leave more stock on the walls so the insert can stay buried. That would leave less chance for chatter and a smooth finish.

 

If you get a chance and are allowed to, post some pictures so that we can see what is going on. This sounds like and interesing job and I would like to see your tooling.

 

Good luck,

[Kevangel]

If you have trouble holding bore size all the way through, I would buy a portable hone from Sunnen Products in St. Louis,Mo. They have various sizes and styles(prices), some for use in a machine tool and some for a hand drill. Located in back of sunnen catalog if you have one. Speaking in generalities, I have had better luck holding tight tol. with smaller radius on inserts or boring bar.i.e. .007R works better than .o15R for holding size, but you trade some strenght for that. A simple 45 degree angle "dubbed" on the end of a boring bar works well for holding size and is strong. Do not know what that will do for an insert. On long bores(tight tol.) I have had better luck using cutting oil VS. coolant.Little things can add up to make a difference.

[Andy]

That tolerance in that length and bore: Definitely honing is the way.

That would be the automatic response if we were doing the job. Less headaches!!!

[Elad]

Who is that rich that attacking Tony???????

I wonder if he is illegel Mastercam user!

Forget my help untill i hear an apologize

[Fig sign]

Hey , man ,you must apologize!

 

And THERE ARE NO DUMB ANSWERS!

 

From the other side, Elad !

It is not fair to say somebody is illegal only because you don`t like his behavior.

[Elad]

Yes I know,Alex.

But with 6 posts,this rich attacking?????

What did he do for other forum members.

I say we should ignore him untill he apologize!

How will he feel if in his next question i'll will post him this answer :

"what a stupid question,go to a course before wasting our time"

[Fig sign]

quote:

---

How will he feel if in his next question i'll will post him this answer :

"what a stupid question,go to a course before wasting our time"

---

Beeng in real life not a very polite person and having once a nickname "rude" for my dirty language I anyway try my best and think that we must be a gentleman.

A gentleman wil ALWAYS speak with everybody like

with a gentlemen .

And come on - attack somebody ,respond in the same manner - it is not for me.

We all work hard in real life and everybody has nerves.

So for me apologize it`s enough.

quote:

---

But with 6 posts

---

We are the brotherhood of crazy cnc fellows ,no matter what the man`s contribution,race or experience ,why not to help somebody?

 

Mastercam is fun =>Life is fun ==>Mastercam is life

[Elad]

Amen

[Tony]

It's alright guy's....

I read the question/post

And thought "This is some 19 yearold kid

who was left to cut this impossible job

all by himself and was scrambling to

pull it off"

That was my mistake by assuming that.

I was trying to drag more information

out of him.(Didnt happen)

 

I have cut 4.000 I.D. through 24" ( In 1988)

They were "Necking stations" for National Can.

I finished them in A Large capacity

sunnen Hone Machine

The machine cut with WHALE OIL!!!

 

[ 01-12-2003, 01:35 PM: Message edited by: Tony ]

[tfb2000]

hi everyone,

this is "RICH", i logged on as different user because i did not remember my password and i'm using a computer outside work and i felt i needed to respond to what my statement has created. first of all i do apologize to TONY for what i said eariler. it seemed to me at the time that he responded to the orignal ? as if it was a dumb ? i don't know tony anymore then he knows me and i know that typing on a computer without seeing a persons facial expressions leave a-lot of what a person is actually trying to get across up to the imagination? i hope you "tony" can accept my apology

 

"ELAD" for your information our company has 3 liscened seats of mastercam and if you want the sim #'s so you can check it out for yourself i'll be glad to give them to you.

[resjun]

Nasty but funny

quote (don't let your mouth write a check your butt can't cash) not to anyone in mind

 

[ 01-12-2003, 03:08 PM: Message edited by: resjun ]