Opening hole from .215" to .240" ideas

IndGild · Aug 1, 2014

Hello all
I am having some issues with enlarging existing hole.
I use blanks with .215" hole TIR up to .01"
Need to have .245" hole at the end within TIR of .001" +/-.ooo5 on the size

Do not ask me why is hole .215"& TIR..01"

Hole is thru
1.1" long
Od is finished at the same set up
I do not want to throw in what i tried so far

I can only use 2 tools
Better yet 1

Thank you

ewlsey · Aug 1, 2014

Get yourself a 6mm end mill. Plunge as deep as it will reach. Then get a .245 reamer and finish it up.

The end mill takes care of the TIR, the reamers takes care of the size.

If anyone suggests single point boring, I will throw my beer bottle at them :nutter:

grantmorgan51 · Aug 1, 2014

I also would use a .245 reamer. But with an existing hole, i dont know that it would run true enough for the .0005 per side TIR. maybe take a boring nar and bore the .215 to like .230 so that you true up the bore, then run your reamer in taking out the last .015. Thats how I was taught to do it. Good luck

jrmach · Aug 1, 2014

grantmorgan51 said:
I also would use a .245 reamer. But with an existing hole, i dont know that it would run true enough for the .0005 per side TIR. maybe take a boring nar and bore the .215 to like .230 so that you true up the bore, then run your reamer in taking out the last .015. Thats how I was taught to do it. Good luck

Pushing Buttons,ha

Seekins · Aug 2, 2014

I would just start with something that had no hole in it

.

Endmill to straiten, reamer to size

IndGild · Aug 2, 2014

Part with no hole is not an option
I am using 6 mm endmill , problem is part is run in closed chuck with coolant thru , so chips goes back along em, clog it and break EM.
Smaller em is not strong enough.
Basically i use em as a drill to enlarge hole to .236, than mill to .242" than ream .
Need close size to eliminate burr at exit hole from reamer.
I was hoping somebody have some special tool for this, some experience

Or what best endmill would be for this
Would 2 flute be stable, cut well?
Who makes long reach cheep endmills

aerodark · Aug 2, 2014

If you get a stub 2 flute end mill with plenty of shank length, you can (and should) spin grind the shank down to about .02 under the EM cut size. That will help with the chip clearance and shorter flute engagement is also a big plus. Buy a couple extras!

You may need to peck at it and clear the chip periodically in any event..........

If you can afford it:

http://robbjack.com/tools/MFM-204

DMF_TomB · Aug 2, 2014

IndGild said:
Part with no hole is not an option
I am using 6 mm endmill , problem is part is run in closed chuck with coolant thru , so chips goes back along em, clog it and break EM.
Smaller em is not strong enough.
Basically i use em as a drill to enlarge hole to .236, than mill to .242" than ream .
Need close size to eliminate burr at exit hole from reamer.
I was hoping somebody have some special tool for this, some experience

Or what best endmill would be for this
Would 2 flute be stable, cut well?
Who makes long reach cheep endmills

.
drill then use end mill them reamer.
.
every day millions of holes are done this way. i would say figure the 1st year apprentices basics out.
.
of course end mill can circular interpolate so a .1875 dia end mill can make a hole any size you want

Ox · Aug 2, 2014

DMF_TomB said:
.
drill then use end mill them reamer.
.
every day millions of holes are done this way. i would say figure the 1st year apprentices basics out.
.
of course end mill can circular interpolate so a .1875 dia end mill can make a hole any size you want

Or at least he should have learned in the first year to read the whole post before answering eh? :dopeslap:

(Yeah - I'm sure I've been there and gotten in a hurry before too

)
I was thinking the same process untill I read a little further and/or considered what he actually said.
I was pretty sure there was a fly in the ointment somewhere as I know he aint that stoopid.

-------------------

Think Snow Eh!
Ox

DMF_TomB · Aug 2, 2014

IndGild said:
Part with no hole is not an option
I am using 6 mm endmill , problem is part is run in closed chuck with coolant thru , so chips goes back along em, clog it and break EM.
Smaller em is not strong enough.
Basically i use em as a drill to enlarge hole to .236, than mill to .242" than ream .
Need close size to eliminate burr at exit hole from reamer.
I was hoping somebody have some special tool for this, some experience

Or what best endmill would be for this
Would 2 flute be stable, cut well?
Who makes long reach cheep endmills

.
go part way in with end mill circular interpolate size you want then pull out of hole
.
then go in further depth and repeat.
.
you can do this as many times as needed to get diameter and depth. again i would say figure the 1st year apprentices basic out

Ox · Aug 2, 2014

BTW - he's in a lathe.... :popcorn:

Again - a first yr apprentice should have been able to understand that as he said "OD done at the same time".

-------------------

Think Snow Eh!
Ox

John Welden · Aug 2, 2014

Why don't you just make the parts out of solid stock and quit messing around?

DMF_TomB · Aug 2, 2014

Ox said:
BTW - he's in a lathe....

Again - a first yr apprentice should have been able to understand that as he said "OD done at the same time".

-------------------

Think Snow Eh!
Ox

.
on a lathe i would use a end mill as a boring bar if i did not have a real boring bar. using end mill i would peck drill (the endmill) or pull out if too many chips.
.
on a lathe i would use a short screw machine length drill bit they tend to not wander out of position much
.
still think it is a 1st year apprentice thing. duh i use end mill and it breaks from too many chips !!!
.
just saying the questions people ask, i am machining steel what rpm i use?? give me a break. sink or swim ? just saying how long should a apprentice be given every little answer. sometimes better to tell them figure it out.

IndGild · Aug 2, 2014

DMF_TomB said:
.
drill then use end mill them reamer.
.
every day millions of holes are done this way. i would say figure the 1st year apprentices basics out.
.
of course end mill can circular interpolate so a .1875 dia end mill can make a hole any size you want

Ammm
Let me respond

I get parts with .215 hole and .01" tir
So drill goes out , since it will follow .01 tir or chip out

As i mentioned before .187" EM is week , hole is 1.1 long, mill deflects and break

My problem is actually i need to make million holes. So far i made 50000 but i do not like it. It is not reliable
Um... i need to do it as quick as possible...no time to play

Why you need to sound smart.
Al i was asking is hey is there something magical, which i never heard of.
All so far mentioned is tried and not good enough

Just to clear it for you i am not using drill press for this job

I was hoping for something similar to this
ISCAR Cutting Tools - Metal Working Tools - PICCO-MF

jrmach · Aug 2, 2014

"My problem is actually i need to make million holes. "

Send to China

TDegenhart · Aug 2, 2014

"Hole is thru
1.1" long
Od is finished at the same set up"

I am a little confused. Is this a bushing or similar that you have to machine both the inside and outside at the same time or setup?

Assuming that the operations can be on separate machines, I would first do the ID on a vertical mill, using a nest to clamp the part. There would be a drill bushing to guide a stepped reamer to open and size the hole. The fixture is open at the bottom for chip evacuation and I would use a left hand spiral reamer.

Move the part to a lathe with a power expanding arbor and finish the OD.

This is two handling's I know, but I don't see how you can avoid that.

Tom

aerodark · Aug 2, 2014

One tool? Magical thing called solid carbide boring bar. Micro 100 is my fave..............

I am far outa range ewlsey, and I throw carbide end mills in retaliation!

dstryr · Aug 2, 2014

.236 2fl endmill and then a reamer. Should be a piece of cake. What material?
Get a 2fl with as short as possible flute length and then neck relieve it.

ewlsey · Aug 2, 2014

aerodark said:
One tool? Magical thing called solid carbide boring bar. Micro 100 is my fave..............

I am far outa range ewlsey, and I throw carbide end mills in retaliation!

Please post a video of this operation.

:popcorn:

dstryr · Aug 2, 2014

ewlsey said:
Please post a video of this operation.

Its doable? I just wouldn't use it for a production run.... I have a lot of SCT bars with 1" reach and .235 mininum bore.

Opening hole from .215" to .240" ideas

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