WNMG boring bar in a boring head?

S

shott8283

Plastic

Joined

Jun 2, 2012

Location

United States

• Aug 1, 2016

• #1

My boring head for my 40 taper mill has 1" tool capacity. Have a job to bore some axle spindles for an off road shop. The only bar i have that is 1" diameter is a WNMG 432 bar.


Is there anything saying that I shouldnt use that bar in a boring head? Ive never seen it done nor have I tried it.

 

JRIowa

Diamond

Joined

May 27, 2003

Location

Marshalltown, Iowa, USA

• Aug 1, 2016

• #2

I use a 3/4 insert bar in my Critereon head without a problem. Just check to make certain it's cutting on center.
JR

 

S

stephen thomas

Diamond

Joined

Jun 3, 2001

Location

downhill from Twain\'s study outside Elmira, NY

• Aug 1, 2016

• #3

Most of my boring heads have 3/4" holes, but sometimes a 1/2" bar suits better. So I also have some 3/4" OD split sleeves with a SS flat to go in 3/4" holes, bored to take 1/2" & 3/8" bars. You can sleeve the 1" hole down the same way.

Make/bore a steel bushing, put a flat on the OD so the burr from the SS does not cause it to stick, slit it on the bandsaw, and bob is your dad's wife's brother.

Or buy a set of 1" shank bars.

I'[m not fond of neg rake for boring. For small holes, you may have to verify the heel on the insert you propose is not dragging (I don't know)

smt

 

aerodark

Titanium

Joined

Feb 15, 2008

Location

Eugene OR USA

• Aug 1, 2016

• #4

Trying to imagine the futility of a negative rake insert in a boring head.

 

H

Hazzert

Stainless

Joined

Dec 21, 2014

• Aug 1, 2016

• #5

aerodark said:

Trying to imagine the futility of a negative rake insert in a boring head.

Click to expand...

Agreed, I'll toss a CCMT in ours all the time but wouldn't consider using a negative tool.

 

C

CarbideBob

Diamond

Joined

Jan 14, 2007

Location

Flushing/Flint, Michigan

• Aug 1, 2016

• #6

aerodark said:

Trying to imagine the futility of a negative rake insert in a boring head.

Click to expand...

I'm trying.
Yet if you drive a car the holes in the cylinders, con rods, brake cylinders, crank, and cam bores got punched in by guess what?
No way,...... negative inserts, millions of parts with micron tolerances, How can that work, ....it's just wrong.
Welcome to my world where a tenth penny per part in tooling counts big.
Bob

 

M

Mike C.

Diamond

Joined

Nov 25, 2004

Location

Birmingham, AL

• Aug 1, 2016

• #7

Try a positive rake cutter hung way out in a boring head and let me know how that works out...

 

A

adama

Diamond

Joined

Dec 28, 2004

Location

uk

• Aug 2, 2016

• #8

The high positive negative inserts work just fine, i like the HA chip breaker from Korolly in a WNMG. No more a vibration risk than most positive inserts, because, well it is a positive cutting insert! Just in a negative form!

 

S

shott8283

Plastic

Joined

Jun 2, 2012

Location

United States

• Aug 11, 2016

• #9

WNMG in a 3/4 bar 12" out didnt work well.. it wanted a lot of DOC and i wasn't gonna give it. went to a TPG style fat stubby, and had to fumble fu*k around with the knee about 700 times. job done, cash in hand, customer happy.

 

Bobw

Diamond

Joined

Feb 8, 2005

Location

Hatch, NM Chile capital of the WORLD

• Aug 11, 2016

• #10

adama said:

The high positive negative inserts work just fine, i like the HA chip breaker from Korolly in a WNMG. No more a vibration risk than most positive inserts, because, well it is a positive cutting insert! Just in a negative form!

Click to expand...

Exactly.. The material doesn't know or care how the insert is sitting in the holder, it only knows what is tearing through it..

I could only click "like" once... This also seems like a home shop board argument... "But its a negative insert"

Waiting for somebody to say carbide isn't "sharp".

 

Matt_Maguire

Stainless

Joined

Oct 17, 2011

Location

West-Central Illinois, USA

• Aug 12, 2016

• #11

LOL, not to detract from CarbideBob & Bobw’s posts I remember using a 12” Flynn boring head that took 2” bars & had no trouble with the negative geometry… 12” bar had 8” sticking out & could use horsepower pretty well.

Jib crane handling only for that puppy & it was still a pain in the butt. When stuck on a 4 or 5" horizontal spindle with plugging motor or DC injection stop even at moderate RPM’s pushing the stop sounded like a trane crash. Ahhh, the good ‘ol days...

Good luck,
Matt

 

S

shott8283

Plastic

Joined

Jun 2, 2012

Location

United States

• Aug 12, 2016

• #12

Bobw said:

Exactly.. The material doesn't know or care how the insert is sitting in the holder, it only knows what is tearing through it..

I could only click "like" once... This also seems like a home shop board argument... "But its a negative insert"

Waiting for somebody to say carbide isn't "sharp".

Click to expand...

but, it isn't sharp..