Go Back OFN Forums > Shop and Tool Talk > Metal Forming Tools

Metal Forming Tools Air Shaping and Planishing Hammers, English Wheels, Shrinking/Stretching Machine, Metal Formers, Bead Forming Machines, Sheet Metal Brakes


Metal Forming Tools Air Shaping and Planishing Hammers, English Wheels, Shrinking/Stretching Machine, Metal Formers, Bead Forming Machines, Sheet Metal Brakes

Reply
 
Thread Tools
  #1  
Old 03-28-2010, 04:08 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
How to use a lathe cut off tool?

I ahve a tool similar to thsi for my lathe:



I readily admit that I am at the very beginning stages of learning to use my lathe properly. I teach myself as I go basically.

But I have been totally unable to figure out how the hell to get this tool to work properly.

I know you spin it REAL SLOW. But even on my lathe's slowest speed (45rpm) it just seems to overheat and wear. half the time the material just cuts the cutter and not vice-versa like it should.

I know you feed it slow. But to feed it slow enough to where it doesn't make a rucous and overheat it would take me like 30 minutes to get through a piece of 1" bar.

Not to mention that the final result of the cut is terrible quality, bad enought o where I would be better off just pulling the piece out, cutting it with a bandsaw, and putting it back in to finish.

I've tried spinning it fast, anywhere from 90 - 1800rpm and to be honest I get about the same results no matter what speed I go with.

Is there some trick I am missing?

J. J.

Last edited by patooyee; 03-28-2010 at 04:22 PM.
Reply With Quote
  #2  
Old 03-28-2010, 04:45 PM
TheBandit's Avatar
TheBandit TheBandit is offline
Theoretical Fabricator
 
Join Date: Jan 2006
Location: Oxnard CA
Posts: 3,444
What material are you cutting?
Do you have a proper edge on your parting tool?
Do you have the height of the tool adjusted to centerline or just below?
Usually when using a parting tool I get a pretty nice chip that forms like a spiral wound clock spring. What does your chip look like?

Snap a picture from the side of your parting tool edge. That may help diagnose the cutting problem.
__________________
Clint
Cancer Survivor Since 10/06 - Hear me speak: https://www.youtube.com/watch?v=LUDZ-gMfiAU
Reply With Quote
  #3  
Old 03-28-2010, 05:10 PM
MeanMike's Avatar
MeanMike MeanMike is offline
Master Fabricator
 
Join Date: May 2008
Location: Hendersonville, TN
Posts: 143
I've never had good luck with HSS parting tools in anything other than plastic and aluminum. If your going to use one, get one with a carbide tip. There is a lot of cutting edge working on a cut-off tool even when they are setup square. More so if they are cutting on a side. All three edges need plenty of relief or you'll gall/ work harden the material and make the cutting load worse. Your lathe also need to be pretty rigid to use one.

I only use mine for cutting off stock less than 1" OD. Any thicker than that and I cut a groove and put it in the bandsaw.
Reply With Quote
  #4  
Old 03-28-2010, 05:16 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
I've tried steel and aluminum. Both suck.

I've tried both centered and slightly below. No difference.

I don't know what a "proper" edge is but I've basically duplicated the angle that it came with every time I've sharpened it.

I definitely don't get a spiral wound chip. More like shavings.

J. J.
Reply With Quote
  #5  
Old 03-28-2010, 07:01 PM
CAPTAIN CNC's Avatar
CAPTAIN CNC CAPTAIN CNC is offline
Master Fabricator
 
Join Date: Mar 2008
Posts: 1,266
Quote:
Originally Posted by TheBandit View Post
What material are you cutting?
Do you have a proper edge on your parting tool?
Do you have the height of the tool adjusted to centerline or just below?
Usually when using a parting tool I get a pretty nice chip that forms like a spiral wound clock spring. What does your chip look like?

Snap a picture from the side of your parting tool edge. That may help diagnose the cutting problem.
Quote:
Originally Posted by patooyee View Post
I've tried steel and aluminum. Both suck.

I've tried both centered and slightly below. No difference.

I don't know what a "proper" edge is but I've basically duplicated the angle that it came with every time I've sharpened it.

I definitely don't get a spiral wound chip. More like shavings.

J. J.
You need to feed it harder and continuous to get the chipform he is speaking of.
Reply With Quote
  #6  
Old 03-28-2010, 07:17 PM
Domino2205's Avatar
Domino2205 Domino2205 is offline
Master Fabricator
 
Join Date: Jun 2009
Location: SW Washington
Posts: 226
nice question and me to

Dave
Reply With Quote
  #7  
Old 03-28-2010, 07:58 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
I have tried setting it on my auto-feed at the slowest rate on the slowest spindle speed and at first is starts out OK, albeit no spirals, still just chips, and eventually the feed rate becomes too fast and it starts chattering and then collides causing terrible carnage. Thus, I can not feed it any slower and that is the most constant feed method I know of ...

J. J.
Reply With Quote
  #8  
Old 03-28-2010, 08:50 PM
TitanFab's Avatar
TitanFab TitanFab is offline
Master Fabricator
 
Join Date: Nov 2006
Location: Prattville AL
Posts: 623
Couple things,
Tool set slightly below centerline.(I mean Slightly)
Sharpent tool, HSS needs to be sharp.
Run some coolant (use a 16 oz bottle and poke a hole in the cap squirt it on it as its cutting.(gotta keep it cool)
Constant feed pressure.( I do not use the auto feed)
I use my parting tool, Carbide at 250.
Hope this help. Money well spent buying a indexable cut off tool. MSC usually runs them at @ 120$ for the kit
Reply With Quote
  #9  
Old 03-28-2010, 09:26 PM
jackalope's Avatar
jackalope jackalope is offline
Master Fabricator
 
Join Date: Aug 2004
Location: St. Peters, MO near St. Louis
Posts: 1,384
As mentioned, have a very sharp edge. If you look down at it from above there should be a very minimal angle as to start a small point into the work. Basically don't want it perfectly flat across.

Feed pressure is where it is at. If you allow the cutter to simply rub the piece you are turning, you will dull the edge instantly. Once you are at the work, feed it in and keep the coolant flowing. Just keep good constant pressure on the tool.

It will work.

Grant
Reply With Quote
  #10  
Old 03-28-2010, 09:33 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
Quote:
Originally Posted by jackalope View Post
As mentioned, have a very sharp edge. If you look down at it from above there should be a very minimal angle as to start a small point into the work. Basically don't want it perfectly flat across.
That could be it. Mine is flat accross, came that way so I never figured it needed to be any different. I will also try raising the tool slightly.

J. J.
Reply With Quote
  #11  
Old 03-28-2010, 09:34 PM
CAPTAIN CNC's Avatar
CAPTAIN CNC CAPTAIN CNC is offline
Master Fabricator
 
Join Date: Mar 2008
Posts: 1,266
Quote:
Originally Posted by patooyee View Post
I have tried setting it on my auto-feed at the slowest rate on the slowest spindle speed and at first is starts out OK, albeit no spirals, still just chips, and eventually the feed rate becomes too fast and it starts chattering and then collides causing terrible carnage. Thus, I can not feed it any slower and that is the most constant feed method I know of ...

J. J.
Not slower, Harder (faster). Feeding harder will reduce/eliminate the chatter also. You've got to feed hard enough that the cut edge gets below the surface (think per revolution) to get the spiral chip mentioned.

Dont use autofeed. You're basically reducing the surface speed while the chipload stays the same as the tool gets closer to cutting off. Feed it by hand as Titanfab said. Ya wanna keep a constant "feed pressure" just as he said too.
Reply With Quote
  #12  
Old 03-28-2010, 09:38 PM
entropy's Avatar
entropy entropy is offline
This space for rent.
 
Join Date: Sep 2007
Location: ~40Miles from the center of Oregon
Posts: 7,394
Basic tip.
Use Cutting OIL not water-sol for manual cutting.
For steel a heavy sulfur or Moly-Dee. Optional would be Tapmatic Gold.
Make sure you have enough relief angle but not to much and as mentioned are on Ctr. to 0.015'ish below. Steel should be running at 80SFPM or so and it completely depends.
Are you running a good quality tool and not something from HF...
Always but Cobalt HSS when buying blanks.
__________________
“No matter what people tell you, words and ideas can change the world.” RW
Reply With Quote
  #13  
Old 03-28-2010, 10:20 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
I dont' recall what brand it is. I want to say Aurora? I got it from KBC Tools.

J. J.
Reply With Quote
  #14  
Old 03-28-2010, 11:17 PM
entropy's Avatar
entropy entropy is offline
This space for rent.
 
Join Date: Sep 2007
Location: ~40Miles from the center of Oregon
Posts: 7,394
Quote:
Originally Posted by patooyee View Post
I dont' recall what brand it is. I want to say Aurora? I got it from KBC Tools.

J. J.
How are you setting the tool on the CL?
__________________
“No matter what people tell you, words and ideas can change the world.” RW
Reply With Quote
  #15  
Old 03-29-2010, 12:13 AM
Fusionhands's Avatar
Fusionhands Fusionhands is offline
Junior Fabricator
 
Join Date: Jan 2010
Location: Boca Raton FL, Milwaukee WI.
Posts: 4
I heard this rocks.

http://www.amazon.com/How-Run-Lathe-...9489560&sr=8-2

good site to read and learn.

http://www.practicalmachinist.com/

Good luck and stay safe with it.
Reply With Quote
  #16  
Old 03-29-2010, 04:53 AM
De Ranged's Avatar
De Ranged De Ranged is offline
Master Fabricator
 
Join Date: Nov 2007
Location: New Zealand
Posts: 320
Something that no one has mentioned is tool and lathe size... if your tool is too big for the lathe you can get this issue
I had a similar issue trying to cut a 5mm groove in 304 stainless on my lathe, the cut was too great a drag and would slow the lathe down and then burn the tip... I beat it by plung cutting yea all you fitters can cringe, but you know it works
Set you speed at or slightly above the recomended surface fps and feed in hard you want a nice cut then back off as the spindle slows down, you are on the mark if you get a nice clean spiral chip that stays shinny (dosn't turn blue)
Reply With Quote
  #17  
Old 03-29-2010, 11:04 AM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
Quote:
Originally Posted by entropy View Post
How are you setting the tool on the CL?
Eyeballing it and movign it around until I get the best results. :)

Lathe is a 7 hp 15.5" Leblond. Its hard to slow this thing down. :)

J. J.
Reply With Quote
  #18  
Old 03-29-2010, 11:46 AM
entropy's Avatar
entropy entropy is offline
This space for rent.
 
Join Date: Sep 2007
Location: ~40Miles from the center of Oregon
Posts: 7,394
Quote:
Originally Posted by patooyee View Post
Eyeballing it and movign it around until I get the best results. :)

Lathe is a 7 hp 15.5" Leblond. Its hard to slow this thing down. :)

J. J.
Ok, there may be part of your problem so QAD...

You know them 6" steel rules and are 1/2" wide; You need a few!
With the lathe OFF you bring the tool gently to the work so that it JUST pinches the rule against the work.
Then you look at the rule and if the cutting tool is vertical the tool is on the CL, if the top of the rule leans away from the work the tool is low and if the top of the rule leans towards the work the tool is to high.
__________________
“No matter what people tell you, words and ideas can change the world.” RW
Reply With Quote
  #19  
Old 03-29-2010, 12:18 PM
patooyee's Avatar
patooyee patooyee is offline
Master Fabricator
 
Join Date: Dec 2007
Location: Gulf Breeze, FL
Posts: 772
I will try that. What about just moving the tool gently up and down as you slowly move it in? The point where it just barely scrapes the work piece at its furthest point out should be center, too?

And just for future reference, what is QAD?

J. J.
Reply With Quote
  #20  
Old 03-29-2010, 12:20 PM
entropy's Avatar
entropy entropy is offline
This space for rent.
 
Join Date: Sep 2007
Location: ~40Miles from the center of Oregon
Posts: 7,394
Quote:
Originally Posted by patooyee View Post
I will try that. What about just moving the tool gently up and down as you slowly move it in? The point where it just barely scrapes the work piece at its furthest point out should be center, too?

And just for future reference, what is QAD?

J. J.
Quick And Dirty.
You will never get a tool on center with the work turning if that is want you mean. the act of locking it will move it.
__________________
“No matter what people tell you, words and ideas can change the world.” RW
Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:45 AM.

Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Template-Modifications by TMS
Copyright ©2012, Offroad Fabrication Network