# Cutoff/parting Holder/blade



## billr (Jan 16, 2016)

I bought the AXA qctp from CDCO and a 3/32" blade for the parting tool in the set for my G0602 lathe.
I was disappointed in the action of the blade when parting off on 12L14 steel; 1-1/4" diameter.
Blade was 90 deg. to the stock and on center.
Spindle speed was 560 and moderate feed pressure with cutting oil.
A lot of chatter  so I am looking for suggestion and hints.
It may just be me.
Thanks,
Bill


----------



## Redirish (Jan 16, 2016)

Speed is way to fast, I usually cut off at less than 100 rpm.


----------



## savarin (Jan 16, 2016)

whilst attempting the cut place a finger on each of the slide joints in the cross slide and top slide and see if you can feel any movement.
Also check very closely to see if the whole tool post is flexing.
I would suspect that flex somewhere in that area is the culprit if the tool is sharp.
Until I removed those areas of flexure on my 9x20 I couldnt make a full cutoff part.


----------



## master of none (Jan 16, 2016)

Hey Billr,I was having the same problem only with 1" stainless steel I think they were cheep parting blades so I ordered some 3/32 from Shars and it was like night and day so maybe either they were cheep or dull but again I was only cutting stainless steel .


----------



## billr (Jan 16, 2016)

I'll try it at 150 RPM (slowest this lathe will turn) and see what the results are.
I thought it might have been something I was doing incorrectly.
Thanks,
Bill


----------



## billr (Jan 16, 2016)

It was a brand new blade.


----------



## brino (Jan 16, 2016)

billr said:


> It was a brand new blade.



...but that does not guarantee sharpness...

Also lots of good info here:
http://www.hobby-machinist.com/threads/parting-for-idiots.32938/

(no insult intended with the title of that other post!)

-brino


----------



## billr (Jan 16, 2016)

No insult taken,
You are right on sharpness so another thing to check.
Thanks.


----------



## David VanNorman (Jan 16, 2016)

Was it a p type blade or one with the bevels on . Keep the speed down run oil on the cut. and a p type blade.


----------



## billr (Jan 16, 2016)

It was a HHS flat blade and probably not the highest quality.
I'll look into the Shars insert type.
Thanks


----------



## TOOLMASTER (Jan 16, 2016)

try lowering blade too.


----------



## billr (Jan 16, 2016)

Below the centerline?
I thought that was not recommended.


----------



## JimDawson (Jan 16, 2016)

Here is a picture of my parting tool.  It always cuts, never jams.



Just hit the E-stop and start cutting.  The only parting tool I have ever owned.


----------



## Chipper5783 (Jan 17, 2016)

Parting is a tough task.  I struggled with it for years - applying the suggestions shared above, and gradually worked it out.  I guess, like nearly everything else in life, it gets easier with practice.  I now find parting off a routine task.

Even still, I don't hesitate to grab a hacksaw, or cut the part off in the band saw and face it clean.  It depends on the job at hand.

Are you using a T-blade?  My PhaseII part-off blade holder did not have a relief cut for the T of the blade, so the blade leaned over (I cut a relief).
The past couple years, I usually use a carbide insert part off tool - it works great.  It is held in a bolt on holder for the PhaseII CXA - drop it in, lock it - no issue.
I have set up a rear tool post (parting tool being upside down - lathe running in the normal direction).  This also works very well (chips clear well on deep cuts) - but the conventional works so well that I rarely bother with the rear post.

Let us know how it works out.


----------



## dave2176 (Jan 17, 2016)

That diameter I part at 360. 1" and under I part at 600 rpm. You may have been a little fast but I suspect the blade was main issue. Hollow grind the front to get a sharper edge and make sure it is dead center. 
Dave


----------



## Ozwelder (Jan 17, 2016)

No one yet has mentioned part off feed speed.
The feed requires a constant pressure. Feed pressure, or lack of of is responsible in part for chatter. Another factor is more stick out that required as in just over 1/2 diameter of the part off.

The curl of the swarf is a real good indicator you are doing things right. It should come out like a C with a little curl one end.
I stick to a cutting speed of 1/3 of normal cut speed an use plenty of lube on a sharp tool.


----------



## billr (Jan 17, 2016)

Thanks for all the suggestions.


----------



## juiceclone (Jan 17, 2016)

try this   solid    doesn't chatter    cheap


----------



## billr (Jan 17, 2016)

That is certainly solid and quite a concept.


----------



## epanzella (Jan 17, 2016)

juiceclone said:


> try this   solid    doesn't chatter    cheap
> 
> View attachment 119541


What is that? A small circ saw blade?


----------



## billr (Jan 17, 2016)

Looks like about 4" biscuit cutter blade.


----------



## epanzella (Jan 17, 2016)

billr said:


> Looks like about 4" biscuit cutter blade.


Duh, of course! I have a biscuit cutter. I thought that blade looked familiar but I just couldn't place it.


----------



## dlane (Jan 17, 2016)

Jim dose your parting tool come in carbide


----------



## JimDawson (Jan 18, 2016)

dlane said:


> Jim dose your parting tool come in carbide




Sure does


----------



## David VanNorman (Jan 18, 2016)

Now that is a cut off tool. How is it mounted . I like it.


----------



## juiceclone (Jan 18, 2016)

It's a HarborFright "joiner" blade ... around ten bucks as I remember.  Made a shaft to mount it in a boring bar holder.   Drilled index holes in it to pin it to keep from being rotated down.  Been using as necessary for a year now and broke one of the carbides out cutting off a tube (too thin wall).    I think you could use an even thinner blade as it is quite stiff with all the matal supporting it.


----------



## juiceclone (Jan 18, 2016)

if U want more on it it's at my photobucket page
pix 4 thru 10
http://s1201.photobucket.com/user/J_Franklin/library/Machining?sort=3&page=1


----------

