PARTING TOOLS

[markba633csi]

You want the narrowest possible blade on a small light lathe such as that

 

[Ken226]

not height 1/2 in width

I think we found your issue!

My 13x40 has a 3hp motor, and I don't think I could part with a 1/2" wide cutoff blade.

I'm kidding, and I'm assuming you're in error here. Or, are talking about a different dimension than the rest of us.

So, how 'thick' is the parting blade?

Dimension W, here:





For some reason, the pic is upside down.

 

[Dabbler]

Perhaps the more pertinent question is: what is the width of the cut of your current parting blade (in thousanths, if you have a micrometer)?

On my small lathe I have a .065 and a .055 width of cut parting blade, both of which go in the same holder.

On my 7.5 HP lathe, I use a .125" width of cut parting blade.

perhaps an update, @riversidedan ??

 

[riversidedan]

Wait….when you look down at the parting blade in the tool holder are you saying it’s 1/2” wide???

no, more like 1/16 ............the wide flat part that goes in the T.H. is 1/2 in. X 4 in. long

will post a pic thatll clear things up....

 

[riversidedan]

I think we found your issue!

My 13x40 has a 3hp motor, and I don't think I could part with a 1/2" wide cutoff blade.

I'm kidding, and I'm assuming you're in error here. Or, are talking about a different dimension than the rest of us.

So, how 'thick' is the parting blade?

Dimension W, here:




View attachment 446931
For some reason, the pic is upside down.

1/2in. wide 4 in. long 1/16 thick

 

[riversidedan]

You want the narrowest possible blade on a small light lathe such as that

its a V shape big part on top

 

[riversidedan]

You can't possibly part with a 1/2" wide parting tool on a mini lathe. Typical parting tools for a mini lathe are 4-5" long x 1/2" high x 1/16" wide. No mini lathe has the power to handle a 1/2" wide parting cutter. Using an 1/8" wide blade is tough on a mini, I know, I've tried it.

the measurments you said above are correct.

 

[mmcmdl]

1/2in. wide 4 in. long 1/16 thick

4" long x 1/2" thick x 1/16" wide . Lets get you straight on how to measure things . You should be able to part with an .062 blade , if not , go smaller . Parting takes a good rigid set up also or bad things happen .

 

[Makintrax73]

I'm a beginner also, but FWIW:


I have a small lathe. When I have had trouble parting there have always been some fundamental issue that I overlooked.

- First and foremost being is the tip of the tool EXACTLY on center. I made a center height gauge because I found it hard to get a good sight angle using a center in the tail stock.

- Is the tool sharp?

- is the tool EXACTLY perpendicular to the work? I have cheap chinese tool holders. I had been aligning the cut off tool using the tool ho!der against the chuck. I noticed something weird about the cut. Checked it out and the tool holder wasn't aligning the tool with the holder. It was slightly cocked. That made a difference too.

- Stick out is your enemy.

- are your gibs adjusted? If you don't need the compound for the operation lock it down.


I made a hex die threading tool by parting off a chrome plated CroMoV socket once I got the above issues worked out. It parted with minimal drama once I had the above issues under control. So something is working for me.

 

[MrWhoopee]

Parting will always be difficult with a flimsy underpowered lathe, and insert parting tools will only cost money and break quite easily.

OTOH, it's unlikely his machine has sufficient power to break an inserted tool.

Even with the thinnest available HSS blade, the combination of low power and lack of rigidity will always make parting challenging. This is the type of difficulty that motivates an upgrade of the motor, the tool post and, ultimately, to a better lathe.