Advice on purchasing a lathe parting blade & block?

[PatMiles]

I've never been comfortable trying to part off round stock on my lathe (14x40), crashed it once during a parting procedure and had to throw a pair of skivvies away. I'm toying with the idea of buying a block, blade and insert combo which will mount in my KDK tool post.
Would any of the machinist care to comment on one of my possible choices? I'm looking at the set 1 as the block has a 1/2" x 1/2" shank which will fit my KDK tool holder.

 

[rsmithsr50]

my parting is less stressful, and cleaner since I went to a similar tool.
check amazon for pricing

 

[billlarson]

I use a similar calorie set up.c.inserts are costly.Set tool just a hair below center.some materials are just plain gummy....use oil to help get chips out....
Good luck
Bill

 

[ebb]

After reading what some gunsmiths and machinist said about a parting tool, and seeing some pictures, I don't think I will be using one.

 

[shortgrass]

When you crash with that, you can mess it up , too,,,, right there where the inset is held.............. The biggest mistakes people make are, tool tip below center, tool not square to the work, too much or too little feed/speed, blade sticking out of the holder too far, not parting as close to the work holding (chuck or collet) as possible......

 

[JSH]

No sense in being afraid.
Go look at MrPete or Joe Pi

 

[butchlambert]

I have one that is similar to the pictured one, but I hate parting. I've had my best luck using the power feed and coolant. Of course, proper feed and speed is most important.

 

[Dusty Stevens]

I use one like that but the insert bolts on. Those type that the insert just sits in there if it crashes you ruin the whole toolholder not just the insert. Im 99% sure its a carmex

 

[butchlambert]

I use one like that but the insert bolts on. Those type that the insert just sits in there if it crashes you ruin the whole toolholder not just the insert. Im 99% sure its a carmex

I guess I'm lucky. My crashes have only destroyed the insert.

 

[Dusty Stevens]

I guess I'm lucky. My crashes have only destroyed the insert.

That bottom part below the insert where it comes up to a point bends to the side

 

[butchlambert]

That bottom part below the insert where it comes up to a point bends to the side

Guess I've been lucky Dusty. "so far"

 

[PatMiles]

Guess I've been lucky Dusty. "so far"

Yeah, I'd rather be lucky than good some days.

 

[jdh47]

I have insert parting tools but use HSS parting blades. The parting inserts are wide and require lots of power and rigidity to cut correctly. With my 15" Clausing Colchester I can run a HSS parting blade at 140-200 RPM feeding by hand with lots of oil. Parting is hard on smaller manual machines especially after they start to wear. I have had luck sharpening my blades with enough bottom relief to not tend to rub the work. They must be kept sharp to work.

 

[JSH]

That was where I messed up, not having enough relief.
I went back to the old school and lots of lube after trashing the insert style.

While all have an ear to this. I have a heck of time getting mine nice and square. Seems I always either go left or right with a taper or a crown.
Any tricks?
Jeff

 

[hogpatrol]

Carbide, on center and run it as fast as it will go. Keep the pressure on the tool. Most problems arise with too slow an rpm, off center tool, too light a feed, tool not rigid and no coolant or lube. For production work, I prefer the insert tools with flood coolant.

Run it fast and keep the feed going.

 

[AckleymanII]

A T style part off blade is THE END of any and all problems parting off. Use a height gauge and DO not have the tip above the centerline. I use a $59 Harbor freight belt sand and touch up the front of the bit about every 10 cuts. These T blades can also be found with carbide tips. Carbide tipped blades will cut hardened dies in half, likkedy split. A T15 Grade T style part off bit will need touching up seldom. Also, if you root around you can find these T style part off bits in Tangung G and Stellite.

Drip oil while you are cutting. I part off at 190 rpm.

T style blades are NOT for production work.

 

[PatMiles]

I think I am going to blow off the insert style parting blade and go with a T style as I already have a K&D block for the T style.

 

[jdh47]

You can square up on the front of the lathe chuck or the work if it's been faced like HP shows. I usually get center by rotating my Aloris tool post around and centering to a live center point before a square up to cut off. If you are high you will go in to a point where it won't feed anymore. Too low and you risk the problem of a crash when the work climbs over the tool.

The smaller the lathe the slower you can go. Rigidity is needed for cutting off.

 

[Steve Ladino]

I've never been comfortable trying to part off round stock on my lathe (14x40), crashed it once during a parting procedure and had to throw a pair of skivvies away. I'm toying with the idea of buying a block, blade and insert combo which will mount in my KDK tool post.
Would any of the machinist care to comment on one of my possible choices? I'm looking at the set 1 as the block has a 1/2" x 1/2" shank which will fit my KDK tool holder.View attachment 1155910

Joe Pieczinski " Joe Pie " on you tube has a good video tutorial on proper tool grind etc. for parting jobs.

 

[Walt Krafft]

Rigidity is key. I have an insert tool and only use it for hardened material. The insert tools create a higher cutting force. T style with flood coolant is my primary parting tool.