Lathe tool advice

[morrisman]

this large tool holder came with the HENDEY

Can somebody advise as to its appliations eg , general machining .

MIKE

[morrisman]

.....................................................................

[.RC.]

Profiling holder that uses a DNMG insert...

Good for general work... but the nose is weak compared to say a WNMG

[Clubman7]

Handy for clearing a live centre when doing supported shafts.
Most insert manufacturers will have a range of carbide inserts to suit this, and to suit many materials.

[morrisman]

ok

So the negative rake on this tool would make it suitable for harder materials ?

Or is the negative rake angles eg. opposite to HSS , just a normal thing with carbide tooling ?

Mike

[pipeclay]

Negative rake tooling is more suited to higher HP machines 2+.

Carbide tools come in negative or positive rake.

Once the tool starts to get large in the shank 5/8",16mm plus they tend to only be negative,under this shank size they can normally be found in positive or negative rake.

The advantage of the negative rake over positive is that you can invert the tip ,where as on positive tips there is only 1 cutting face.

Normally negative rake turning tools will come with a shim/seat under the cutting tip.

Judgeing by the approach angle and size of the holder it would require a very large centre before it would be usefull for cleaning a damaged one.

[.RC.]

ok

So the negative rake on this tool would make it suitable for harder materials ?



What the insert is suitable for depends on the grade of the insert... Some are softer but tougher, some are harder and brittle..

As for the negative insert all that means is the holder points down as the insert has square sides at the, so needs to point down for clearance... As they have square sides they can be double sided....

[morrisman]

Negative rake tooling is more suited to higher HP machines 2+.

Carbide tools come in negative or positive rake.

Once the tool starts to get large in the shank 5/8",16mm plus they tend to only be negative,under this shank size they can normally be found in positive or negative rake.

The advantage of the negative rake over positive is that you can invert the tip ,where as on positive tips there is only 1 cutting face.

Normally negative rake turning tools will come with a shim/seat under the cutting tip.

Judgeing by the approach angle and size of the holder it would require a very large centre before it would be usefull for cleaning a damaged one.


OK , that's the information I was looking for :2tsup:

Mike

[Dave J]

I will just add that some negative tooling can have tips to make it positive, does that mix things up, LOL

If you look at the point where the tip contacts the work the insert has a chip breaker which then makes it positive rake at the tip, even though the insert is set at a negative angle in the tool holder.
The one you have there looks to have that tip.

Dave

[morrisman]

I will just add that some negative tooling can have tips to make it positive, does that mix things up, LOL

If you look at the point where the tip contacts the work the insert has a chip breaker which then makes it positive rake at the tip, even though the insert is set at a negative angle in the tool holder.
The one you have there looks to have that tip.

Dave

Yes I get it . The chip breaker groove makes a rake all on its own

thanks .... :cool:

[Clubman7]

Inserts can be bought to suit this tool for machining steel, non ferrous metal, cast iron, stainless steel.
Hard materials require a CBN or Ceramic grade of insert.
Not sure if they are available in a DNMG style insert.
Oops no Google says there are.

[Crossfeed]

This quite a handy tool for general profiling and while the edge is not as strong a CNMG or WNMG insert I have used them for medium to heavy interrupted cuts and they hold up. Where they shine is starting a large groove, Set the longitudinal feed and wind in the cross feed fast enough that the groove almost hits the back edge of the insert until the desired depth is reached, switch to a LH tool to finish the other side of the groove. Another use is doing the undercut at the root of a shoulder which many grinding jobs require.

Positive rake chipbreakers on negative rake inserts work well, I have taken .02 cuts with them.