Facets in my 16 TPI Threads - Need some help!

[Liljoebrshooter]

Is that tool that much of a negative rake or just the picture makes it look like it?
My lathe threads much better with positive rake inserts.
Joe

 

[TX COWDOC]

Is that tool that much of a negative rake or just the picture makes it look like it?
My lathe threads much better with positive rake inserts.
Joe

https://www.mscdirect.com/product/details/60873023?orderedAs=SER+0625+H16&pxno=13296405&refnum=13296405&rd=k&tg=Recommendations&tpp=false&searchAhead=true&searchAheadTerm=ser%200625&typahddsp=SER%200625%20H16&hdrsrh=true

https://www.mscdirect.com/product/details/85108983?fromRR=Y

Here's the tool I'm using.

 

[Aukai]

See post #13 for the possibilities of what I was thinking, 0n page 10 it gets resolved.

Single Phase or 3-Phase?

This is not correct. You lose horsepower with a static phase converter, not a VFD and not with a rotary phase converter. Err, no:: A single phase motor has 3 windings (just like a 3-phase motor) and operates like a 3-phase motor but with the phases running 0 degrees, 180 degrees and 90...

www.hobby-machinist.com

 

[Liljoebrshooter]

I can't see in the specifications for this tool holder or insert what the rake is. I tried looking at the Iscar site but it won't load for me.
Joe

 

[TX COWDOC]

I can't see in the specifications for this tool holder or insert what the rake is. I tried looking at the Iscar site but it won't load for me.
Joe

This has positive rake. Photo is not level.

 

[Lo-Fi]

I can see the photo in post #6 is not level, but judging by the angle against the top of the holder and the edge of the tool post it definitely looks like heavy negative rake which would require a very rigid machine and explain the chatter you're experiencing.

You'll have much better results with positive rake tool, for sure.

 

[rwm]

This is very mysterious! Motor artifact? Chatter? Tool rake? Variable X?

Anxiously awaiting the solution.
R

 

[Jubil]

I'm feeding on the compound at 29.5 degrees. Not sure how well I will do grinding a 60 deg threading tool.

I agree with Danallen. Hss would probably help a lot and the tool is not hard to grind. You tube is a good place to look for “how to”.

Chuck

 

[davidpbest]

This has positive rake. Photo is not level.

I can confirm. I own this toolholder (and the Carmex which is almost identical) and this 16ER AG60 insert. The toolholder sets the insert at negative 10-degree rake, but the insert itself has geometry that reverses that to a plus 3-degree rake at the cutting edge. This is straight out of the book I'm about to publish on indexable tools for the lathe.

This is the toolholder from the Iscar catalog:

If the tools is hung-out or the compound cranked out past the swivel base, the tool will chatter on this size lathe - especially at low RPM's into aluminum. The compound mount on this lathe is pretty flexible due to the postion of the t-nuts where the compound bolts to the cross slide when set at 30-degrees for threading. OTOH, my guess is this could be harmonics from the single-phase motor which has been discussed here before. Is there any evidence of this kind of chatter or waviness in surface finish with turning or facing tools? Have you set a glass of water on top of the headstock and watched the ripples in the surface of the water when the lathe is running at this F/S? That's usually a give-away for single-phase harmonic vibrations.

 

[Aukai]

The book is going to be a big help David