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Lathe insert tool holder, why extra screw on the side

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
I have a SER1616H16 threading tool holder like the picture below. It uses standard 16er laydown inserts. My question is it has an extra horizontal screw on the side kind of under the insert. It is just under the rear most cutting tip. What is the purpose of that screw. I suppose it might rotate the insert slightly or be used to hold down a shim or something.
My google searches for extra screw just tells me who sells replacement hold down screws. The only information I can find is this tool holder is used to cut external threads on a lathe.
BilL D
 

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Just pull the holder apart and take a look. From memory some of my holders have them and they are related to the shim hold down.
 
You learn something new everyday. What's the max helical angle available?

For sandvik i believe 4*. I really like the sandvik corothread 266 system.

Changeable shims make for 0* clearance for more insert edge strength. I'm not familiar with any on-edge systems with changeable shims. They all have clearance built into the insert, so less edge strength.
 
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I've always heard that called the 'anvil' when under a laydown threading insert, but that might be a Carmex thing. I've had to use them when adjusting the helix angle when cutting an odd thread since the cutting insert is made for a 'standard' range of helix angles. An unusually small or large diameter or multiple start thread will give you weird helix angles.

Here's a chart with the standard range of helix angles and threads and where you need to change the anvil, look at the 7th page:

 
I have a SER1616H16 threading tool holder like the picture below. It uses standard 16er laydown inserts. My question is it has an extra horizontal screw on the side kind of under the insert. It is just under the rear most cutting tip. What is the purpose of that screw. I suppose it might rotate the insert slightly or be used to hold down a shim or something.
My google searches for extra screw just tells me who sells replacement hold down screws. The only information I can find is this tool holder is used to cut external threads on a lathe.
BilL D
I have purchased a number of that particular threading tool for my auto-retract threaders. Some come with the shim/seat/anvil, some don't.
 
Shim seat make sense. I noticed when I installed an insert the hold down screw was extra long. Like almost twice as long as normal.
Bill D
 
The insert could be made with three usable points but this on has only one.
The shim looks like a foot print for the Iscar threading inserts I use.
How much advantage is it to own a holder with an adjustment like this?
Is there a tool holder size below which does not permit this anvil adjustment?
 
The shim looks like a foot print for the Iscar threading inserts I use.
How much advantage is it to own a holder with an adjustment like this?
Is there a tool holder size below which does not permit this anvil adjustment?
It's not an adjustment. The shim provides a replaceable support for the insert. In the event of a crash the tool itself is not damaged, only the shim. I believe the 12mm shank tool (SER1212H16) is too small to allow the use of a shim.

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