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Author Topic: whats happening with threading  (Read 16874 times)

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Re: whats happening with threading
« Reply #40 on: April 12, 2011, 08:10:40 AM »
Actually this is what i was looking for. It was in version 1.84 but I don't know how successful it was as it seems to have been removed in later versions.
I had a few parts left over - still it's always the same when you try a bit of "do it yourself"

Offline Hood

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Re: whats happening with threading
« Reply #41 on: April 12, 2011, 08:14:45 AM »
Think all that will do is calculate the depth required to form the full thread width depending on the tools profile, not offset to widen the thread, but worth a try.

Offline RICH

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Re: whats happening with threading
« Reply #42 on: April 12, 2011, 08:46:04 PM »
As Hood posted you need to account for the shape of the tool tip and adjust cut depth accordingly when using the wizard.

This is a problem cutting threads on thin wall tubes that engineers have designed to be strong enough with a proper thread form.

Well maybe the engineer needs to be educated on current tool profiles and thus adjust his calcs to take into account stress intensification factors and wall thickness so that tooling costs are minimized and specialty designs are not required. Matter of fact, the thread form should comply with industry standards and most thread inserts provide for the correct shape. Even if you use a rounded tip you still have the same factors ....I guess it depends some on the number of threads threads being done.

Is there a way to tell mach 3 to create the bottom radius and extra width to compensate for the lack of tip radius on the tool.

Actualy there is a way to get  the extra width but will have a flat bottom. You better have a good lathe system.
Go to Config>Ports & Pins>Turn Options  and in box for Cut Type enter a value of 1
as that defines that the threading will be done with Alternate FLank Cutting and the Wizard will generate the correct code. During threading
it will cut alternately  between the front and back flanks of the thread, you will need to set the depth correctly for a sharp point and set up correctly.
You can actualy cut an acme thread in this way with a sharp V tool. Note that it will not radius the thread root though. No Sharp V tool is
exactly a point and will have a radius, may be small, but it will have one.

You may want to have a read of the Threading On the Lathe Manual which can be found  in Members Docs.
See section 5 and section 7.1 on configuration settings on Cut Types.