Custom Thread: <ThreadForm> not doing anything

[Anonymous]

I followed the instructions here to create a custom thread. The article suggests using the <ThreadForm> to define the thread type. However I am unable to create a 'Sharp' shaped threading. No matter the value I get Trapezoidal.

My custom thread XML:

<ThreadType>
	<Name>Rainbird Thread</Name>
	<CustomName>Rainbird Thread</CustomName>
	<Unit>in</Unit>
	<Angle>60</Angle>
	<ThreadForm>1</ThreadForm>
	<SortOrder>1</SortOrder>
	<ThreadSize>
		<Size>2.20</Size>
		<Designation>
			<ThreadDesignation>RB-5000</ThreadDesignation>
			<CTD>RB-5000</CTD>
			<TPI>6.5</TPI>
			
			<Thread>
				<Gender>internal</Gender>
				<Class>2B</Class>
				<MajorDia>2.204</MajorDia>
				<PitchDia>2.132</PitchDia>
				<MinorDia>2.058</MinorDia>
				<TapDrill>2.048</TapDrill>
			</Thread>
		</Designation>
	</ThreadSize>
	
</ThreadType>

 With my XML It creates trapezoidal.

I am looking to create "Sharp" like this:

Thank you!

[HughesTooling]

Looks like removing the thread form from the XML fixes the problem. Seen this bug in the past, thought it got fixed. @jeff_strater  is this bug logged?

Modified file attached. Also looks like only whole numbers can be used for TPI, so 6.62 gives a 6.0 TPI. You can work around this using Pitch instead. So @Anonymous  You seem to have run into 2 bugs here. Attached file used pitch and gives the correct form and pitch of 0.151

<?xml version="1.0" encoding="utf-8"?>
<ThreadType>
  <Name>Test Custom Thread</Name>
  <CustomName>Test Custom Thread</CustomName>
  <Unit>in</Unit>
  <Angle>60</Angle>
  <SortOrder>1</SortOrder>
  <ThreadSize>
    <Size>2.20-A</Size>
    <Designation>
      <ThreadDesignation>TestThread</ThreadDesignation>
      <CTD>TestThread</CTD>
      <Pitch>0.1510574018126888</Pitch>
      <Thread>
        <Gender>internal</Gender>
        <Class>2B</Class>
        <MajorDia>2.221</MajorDia>
        <PitchDia>2.149</PitchDia>
        <MinorDia>2.075</MinorDia>
        <TapDrill>2.048</TapDrill>
      </Thread>
    </Designation>
  </ThreadSize>
</ThreadType>

Mark

[HughesTooling · Accepted solution]

I replied in your other post about this but I'll put some info here as well. The sharp option does work but I think it's supposed to create sharp for the major and minor diameter. If the major is too small or minor too big I'm not sure how predictable the outcome will be.

If you calculate off the pitch diameter to diameters where you will get sharp points I get this. I used the sizes from your other post. I guess if the sizes for major are too small or minor too big it will truncate those corners. Don't have the time to play around experimenting at the moment.

Mark

[Anonymous]

For bringing closure to this thread, @HughesTooling identified the issues/bugs and gave a great resolution. If you have run into this, look at the sister thread as well: https://forums.autodesk.com/t5/fusion-360-support/custom-threading-xml-pitch-is-wrong/td-p/9535074