3 tries and 3 fails to make a 1/4 20 thread - part 2

Your original threads looked horrible. Your compound angle is WAY off.

Here's the scoop on using the thread dial (both .jpg and .pdf versions):


Using the Thread Dial.jpg
 

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I see you have two "zeros" on your compound. I don't think the one on the side is from SB, but was added by a former owner. I can see how you got confused by the angles.

A man with one watch always knows what time it is. A man with two watches never knows what time it is.
 
SLK001 said:
Your original threads looked horrible. Your compound angle is WAY off.

Here's the scoop on using the thread dial (both .jpg and .pdf versions):


View attachment 357868
Click to expand...
A little confused on this chart
On my lathe Even numbered threads Have to be divided by 4 then you can use all 8 lines
Otherwise you have to use 123and 4 marks
Maybe my chart is wrong
Can anyone verify this chart works I have an 8tpi leadscrew
Thanks
 
My South bend with 8TPI screw is exactly the same. Maybe yours cannot do 1/2 or 3/4 threads so they do not mention them.
 
martik777 said:
My South bend with 8TPI screw is exactly the same. Maybe yours cannot do 1/2 or 3/4 threads so they do not mention them.
Click to expand...
They do show settings for fractional threads the chart is mounted on the dial housing
I have threaded fractional a few times they turned out okay
Maybe I will try to cut an even number of threads using any of the 8 lines and see what happens(tomorrow)
Will let you know how it goes
 
Nigel123 said:
A little confused on this chart
On my lathe Even numbered threads Have to be divided by 4 then you can use all 8 lines
Otherwise you have to use 123and 4 marks
Maybe my chart is wrong
Can anyone verify this chart works I have an 8tpi leadscrew
Thanks
Click to expand...

The chart I posted is right out of the How to Run A Lathe booklet from South Bend, so it will work for all SB lathes out there. I'm not positive that it will work for other lathes from other manufacturers.

I reworded some of the text to make it clearer (for me) to understand.

I printed out the .pdf version, took it down to Office Depot and had it laminated, then posted it above my lathe.
 
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