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I was taught, back in the stone age, one could engage even threads on any line, numbered or unnumbered. However, this was using threading dials that were numbered one through four (90 degrees apart) with unnumbered lines half way in between each numbered line.
Odd numbered threads, either on numbered or unnumbered. Start with a numbered line, continue until finished with a numbered line. Or start with an unnumbered line and continue with an unnumbered line.
Fractional threads, pick a line and stay with it. Typically I'll only use the number one line.
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(04-26-2015, 08:41 PM)Mayhem Wrote: ...
So - what was the problem?
Ah, Julia made me do it. Yup, that's it.
Ed
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(04-26-2015, 04:56 PM)EdK Wrote: All is good, back to normal. Now I need to make a new nut blank.
Ed
Ed,
I'm glad it is all sorted 
DaveH
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(04-26-2015, 09:38 PM)Dr Stan Wrote: I was taught, back in the stone age, one could engage even threads on any line, numbered or unnumbered. However, this was using threading dials that were numbered one through four (90 degrees apart) with unnumbered lines half way in between each numbered line.
Odd numbered threads, either on numbered or unnumbered. Start with a numbered line, continue until finished with a numbered line. Or start with an unnumbered line and continue with an unnumbered line.
Fractional threads, pick a line and stay with it. Typically I'll only use the number one line.
Apparently that worked back in the stone age because I'm assuming most all lathes were geared in the same way. That's the way to do it according to the South Bend 'How to Run a Lathe' book that everyone says is a must buy for new lathe owners. I botched a lot of threads in the beginning because of that book. My lathe didn't come with any kind of chart in the owners manual or on the lathe itself either. It took me a long time to figure out the South Bend way doesn't work for my lathe. Some pitches came out fine - some didn't. 
So again I can only assume that my lathe is geared differently in order to be able to cut imperial and metric threads. It would seem that Ed's lathe is also geared differently from mine based on the threading chart on his lathe. The chart that Dave posted works perfectly for mine and I assume for his lathe also. Ed just had to be a rebel I suppose and go with option #3 for his lathe. But I guess we will never know since he isn't talking...
Willie
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(04-26-2015, 03:41 PM)EdK Wrote: Doing some experimenting, I tried the following numbers on the threading dial.
1 - cuts overlapping threads.
2 - see 1.
3 - see 1. (this is the number I used when I cut the practice 10TPI acme thread)
5 - see 1.
Leaving half nuts engaged - see 1.
Clearly there has to be a gearing issue. I'm taking a break from this and then I'll go over all of the gears and levers once again for the umpteenth time. 
Ed
P.S. By the way, the so called manual that came with the lathe is a far cry from being a manual. It has no content on operating the lathe and does not even include the chart shown on the front of the threading dial mechanism.
If leaving the half nuts engaged still results in overlapping threads then something is moving Ed. Either the part (which you'd see) or there is a key sheared somewhere in the gear train.
Im thinking the people writing the manuals they supply with lathes are making the bad assumption that we know what we're doing if we're buying a lathe.
Free advice is worth exactly what you payed for it.
Greg
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(04-27-2015, 09:19 AM)Highpower Wrote: The chart that Dave posted works perfectly for mine and I assume for his lathe also.
Works for me as well
DaveH
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(04-27-2015, 09:39 AM)f350ca Wrote: Im thinking the people writing the manuals they supply with lathes are making the bad assumption that we know what we're doing if we're buying a lathe.
True
DaveH
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(04-26-2015, 09:38 PM)Dr Stan Wrote: I was taught, back in the stone age, one could engage even threads on any line, numbered or unnumbered. However, this was using threading dials that were numbered one through four (90 degrees apart) with unnumbered lines half way in between each numbered line.
Just to put this in some sort of perspective I was also told I could engage even threads on any line .............. and it was true because the dials on the lathes then only had 4 marks (lines) usually numbered 1,2,3,4. The problem arises because the dial on most lathes now have 8 marks (lines) so any of the old text books that say use any line really refer when the dial on the lathes only had 4 lines.
This is where the most of the confusion comes in, until one decides to cut a metric thread that is 
DaveH
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The following 2 users Like Mayhem's post:
EdK (04-27-2015), Highpower (04-27-2015)
(04-27-2015, 09:39 AM)f350ca Wrote: ...Im thinking the people writing the manuals they supply with lathes are making the bad assumption that we know what we're doing if we're buying a lathe.
and mills, welders etc etc.
That is gold Greg
Hunting American dentists since 2015.
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(04-27-2015, 09:19 AM)Highpower Wrote: So again I can only assume that my lathe is geared differently in order to be able to cut imperial and metric threads. It would seem that Ed's lathe is also geared differently from mine based on the threading chart on his lathe. The chart that Dave posted works perfectly for mine and I assume for his lathe also. Ed just had to be a rebel I suppose and go with option #3 for his lathe. But I guess we will never know since he isn't talking...
I think you hit the nail on the head when dealing with a lathe that can cut imperial and metric threads.
The first time I cut metric threads on a Clausing with both capabilities for the life of me I couldn't figure out just what the heck I was doing wrong as I was splitting my metric threads. I finally used only the #1 line (its was graduated with four numbered and four unnumbered lines) and it worked just fine. BTW the Clausing in question had an imperial lead screw.
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