# My First Single Point Threading - Lathe Spindle Modeling



## PurpLev (Jun 8, 2012)

I am planning on making some chucks/plates/adaptors for the lathe spindle, and it being a not so common size (1-3/4x8tpi) I figured I might as well make a copy of the spindle to use as a fit-testing plug. 



I turned some UHMW to 1-3/4" the length of the spindle, including the registration shoulder.
I cut a relief notch 1" from the edge (where the threading on the spindle ends)
I threaded 8tpi, and used a small(er) jacobs headstock chuck to test for fit
chamfered the end




Fits like a glove and I'm very pleased with this first experience:




I can now use this to test for fit if I'm making adaptors/plates/chucks for the lathe while the part being worked on is still chucked on the lathe without losing the settings.


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## Old Iron (Jun 8, 2012)

Nice job especially for a first time. I wished mine first looked that good.

Paul


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## jumps4 (Jun 8, 2012)

nice job  they look nice and smooth
did you use the compound at 29* for your infeed?
steve


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## PurpLev (Jun 8, 2012)

jumps4 said:


> nice job  they look nice and smooth
> did you use the compound at 29* for your infeed?
> steve



um.... I actually didn't. I thought that I did, but when I looked at the thread I noticed it was out-of-shape, and noticed I set the compound to 31 and not 29... ended up the last few passes using the cross slide and not the compound slide to fix it and realign the thread


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## Kennyd (Jun 8, 2012)

You could have made me one while you where at it Sharon

Seriously though...nice job :thumbzup:


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## Plumber (Jun 8, 2012)

Great looking threads and that was your first try   VERY NICE!!!  Jack


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## SamIAm (Jun 9, 2012)

PurpLev said:


> I am planning on making some chucks/plates/adaptors for the lathe spindle, and it being a not so common size (1-3/4x8tpi) I figured I might as well make a copy of the spindle to use as a fit-testing plug.
> 
> 
> 
> ...



Purplev,
Im about to go down that same street. fortunately for me I have a spare spindle shaft to use as a test (male)
But I need to do some test runs my self. probably locate some PVC. looks good though I hope my test runs look that good. 
My first project will be a er40 adaptor so not only will I need to do some 1-1/2x8tpi it'll be an internal thread.! YIKES!!!
Sam


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## GK1918 (Jun 9, 2012)

Looks like you passed the test, looks fine, now for the internals, I dont know if you have or have not
to make life easier, a thread stop and carriage stop.  A plastic hand clamp on the way works for the
carriage just so it bumps it.  Maybe im lazy but i cant live without a thread stop, and to swing the
compount to the right.  Funny i just did the same thing last week same threads.  Internal threads, put
that thing in the slowest gear its got even so, things happen fast you are in pitch black without a flashlight.
I cant speak high enough about a thread stop, its positive, no guesswork. I got by for years by simply
clamping two brass dowels in the crossilde dovetails until I made a real one like this good luck the other
Sam


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## jumps4 (Jun 9, 2012)

I wondered why it is 29* and not 30 
probably due to deflection. but i still don't know
nice job though and a good eye for catching the problem and adjusting for correction
I need to make one for my 9x20 but it's m39x4  
steve


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## OldMachinist (Jun 9, 2012)

I made the text on the picture too small to read. Under the first picture it says "Tool fed in at 30 degrees tries to cut on both sides of the tool and will produce rough threads and likely break the tool tip". Under the second picture it says " Tool fed in at 29 degrees cuts only on the leading edge"


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## PurpLev (Jun 9, 2012)

Thanks for the comments everyone*

Kenny* - pm me your addy and it'll be shipped 

*GK1918* - yes, carriage and cross slide stops is definitely on the list of 'to-do's ... with the other hundreds of things on it  thanks for the reminder.

*TheSniper* - My plan was to make an ER32 chuck, but just found a chuck at a decent price and ordered it - I might do an ER40 in the future if I happen to go that route and replace my collets (unlikely, but you never know). I'm ok with the external/internal threads, but am currently not sure how to tackle the metric threading for the ER collet nut... some lathes have it easier than others, but I'm sure there is a way for me to do that as well - just need to find it.

*jumps4* - as *OldMachinist* mentioned, the 29 degrees is slightly LESS than the 30 degrees each face on the tool is cut at so having the compound advance in that way results in just 1 face cutting (After the initial pass), making the cut smoother with less resistance and heat generated, and a better finish (and less likelihood for mishaps).


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