# Spindle Crank for South Bend 10L Lathe



## wlburton (Feb 9, 2018)

I decided to make a hand crank for the spindle of my 1950 South Bend 10L lathe so I could use it when threading internally toward the chuck.  This is an issue on most South Bend lathes (and many others) since they have screw on chucks, which makes threading in reverse from the inside out potentially risky.  The idea behind a spindle crank is to do the last part of the thread by hand so there's no danger of running into anything under power.  It can also be useful when tapping in the lathe.

The crank is held in place in the same way an expanding arbor works--by pulling a tapered plug into a tapered socket which spreads six "fingers" against the inside of the spindle--and it seems to be quite secure.  (I also included a key which goes into the keyway which engages the collet closer when it is installed--but I doubt that it is really necessary.) 

Like most of my projects at this point, it was mostly about learning to use my equipment (AKA "toys") better--and figuring out how to design a useful accessory for the lathe.  There are so many lathes like mine out there that I thought someone else might want to make one and would be interested in what I came up with.  I haven't used it for threading yet but it worked very well for tapping and should be a good addition to the arsenal.

Bill


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## middle.road (Feb 9, 2018)

OK, that puts my idea that has been brewing in my mind for the last couple of weeks to complete and utter shame.

D*mn that is one very nice piece of craftsmanship! well done.


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## dlane (Feb 9, 2018)

Nice work should help with threading, just don’t forget it’s in there and start the lathe


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## Dave Paine (Feb 9, 2018)

Very well done.   I like it.   I may have to put this on a future project list.


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## JBuckley13f (Feb 9, 2018)

Looks great, this is something I've wanted to build for my southbend model 9 for awhile. Great job!


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## RandyM (Feb 9, 2018)




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## Bob Korves (Feb 9, 2018)

wlburton said:


> I decided to make a hand crank for the spindle of my 1950 South Bend 10L lathe so I could use it when threading internally toward the chuck.  This is an issue on most South Bend lathes (and many others) since they have screw on chucks, which makes threading in reverse from the inside out potentially risky.  The idea behind a spindle crank is to do the last part of the thread by hand so there's no danger of running into anything under power.  It can also be useful when tapping in the lathe.
> 
> The crank is held in place in the same way an expanding arbor works--by pulling a tapered plug into a tapered socket which spreads six "fingers" against the inside of the spindle--and it seems to be quite secure.  (I also included a key which goes into the keyway which engages the collet closer when it is installed--but I doubt that it is really necessary.)
> 
> ...


Nice!


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## Rooster (Feb 9, 2018)

Very nice, i made a similar one awhile back so i could safely make small compression springs on my lathe.


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## Suzuki4evr (Feb 9, 2018)

That looks sharp. Very nice piece of engineering.


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## wlburton (Feb 9, 2018)

dlane said:


> Nice work should help with threading, just don’t forget it’s in there and start the lathe


I won't! (But I'm tempted to flip it on for a half second to see what it would look like.  I'm sure it would stay put, but that handle would really be moving!  Maybe in back gear.)


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## mikey (Feb 9, 2018)

Very nice job on a really useful device. This one goes on my list!


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## MrWhoopee (Feb 10, 2018)

Nice work, and you can use the lathe when the power is out!


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## woodchucker (Feb 10, 2018)

middle.road said:


> OK, that puts my idea that has been brewing in my mind for the last couple of weeks to complete and utter shame.
> 
> D*mn that is one very nice piece of craftsmanship! well done.


Yep, that's well done..


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## woodchucker (Feb 10, 2018)

wlburton said:


> I won't! (But I'm tempted to flip it on for a half second to see what it would look like.  I'm sure it would stay put, but that handle would really be moving!  Maybe in back gear.)


Don't do it. Just leave sleeping dogs lie..


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## T Bredehoft (Feb 10, 2018)

wlburton said:


> I'm tempted to flip it on for a half second to see what it would look like.  I'm sure it would stay put, but that handle would really be moving!  Maybe in back gear.)



Any RPM and the lathe wants to jump up and down. I did it inadvertently.


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## wlburton (Feb 10, 2018)

T Bredehoft said:


> Any RPM and the lathe wants to jump up and down. I did it inadvertently.


The voice of experience!  I will not be trying it.

Bill


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## gmcken (Mar 21, 2018)

Are you willing to share your drawings for the spindle crank.  It looks great for finer threads close to a shank


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## wlburton (Mar 21, 2018)

gmcken said:


> Are you willing to share your drawings for the spindle crank.  It looks great for finer threads close to a shank


I'm afraid I just made it up as I went along--no drawings--so the "exploded" view above is probably the best I can do.  I started with a 1 3/4" diameter piece of steel.  The angle of the tapered parts isn't critical, as long as they match.  I cut six slots in the expanding part but four would probably work as long as it fits fairly snug inside the bore of the spindle.  I hope this helps.

I still haven't used it for threading, which is what I made it for, but I've used it for tapping and to finish parting off a piece which had to be "trapped" by the live center, making me nervous about finishing the parting off under power.  It worked well for both of those things.  I'm going to stick a label on it to remind me to never insert it without unplugging the lathe, after reading some of the comments above!


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## gmcken (Mar 22, 2018)

Thank you for your response.  Great project.


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## SLK001 (Feb 1, 2020)

This is my take on @wlburton 's spindle crank (I made my drawings based on the photos he provided).




In the above photo, the plastic grip isn't completed, because my knurler was disassembled for a trip to the blackening tank (along with the crank).  

Here is everything completed:




... and assembled:




The next post will have photos of the individual parts.


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## SLK001 (Feb 1, 2020)

Continuing on the previous post, here are photos of the individual parts:

The expander body:




A washer for the expanding screw:




The crank arm:




The handle axle:




The handle end cap:




The expander screw.  This is a Home Depot zinc plated screw that had the zinc coating removed with a trip to an acid bath:




The handle grip, here in its yet unfinished state (I need to knurl and cut to length):


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## SLK001 (Feb 2, 2020)

Here are the drawings that I used.  I didn't make a drawing for the screw washer, since it is a 1" diameter x 0.10" thick piece that I just made for the occasion.  

Let me know if these are of any use to anyone.


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## SLK001 (Feb 6, 2020)

I seemed to have missed posting one of the pics for the crank.  Here is the missing part - it is what I call the spindle slip cone.


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## woodchucker (Nov 4, 2021)

just to throw another method of doing the same, instead of making the shaft like an expanding mandrel, the mandrell can be drilled and threaded at the end, then cut at a steep angle like a bicycle handle bar stem... a baloney cut ..
yours works, but this is simple.  just offering another way of doing it.


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## ericc (Dec 5, 2021)

woodchucker said:


> just to throw another method of doing the same, instead of making the shaft like an expanding mandrel, the mandrell can be drilled and threaded at the end, then cut at a steep angle like a bicycle handle bar stem... a baloney cut ..
> yours works, but this is simple.  just offering another way of doing it.


I tried this method out.  It makes a great crank and is good for turning the spindle for various fiddly operations.  It does not, however, grip tightly enough to use for removing a stuck chuck.  Still a useful tool.


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