As others have cautioned above I too would not place a crank handle on the back end of the lathe spindle. If you really must do this at least make sure that it is statically balanced!
Instead I have a large hand wheel -6" or so- in diameter that I can fix at the spindle back end for turning very short threads or whatever.
The diagram posted by DoN above illustrates the use and position of the spacer bar/rod as discussed earlier.
Wolfgang
Fabricating and using a lathe spindle hand crank is a fairly common early project for a new/beginning lathe user.. many lathe owners use the cranks regularly, including myself.
It's no problem to unplug the lathe power cord before installing the crank, which is the method I use, and recommend.
There are many advantages to using a hand crank which is often easier than using power feed. Lots of the imported bench lathes don't have spindle speeds low enough to make power threading short pieces practical.
Not too long ago (a few weeks maybe) someone posted a link to a kit/plans for building a manual lathe spindle crank that only engages when being turned by hand. I haven't seen one of that design, and I would most likely still unplug the lathe's power cord.
I don't have any trouble unplugging the power cord of my small lathe, since the power receptacle is located just to the rear of the left end of the spindle. I have a lock-out no-power switch position on my other machine.. and I also pull the power cord plug on that one when doing anything that might result in injury if the motor were to start.
Thousands of simple actions are dangerous if one is not aware of what they're doing/paying attention.
I pull on the leather belt to finish a threading cut.
As part of the hand crank project a centering spider for the left end of the spindle can be useful. Grizzly puts them on their gunsmith lathes. Mine is a cheap 1/2" drill chuck with the nose turned down to fit into the spindle bore. The rod it's centering keeps it in place.
jsw
Have you ever seen this one:
The price is right, too...
Michael Koblic, Campbell River, BC
Or you could just remove it when not needed.
If I am interpreting this right you can position a 3-jaw chuck in 60 degree intervals using this method. I do not see 90 degrees.
Michael Koblic, Campbell River, BC
You said it!
It never occurred to me that anyone would leave the power connected when having the crank in place!
The plans for the crank I saw involve the sort of joint used in bikes (I don't know the name, it is a bar which is cut diagonally and connected by a bolt. when tightened it expands inside the spindle).
The only time I did (re) threading I just pulled on the workpiece (8" faceplate).
Confused. What is the purpose of the said 1/2" rod?
Michael Koblic, Campbell River, BC
The thought of a 12" handle going round at 1000 rpm makes my eyes water...
kannitverstan
jsw
The up-to-1/2" rod is the 3' drill rod etc chucked in the lathe, which might whip around if uncontrolled. Thin brass brazing rod is the worst.
jsw
Before I got an indexer I put an ignition timing degree wheel behind the chuck to set an angle and blocked up the chuck jaws to hold it. The locating and clamping functions were separate and perhaps you could apply that here, set one jaw either parallel or perpendicular to a bar lying across the ways.
jsw
That's what 4-jaw self centering chucks were invented for.:-)).
As I said 3 divs are easy and a cross hole is a cinch.
Wolfgang
I guess the one advantage to buying one of the HF/other Router Speed Controls on sale is that the unit is already assembled*, cheaper than building one from individual components.
*Assembled, in Chinese terms can mean anything close, and the 2 units I bought maybe 8 years ago needed the hand-soldered connections to be reflowed, as a few AC wires popped free from their connection points with almost no effort.After checking to make sure the wiring and the earth ground are secure, and not pinched, etc.. the finished unit has a power cord, AC receptacle, hi-lo switch, speed pot.. and is stated to have a 15 amp capability (although I've only used them for light duty applications, die grinder etc).
The units can be very versatile for various resistive loads, small universal motors and various other applications.
Much of the hand-soldered and wave soldered thru-hole connections will be even more suspect (crap quality) now, for nearly all consumer and commercial products, since the lead-free solders are being used almost universally (aviation and a few other industries are exempt).
I opened my dozen HF multimeters to calibrate them and didn't see any bad solder joints. A couple of under-counter fluorescent fixtures from Lowe's were trash, though.
jsw
Use a 4-jaw chuck?
Perhaps (if the spacer is made just the right height) use on the back ways on the other side of the same jaw? (That gives you 180 degrees from each front postion, or 60 degree steps.)
Enjoy, DoN.
Right. I's a stock you are working on. I thought for a moment it was a part of the handle in some way.
Michael Koblic, Campbell River, BC
You haven't seen *my* 4-jaw chuck. Come to think of it I need one of them, too.
Michael Koblic, Campbell River, BC
I just habitually take AC line-powered gear apart whether it's new imported stuff, or used equipment of any pedigree.
There appear to be fewer China bashing flag wavers around in RCM these days, but I've often mentioned that it's not that the offshore sources Can't produce any better quality of goods, but instead, it's just not required to get average consumers to buy the crap goods (repeatedly).
I have a few very good quality assemblies that originated from China, but it's not what I generally expect.
Some of us can remember the typical toy-quality goods from Japan in the
1950s, but then Japanese precision design/manufacturing surpassed many other sources to become a world leader in quality. I don't expect a great change like that to happen again, not for consumer goods, at least.That type of expanding anchor/holding joint was the type I fabricated for my
9x20 lathe shortly after I started using it. Someone mentioned what that type of joint is, but I used it because I remembered it from a bicycle I had.. it was used where the handlebar stem was held in the fork tube.After drilling the stock that's been turned to a slip-fit diameter for the spindle I.D. (and leaving a stop shoulder), I made the diagonal cut with a hacksaw, then filed the center hole oval at the contact point on both sections to allow the two sections to shift on the angled surfaces when the nut was snugged, effectively locking it in the spindle.
There may be a method of fabricating a hollow version (for longer workpiece pass-thru), but I haven't encountered a need for one. A hollow handle extension with an internal thread could be added to the left spindle end, in place of the nut that's used to set/adjust the spindle bearing preload (with a soft-point setscrew or other means of preventing overtightening of the preload).
That type of fitting presses the spindle tube oval, not good at a bearing.
I'd consider two concentric tubes, the inner one having a taper on the end that wedges the slit outer one evenly tight against the spindle ID somewhere far from bearings. It would work like a ball hole gage, but have an over-center cam instead of a slow-acting screw to operate it. The tapered cone could be a separate piece that screws on, giving an easy tension adjustment.
jsw
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