What to practice on lathe

[Creativechipper]

Rediscovered some 10-12' long pcs of metal round rod in my back yard. I have no idea what they are from or for.
Was thinking taking a hack saw over to one and cutting off a 10" pc.
Any ideas?

 

[francist]

What about a simple lidded container? Nothing fancy, and don't worry about threading the lid right away but just make it a nice snug fit. Something like this:



It would involve number of steps, some accurate measuring, and subsequent efforts to hit those measurements in order to work nicely. In other words, there is a penalty if it's not on the money!

You'd need to be able to drill a hole using the tailstock, ideally bore the inside but it's ok if you can't right now, and part off on the lathe. But you'll notice it's perfectly sized to fit your aluminum rod....

You may want to flesh the dimensions out some unless you're used to working on the fly, but that's easy enough for you.

-frank

 

[Creativechipper]

Thanks Frank,

This I totally understand and will attempt right away!! I think I have all the stuff to accomplish this.

 

[francist]

A "wiggle bar" would make good use out of one of those printer rods. I don't know what kind of steel they are, but all the ones I've used have turned very nicely.

So what's a wiggle bar? Simply a rod with a point turned accurately on one end and a centre drill hole in the other. You can use it for centring work in a chuck where the outside of the work might not be a useful reference. If you have a centre punch mark the pointy end of the bar rests in the mark, the other end is supported on a tailstock centre, and an indicator placed against the bar near the chuck. When the bar registers zero runout (or as close as you can get it) on your indicator as you rotate the chuck by hand, the centre punch mark on the stock is centred in the chuck. This is also useful for when you want to purposefully offset work in the chuck, such as a crankshaft lobe or something.

I don't know if it's really called a wiggle bar or something else, I just heard it called that and continue to do so myself. Here's a sketch, dimensions are not critical:



-frank

 

[Creativechipper]

I have started the 1" round container, any larger will not go through the spindle, so I down sized slightly.

May need some boring bar insight. My boring bar holder has a 3/4 hole( qctp tool holder) my boring bar is more like 1/2" and has carbide replaceable tips. How do I hold in QCTP, regular holder or do I need some sort of plug?

 

[GunsOfNavarone]

A "wiggle bar" would make good use out of one of those printer rods. I don't know what kind of steel they are, but all the ones I've used have turned very nicely.

So what's a wiggle bar? Simply a rod with a point turned accurately on one end and a centre drill hole in the other. You can use it for centring work in a chuck where the outside of the work might not be a useful reference. If you have a centre punch mark the pointy end of the bar rests in the mark, the other end is supported on a tailstock centre, and an indicator placed against the bar near the chuck. When the bar registers zero runout (or as close as you can get it) on your indicator as you rotate the chuck by hand, the centre punch mark on the stock is centred in the chuck. This is also useful for when you want to purposefully offset work in the chuck, such as a crankshaft lobe or something.

I don't know if it's really called a wiggle bar or something else, I just heard it called that and continue to do so myself. Here's a sketch, dimensions are not critical:

View attachment 273510

-frank

is one end tapered (M.T.) To fit tailstock?

 

[francist]

I've seen sleeves that will adapt the larger hole size to the smaller shank, much like using a sleeve to adapt a pulley with a large hole to a motor with a smaller shaft. Don't suppose you got one of those with the holders? There are also some holders with a vee notch longitudinally in the bottom so that a round bar nests in there.

 

[royesses]

I have started the 1" round container, any larger will not go through the spindle, so I down sized slightly.

May need some boring bar insight. My boring bar holder has a 3/4 hole( qctp tool holder) my boring bar is more like 1/2" and has carbide replaceable tips. How do I hold in QCTP, regular holder or do I need some sort of plug?

Is your bar round or square? My qctp has a tool holder that will hold round or square bars. V notch bottom.


Also my round only boring bar holder has a split bushing so it will hold 2 different size round only bars. You could turn a bushing and split it.

Roy

 

[francist]

is one end tapered (M.T.) To fit tailstock?

No, just a small centre drill divot. It needs freedom of motion to swivel around (pivot, gimbal) on the support. You can use a spring loaded tap follower between the bar and the tailstock to supply a bit of pressure, but it's not required.

Edit: sorry if my little sketch looks like a tapered end, tough to do the "finger sketch on iPad" thing with any real degree of accuracy sometimes!

 

[Creativechipper]

The boring holder is round 3/4", Also a bottom V in one of the holders. My boring bar is round with two flat spots 180 offset from each other running the length of bar. I think I can get it in the v notch holder.
I want to try and use the boring bar to finish up the inside diameter. I used my center drills to the largest size #5 so far. Then used a drill bit size 3/8".
With the boring bar I think I can turn a larger diameter from the shoulder down by 1/8".