Mini Lathe Thread Tapping - Not Enough Torque

[MaverickNH]

Newbie question: My LMS 7x12 Mini-lathe doesn’t have enough power (500W) to tap a 10M metric hole. While I can hand-tap that with the 1.5in round stock in a vise, is there a way to rig a tap and handle between the chucked workpiece and a dead end in the tailstock to keep it aligned while Turing the tap by hand? I see the taps have dimples in the end that fit a dead end point. I don’t see where the LMS Mini-lathe has a spindle lock, so I’d have to wedge a tool between the jaws and bed to resist the chuck turning (with power locked off, of course).

I’m asking a little machine to do more than intended. Any suggestions appreciated!

BRET

 

[Janderso]

Kind of like this?
I have a MT4 tailstock.
You can buy these or make them.
Super handy.

 

[RJSakowski]

I made a floating tap follower for the lathe and mill. It has a 3/4" shank and I have a 3/4" chuck for that specific purpose. It has a 1-1/4" travel which is nice for larger taps and interchangeable tips, one a cone and another that is a 3/8" cylinder with a countersunk end. I use Irwin tap holders that accept a 3/8" square drive and the cylinder fits this nicely.

I prefer to fix the tap and rotate the chuck when tapping in the lathe. Even though I have sufficient torque to power tap, I prefer to manually tap as I have better control over the process. Nothing ruins your day more than breaking a tap in a part you just spent hours on.

 

[MaverickNH]

It’s a bit too soon for me to build one, but I found one on Amazon to order. The package is 6.5” so assembled it might be pretty long, but I’m upgrading my 7x12 to a 7/16. If I cut off the tang on the back of the MT2 arbor I’ll get a bit more space too.

Thanks!

 

[WobblyHand]

Newbie question: My LMS 7x12 Mini-lathe doesn’t have enough power (500W) to tap a 10M metric hole. While I can hand-tap that with the 1.5in round stock in a vise, is there a way to rig a tap and handle between the chucked workpiece and a dead end in the tailstock to keep it aligned while Turing the tap by hand? I see the taps have dimples in the end that fit a dead end point. I don’t see where the LMS Mini-lathe has a spindle lock, so I’d have to wedge a tool between the jaws and bed to resist the chuck turning (with power locked off, of course).

I’m asking a little machine to do more than intended. Any suggestions appreciated!

BRET

One of these are handy. Tap Follower I'm sure you can get one elsewhere, but since you know LMS, I posted it.

I wouldn't power a tap using a mini-lathe. 1) Not enough guts, 2) No auto-stop or back off when you hit bottom. Not stopping at bottom is bad news. Just tap by hand using a good HSS tap, which usually is not what you buy in a kit. Buy taps as you need them, and after a while you will have a good collection. Or buy some used quality ones in quantity and sort them out (before using them for something important). A good tap is a pleasure to use, as it cuts cleanly and efficiently.

 

[markba633csi]

You'll find that stopping the chuck from turning in one direction is only half the battle- when you go to break the chip
the chuck needs to be restrained in the other direction as well.
One advantage of a lathe with backgears- easy spindle lock

 

[WobblyHand]

Correctly sized holes and good sharp taps make life easier. I haven't had trouble tapping M10.

 

[benmychree]

I have always just used a drill chuck in the tailstock for power tapping, or at least starting the tap squarely, then tapping to depth by hand.

 

[MaverickNH]

I made a floating tap follower for the lathe and mill. It has a 3/4" shank and I have a 3/4" chuck for that specific purpose. It has a 1-1/4" travel which is nice for larger taps and interchangeable tips, one a cone and another that is a 3/8" cylinder with a countersunk end. I use Irwin tap holders that accept a 3/8" square drive and the cylinder fits this nicely.

I prefer to fix the tap and rotate the chuck when tapping in the lathe. Even though I have sufficient torque to power tap, I prefer to manually tap as I have better control over the process. Nothing ruins your day more than breaking a tap in a part you just spent hours on.

So, does one just gradually advance the tap held by a chuck in the tailstock, while rotating the chuck by hand or chuck key?

 

[WobblyHand]

So, does one just gradually advance the tap held by a chuck in the tailstock, while rotating the chuck by hand or chuck key?

Not with a tap follower.

Install the tap follower in the chuck in the tail stock. Put tap in tap holder. Put tap in hole of part, which is held by the main chuck. Align tap wrench such that the tap follower point is in the divit of the tap wrench. Adjust tail stock so that the tap follower spring is compressed. Hold tap still and rotate main chuck, or hold main chuck and turn tap. The spring loaded tap holder simply centers the tap to the bore.