Turning on centers

[TomH]

Hi
I have an old monarch lathe with a threaded spindle, there is no taper in the spindle.
Could someone tell me how to mount a center in it, or how to turn between centers on a machine like this ?
Thank you, Tom

 

[hvnlymachining]

One method is to mount your center in a chuck....

Can't say I have ever seen a lathe without a spindle taper. Interesting

 

[tylersteez]

mount a chunk of steel in the chuck and turn a point on it, quickly makes a dead center that's already true to the chuck. If you end up having to flip the part around or whatever then you will have to make a couple passes on the dead center you made to true it back up if the part bites into it. get or make a lathe dog as well

 

[johnoder]

Like so. Even has a sholder so it won't push back. Rest "dog" doing the driving on a jaw

The four jaw lets you get it running like you like - follow up with a light pass and its as perfect as its going to get in that lathe

 

[michiganbuck]

mount a chunk of steel in the chuck and turn a point on it, quickly makes a dead center that's already true to the chuck. If you end up having to flip the part around or whatever then you will have to make a couple passes on the dead center you made to true it back up if the part bites into it. get or make a lathe dog as well

As tylersteez said, this makes a dead center, dead-on accurate to the spindle centerline. Use your fish gauge to gauge the angle with turning your compound and tool edge skim the soft or tough center's point (note the exact place/angle spot in your notebook /not marking the lathe with a punch mark. Good to put on a small flat so you don't snag your hand in a sharp point and it doesn't bottom out. Dog off a chuck jaw so the center turns with the part.
Good to line it up with a set line on one chuck jaw so next time you install it will be pretty close. (but not perfect unless you skim it.)
*Centers have to be dead-on to do good work.

 

[TomH]

Thanks guys, just what I was looking for.
Tom

 

[michiganbuck]

(X) TomH note your location in your profile, it may prove handy.