Newbie help hole boring

[m_c]

By the sounds of it, you want a less springy boring bar.
Use as large a boring bar as possible, and if you really do have to use a relatively long overhang from the tool post, a carbide bar will help as it's not as springy.

As mekanik says, HSS should help, as it's a sharper edge, and not relying on a blunt edge with brute force to cut the metal. Although one thing you could try if you have an insert bar, is use an aluminium insert, as they typically have sharper edges than inserts for steel. You won't be able to take as big a cut, and the insert won't be as durable, but should produce a smoother finish.
And a key thing with inserts, is keep them cutting. Don't let them rub.

[dfox1787]

thank you for responding.

Still struggling with it not sure if i reach the limitation of my lathe if its my tools. Ill see if i can find some more time to have another go.

[cropwell]

Have you got a fixed steady to support the end of the tube ?

[dfox1787]

Have you got a fixed steady to support the end of the tube ?

i havent no. i could look at making one if that is what i need

[m_c]

You've got a major chatter problem.

I would invest in a bigger boring bar, and cropwell's suggestion of a fixed steady would also help.

[dfox1787]

You've got a major chatter problem.

I would invest in a bigger boring bar, and cropwell's suggestion of a fixed steady would also help.

any suggestions for a boring bar. Not sure where i would get a fixed steady for my lathe.

[m_c]

any suggestions for a boring bar. Not sure where i would get a fixed steady for my lathe.

I would go for at least a 16mm bar, or even 25mm, provided it'll fit in your lathe.
And I prefer ones that take CCxT inserts.
I wouldn't be too bothered about brand, as there's not much to choose from with cheaper bars.

It'll also likely be worth making sure all the slides on the lathe are adjusted properly as well, as with that kind of overhang, any play will be magnified.

Depending on how much you use the lathe, it could be worth fitting a quick change tool post, as they'll also give a far more secure mount for any tools, than the bog standard tool holders. I've personally always used ones from Arc Euro Trade, so I know I can buy extra tool holders.


Regardless of all that, you'll need to be aware that even with the best setup, you do risk ending up with a tapered bore. A more consistent method for accurate boring on lathes, is to mount the workpiece on the cross slide, then spin a boring bar between centres.