Thread: Boring 300mm deep in one pass

from solid or hollow bar?

Wouldnt really matter if solid or hollow.
If solid it would need a hole for the bar anyway.
The way the question is asked it appears that the bar would need to be able to take a 35mm depth of cut .
Would have to be done on a reasonably large lathe,maybe one of the members that has an older Macson machine might be able to make a bar and use a bit of 1" HSS.
Would need to be a 3 phase machine with around 10HP,at the lowest feed rate .001 and around 30 RPM about 7hrs for the cut.

Alittle more info would be good.
What is the tollerance.(diameter and taper).
Is the outside machined or rough.
What does the finish have to be.
Does the bottom of the bore need to be square.
What part of Sydney are you in.

i have hollow bar 70mm ID and 106 mm OD
the OD is not machined but i can do this on my lathe once i do the ID
It is a bush for a 75mm pin so it needs to be a nice finish
tolerance 75mm -0 +.1
I live in Kellyville but my lathe and mill are at Orchard Hills

Originally Posted by pipeclay

Alittle more info would be good.
What is the tollerance.(diameter and taper).
Is the outside machined or rough.
What does the finish have to be.
Does the bottom of the bore need to be square.
What part of Sydney are you in.

Sorry if I'm missing something obvious here, but why does this need to be done in a single pass of the cutter? Can't you take multiple cuts to achieve the same outcome?

Any reason why you cant do this on your own Lathe.
Is the OD just for appearance.
Does the bore have to be the same Dia throughout or can the centre be undercut.
Are you sure your Hollow Bar is mild steel.

You could set up a 40-50mm bar between centres with a hole drilled in it for a piece of HSS as a boring bar. Then clamp the job in a jig on the cross slide.

Dave

I dont think he means it needs to be done in one cut he means he wants it bored all the way from the same end. If you machined the out side first with that sort of tolerance you could turn it around and set it up true again off the od and machine the other end

unless you have a lathe with a large spindle bore you are going to have to use a steady... That makes it a bit more expensive to do..

my lathe spindle bor aint big enough and i need the finish cut to be done in one cut