Stepped feature in inner bore of turned part

[Anonatron1234]

Hi all,

New poster here, sorry for what is probably a silly question. I'm designing a turned part, roughly as shown below:



Probably mild steel or aluminium. A is approximately 30 mm, B approximately 70 mm, and C approximately 70 mm. I'm looking to position another part at roughly halfway along the inside of this part. My question is: is it possible to create the stepped featured in the internal bore, specifically can it be machined flat as I have shown it in the diagram?

I'm guessing there's a limit to how large dimension C can be given the tool being used? How would you actually go about turning this? I'm a designer, not a machinist :P

Appreciate any and all help.

 

[DDoug]

Are you expecting both bores marked "A" to be concentric ? And the shoulder dia. ? let's call it "D", I see no dim.
Your sketch needs some GD&T to begin with.

 

[ViktorS]

That is no problem from what I can see. Expect a small radius (0.2-0.8 mm) in the inner corners though, from the tool nose radius.

I would turn half of the part from one side, including half of the bore. Then flip the part or grab it with subspindle and machine other side.

From a normal boring bar, expect somwhere between 4:1 - 5:1 length to diameter as max depth. I have gone over to only use carbide bars so can usually go about 8 in my machine without magic tricks.

The bore might as well be done with a flat drill too and in that case can be deeper.
But don't expect that every shop has the tools for that so stick with 4/5:1 as max to keep the part easy and cheap.