lining up a casting for boring.

made a rectangular faceplate to hold casting for milling machine project.

needs boring out but not sure of best way make sure its central.

would making a stepped ali pce to fit in it then centre drill back to use live centre work.

thinking i fit it loosely then use above method to centre and while in place tighten it up.

or would i be better making a bullnose bit to do it?

its the pce that motor bolts to.

never used faceplate before so uncharted territory

thanks.

So you are making THIS part

no i have that part but needs boring out as rough casting inside.

also id is slightly smaller than od of shaft going into it.

An alternative method would be to hold the boss in a 4 jaw independent chuck, you could then face the motor mounting plate and bore through to suit the overarm diameter at the same setting. You will no doubt have to dress the casting at the jaw gripping points to ensure the part is secure, The casting will be way out of balance, more so if it's cast iron, so spindle speed will need to be kept to safe limits. DOC and feed rates to suit spindle speed and material.

Which ever way you decide on, chuck or faceplate, you will need a fairly large capacity lathe.

Emgee

Plug the cored hole with a bit of roughly shaped wood and mark the centre of the hole.

Bolt the flat surface to your face plate and indicate the marked hole true. Ideally with a sprung centre and DTI

Just bolt a few spare change wheels to the opposite side of the faceplate to keep things balanced

Edited By JasonB on 16/10/2015 12:24:50

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Interesting semantic difference between you and Ady.

I'm inclined to agree with Ady: Yes you are making that part ... from a casting.

MichaelG.

[end of irritating pedantic intrusion]

Edited By Michael Gilligan on 16/10/2015 12:35:35

my misunderstanding.

i thought he meant from making from scratch.

Is the alternative approach possible with the casting clamped to an angle plate bolted down to the cross slide to bore the hole using a boring head from the lathe spindle? Much will depend on how much clearance you have and the availability of a boring head of course.

Less precise is a boring bar held in a 4 jaw chuck and move it out in feeler gauge amounts between cuts.

With a deep angle plate it might be possible to mount it upside down if there isn't enough room to get it done upright.

Brian

Just one other thought:

After boring the hole to size; I would re-mount the part on a turned-in-situ stub mandrel and take a facing cut across the flat surface ... May not be needed, but it should remove any minor errors introduced by using the impromptu faceplate.

MichaelG.

Good thought Michael, i would second that

Brian

A lot of the larger surfaces and ways are already machined so the motor mounting face may already be done.

.

Jason,

That wasn't quite my point:

[quote] ... May not be needed, but it should remove any minor errors introduced by using the impromptu faceplate.[/quote]

MichaelG.