Rich Gouette
12-02-2022, 3:59 PM
Hi all, in the pic below, you can clearly see how my long hole boring job went...astray.
This seems to be repeating itself, a few things come to mind that might be at play here.
1) Bad job of boring
2) Bad job of marking center(s)
3) Workpiece wasn't faced accurately?
Maybe both?
Full disclosure: I've been relying on the facing that was done before it came to me...maybe that's dumb to do.. I don't have any specialised tooling to face: should I use my
cut off saw?
This is a 14" conical boring job done using this process:
1) I mark the center of the piece using a metal ruler, my eye, & a drawn/marked "X" (I tried using a jig I bought for this purpose, but it didn't result in a dead-center mark
when tested with a caliper)
2) I chuck it up with a 4 jaw, and drill a pilot on the tailstock end using a center-drill bit(using a jacobs chuck)
3) I increase the size of the pilot with a larger center bit
4) I begin drilling with regular twist bits, starting at 1/2" diameter(for a short distance), then I start reducing
the size of the drills until I come to to a 3/16" bit, which doesn't reach the end of the piece, simply because it's not 14"
5) I reverse the piece, drill a pilot hole again, and drill with a shorter 3/16" bit till it meets the existing bore.
6) After this "step-drilling" operation, I ream the bore smooth
7) I turn down the body to round
I actually didn't detect anything was amiss until I decided to saw the thing in half, and then saw what you see here.
(attaching a larger version also)
490937
Thoughts?
Kind regards,
Rich
This seems to be repeating itself, a few things come to mind that might be at play here.
1) Bad job of boring
2) Bad job of marking center(s)
3) Workpiece wasn't faced accurately?
Maybe both?
Full disclosure: I've been relying on the facing that was done before it came to me...maybe that's dumb to do.. I don't have any specialised tooling to face: should I use my
cut off saw?
This is a 14" conical boring job done using this process:
1) I mark the center of the piece using a metal ruler, my eye, & a drawn/marked "X" (I tried using a jig I bought for this purpose, but it didn't result in a dead-center mark
when tested with a caliper)
2) I chuck it up with a 4 jaw, and drill a pilot on the tailstock end using a center-drill bit(using a jacobs chuck)
3) I increase the size of the pilot with a larger center bit
4) I begin drilling with regular twist bits, starting at 1/2" diameter(for a short distance), then I start reducing
the size of the drills until I come to to a 3/16" bit, which doesn't reach the end of the piece, simply because it's not 14"
5) I reverse the piece, drill a pilot hole again, and drill with a shorter 3/16" bit till it meets the existing bore.
6) After this "step-drilling" operation, I ream the bore smooth
7) I turn down the body to round
I actually didn't detect anything was amiss until I decided to saw the thing in half, and then saw what you see here.
(attaching a larger version also)
490937
Thoughts?
Kind regards,
Rich