I'm making a rack out of several ~ 9" long sections of 2 1/2" PVC pipe.
Each section of pipe is cut square on the bottom, and at a 45 degree
angle on the top end. The idea is to fasten them to a pair of horizontal
rails, using a through bolt on the bottom (which will prevent the objects
from falling out), and a short bolt through the back of the top wall with
the angle cut sloping forward & down. I have the tubes all cut, and now
I need to drill them.

The thing I'm pondering is how to best align the slopes so that I can
drill the holes on my mill. I can clamp the tubes horizontally using a
V-jaw in my vise, but I'd like to come up with a repeatable way of making
sure the holes are "square" to the sloping section. I need to make sure
the two holes in each tube are parallel to mate well with the rails. IF
I could be assured of repeatable rotational alignment, I could drill all
the holes in the square ends, and then all the holes in the beveled end.
This would be a lot faster than clamping each piece & cranking back &
forth 8 inches to drill both holes without removing each piece from the
vise.

The best idea I've come up with so far is to clamp a rod horizontally at
the approximate height of the middle of the tube. If the rod is square
to the mill, the rod can serve as a "stop" to push the tube against, and
it should force the slope to rotate & align correctly. I have one of
these that I could use:

http://www.use-enco.com/CGI/INSRIT?PMAKA=TN337-9322

My only concern is if it's rigid enough & getting it aligned in the first
place.

I have a gut feeling that there ought to be a better way, either simpler
or more accurate, but I'm damned if I can think of one.

Any ideas?

Thanks!

Doug White

On 26-Jul-2011 21:50, Doug White wrote:

The thing I'm pondering is how to best align the slopes so that I can
drill the holes on my mill.

The only thing about the part the way it's cut that is not radially
symmetrical is the 45-degree cut on one end. Whatever you come up
with is going to have to index that somehow. If it were me, I would
make a plywood box jig with sides to locate the pipe, with one end
cut at 45-degrees and boxed in. Shove the pipe into the 45 wedge
section and it is forced into alignment for drilling.
__________________________________________________ __________________
Gardner Buchanan gbuchana(a)teksavvy(dot)com
FreeBSD: Where you want to go. Today.

On Jul 26, 9:50*pm, Doug White wrote:
I'm making a rack out of several ~ 9" long sections of 2 1/2" PVC pipe. *
Each section of pipe is cut square on the bottom, and at a 45 degree
angle on the top end. *The idea is to fasten them to a pair of horizontal
rails, using a through bolt on the bottom (which will prevent the objects
from falling out), and a short bolt through the back of the top wall with
the angle cut sloping forward & down. *I have the tubes all cut, and now
I need to drill them.

The thing I'm pondering is how to best align the slopes so that I can
drill the holes on my mill. *I can clamp the tubes horizontally using a
V-jaw in my vise, but I'd like to come up with a repeatable way of making
sure the holes are "square" to the sloping section. *I need to make sure
the two holes in each tube are parallel to mate well with the rails. *IF
I could be assured of repeatable rotational alignment, I could drill all
the holes in the square ends, and then all the holes in the beveled end. *
This would be a lot faster than clamping each piece & cranking back &
forth 8 inches to drill both holes without removing each piece from the
vise.

The best idea I've come up with so far is to clamp a rod horizontally at
the approximate height of the middle of the tube. *If the rod is square
to the mill, the rod can serve as a "stop" to push the tube against, and
it should force the slope to rotate & align correctly. *I have one of
these that I could use:

http://www.use-enco.com/CGI/INSRIT?PMAKA=TN337-9322

My only concern is if it's rigid enough & getting it aligned in the first
place.

I have a gut feeling that there ought to be a better way, either simpler
or more accurate, but I'm damned if I can think of one. *

Any ideas?

Thanks!

Doug White

I would try to use an angle plate for the stop to drill the first
hole, then set up a vertical peg to locate the pipe for the second
one.

Perhaps you could clamp a bar across the top of the vise and jam the
angled end of the pipe under it.

jsw

Doug White wrote:

I'm making a rack out of several ~ 9" long sections of 2 1/2" PVC pipe.
Each section of pipe is cut square on the bottom, and at a 45 degree
angle on the top end. The idea is to fasten them to a pair of horizontal
rails, using a through bolt on the bottom (which will prevent the objects
from falling out), and a short bolt through the back of the top wall with
the angle cut sloping forward & down. I have the tubes all cut, and now
I need to drill them.

The thing I'm pondering is how to best align the slopes so that I can
drill the holes on my mill. I can clamp the tubes horizontally using a
V-jaw in my vise, but I'd like to come up with a repeatable way of making
sure the holes are "square" to the sloping section. I need to make sure
the two holes in each tube are parallel to mate well with the rails. IF
I could be assured of repeatable rotational alignment, I could drill all
the holes in the square ends, and then all the holes in the beveled end.
This would be a lot faster than clamping each piece & cranking back &
forth 8 inches to drill both holes without removing each piece from the
vise.

The best idea I've come up with so far is to clamp a rod horizontally at
the approximate height of the middle of the tube. If the rod is square
to the mill, the rod can serve as a "stop" to push the tube against, and
it should force the slope to rotate & align correctly. I have one of
these that I could use:

http://www.use-enco.com/CGI/INSRIT?PMAKA=TN337-9322

My only concern is if it's rigid enough & getting it aligned in the first
place.

I have a gut feeling that there ought to be a better way, either simpler
or more accurate, but I'm damned if I can think of one.

Any ideas?

How about just a rectangular piece of scrap? Or a few-inch long piece of
square tube the right size?

Good Luck!
Rich

On Wed, 27 Jul 2011 21:48:38 +0000, Doug White wrote:


I must not have described it clearly enough. The holes are
perpendicular to the pipe, so I don't need to rotate the axis of the
pipe in any odd direction. I just need to ensure that when I clamp the
pipe in the V-jaw that the 45 degree cut is facing up, and not tilted
slightly one way or the other.


Drill all the holes first, use them to index your 45 degree cuts.

....next time...

xpzzzz wrote in :

On Wed, 27 Jul 2011 21:48:38 +0000, Doug White wrote:


I must not have described it clearly enough. The holes are
perpendicular to the pipe, so I don't need to rotate the axis of the
pipe in any odd direction. I just need to ensure that when I clamp
the
pipe in the V-jaw that the 45 degree cut is facing up, and not tilted
slightly one way or the other.


Drill all the holes first, use them to index your 45 degree cuts.

...next time...

Yup. I figured that one out just about when I cut the last one...

As it turns out, I had a piece of pipe JUST long enough so that I could
get all the sections I need, but ONLY if I made the 45 degree cuts to
separate them. If I cut them square to separate & drill before beveling
the ends, I would have had to go buy more pipe. I probably could have
done them in pairs cut with the ends square, drilled them, and then
separated them at 45 degrees.

Live & learn...

Doug White