On Aug 13, 10:20*am, nick hull wrote:
I wrote
The crude way is to enlarge it in steps with a flycutter. You need a
reference surface on the flycutter body to measure bit extension.

My milling machine is tiny and cannot help. *I don't dare use a
flycutter on the drill press because the chuck will come off the JT33
arbor. *

Here's your justification for a larger milling machine.

In article ,
"Martin H. Eastburn" wrote:

Martin, its the sort of job you do in 10 minutes with basic hand
tools. (Which most hobbyists, like young apprentices, never learn to
use - they are in love with the power of big machines.) The ONLY skill
required is to be able to mark out accurately the ellipse of the
cutout (I said that as well, previously) - and even thats optional -
plumbers certainly don't do it. I would, because I learnt how to apply
basic geometry, engineering drawing and marking out at Trade School.

I likely will wind up doing some variant on that method, there is a lot
to be said for simple and cheap.

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

nick hull fired this volley in news:nhull-
:
It's not just fitting a drainpipe, it's fitting the entrance to my
drinking water cistern and we are currently in the worst drouth I've
seen in 30 years ;(


Nick, I have one VERY silly question: If this is schedule 40 3" pipe, what
the hell would keep you from using standard plumbing fittings to change the
entry angle to vertical?

Then you could just bore a straight hole...

LLoyd

nick hull wrote:

Interesting. I would expect carbide grit would quickly clog with
plastic, but maybe there is a coarser tooth blade available. It would
have to be a long blade, at least 12", and would need a very wide
hacksaw frame for clearance and would have to cut omnidirectional unless
the frame allowed omnidirectional settings of the blade.

The carbide grit blade under discussion will cut in any direction. It is
a wire with fairly coarse carbide chunks fused to it.

http://www.antonline.com/p_15-410-GP_402354.htm


Kevin Gallimore


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nick hull wrote:

I likely will wind up doing some variant on that method, there is a lot
to be said for simple and cheap.

The simple way of marking the entrance/exit of a large hole, as done in
boatbuilding:

Drill a 1/4" hole in the center of the eventual hole in the workpiece at
the desired angle.
Affix a 1/4" dowel to one leg of a compass (the ones that let you clamp
a pencil in one leg make this easy).
Set the compass for the radius of the large hole.
Slide the 1/4" dowel/compass leg into the hole.
The other compass leg will draw the outline of the large hole.
Repeat on other side of workpeice.

Kevin Gallimore


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This appears to be a great hole layout method Kevin.. thanks for mentioning
it.

But, the HSM tool should involve a linear bearing on precision ground shaft
(scrounged from a free/curbside printer) to attach an old, derusted set of
dividers to (with tig or silver solder).

Replaceable carbide scriber tip optional.

WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"axolotl" wrote in message ...
nick hull wrote:

I likely will wind up doing some variant on that method, there is a lot
to be said for simple and cheap.

The simple way of marking the entrance/exit of a large hole, as done in
boatbuilding:

Drill a 1/4" hole in the center of the eventual hole in the workpiece at
the desired angle.
Affix a 1/4" dowel to one leg of a compass (the ones that let you clamp a
pencil in one leg make this easy).
Set the compass for the radius of the large hole.
Slide the 1/4" dowel/compass leg into the hole.
The other compass leg will draw the outline of the large hole.
Repeat on other side of workpeice.

Kevin Gallimore