Drilling holes in steel tubing

Thanks for the tips guys.

Epoxy is pretty much out of the question for me. Kinda hard to find
things like that out here in Denver. Its gonna hafta be machine
screws... that's what I have on hand. The table saw is also packed away
right now.... grumble... grrrr.

I'd use better tubing and just braze everything, but my MAPP gas torch
just isn't hot enuf. Already tried it.

I am going to use another EMT tube running from the bike's down-tube to
the wheel as a brace. This setup is similar to the way old delivery
bikes were made. Most of the replica Wright test-bikes that I've seen
use pannier-style struts attached to the front fork and handlebars. But
this would introduce a lot of lateral motion into the experiment wheel
as the bike is ridden. I'm guessing that the Wright boys knew that and
used a frame-mounted setup.

Smitty Two wrote:

Anyway, I can see you like the bolts. You could make your own clamping
fixture, a combination of the V-block idea and the two by four idea. If
you have a table saw, you could cut stepped grooves in two 6 or 8 inch
long wood blocks. The inner step has a width and depth of 1/2". The
outer step has a width of 1" and a depth of 1/2." Drill some holes for
drill bushings, available at the industrial hardware store, press them
in, clamp the two halves around the three tubes, and drill.

If you're going to do all that cutting on a table saw, then just set the
blade at a 45 degree angle and run a block through twice so that it cuts
a nice V. If you use a 2x4 block, set your fence at about 2.25" from
center and you'll get a 1/2" wide V. Drill a couple holes to bolt it to
the drillpress table. It won't be a permanent tool, but it'll work
perfectly to build one bike.

A further enhancement, I welded a short piece of angle to a C clamp.
Makes holding the tube much easier.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

"Smitty Two" wrote

Anyway, I can see you like the bolts.

It kinda' more in lines with what the Wright brothers would have used, too,
isn't it? I'll bet they didn't have epoxy to put their bicycle wind tunnel
together, right? g
--
Jim in NC

In article ,
Ernest Christley wrote:

Smitty Two wrote:

Anyway, I can see you like the bolts. You could make your own clamping
fixture, a combination of the V-block idea and the two by four idea. If
you have a table saw, you could cut stepped grooves in two 6 or 8 inch
long wood blocks. The inner step has a width and depth of 1/2". The
outer step has a width of 1" and a depth of 1/2." Drill some holes for
drill bushings, available at the industrial hardware store, press them
in, clamp the two halves around the three tubes, and drill.

If you're going to do all that cutting on a table saw, then just set the
blade at a 45 degree angle and run a block through twice so that it cuts
a nice V. If you use a 2x4 block, set your fence at about 2.25" from
center and you'll get a 1/2" wide V. Drill a couple holes to bolt it to
the drillpress table. It won't be a permanent tool, but it'll work
perfectly to build one bike.

A further enhancement, I welded a short piece of angle to a C clamp.
Makes holding the tube much easier.

It seems you're talking about a fixture to drill one piece of tubing at
a time, while I envisioned a fixture to drill all three pieces at once,
while clamped together. I don't have the patience to draw in ascii, and
I know my written description was somewhat lacking.

I think having access to a machine shop has made me more particular
about how things fit, probably too particular. If it were my project, I
wouldn't drill mating holes in any two pieces of anything ever, unless
they were either clamped together, or dialed off to the 0.001 on the
mill. I'll freely concede that that may be overkill for this project.

On Fri, 30 Sep 2005 21:24:47 -0700, Smitty Two
wrote:

In article .com,
"wright1902glider" wrote:

If you're paralleling the tubes for six inches or more, and you filled
the notches between them top and bottom with a fillet of serious
industrial epoxy, (not the five minute stuff) I'd think you'd be able to
support more of a cantilevered load before the glue sheared, than you
would before the tubing folded at the bolt holes.

From a strenght issue, I agree; most adhesives I've worked with will
fail from the concentrated peel forces in an application like this.
What he wants to do is taper a wedge, probably of wood, over a few
inches so the load is unifirmly imposed. No, I cannot do a sketch.

(EMT isn't very
strong, and you're going to need a 0.187" hole for a #10 bolt.)

I want to see how hard he has to drive to get a 0.190" fastener (#10)
through a 0.187" hole ...

In reality, I agree with you. Most #10 are specifically on the low
side of tolerance so they can fit the 3/16" spec, and most drills
drill oversize.

Anyway, I can see you like the bolts. You could make your own clamping
fixture, a combination of the V-block idea and the two by four idea. If
you have a table saw, you could cut stepped grooves in two 6 or 8 inch
long wood blocks. The inner step has a width and depth of 1/2". The
outer step has a width of 1" and a depth of 1/2." Drill some holes for
drill bushings, available at the industrial hardware store, press them
in, clamp the two halves around the three tubes, and drill.

And leave the v-grooved blocks installed, extending past the fasteners
in the loaded direction.

Anyway, I can see you like the bolts.

It kinda' more in lines with what the Wright brothers would have
used,

In keeping with the way the brothers might have done it - how about
drillining 3 holes in a couple of pieces of wood of the diameter needed
to fit the EMT and the bicycle tube, saw in half and bolt together
clamping the tubes together? Might need 3 sets of blocks to keep
things torsionally rigid.

--0-O-0--

====================
Leon McAtee

There is a company named Micro - Mark (the small tool specilalists) (
www.micromark.com) which sells a tool called, "center finder for round
stock". Here is the item number : 82281 . Maybe it will work for you.

Rich A.


wright1902glider wrote:
Hello everyone,

I'm back in the shop again with a new problem. That is, how to drill
accurate holes on-center through steel tubing.

Thanks for all of the advice.

Orville probably brazed his tubes on, but then he was in the business
of building bicycles and had a hotter torch than I do.

Once I get the holes drilled in the bike frame accurately, I should be
able to clamp one of the EMT tubes to the frame and just drill through
the holes. Then, clamp the second EMT tube to the other side and drill
through the entire works. It doesnt have to be perfect, just good
enough not to spot from 5 feet away. The EMT is pretty forgiving and I
can tweek it into alignment with a B. A. H. if necessary.

Tomorrow is Monday, and that means its time for my weekly trip to the
local HF store. (evil, evil, evil store.. oh, evil cheap chineese
tools...) They have v-blocks listed in the catalog. Crossing my fingers
that the store carries them.

Anyone ever seen anything like them at Home Cheap-O or Lowe's Aircraft
Supply? I've seen one online thats made of aluminum and bolts to the
table of a drill press. That would be ideal I think.

Harry

"wright1902glider" wrote

Once I get the holes drilled in the bike frame accurately, I should be
able to clamp one of the EMT tubes to the frame and just drill through
the holes. Then, clamp the second EMT tube to the other side and drill
through the entire works. It doesnt have to be perfect, just good
enough not to spot from 5 feet away. The EMT is pretty forgiving and I
can tweek it into alignment with a B. A. H. if necessary.

Just make sure you put a wooden plug or something in the EMT where the bolts
go through. If you don't, they will crush when you attempt to tighten the
bolts. Don't ask me how I know that!

You could use a dowel rod, or turn a plug, using a drill press, bolt for
arbor, and a rasp.
--
Jim in NC

Have you tried JB Weld. Tough as hell and sticks like glue.

Big John
`````````````````````````````````````````````````` ``````````````````````````````````````````````

On 30 Sep 2005 19:40:40 -0700, "wright1902glider"
wrote:

Has anyone seen v-blocks for sale at Lowe's or HD?

Epoxy doesn't offer enough strength. I'm attempting to recreate a
test-rig that the Wrights used before building the wind tunnel. It
consists of a regular bicycle with third wheel mounted horizontally out
in front of the handlebars. Attached vertically to either side of the
horizontal wheel are model airfoils or flat plates.

The theory was that using trigonometry, the wrights could evaluate
various airfiol sections by measuring the angle of deflection off
center, one airfoil vs. another.

Of course, it wasn't acurate enough for scientific purposes, hence the
wind tunnel, but it'll be fun to demonstrate at airshows.