Drilling holes in steel tubing

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.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite

I would cut a couple chunks of 2X4 and clamp them to the frame and both bars
at the same time. If you don't have a centerdrill, use a punch to insure
your drill starts in the right place. Then you can clamp the whole thing
down to your drill press table.

--
"Don't be misled, bad company corrupts good character."
www.LCTPaintball.com
www.LCTProducts.com


"wright1902glider" wrote in message
oups.com...
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.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite

Find two pieces of angle iron. Weld, bolt, glue, or tape together -
one up and one down. Set on the drill press and center the "V" section
under the spindle using the smallest drill bit you have. Clamp in
place. Just drop the EMT into the "V" and drill away. You can use the
welded seam to keep the holes at each end in phase. Do the same for
the bicycle frame or use the drilled EMT for a drilling jig.

If you drill first with an 1/8" bit and bolt together using 8-32 bolts
you can go back and drill with a long 3/16 bit in your cordless and
have everything nice and tight.

Hose clamps with a bit of old inner tube make good clamps on irregular
things such as this.........
======================
Leon McAtee

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.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite


Harbor Freight has a jig for about $5. Just a V-shaped piece of
aluminum that bolts to the bench press table. Position it so that the
bit drops down into the bottom of the V. Center punch the tube, and
position the tube on the jig so that the bit drops to the punch
depression. You'll get a centered hole every time.

I build my own jig from a piece of steel angle and a couple of bolts
before I realized that Harbor Freight sold the jig.

--
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)."

In article .com,
"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.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite

Any reason you've ruled out epoxy in lieu of the bolts? Seems like you
could make a nice neat job of it. You can get it in different colors, or
add pigment to the clear stuff.

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.

In article .com,
"wright1902glider" wrote:



Epoxy doesn't offer enough strength.

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. (EMT isn't very
strong, and you're going to need a 0.187" hole for a #10 bolt.) But
that's just a feeling. I was the guy who built the weakest cardboard
bridge in high school physics, so I'm probably wrong.

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.

The best (strongest) epoxy is Belzona 1111 also refered to as Belzona
Super Metal.
Super Metal is machineable, no VOC's, no solvents, does not rot, does
not rust, does not shrink, or does not corrode. It is compatable with
all metals.
The same can not be said of Devcon, JB Weld, and most other epoxies on
the market. Yes many claim to be as good as Belzona but experience and
research has proven time and again they do not produce results as good
as the Belzona product. Belzona is may be more expensive but, if
results are important, is actually less expensive.
www.belzona.com

In article .com,
"Clay" wrote:

The best (strongest) epoxy is Belzona 1111 also refered to as Belzona
Super Metal.
Super Metal is machineable, no VOC's, no solvents, does not rot, does
not rust, does not shrink, or does not corrode. It is compatable with
all metals.
The same can not be said of Devcon, JB Weld, and most other epoxies on
the market. Yes many claim to be as good as Belzona but experience and
research has proven time and again they do not produce results as good
as the Belzona product. Belzona is may be more expensive but, if
results are important, is actually less expensive.
www.belzona.com

And speaking of epoxy and bicycles, recumbent bike guy might want to
know, if he's still hanging around here, that there's a carbon fiber
bicycle whose tubes are secured to titanium lugs with epoxy.

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)."