Enlarging a bushing hole?

In article ,
Michael Horowitz wrote:

This is not an aircraft repair.

I've got a piece of 4130 tubing, about 3" long, 3/4" dia and I'm
trying to slip it over a like size tubing.
Just because I'm trying to let friction do the holding, I'd like to
remove as little metal from the external sleeve as possible.
I made a slot in the tube and expanded it slightly with a wedge.
I though maybe heating the insides would cause it to open like a clam.

I could wedge it open and apply heat, thus deforming the tube.

Other suggestions? - Mike

At least for larger diameter tubes, you can buy a tubing expander from
Harbor Freight -- and they work!

On Fri, 31 Aug 2007 10:43:56 -0400, Michael Horowitz
wrote:


I did it; very crudely. welded a piece of bar stock to a piece of
tubing (along the tubing's axis,(looking vaguely like a hand axe, only
much smaller), inserted the bar stock into the slot, then pushed down
on the 'handle/tube" . that opened the slot enough to allow me to slip
1/8" over the tube I wanted to surround. hammered it the rest of the
way.

Now, there are aircraft repairs(I'm thinking of streamlined tube and
landing gear) which say take a like sized piece of tubing, split it
and slip it over the original tube.

Can I use the same brute-force method or is that too much scaring of
metal? - MIke

For 3/4" tube--take a 3/4" ball bearing--drive it in until it's flush,
then take a short pc of 5/8" tube place on top of the ball bearing,
(ends have to be square) and push-- Jerry


Orval Fairbairn wrote:
In article ,
Michael Horowitz wrote:

This is not an aircraft repair.

I've got a piece of 4130 tubing, about 3" long, 3/4" dia and I'm
trying to slip it over a like size tubing.
Just because I'm trying to let friction do the holding, I'd like to
remove as little metal from the external sleeve as possible.
I made a slot in the tube and expanded it slightly with a wedge.
I though maybe heating the insides would cause it to open like a clam.

I could wedge it open and apply heat, thus deforming the tube.

Other suggestions? - Mike

At least for larger diameter tubes, you can buy a tubing expander from
Harbor Freight -- and they work!

On Mon, 27 Aug 2007 17:51:37 -0700, "Rich S."
wrote:

"Michael Horowitz" wrote in message
.. .
I find myself having to enlarge a bushing's ID by 1/16ths to 3/8ths.
My concern is I don't know how to insure the 3/8" bit is aligned with
the axis of the hole. Centered is good, but I'm more concerned with
the alignment.
Suggestions? - Mike

Chuck a rod in the drillpress the same size as the existing hole. Slip the
bushing on the rod and clamp it to the table. Replace the rod with your new
drill or reamer. Make shavings.

Rich S.


And what if the hole is whollowed out such that rod or any drill bit
you have doesn't touch the bushing walls evenly? - Mike

"Michael Horowitz" wrote in message
...
On Mon, 27 Aug 2007 17:51:37 -0700, "Rich S."
wrote:

"Michael Horowitz" wrote in message
. ..
I find myself having to enlarge a bushing's ID by 1/16ths to 3/8ths.
My concern is I don't know how to insure the 3/8" bit is aligned with
the axis of the hole. Centered is good, but I'm more concerned with
the alignment.
Suggestions? - Mike

Chuck a rod in the drillpress the same size as the existing hole. Slip the
bushing on the rod and clamp it to the table. Replace the rod with your
new
drill or reamer. Make shavings.

Rich S.


And what if the hole is whollowed out such that rod or any drill bit
you have doesn't touch the bushing walls evenly? - Mike

You can use a light weight rod and bend it slightly, so it traces the OD of
the hole, as the shaft rotates.

Machine shop supplies sell a "wiggler". It chucks in a drill or mill and has
a pointer about 2 inches long mounted on a ball. The ball fit allows you to
bend it easily, and many times over in daily use. But bending an 1/8 welding
rod will perform the same function, if you are patient with bending it.

"Michael Horowitz" wrote

And what if the hole is whollowed out such that rod or any drill bit
you have doesn't touch the bushing walls evenly?

Depends on the style of bushing, and if it is installed in a larger
structure, at present.

If it is bushing with a flange, level the drillpress table, by chucking the
rod, then using a good square to get the table perpendicular in all
directions; then clam the bushing and drill.

If it is without flange, and rather tall, chuck up rod, get bushing clamped
so that the outsides of the bushing is parallel to the rod, and drill.

If you have access to a lathe, chuck the bushing, and tailstock drill it.
--
Jim in NC

On Mon, 27 Aug 2007 20:42:47 -0400, Michael Horowitz
wrote:

I find myself having to enlarge a bushing's ID by 1/16ths to 3/8ths.
My concern is I don't know how to insure the 3/8" bit is aligned with
the axis of the hole. Centered is good, but I'm more concerned with
the alignment.
Suggestions? - Mike

I went to the machine shop around the corner with the intent of
picking their brains. He took one look at it and said "push out the
old bushing and push this one in". The new bushing had the ID I was
looking for. Total time - :15 - Thanks for the replies - Mike

On Sun, 16 Sep 2007 09:27:23 -0400, Michael Horowitz
wrote:

On Mon, 27 Aug 2007 20:42:47 -0400, Michael Horowitz
wrote:

I find myself having to enlarge a bushing's ID by 1/16ths to 3/8ths.
My concern is I don't know how to insure the 3/8" bit is aligned with
the axis of the hole. Centered is good, but I'm more concerned with
the alignment.
Suggestions? - Mike

I went to the machine shop around the corner with the intent of
picking their brains. He took one look at it and said "push out the
old bushing and push this one in". The new bushing had the ID I was
looking for. Total time - :15 - Thanks for the replies - Mike

your machine shop actually gave you the correct answer.