# Machined Sleeves for Very Thin Tubing



## erikmannie (Sep 7, 2020)

I am working on a project where the steel is well over 100 years old and the wall thickness is .020”.

I make these “internal sleeves“ out of mild steel so that I don’t blow holes in the old, thin tubing.

The following pictures are for a non-mitered sleeve for old tubing with an ID of .973”.

I started with 1” round stock. Faced, turned to .972”, drilled and bored to a thickness that I feel very comfortable welding on (the sleeve ended up with a wall thickness of .111”).

Later today I will use drills and a boring head on a mill to miter this to fit to a 1.900” tube.

Old tubing, raw stock, turning and facing:


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## erikmannie (Sep 7, 2020)

An old timer showed me this trick how to center a lathe tool. I had never seen it.

You don’t have to use a fishtail. The guy uses a piece of brass that he knows is straight.

You put your cutting tool against a turned surface and adjust your tool until the fishtail is perfectly vertical. This centers the tool.


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## erikmannie (Sep 7, 2020)

Drilling, boring and fitting the sleeve:


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## erikmannie (Sep 7, 2020)

I chamfer the edges so it fits in the tube nicely:


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## Bi11Hudson (Sep 7, 2020)

Congratulations Sir; It looks like you've found a solution to a problem. The tubing looks mightily like 3/4 EMT without the galvanizing. I have used watertight couplings to join EMT but they leave quite a bulge at that point. And the rings are not really reusable, despite claims to the contrary. I've also used an internal wedge-like device when building frames. But they block the tubing so wires can't run through it. Might I ask how you plan to attach the tubing. My first instinct is to use a flat wheel tubing cutter and roll the tubing into an external groove. Your solutions could prove interesting.

For what it's worth, I'm an old timer myself. And been using your system of tool alignment for ages.
.


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## erikmannie (Sep 7, 2020)

Bi11Hudson said:


> Congratulations Sir; It looks like you've found a solution to a problem. The tubing looks mightily like 3/4 EMT without the galvanizing. I have used watertight couplings to join EMT but they leave quite a bulge at that point. And the rings are not really reusable, despite claims to the contrary. I've also used an internal wedge-like device when building frames. But they block the tubing so wires can't run through it. Might I ask how you plan to attach the tubing. My first instinct is to use a flat wheel tubing cutter and roll the tubing into an external groove. Your solutions could prove interesting.
> 
> For what it's worth, I'm an old timer myself. And been using your system of tool alignment for ages.
> .



I will choose gas welding because the tube that it is being attached to is .020”.


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## erikmannie (Sep 7, 2020)

That took a long time to bore a 1.900” hole. I drilled to 1/2” and then set about using a boring head with brazed carbide boring bars. There were many passes.

Here are some pictures:


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## erikmannie (Sep 7, 2020)

It was a weird setup because the workpiece was 0.972” and the hole diameter was 1.900”.

Again, these are sleeves that slide inside 0.973” tubing that butts up to a 1.900” tubing at a 90 degree angle.

You can see the sacrificial aluminum “parallels”.


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## erikmannie (Dec 10, 2020)

Here are pictures of 4 sleeves which were gas welded in. These mitered sleeves will be gas welded on to .050” tubing (which is over 100 years old).


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## erikmannie (May 9, 2021)

My aunt & uncle got this bench back from the powder coater. The powder coater charged them $500 to powder coat it.

My aunt supplied the very old bed + paid me $1,200 total for time & materials.

I used the earnings from my labor to buy lathe dogs as well as lathe files & handles.







My uncle will put in the redwood for the seat.


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## Just for fun (May 9, 2021)

That's an expensive bench!  But looks very nice.


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