Cutting Copper Lengthwise

[Velocity]

OK, cutting copper to make a solder joint is fairly straightforward; you use a tube cutter, or, if you are feeling particularly ambitious, you use a hacksaw. However, how would one cut copper lengthwise? I need to remove a small, 1/4" x 6" chunk of copper from a 3/4" tube. I would like this cut in be as smooth and straight as possible. I am trying to figure out the best way to do this, short of a mill. Perhaps a Dremel cut out tool? If I traced the lines to cut, ground down part of it with a sanding drum to make a distinct path, then hit it with the cutoff tool, I might be able to pull it off. Anyone have any opinions on better ways to go about this? Thanks.

[CS]

Hmm...

Well if you have a drill press you might try this. Get one of those little abrasive disc dremel bits and put it in the chuck. Next put the pipe in a machine vise (you may have to use some risers to get the pipe more then half ways out the vise) then just feed the pipe and vise into the bit and use it to make your 6" cuts. Then finish those two cuts off with a perpendicular cut from a hacksaw or tube cutter.

[Ragnarok]

OK, cutting copper to make a solder joint is fairly straightforward; you use a tube cutter, or, if you are feeling particularly ambitious, you use a hacksaw.

For that, I'll use the hacksaw, as it doesn't crush the end of the pipe - makes for better ends, although they need a little filing to get them square and cleaned up.

Perhaps a Dremel cut out tool?

That's what I do when I need to do such a thing, although I warn you, the Dremel will eat discs like chocolate buttons when you're cutting copper - they get worn away PDQ.

[TurboSuper]

Try an angle grinder, it's really just a Dremel on steroids.

[Hotwired]

An angle grinder to make lengthwise cuts in 3/4" copper?

Madness.

If I was personally doing that I'd be using a dremel and freehand cutting firstly because I have no other option and secondly I'm quite used to it.

Have the pipe clamped firmly and the line marked out with a scratch or tape and fairly slowly (no other option really with a dremel and metal that thick but at least the speed means it's easy to keep on course) cut along the line.

Works for me anyway.

All I can say about cutting copper with abrasive disks is I'm glad I can buy non branded replacement abrasive disks... they die after only a few inches of cutting unless you manage to snap them in the slot by not having the tool dead straight.

[Ragnarok]

All I can say about cutting copper with abrasive disks is I'm glad I can buy non branded replacement abrasive disks...

Yeah, I picked up a truckload of 'em a while ago when Maplin had a £10 offer on their rotary tool bit set, and that had huge numbers of the discs in them, which is a good thing.
There is a tougher variety of abrasive disc you sometimes find in sets that will usually do a lot of cutting before they wear out, but they are scarcer.

[Gippeto]

Let's start with "What tools DO you have?"

Sounds like you have a Dremel tool, anything else?

Dremel ideas have been covered, so I'll skip that, and add to the drill press ideas.

If you have a drill press, you could fabricate a "sled" to hold the copper pipe, clamp a straight edge to the drill press table, and use the thing like an inverted router table.(requires either a 1/4" rotozip bit, router bit, or milling bit)

Make multiple light cuts. You will need to file the edges afterwards.

[mark.f]

Actually, as you know, copper is pretty soft.

A hard, sharp blade should be able to score the initial cuts, at which point you could use a small saw to finish it.

[jimmy101]

Like Gippeto said, A drill press or a router table (or a router) with a small ID straight cutting carbide tip should'nt have any problems cutting copper. Even a HSS bit should be OK.

If all you have is a router and bit then just make a pair of fences from 1x2 or 2x4 wood, clamp the pipe inside the two fences, use a guide on the router base to follow one of the pieces of wood ...