How would you machine this?

[Halo4life]

If you have access to a horizontal mill with a long enough table, you could just bolt the piece directly to the table and use a 3/4in cutter. You'd have it done in one pass and it'd be almost dead on. Just make sure the piece is square to cutter.

[EricH]

Originally Posted by Halo4life

If you have access to a horizontal mill with a long enough table, you could just bolt the piece directly to the table and use a 3/4in cutter. You'd have it done in one pass and it'd be almost dead on. Just make sure the piece is square to cutter.

Yep. The problem is, you need 60" (5') of travel. Most mills I've seen have nowhere near that length of travel in one pass.

Now, if you have the sides accurate enough, you could do it in two or maybe three passes. Pass one: one end to about the middle. Make sure the vise or other holder is straight first, though.
Pass two: Move the table back to start. Move the part to the middle, using the quill to help align. Repeat first pass. Do not have the tool contact the metal when you start!
Pass three: Repeat pass two.

[Ben Piecuch]

How about a metal blade on a table saw? To get the 3/4" slot you may need to rip it twice, but it should be fairly accurate. You can always plug the extrusion with some wood after the first cut to keep it straight and true. Metal blades aren't cheap, but neither are 5' travel horizontal mills...

Bengineer

[AdamHeard]

Is this to lighten the part, or is it a track for something to move in?

A manual mill may do it like eric said if you can keep the vice straight. I also like Ben's idea of a table saw.

[Tapoore]

Originally Posted by Ben Piecuch

How about a metal blade on a table saw? To get the 3/4" slot you may need to rip it twice, but it should be fairly accurate. You can always plug the extrusion with some wood after the first cut to keep it straight and true. Metal blades aren't cheap, but neither are 5' travel horizontal mills...

Bengineer

That was my first thought because we have already have a metal cutting blade for our table saw, but I'm just not sure if we could get a high enough level of accuracy. I'll try this tonight on a piece of scrap.

Originally Posted by AdamHeard

Is this to lighten the part, or is it a track for something to move in?

A manual mill may do it like eric said if you can keep the vice straight. I also like Ben's idea of a table saw.

The slot is for nylon rollers to run in. It's supposed to be kind of like Bishop Wisecarver's DualVee but cheaper and lighter (the rollers won't be so "V" shaped so we won't have to make the 45-degree bevel on the edge of the slot.)

Thanks for all of the quick replies!

[Laxphan1525]

Originally Posted by Ben Piecuch

How about a metal blade on a table saw? To get the 3/4" slot you may need to rip it twice, but it should be fairly accurate. You can always plug the extrusion with some wood after the first cut to keep it straight and true. Metal blades aren't cheap, but neither are 5' travel horizontal mills...

Bengineer

I myself would not enven dare to try to make that big of a rip cut with a table unless its a saw you have no desire to use again for its proper use of cutting wood. The table motors arnt made for the kind of force need to cut aluminum. I tried this before on a dewalt table saw and didnt end very pretty not only is it bad for the machine its dangerous. I was trying to cut a 1/8 sheet of aluminum on a table saw and the piece vibrated uncontrolably and didnt leave a good cut what so ever.

[Ben Piecuch]

Laxphan,

We regularly cut 1/8", 1/4", and 1/2" thick aluminum on our table saw here at work. It is, obviously, a little more heavy duty than your run-of-the-mill consumer table saw. But with the proper tooling and use, a table saw can certainly cut aluminum material.

I'm not saying that I'm the one doing the cutting, as I know that I am not experienced enough to work with the thicker materials. But, it can be done, and could actually provide the precision that is asked for in this application.

Bengineer

[sanddrag]

The shape you are looking for could presumably be formed from 3 pieces. A C-channel and two pieces of L angle. Rivited, welded, whatever.

[Laxphan1525]

Originally Posted by Ben Piecuch

How about a metal blade on a table saw? To get the 3/4" slot you may need to rip it twice, but it should be fairly accurate. You can always plug the extrusion with some wood after the first cut to keep it straight and true. Metal blades aren't cheap, but neither are 5' travel horizontal mills...

Bengineer

I myself would not enven dare to try to make that big of a rip cut with a table saw unless its a saw you have no desire to use again for its proper use of cutting wood. The table saw motors arnt made for the kind of force need to cut aluminum. I tried this before on a dewalt table saw and didnt end very pretty not only is it bad for the machine its dangerous. I was trying to cut a 1/8 sheet of aluminum on a table saw and the piece vibrated uncontrolably and didnt leave a good cut what so ever. By the way the saw was securely mounted to the floor. Personally i would never dare to use my own table saw to rip metal. On top of that most abrasive cutting wheels are about 1/8 at most 3/16" which means you be making a lot more passes than two. Also to rip a 3/4" slot in wood you use a dado blades but there is no such instrument for cutting metal for the table saw.

As for my personal solution to machining this object you two option if you have access to mill you can mill the slot in two passes with 3/4" 2 flute mill bit by flipping the piece around. You should have no trouble doing this on any stage 1 or 2 bridgeports 9" x 41" tables. However if you dont have a nice mill. you have another option. We have a dewalt router about 4hp that we can put mill bits in for doing similar processes. If you go this route you need to create a jig to clamp the work piece and also a guide for the router to follow so it stays on the same cutting path. The mill is a far better option but we have used the router before and it works great much better than a table saw ever would. However you need the correct machine for any process therefore a 3/4 hp router is made for cutting wood not cutting metal.