Straight edge cuts

[cdm]

What is the best way to get straight edge cuts in alum plates of 2-4mm thick? For instance when you want to make some body panels that actually fit together..

I have been told horizontal bandsaws are better than vertical ones (what i use) due to less blade wandering but in order to have a 10" cutting reach you have to buy industrial grade.. All the tabletop ones i've seen are for pipes or angle irons and wont span more than say 5" at very best.

Metal cutting places give wild accuracy guarantees ranging from 1/8" to 1/4. And only go straight pieces, if you need an L shaped piece, you are still out of luck.

I wont bore you more. How do you guys get those precision cuts done?

[doodlebug]

Set up a rip fence on a vertical bandsaw. If using a table saw, sandwich it between 2 sheets of plywood , and a fine pitch blade. Is that any help?
Cheers, Neil.

[RCP57]

I use my vertical bandsaw and then file them to fit.

[ihbuilder]

Originally Posted by RCP57

I use my vertical bandsaw and then file them to fit.

was just going to say that . when cutting use some bees wax

[cdm]

That's what i have been doing. Then i powersand them at 90D to get the burs and lines straight. this means i must always leave at least 1 edge factory straight which results in wasted material and a lot of time.

Given how many steps there are and how long it takes, i considered i might be doing something wrong. I use clamps and a piece of alum bar as a guide and slide across it as i cut. Setup is a nightmare though. I wish there was a XY or even X table for bandsaws like the proxxon stuff for drills.

[Ken Orme]

I use a vertical band saw with a metal cutting blade on it. The metal cutting blade is tempered and has fine teeht. I cut alum, brass and copper. I found out the hard way not to try to cut steel with it, sparks will fly. I have cut square aluminun tube to make a special size channel. I either use a belt sander then files on a piece 2 feet or longer.

The trick is to use a metal cutting blade or a very fine tooth blade

[ihbuilder]

how wide of blade are you using ? I went with a 1/2" it doesn't seem to wander as much .

[cdm]

1/4 cuts like butter but teeth are too wavy to prevent side bite. not good

1/2 to 3/4 blades at 18 to 24tpi work best for me

my biggest issue is precise and stable centering especially across

[Espeefan]

I cheat and use my milling machine!

[cdm]

Originally Posted by Espeefan

I cheat and use my milling machine!

what type of end mill and size do you use for that (and rpm)? my square end 5mm isn't exactly up to snuff for line cutting.

[Dieselchopper]

Originally Posted by Espeefan

I cheat and use my milling machine!

I guess I really cheat then using the 10' shear at work!!!

[Espeefan]

Originally Posted by Dieselchopper

I guess I really cheat then using the 10' shear at work!!!

I've got access to a few of those at work also, and I've used them, but I didn't want to rub it in anybody's face. Shears still don't leave a perfectly clean edge. They cut nice, but the face of the cut is never as nice as milled edge.

[Mt.Dew]

I have a Wet saw with a diamond blade for tile cutting. tried a sheet of 1/8" it cut great.

[Espeefan]

Chris, I'm not a pro machinist, so I just go by how it sounds, and my mini-mill doesn't have an actual RPM speed chart, though I bought an optional tach that I never hooked up. I am guessing I run about somewhere between 1,250 to 1,800 RPM, using a 1/2" diameter sq. end mill. I rough cut sheets of aluminum with a saw, then clean and square the edges with the mill. Sometimes the smaller pieces can be clamped, on edge, in the work vise, but if the edge you are cleaning up is not well supported, it will flex and vibrate, and that doesn't do the end mill or the piece any good. More so on the thinner material, obviously. It depends how much hangs outside the vise jaws, and how thin the sheet is. All of my end mills are just high speed steel, coated with TiN. I also run some oil, applied manually with a bottle. Kind of low buck operation!

[cdm]

Thanks guys. I'll get to it and see how it turns out

[Dieselchopper]

I agree with ya Espeefan on the cut. But when comparing price of equipment ill take the shear. I bought a little one that works great on 22 ga steel. 8" working width and gives real clean cts for small parts.