Rounding Corners on Aluminium Plate

[Jigantor]

I don't suggest anyone try this because it could be dangerous.
I have tried all sorts of ways to round the corners on the plates I use.
Band saw, linishing and a press with a die but it never gets a perfect round corner and it always needs linishing. Today I decided to try using a router.
I have a router table and purchased a cheap router bit to use.
Clamped the 6mm or 1/4" thick plate between some pine studs to cut down the chatter.
Here is the result.
I then tried rounding the corners of a 100mm or 4" diameter tube that had been 1/3rded.
Here is the result of that test.

Ji

[chewinggum]

That's a good idea. I have used a router to round the edges of plates for years, but I never thought about standing one up and doing the corners.
Nice.
CG

[aametalmaster]

Must be a down under word 1/3rded
Great idea. Plus the wood prob keeps some vibration down...Bob

[Jigantor]

The wood also helps keep the job in line with the fence when passing the gap in the fence around the cutting bit.

Ji

[Helios]

It makes sense, since they say that the cut speeds on bandsaws, etc., are similar for wood and aluminum.

Thanks for posting up.

[Jigantor]

This is not as precise as a mill but have you ever set up a mill to round corners off a plate. You require an indexing head worth $500.00 and the time required will make you think weather this part is worth it. To set the fence on the router table took a few minutes and the clamping similar. The actual run time through the router was lets say 3 seconds then I just had to unclamp and reclamp on the next corner. Total time from start to finish 10 minutes.
It was so easy I bought a larger diameter bit and recornered them to get just what I was looking for.

Ji

[kevbooth]

This is not as precise as a mill but have you ever set up a mill to round corners off a plate. You require an indexing head worth $500.00 and the time required will make you think weather this part is worth it.

Or you could use a corner rounding endmill?? Maybe a bit pricey depending on the project, but still an viable option. Takes about 60 seconds to put the bit in. Clamp said project in the table vise and have at it.

I've used cemented carbide router bits in my mill before. They actually work pretty good and you can't beat the price for the shapes you can buy. The smaller shaft (most of the ones I've found are 1/4" shaft) will cause some chatter, but other than that they work fine. Same goes for carbide tipped circular saw blades.

I've also used a router on big aluminum plates (steel too, but that was super noisy and hot and just all around not a great idea). It's best if you have a variable speed router and you can turn it down a bit. Then just ease into the cut and don't try to take the whole thing at once, take a few passes, lowering the bit, (or I guess raising the guide on a router, same thing) as you go. Wear hearing protection, some good tight gloves aren't a bad idea, and some kind of cool cut or bees wax or something to lubricate the bit.

Later,
Kev

[Jigantor]

A corner rounding end mill?
The diameter I required was 26mm and all the milling stores here don't have a mill bit over 16mm diameter that I could find. May be special order but that would take weeks and cost a bit.

Ji

[kevbooth]

I use 1/2" radius (25mm diameter) quite a bit. Available via catalog here overnight for $10.97. No biggie though like I said router bits work great. I was mostly referring to your suggestion that making that cut in a mill would be expensive and time consuming. But hands down for the money and versatility router bits cut the mustard 90% of the time.

[Jigantor]

This is a great discussion.
So how much did the mill cost brand new.
With that rounding bit do you need collets?
If so how much did the collet set cost?
Did the mill come with a machine vice?
If not how much does a brand new machine vice cost?
Unless you have the mill set up for just round cornering how long does it take to find the correct collet, collet spanner and bit and install into the mill?
How much space does your mill take up in your workshop including walking around space?
Is your mill single phase or 3 phase?
If it is 3 phase was that already hooked up in your workshop or did you have to have it done?
Does your mill run coolant?
If so how much did the coolant system cost?
Is your mill portable, you know can you take it to the job or move it if the area is needed for a special project?

I only have a very small workshop and the area to me is worth more than a machine. If I can get a machine to do multiple jobs than it gets some space if not I keep looking. I have a mill but find the router table easier as it can be packed down and stored hanging up on a wall, is portable, comes with two collets that is all that is required, fast to set up for rounding corners, edging and slotting & did not cost much. The only material I use it for is aluminium so no need for any more power.

Ji