Things I've learned this weekend.

Brent Dowell

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For some reason, I got a project in my head of some things I wanted to make. I thought it would be fun to work at making some custom 'coins' out of aluminum. Mainly I thought it would be fun to learn how to mill aluminum.

What I've learned is:

1) Calculating Chip load is very helpful. Instead of just randomly plugging in feed rates, it helps to use it as a guide.
2) When cutting Aluminum, In my case, Lubrication helps. I just used som tapping fluid, but it made a huge difference in how things cut.
3) When cutting little discs out of aluminum, I had much better luck doing a rough cut, and then a final finish cut to cut it out.
4) Explore the simple engraved lines more than than necessarily doing a bunch of vcarves.
5) I should really look at getting some smaller bits than 1/8", 1/16" might be enough to help with pocketing some smaller areas.
6) I gets really cold standing around in the garage at temperatures right around freezing watching a CNC run it's programs.

20151213_185021.jpg
 
Dang it. Left out the most important thing I learned.

Using a touchplate to set the Z-zero. That is super userful. You connect an alligator clip to the bit, and put a little plate underneath the bit, then the cnc will automatically figure out where the exact zero to the top of the workpiece is.
 
Thanks Vaughn, I've still got a long, long way to go, but these were the first 2 that turned out halfway decent.

I'm not sure what is more difficult, the design, or getting it to actually render the way I imagine it should. But working my way over both those learning curves.
 
So you just bought the discs? One think I like about US is that you can buy almost anything, unlike here. Those coins look great, I can imagine may uses of them.
 
Brent very very cool. As a guy that has been fascinated by all the money in the world , had a fair bit to deal with making validators for coins and was a franchisee for commemorative coins for Rugby World Cup once .....man those came out real nice.

Now lets have a collectors edition FWW one with a woodworking tool on one.

Toni in my view what makes things work in the USA is the freedom, and UPS and Fedex. :rofl:
 
I can't believe you didn't turn a FWW coin!!!! They do look cool!:thumb:

I need to do that next!

Brent very very cool. As a guy that has been fascinated by all the money in the world , had a fair bit to deal with making validators for coins and was a franchisee for commemorative coins for Rugby World Cup once .....man those came out real nice. Now lets have a collectors edition FWW one with a woodworking tool on one.
Toni in my view what makes things work in the USA is the freedom, and UPS and Fedex. :rofl:

I'll work on one!

So you just bought the discs? One think I like about US is that you can buy almost anything, unlike here. Those coins look great, I can imagine may uses of them.

Just started off with 2" flat aluminum bar stock. I cut them into squares then screw it down on the spoil board.



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I polish it up then cut it. Here's what it looks like in the computer.

coin.jpg
 
Brent

I suspect you already know this but there is a world of difference in Aluminum alloys. If that bar stock is the normal hardware stuff it is very gummy and tough to cut cleanly. I used to be familiar with several alloys but don't rememmber many specifics but it is worth looking into.

Garry
 
Very cool, between you and Leo I'm getting a bit of CNC envy.

I think you might need a wood stove out there!

I need to do that next! I'll work on one!

Not to be demanding.. but in brass? :D :rofl:

Just started off with 2" flat aluminum bar stock. I cut them into squares then screw it down on the spoil board.

Why cut them into squares and not just screw down the flat stock and then do multiple coins in one "pass"? Do you have to leave tabs to avoid launching the coins?
 
Brent

I suspect you already know this but there is a world of difference in Aluminum alloys. If that bar stock is the normal hardware stuff it is very gummy and tough to cut cleanly. I used to be familiar with several alloys but don't rememmber many specifics but it is worth looking into.

Garry


Yeah, It is the typical hardware store stuff. I went through several rounds of trying to get things to cut right with it. Welded some aluminum to the tips of a few bits before I got these 2 to work out.

I needed to do 2 things, up the cutting speed and use some lubrication. I've got some other sheets of aluminum plate that I'm thinking of some project ideas for that are of a different alloy, I'm not sure which though, but will probably need to change up some of my parameters.

I have started keeping a spread sheet of parameters that details the material and what settings I used that were successful, as long as calculating the chip load.

Just glad to be cutting!
 
Not to be demanding.. but in brass? :D :rofl:

Why cut them into squares and not just screw down the flat stock and then do multiple coins in one "pass"? Do you have to leave tabs to avoid launching the coins?

I have been seriously considering giving brass a try. Would give the coins a little more 'heft' than you get with aluminum.

Once I get a design I'd like to mass produce, I expect I will be doing exactly that with the bar stock. For now, for one offs, cutting them one at a time is easier.

I'm also considering how to do double sided 'coin's. There are some challenges in registering the position of the stock that I would need to work through.

I've got some ideas on that that would require a combination of software, hardware, and workflow to be able to master.
 
I like it...

I think I'd skip the small lettering under the headline, I have trouble reading it at blown up size (not that my eye's are the best..). It would be interesting to try it and see how it looks but I suspect it'll be too small.

I might replace one of the chisels with a hammer..
 
I like it...

I think I'd skip the small lettering under the headline, I have trouble reading it at blown up size (not that my eye's are the best..). It would be interesting to try it and see how it looks but I suspect it'll be too small.

I might replace one of the chisels with a hammer..

Good suggestions. I might look a little harder for a better saw to use too.

Ordered some 1/8" brass sheet to try. I think these would look better in brass than aluminum.
 
I think I have the double sided machining figured out.

What should I put on the back side?

Maybe make it a 'round tuit' Ala Larry?
 
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