Tips for working with aluminum

rmwarren

rmwarren

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There seems to be enough interest to perhaps fuel a running thread dedicated to this topic?

I've done a fair amount of aluminum work with woodworking tools, but would appreciate feedback on the finer points. Specifically, cutting precise slots using a router.

An upcoming project will require several 8mm slots in 3/8" bar stock and I need them precise, straight and tight width tolerance. I have a Shaper Origin & O flute bits so that seems the best route.

Any suggestions on DOC, spindle speed, etc? Also aluminum series, I tend to default to 6061 but it's just habit. [member=44099]Cheese[/member] [member=25351]rst[/member]

Thanks.

RMW
 
Yeah, I agree about the dedicated thread.

I for one would be very much interested to learn more about this topic from fellow FOGers. I do some metalworking now and then in the shop when it is needed for a project, but most of it is based on educated guesses and information I gleaned in places like this. A little education definitely would not hurt. Not when it comes to doing things right and especially not when it comes to doing things safe.
 
Here are a couple of previous threads dealing with routing aluminum.
https://www.festoolownersgroup.com/...20-for-festool-clamps-using-an-mfs-a-1010/30/
https://www.festoolownersgroup.com/...-mfs-using-an-mfs-a-1010/msg575536/#msg575536
https://www.festoolownersgroup.com/...echuck-on-festool-of1010/msg577899/#msg577899

When I first started to use a router on aluminum I just chucked up a 4-flute HSS end mill because that's what I had and it had worked well for milling steel. I soon found out that the finished slots were oversize and the finish quality was not good. So after I wore that bit out I found a 2-flute HSS end mill in my collection and used that for a while. The slots were now closer to being the correct size and the machined surface was of better quality. I thought about it and I felt that maybe the 4-flute tool didn't have enough room between the flutes to remove & discharge the aluminum chips. I also noticed several small pieces of aluminum "welded" to the end mill.

That observation made me remember my earlier bandsaw fiasco. My band saw is a variable speed so that it can cut metals or wood and I had a special blade made from tool steel, Nicholson Bi-Metalloy III to cut stainless steel with. One day I needed to cut some 1/2" aluminum plate and I was too lazy to change the Nicholson blade thinking it's only a short length of aluminum. Well the 1st inch went fine, then I had to increase the feed pressure considerably for the 2nd inch and after that the blade refused to cut any further. Upon close inspection, the gullets between the teeth were filled with aluminum and there were sections of the blade where the teeth were gone, completely ripped off from the band. 

Here's a shot of the 2-flute HSS end mill, you can see the amount of damage on the end from just routing aluminum slots. This is the reason I moved to 0-flute solid carbide bits for aluminum work, it'd also be appropriate for brass & copper. I've not yet tried the ZrN (zirconium nitride) coated bits but they should prevent aluminum welding and provide a harder surface.

[attachimg=1]

 

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Pat Warner covered this with regard to making jigs and such in
one of his books. I'll will look for it next time in the shop and let
you know the title. I have no doubt copies are still available.
 
Thanks [member=44099]Cheese[/member]. I remember those first two threads quite well. I even bookmarked them at the time. I learned a lot from that.

[member=60461]Bob D.[/member] Might that be his title "Fast, Easy & Accurate Router Jigs"? If so, I will order a copy.
 
Bob D. said:
Pat Warner covered this with regard to making jigs and such in
one of his books. I'll will look for it next time in the shop and let
you know the title. I have no doubt copies are still available.
Click to expand...

Thank [member=76090]bobd[/member] I'd forgotten about Pat as a resource. Prior to his passing we'd chatted a bit, I was aiming to do one of his in-person courses but never had an opportunity to get out there. His website also had a ton of info but looks like his heirs took it down. I should still have some of his old pdfs somewhere. I may even has his book.

He was a blunt guy, really enjoyed interacting with him. Pat's e-commerce system was "OK, I'll send it to you mail me a check...".

His router work with AL was amazing, I have a couple of his straight edges.

RMW

 
[member=8712]Richard/RMW[/member] I treasure my stuff I got from Pat and my interactions with him. On forums he came across as a curmudgeon but he loved to help people and was a wonderful innovator. Towards the end he was self publishing ebooks of tips and techniques.

He had a piece of 1/4 inch stainless rod with a point milled dead center on one end that he used in some drill press jigs and things. I asked him about it and he said “I’ve got an extra, I’ll send it to you send me a check for the postage.”

Ron
 
Richard/RMW said:
There seems to be enough interest to perhaps fuel a running thread dedicated to this topic?

I've done a fair amount of aluminum work with woodworking tools, but would appreciate feedback on the finer points. Specifically, cutting precise slots using a router.

An upcoming project will require several 8mm slots in 3/8" bar stock and I need them precise, straight and tight width tolerance. I have a Shaper Origin & O flute bits so that seems the best route.

Any suggestions on DOC, spindle speed, etc? Also aluminum series, I tend to default to 6061 but it's just habit. [member=44099]Cheese[/member] [member=25351]rst[/member]

Thanks.

RMW
Click to expand...

That bit sounds right but I've only been cutting thin copper by trial and error so can't advise on speed/feed.

I can say I hope the slots you want to mill are not wider than the opening of the Shaper's base. That soft plastic is not good at gliding over metal shards. If you use the Workstation maybe you can drop the aluminum stock below the surface and then do something creative to set Z. Swarf might still be a problem...
 
rvieceli said:
[member=8712]Richard/RMW[/member] I treasure my stuff I got from Pat and my interactions with him. On forums he came across as a curmudgeon but he loved to help people and was a wonderful innovator. Towards the end he was self publishing ebooks of tips and techniques.

He had a piece of 1/4 inch stainless rod with a point milled dead center on one end that he used in some drill press jigs and things. I asked him about it and he said “I’ve got an extra, I’ll send it to you send me a check for the postage.”

Ron
Click to expand...

[member=3192]rvieceli[/member] Ron I searched my files earlier today and found some email from 2012-15 that brought a smile. He was indeed persnickity, and delightful as well. He offered training in his garage in Escondido, which I'd hoped to do, and introduced me to the existence of metrology.

I did find some of the plans I'd purchased from him, I wish I could share them freely as they're a delight. He was also an accomplished photographer, an example of his skills:

[attachimg=1]

I hope his tools and jigs went to a good home.

RMW

[edit] And a snippet of one conversation  [smile]

[attachimg=2]

 

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Found a great thread on routing AL on the SO forum, lots of info that would apply to routing with the MFS also.

[member=44099]Cheese[/member] in some of your posts you recommend IPA as lube. I just loaded up a spray bottle with 91%, do you think that's too strong and I should use 70% instead?

Thanks.

RMW
 
Richard/RMW said:
Found a great thread on routing AL on the SO forum, lots of info that would apply to routing with the MFS also.

[member=44099]Cheese[/member] in some of your posts you recommend IPA as lube. I just loaded up a spray bottle with 91%, do you think that's too strong and I should use 70% instead?

Thanks.

RMW
Click to expand...

Be careful not to get alcohol on machined acrylic pieces. It will cause unseen stress cracks to open.
 
Richard/RMW said:
[member=44099]Cheese[/member] in some of your posts you recommend IPA as lube. I just loaded up a spray bottle with 91%, do you think that's too strong and I should use 70% instead?
Click to expand...

I can't remember what strength I used Richard but you should be fine. Remember it's flammable so no sparks.  [smile]  It also burns with a blue flame so it's tough to see, having said all that, I've not had a single issue in 4-5 years of using the stuff and it evaporates fast so no oily mess. I replaced the hot halogen light that's close to the quill with a LED light so that also eliminates a possible issue.
 
Well this is a timely email from Travers Tool, they're a viable alternative to MSC for metal tooling/machining products. Here are some tips on machining aluminum and other non-ferrous materials including some plastics.
https://solutions.travers.com/metal...ng/the-pros-cons-of-high-and-low-helix-angles

Recently, I purchased a complete set of parabolic drill bits that have a higher helix angle than normal and my intention is to use them exclusively on aluminum and plastic substrates...let's see how that works.  [smile]  The cobalt bits will be reserved for steel and stainless.

As I noted earlier, any aluminum modified coatings (anything that contains Al) are NOT recommended when machining aluminum because they do not prevent the aluminum chips from adhering/welding to the tool.
https://solutions.travers.com/metalworking-machining/holemaking/drill-coating-selection-chart

 
[member=44099]Cheese[/member] thanks for posting those links, I took a quick look and will take some time over the weekend to study. There are 2 chunks of .375" MIC-6 arriving today, so I hope to do some test cuts this weekend.

From my limited experience with true 3-axis CNC machining, I gleaned that getting acceptable results cutting AL is a combination of speeds & feeds leading to an acceptable chip size and avoiding galling, along with using lubricant. One of the challenges is feeding fast enough with a handheld tool, which is largely a question of rigidity when compared to a typical CNC Mill.

I have a roughing mill I may try in conjunction with boring starting holes for the 8mm slots I need. Cut everything with an offset and then switch to an O-Flute bit for final pass. I am hoping to hit a tolerance if a few thou in the slots. I also need an 18" long straight reference edge on this part.

[member=60461]Bob D.[/member] reminded me of Pat Warner which led me back to our conversation on Metrology and his emphasis on rock-solid jigs, securing materials and rigidly controlling interaction with the bit. Back in ~2015 I'd purchased his eBook on Jigs & Fixtures, which included this illustration of his jig for achieving straight edges:

[attachimg=1]

This takes me to a chicken/egg quandary I frequently have, the need to make the thing to use to make the thing...

I also recognized the rabbit hole I'm heading down relative the Pat's comments on the two types of WW I posted earlier. Upon reflection, I see now that a lot of the frustrations I've experienced with cutting parts is due to not properly securing/indexing stock. Some of this is due to trying to use the MFT/TS for some odd cuts that are tough to properly secure the materials, partly due to not having a robust setup for holding smaller stock whil cutting. This opens the can of worms debate on using the MFT/TS to cut things that a table saw is better suited for, but now I'm drifting away from the original topic of cutting AL.

In any case, thanks for the input and I'll report back on progress and what I learn.

RMW
 

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Richard/RMW said:
[member=44099]Cheese[/member] thanks for posting those links, I took a quick look and will take some time over the weekend to study.
1. There are 2 chunks of .375" MIC-6 arriving today, so I hope to do some test cuts this weekend.

2. From my limited experience with true 3-axis CNC machining, I gleaned that getting acceptable results cutting AL is a combination of speeds & feeds leading to an acceptable chip size and avoiding galling, along with using lubricant. One of the challenges is feeding fast enough with a handheld tool, which is largely a question of rigidity when compared to a typical CNC Mill.

3. I have a roughing mill I may try in conjunction with boring starting holes for the 8mm slots I need. Cut everything with an offset and then switch to an O-Flute bit for final pass. I am hoping to hit a tolerance if a few thou in the slots. I also need an 18" long straight reference edge on this part.

3. This takes me to a chicken/egg quandary I frequently have, the need to make the thing to use to make the thing...

4. I also recognized the rabbit hole I'm heading down relative the Pat's comments on the two types of WW I posted earlier. Upon reflection, I see now that a lot of the frustrations I've experienced with cutting parts is due to not properly securing/indexing stock. Some of this is due to trying to use the MFT/TS for some odd cuts that are tough to properly secure the materials, partly due to not having a robust setup for holding smaller stock whil cutting. This opens the can of worms debate on using the MFT/TS to cut things that a table saw is better suited for, but now I'm drifting away from the original topic of cutting AL.
Click to expand...

1. Nice stuff Richard...locally I'm able to purchase some random pieces as drop which means a 50% drop in price. That's nice stuff, you will be spoiled, a flatness of ±.005" if I remember correctly. 

2. Feeding fast is important but feeding at a consistent rate is probably more important, especially when it comes to solid carbide tooling. Solid carbide is extremely stiff, that's the reason it's commonly used for boring bars on lathes, but any sudden movement also means it can crack & break. Strong...stiff...but it fractures. [sad]

3. Ya, I'm modifying a Festool 50 mm hose to work on a Kapex and it will take me more time to produce the fixture/jig I need to modify the hose end than to actually modify the Festool hose end. It's all part of the game  [smile]  and then they wonder why engineering always takes "too long."

4. That's one of the reasons I never went down the MFT rabbit hole, then again I do have the luxury of owning a table saw which you do not have the space for. I don't use the table saw often but it does scratch an itch.
 
When I first started working in 1970, the company I worked for sold aluminum sheets and extrusions.  Our customers used animal fat to lubricate the steel saw blades (no carbide back then).

I used to train the installers and I traveled with my German Shepherd.  He was exceptionally interested in the lubricant. 

Nowadays they have synthetics that work much better.  They are easy to use.  You just rub it on the cutting tool.  And the cuts are much cleaner.

The odds are that it will not interest your dog, but it is best to keep it out of his reach.  They may still be using some animal fat in the concoction.

This is available from Grainger.  I did not check Amazon.com.
4KK73_1


 
I did grab a cutting wax lube off Amazon last week, definitely will give that a try.

The long weekend begins for me today and we have no plans/company coming. Weather is even cooperating for once. Should be lots of fun [big grin]

RMW
 
[member=8712]Richard/RMW[/member] Whilw I'm all for trying new stuff and being self sufficient, might be a time to visit a pro. After trying for a few years to get my son to buy a Bridgeport I've about goven up  [sad]

The is still a working machine shop in my vicinity with real machinists, (down from about 4 shops). If I'm nice and polite and mention that I'm not in a rush, they will do stuff for me  [tongue]

It is rarely more than an hour to an hour and a half of machine time since they charge from set up to clean up.

Might not cost that much to get what you want.

there are also some cnc laser folks online that will do as little as a one-off if you send them a dxf file . Even some that will work with jpg and pdf

Ron
 
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