Solution for sticky aluminum?

[Shopgeezer]

I dug out some brazed carbide lathe tools I bought some time ago to try on aluminum. These were C2 uncoated knife tools. Big lump of rubber gooped on the end over the carbide for shipment. Peeling off the rubber revealed a nice sharp carbide tool. I tried a few 10 thou cuts on round aluminum bar stock and noticed that aluminum was packing up on the tips of the carbide. Noticeable bump you can feel with your thumb. I have had saw blades build up aluminum deposits when cutting round stock. I was told to machine aluminum dry with carbide but there is just too much build up of metal on the carbide tip. Is there a solution to this? Should it be flooded for machining?

Don

[fixerdave]

Some swear by WD40... what I use because it's there. A while back someone mentioned d-limonene, which is in citrus-based cleaners. I tried it, it works, smells nice, easy to clean up, but... you know... WD40 is always there.

Edit: on my bandsaw, which has no flood coolant, I just rub a candle on the blade once in a while. Works well enough and doesn't gunk things up.

David...

[lakeside53]

Does your carbide have (or is mounted at) a positive rake? If they are as I imagine, no... and you will get way better cutting action if so, And lube... kerosene, or WD40 for a better smell..

[Paul Alciatore]

Solutions for sticky aluminum:

1. Buy better aluminum.

2. WD-40 applied liberally while cutting it. FLOOD it!

3. Use HSS cutters with a razor sharp edge and POLISH the rake face. Unless you are going to be making tens of thousands of parts, you really do not need to use carbide for aluminum. And even then, I kind of doubt it.

How do you polish the face of a HSS cutter? Belt sander/fine belt/WD-40 or other light oil on the belt. You will get a mirror finish.

[754]

What is a knife tool ?
High rake helps . If aluminum is annealed it will be very gummy and pile up.
What alloy..
I never polish my HSS tools but clean em up with a fine stone..

[markx]

Very sharp cutting tools (preferably HSS) and cutting oil of some sort will mostly achieve a way better result with Al than getting at it in a dry condition. Also depends on alloy.....chemically pure Al being the most troublesome, as it is soft and sticky. Builds up on cutters and catches taps.
I had to work a lot with pure Al in a previous employment, we made test cells for supercapacitor material research and the only metal that was compatible with the electrochemistry was pure Al. It was quite a joy trying to tap M3 sized blind holes in the stuff. Stuck and broken taps were a very frequent occasion. Amazingly what worked very well as a lubricant for tapping pure Al was ethyl alcohol. Oils would sometimes make things even worse and forcing it dry was already bad enough

[MattiJ]

I dug out some brazed carbide lathe tools I bought some time ago to try on aluminum. These were C2 uncoated knife tools. Big lump of rubber gooped on the end over the carbide for shipment. Peeling off the rubber revealed a nice sharp carbide tool. I tried a few 10 thou cuts on round aluminum bar stock and noticed that aluminum was packing up on the tips of the carbide. Noticeable bump you can feel with your thumb. I have had saw blades build up aluminum deposits when cutting round stock. I was told to machine aluminum dry with carbide but there is just too much build up of metal on the carbide tip. Is there a solution to this? Should it be flooded for machining?

Don

Sometimes you also get ugly looking build-up edge on the tool but it cuts fine. Wouln't worry about build up edge with lathe tool if your finish is still acceptable.
Build up alu on lathe tool is usually less of a problem during heavy cuts but light cuts start to smear.
Mills, drills and taps are different matter as they tend to break about 10000 times easier once they load up.

[Mark Rand]

Kerosene lube and/or 2000fpm. Going at the wrong speed encourages BUE.

[Toolguy]

Use TapMagic for Aluminum. There is another formula for everything else. It works better than all that other stuff, especially on the soft gummy alloys. Just a small amount at the cutting zone. Oftentimes, I put a little bit in a rattle can lid and apply it with an acid brush It works great for all machining operations - lathe, mill, drilling, tapping, etc.

[Bob La Londe]

Use TapMagic for Aluminum. There is another formula for everything else. It works better than all that other stuff, especially on the soft gummy alloys. Just a small amount at the cutting zone. Oftentimes, I put a little bit in a rattle can lid and apply it with an acid brush It works great for all machining operations - lathe, mill, drilling, tapping, etc.

There is a version of Tap Magic labeled as "all metals." I use it on aluminum all the time... and other metals as well. It really works great.

[Toolguy]

They both work very well. I use both on a daily basis. The aluminum one works better on aluminum and all non ferrous metals. It's the only thing I've found to work on copper.

[Shopgeezer]

What is a knife tool ?
High rake helps . If aluminum is annealed it will be very gummy and pile up.
What alloy..
I never polish my HSS tools but clean em up with a fine stone..

A knife tool presents the cutting surface at 90 degrees to the work. So you aren’t cutting just on the tip of the tool but across the entire depth of the cut. These tools have little end relief and so can’t be angled to cut in to a shoulder. They can face, just not in to a shoulder. Great for fast reduction of diameter in round stock. Not much else.

I suspect speed is an issue. It is a pain changing belt pulleys on my lathe so I cheat and cut everything at 500 rpm. I will try 1200 and see what happens. I lust after the 220v 1hp variable speed motors on Ebay. Leave the pulleys on 1200 and slow down from there on the vatiable switch. Sigh. Maybe next pension cheque.

I have a squirt bottle of WD I found at the Bearing shop. Nice since not aerosol. Have to dig it out. Lost all my Tap Magic moving back to the farm. Time to buy more. I seem to remember having a big tube of wax for the band saw. Have to find that. Got a carbide insert holder on order with a variety of inserts. Nice 80 degree diamond shape. Should be able to sneak that in anywhere. Have to see how the inserts like aluminum.

The round stock I tried is miscellaneous scrap yard round bar. Seems hard enough. I have some 6061 T6 coming. Have to give that a try when it arrives.

Thanks for all the input.

Don

[reggie_obe]

WD is mostly Kerosene. I prefer to use straight kero on Aluminum and avoid the stink and extra cost of WD.