Aluminum Sticking To Tool

If you really what have AL stick Try casting less that 1/2 hr from mold
FYI give as less a day or better heat treat first then machine.
I have try even pudding lead in the pot try speed ever thing up.

Dave

HBilly1022 said:
Yesterday was the first time I turned aluminum and thought it was awesome to work with until I started to bore a hole. The tool kept jamming with Aluminum and then would just rub on the surface instead of cutting. I tried difference turning speeds and spraying WD40 into the bore but nothing seemed to work. I kept getting a tapered bore because of it. I had to keep pulling the tool and grinding the Aluminum off the tool and eventually gave up. I finished the bore bore by wrapping emery cloth around a drill bit and running that through the bore until I got it close enough for my little project.

What is the cure for this issue?

Here's a pic of my first ever casting attempt and my first aluminum turning project.

View attachment 123132View attachment 123133
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Bob Korves said:
A lot of boring bars have geometry problems that do not allow free cutting. There needs to be enough relief below the cutting edge so the entire bar below the cutting edge clears the bore. Sometimes just turning the bar to a slightly more negative cutting angle will clear the bar away from the bore. Better yet, grind it correctly. Also, make sure your boring bar is cutting on the center of the work, height-wise.
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Bob, I checked the tool height with my recently made height gauge (glad I made it) but I think you may be on to something with the clearance below the cutting edge. I thought I had enough but didn't really pay attention to the fact that the bore is a small diameter. I bet the tool was rubbing under the cutting edge. I'm going to check that out later.
 
HBilly1022 said:
Mikey; the thing I find weir d about this is that when I was turning the outside and taking heavier cuts, everything went well but and when I first started the bore cut, it too went well. However when I started taking lighter cuts to sneak up on the finished ID things went sideways. I started with a small carbide boring bar that I had to grind down to get it into the bore but I noticed the bar was flexing as it went into the bore. Can't get a uniform ID when that is going on so I went to plan B and made a boring bar out of an old engine inlet valve. That was a lot stiffer and I couldn't see any flex, even though I knew it had to be happening when the bore was still tapered. Maybe the smaller DOC had something to do with too. Next time I'll try increasing the feed and watch for chips and I'll see about getting some Bees wax too.
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How deep is the bore and how big is your bar? Is the bar carbide or steel? What clearance angle does the insert have or are you talking about a brazed carbide bar?

If you are cutting a taper then the bar is defecting, assuming your lathe is level and so on. If your bar is steel then you can only bore 4 times its diameter before it starts to flex. I ask about the cutter because if you're using a solid bar then how deep a cut you can take varies but if you are using an inserted carbide tool then you cannot take too light a cut or tangential and radial forces increase and your accuracy goes out the window. It sounds like the problem might be the type of bar you're using?
 
I basically scanned the posts. Did you mention what aluminum you used? I started with pure aluminum from heavy wiring. Very gummy. Generally, anything that was commercially cast will be a good casting aluminum - Pistons, transmission housings, etc.

Parafin wax works with aluminum, as does Crisco shortening. The Crisco can be brushed on easily. The down side is that the smoke tends to make you hungry. :)
 
Another thing that will help....hone your cutting tool to a mirror finish. That provides less friction and gives the material less to weld to.
 
So I go out to the shop and check the last tool I was using and sure enough there was not enough relief under the cutting edge. I'm not sure if that was the only issue but it sure wasn't helping any.:oops:

Hawkeye; the aluminum I was using came from and old satellite dish that came off the house when the new one was installed. I knew I was keeping that thing for a reason.
 
It sounds like the alloy that you used had insufficient silicon in it. When i cast i use automotive or marine engine castings. The alloy is 356 and has 6 to 8% silicon. the closer the alloy gets to pure aluminum the problem you speak of gets worse. 356 alloy will machine with little problem using WD40 or kerosene. Extruded aluminium, forged aluminum etc i just take into the recycler and trade it for automotive cast. I also process aluminum ingots for the hobbiest, and small foundry casters across the US.

Pistons make excellent castings, they have a higher silicon content.

Art b
 
I don't want to hijack this thread but having dealt with the same issue myself. If Art or someone could answer the question.
I am wondering it there is a way to impart silicon by adding a flux or other additive. I don't usually add anything.
I have been using cast aluminum rims as my source lately but still find occasions of some stickiness and inconsistency.
I don't currently have a source for car pistons but I will investigate further.
I have melted lawn mower engine parts but I think those are actually something besides aluminum as they seem to melt way quicker.
 
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