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How to Turn Square into Round

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oskar

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#1
I want to make a disk 2” OD x 1/2” thick from a 2.2”x2.2”x1/2” aluminum flat stock. This is my first time I use my mini Taig to turn and to get the hang of it I use a piece of MDF. In the attached picture the cutting tool is a carbide insert tool I bought as a set (6 of them all identical with a triangular shaped tip). I have no other turning tools but I’m expecting some materials to arrive soon and I will grind my own.

Is the setup acceptable or there is a better way to do this work?

What kind of a tool will be the best for this job?
 

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JimDawson

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#2
If you have a bandsaw (or even a hack saw) to knock the corners off, you would save some turning time, but other than that you are doing it exactly the same way that I would.

Best tool? What you have should work fine.
 

T Bredehoft

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#3
Just a suggestion, get in the habit of removing your drill chuck from the tailstock. I don't know how many times I've drawn blood from a drill or center drill.
 

Mitch Alsup

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#4
Just a suggestion, get in the habit of removing your drill chuck from the tailstock. I don't know how many times I've drawn blood from a drill or center drill.
I find simply removing the drill bit takes 95% of the problem out of the way.
 

benmychree

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#5
I use the Aloris morse taper tool holder to do drilling etc. and rarely remove the center from the tailstock.
 

Djl338

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#6
I just bought these from my favorite metal guy on eBay, if you get bored with the rounding project.
2” round stock
 

francist

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#7
One other thing to be mindful of when starting with a square piece on the lathe is that it can really tighten your chuck onto your spindle if you happen to have a threaded-nose spindle.
When you first start turning and begin knocking the corners off its almost like an impact wrench effect with the sharply interrupted cut. If you have a threaded chuck, this can really tighten it onto your spindle and make removing the chuck difficult later. Taking a few minutes to knock the corners off the blank first on the sander or bandsaw like Jim says can really help mitigate this.

-frank
 
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P. Waller

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#8
In the recent past I turned 1 1/2" square bars to 1" round for a length of 8" on a 30" long part, 20 parts in total.
304 SS stock, it took 14 hours and about $300.00 worth of carbide inserts to knock the corners off with any speed.
If at all possible avoid interrupted cuts.
 

oskar

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#9
That’s encouraging Jim and I was planning to cut off the corners but I forgot. For sure I will do it on the aluminum.

Good point Tom. The drill chuck should not be there

Thanks
 

oskar

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oskar

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#11
One other thing to be mindful of when starting with a square piece on the lathe is that it can really tighten your chuck onto your spindle if you happen to have a threaded-nose spindle.
When you first start turning and begin knocking the corners off its almost like an impact wrench effect with the sharply interrupted cut. If you have a threaded chuck, this can really tighten it onto your spindle and make removing the chuck difficult later. Taking a few minutes to knock the corners off the blank first on the sander or bandsaw like Jim says can really help mitigate this.

-frank
Very good tip Frank, thanks
 

rwm

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#12
If I leave a drill in the tailstock I always put some Neosporin on the tip...
R
 

GL

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#13
Neosporin is good. I find if you replace the drill bit with a self injecting syringe of tetanus you don't have to go to the doctor nearly as often.
 

mmcmdl

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#14
Another option would be hole saw in a BP or drill press and use some kerosene .
 

GL

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#15
Something more constructive to the actual question: Since it looks like the disk you are making needs the whole edge turned, which I assume is the reason for the spacer behind the part, one issue with driving the part with the bolt/arbor may be it will slip when you get to aluminum, especially on an interrupted cut. You might try pushing the part into the face of the jaws with a live center in the tail stock. Friction drives the part, but further out (diametrically) than just the bolt head in the middle. The tail stock keeps it centered. The sacrificial spacer probably should be round, but it will get a groove cut into it on the first pass anyway. With "normal" stepped jaws you can set the chuck to miss the jaws - your setup is a good workaround. I have done this on about everything, even stainless. Have seen utube videos demonstrating also. Stacked between thicker plates, you can turn thin pieces too.
 

oskar

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#16
Your observations are correct GL and when the time comes to do this work with aluminum I will keep in mind your comments. It was a good idea to do this job on MDF, gave me the "feel" of turning and I learned a lot.
 
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