Machining Titanium

[Deuce Rails]

My current "art" project is definitely off topic.

However, I thought that the practice of machining titanium would be of interest to some people, and I need some help, so I thought I'd ask the HAMB. (And maybe restore some normalcy to the bizzaro recent off-topic posts.)

I've been married for 5 years, and as an anniversary present to myself I decided to make a replica of my wedding ring for my other ring finger. I decided, for better or for worse, to do it out of T-2 titanium.

Aside from being extremely hard, titanium doesn't conduct heat very well. As a result, the cutting tool gets hot quickly, and any cutting oil starts smoking, even at low speeds.

I'm turning the piece in a Taig-type lathe, using TiN coated tools, and good old Tap Magic fluid. I was able to turn the piece to outer size, and start a center-drilled hole. But it was very slow going, and reaming out 3/4" is going to be tough.

Do you guys have any advice? Anything on tool material types, material handling, or any other experiences would be appreciated.

Thanks in advance,

Matt

[noboD]

Matt, I tried that stuff 20 years ago, not much luck. Of course the cutter coatings didn't exist then. Have you tried TiCn, the purple one. It makes an endmill about 82 Rc if I remember correctly. I've used them on some ugly stuff with great results. Good luck,from a fellow 'chinist.

[alchemy]

PM Corn Fed and see if he knows.

[ray]

good luck, it's a bugger to work with! i do it a lot, but not much for advice. make sure you got the sharpest cutting tools possible, dull doesn't cut it with Ti. everything i do i use a water soluble cutting oil, i think it conducts the heat better. carbide is best of course to cut it with, if possible can you pilot drill it with carbide? that would be a start. "cobalt" drills are what we use normally in production though. i don't know about the alloy you are working with, i deal with some medical grade, but you could try annealing it, with Ti i think you just have to heat it to 4 or 500 deg f. then let it air cool, that's it. at least with the stuff i work with, your alloy may be different. when drilling, don't be afraid to put a little force to it, you will make the heat go into the chips not the workpiece.

sharp tools are the most important though.

[oldchevyseller]

check out a google search on titanium machining .alot of hits on it, tap magic is clorintaed and dont recomend using any clorinated or halogen cutting fluid, i have witnessed some titanium milling at a former employer and alot of tool heat is a huge problem ,good luck http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Blownolds]

Instead of reaming the center, could you hone it?

[noboD]

Chlorinated cutting oils eat your liver, too.

[ray]

is tap magic still chlorinated? they changed the formula a few years back. don't know why i care, i never even use the stuff.

[Hot Rod To Hell]

Whenever I machine Titanium for Body jewelry, I use a water based cutting fluid called "Anchor Lube":o... Make sure your tools are SHARP, have your work pice turning SLOW, and use a heavy feed rate.

[Deuce Rails]

Thanks for the responses, guys.

I'll try with some water fluid and a TiCN coated tool.

Is stainless steel (like 316) much easier to machine, or not?

Thanks again,

Matt

[Hot Rod To Hell]

[ QUOTE ]
Is stainless steel (like 316) much easier to machine, or not?

[/ QUOTE ]
YES!!

[Dreamweaver]

Sharp tools (regular WC works well, you don't need the coated ones)

Slow feed

Tapmatic or a water based coolant if you feel the need.

Here's a url to my company's Ti Handbook, see page 16, 17 for machining and fabrication.

Titanium (http://www.timet.com/pdfs/ti-handbook.pdf)

[Spitfire1776]

Go to this forum, the owner is a machinist in CLeveland who's a good guy that made some parts for me in the past. His name is Bob (in life and on Forum). He works with titanium a lot and would probably be more than happy to give you some sort of assistance.

http://www.network54.com/Forum/231665

Check out some of the stuff ion his website too.

[C9]

[ QUOTE ]
Is stainless steel (like 316) much easier to machine, or not?

[/ QUOTE ]


No experience with titanium, but I do machine a lot of stainless.
Both 308 and 316.

I use carbide cutting bits in the lathe and 5% cobalt drills for drilling.

If you use sharp cutting bits, the buffing to a bright finish is easy. You can go directly from lathe to buffer.
(Not sure if titanium buffs up bright or not - I'm guessing it remains dull.)

As a small aside I made some hot stick tools (used to work high voltage electrical lines hot, up to 500kv anyway although the ones I made were for for 16kv and down.)
The tools are installed on the ends of hot sticks so as to accomplish various tasks.
These particular tools designed by an Edison lineman to speed up a couple of specific jobs in a national linemans rodeo.
Seems like the improved tools did the job, our guys got third in a national event.

Anyway, the point to this little story is, once the tools were made (out of 316 stainless, cut down bolts in fact) I buffed them up till they shined like chrome.
The lineman were impressed and I was pleased with my part of the work.

As a completly not applicable to this discussion comment, I remember seeing rings guys made in junior high and my dad told me that such rings were common when he was in school.
The rings were made from coins, stretched to fit by hand working over a long period of time.
Interesting part was, you could see the coins stamped pattern on the outside of the ring.

The stretching done by what dad called a spoon, but I think
the stretching was done with a dull pointed piece of 3/8" or so rod.
Many of the junior high rings were made from nickels and I saw one ring an uncle did that was made from a silver quarter.
Back in the day when money was real.... http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Hot Rod To Hell]

Actually C9, the only Ti alloy I work is 6AL4V-ELI, and it will take a polish that makes it hard (near impossible) to distinguish (with the nekkid eye) from polished 316LVM!

[ray]

Ti will polish nicely, but it will oxidize/dull quickly also.

[Flexicoker]

the outside of this muffler is Ti, doubt its been polished since it was made about a year ago, still looks pretty good.
http://img.photobucket.com/albums/v237/Flexicoker/Formula%20SAE/IMG_4996.jpg

[Dreamweaver]

Hmmmmmm, not true. It does form an oxide film, that's why it is relatively corrosion resistant.

I have samples that were polished in the 60's that still look like mirrors.

Ti does fingerprint badly.

You can also anodize it a variety of colors, if anyone is interested in that, pm me. Also, as evidenced by the muffler, you can heat tint it also.

[ray]

must depend on the particular alloy, the stuff i work with you can see a difference in the parts after they sit overnight. but it's a medical grade, so i suspect more pure. that's why its bad to make generalizations about metal, like "stainless" steel for example.

[Hot Rod To Hell]

Actually Ray, I'm gonna have to disagree on this one too. 6AL4VELI is considered "IMPLANT GRADE", and I never notice it oxidizing quickly! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[Deuce Rails]

You guys are confusing me.

I got T-2 beacuse it was supposed to be a little easier to machine than T-6, but probably not as corrosion resitant.

I didn't choose Ti for the tough challenge. I actually chose it because I thought that it would have a duller, warmer look than stainless, similar to the way nickle plating looks next to chrome.

Should I start again with 316 or will the T-2 actually look different when I'm done?

[Dreamweaver]

All this depends upon what you mean by polishing.

Ive been a metallographer for the US's largest titanium producer for almost 30 years, doesn't matter what grade it is, if I polish it, it stays that way http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif But like everything in this world one man's definition of polish is different from another.