Threading Titanium rod

[yoshie]

Hi, not sure if this is the right place to ask but we seem to have a forum with a huge amount of experience... I need to run a die down a few bits of titanium rod I've has a wee practice and it turned out fine. I'm afraid that after cutting a few threads the die may loose its edge and tear the next ones, can anyone suggest a lubricant to make the cutting easier and protect the die, I just used engine oil the first time. It's been cut by hand so speed isn't an issue.

Thanks

Mike

 

[brightspark]

Hi, not sure if this is the right place to ask but we seem to have a forum with a huge amount of experience... I need to run a die down a few bits of titanium rod I've has a wee practice and it turned out fine. I'm afraid that after cutting a few threads the die may loose its edge and tear the next ones, can anyone suggest a lubricant to make the cutting easier and protect the die, I just used engine oil the first time. It's been cut by hand so speed isn't an issue.

Thanks

Mike

rocol rtd . temaxol. templars , or trefolex cutting compound

 

[gordon stephenson]

on the Rocol rtd, Excellent stuff and I love the smell!!

 

[hareng]

Not to up on TI but do have some here that i wouldnt like threading or even turning.
Could be grade dependant. Sure its 6ALV or similar i tried last year, took edge clean off HSS, a variety of ceramic tips with barely just a clean up pass.

Any idea of the grade and what thread your running down?

 

[yoshie]

The bar is Ti-6Al-4V and I'm running 2 off 30mm x 8mm threads and 4 off 30mm x 1/2 UNF threads, I'll try and get some Rocol RTD. I've never worked with titanium before just trying to help someone out.

Thanks all for the advice

Mike

 

[Lawnmowerboy]

I don't think titanium is that hard, people bang on about it but its only strong for it's weight and strong and hard are 2 different things, a good quality die should be fine, trefolex smells the best when it's hot from cutting, sherwood do one similar to dormer supercut but it's a bit deer

 

[hotrodder]

I don't think titanium is that hard, people bang on about it but its only strong for it's weight and strong and hard are 2 different things, a good quality die should be fine, trefolex smells the best when it's hot from cutting, sherwood do one similar to dormer supercut but it's a bit deer

Have you ever worked with it?

Stainless isn't particually hard but plenty of people struggle to drill holes in the stuff. Ti is, or rather can be, worse albeit for slightly different reasons. Annealed grade 5 (6Al-4V) is harder (and stronger as the two are related) than normalised 4130 chromoly. It's a poor conductor of heat which means that heat stays at the cutting edge. It cuts differently... no built up edge which places higher loads on the cutting edge again increasing temps. It has a relatively low modulus of elasticity which means it tends to deflect more than steels, this means light cuts can result in chatter/rubbing further increasing temps. The other problem with light cuts is that Ti is pyrophoric i.e. like magnesium it can catch fire VERY easily in air when finely divided and ruin your day.

It's also VERY prone to galling i.e. will weld itself to the cutting tools or in the case of threaded fasteners to whatever it's screwed into given the chance.

 

[chunkolini]

hotrodder
Not easy then?
Is this why decent Titanium bikes are so pricy.

 

[penfold]

It's not heating that's the problem, it's the workhardening that rubbing causes; Ti workhardens and ruins your day very quickly.

 

[hareng]

Just got to tool up for it Chunky, specific inserts, speeds and know how.
The actual TI is dear £185 for 2m of 1 1/4" x 2mm ish wall super high pressure tube from US been meaning to do something with for years.

Surprising how heavy TI is, its only light when its kept wafer thin.

Thats the one 6AL-4V, no wonder its wearing the die out. I would seriously look at someone that could screwcut it that knows what they are doing.
It will need turning or drilling out any way for the 1/2"UNF, whats this 30x8 thats course?
Even if you tapped or ran the die down, chances are lubed or not it will lock up.

 

[hotrodder]

It's one of them along with the cost of the stuff itself. I tend to think of it this way... stainless is/can be harder to work with than mild steel i.e. needs more attention to detail (if it's to stay 'stainless') and is harder on tools etc. Ti is kinda to stainless as stainless is to mild if that makes sense. Same goes for welding, Ti is lovely stuff to weld (although the filler wire tends to stick to the weldpool, especially if you catch the edge of the pool) but needs LOTS of attention to cleanliness and inert shielding

Good point on the workhardening. I didn't think it was any worse than austenitic stainless in that respect, i thought it was it's 'springiness', poor thermal conductivity and abrasion resistance that made it (potentially) a PITA compared to stainless. From a quick play with google that might be 'cause i'm more used* to commercially pure grade 2 http://www.crp.co.uk/UserFiles/Documents/Corrosion%20Resistance/Titianium%20and%20Titanium-Pd.pdf which is a lot softer and still a bitch.

Found this on tapping which throws elastic memory into the mix... http://www.eisc.com/support/titanium.htm


* a relative term, not like i'm working with the stuff regularly (thank God)

 

[Shox Dr]

It's elastic all right. I did a MTB Trade show at Olympia circa '97/98. Around the time Raleigh special products section brought out the Ti with hideous paper graphics.

Any way the stand next to me was a Russian Company building Ti MTBs, very nice bikes too one of them, a very large chap, spent most of the weekend bouncing up and down on the rear stays, to prove how strong they were.

At the same time Ti bolts were all the rage in MTB, and the cheaper bolts were cut, instead of rolled.

 

[Wallace]

Surprising how heavy TI is, its only light when its kept wafer thin.

Heavy? I have a pinch bar made of Titanium alloy and most people that pick it up ask if it's hollow! I know it is definitely solid as I cut it to length 30 years ago using 3 hacksaw blades in the process and struggled to break the last little bit. Titanium or Ti alloy (from memory) is about 40 to 45% lighter than the alloy steel equivalent.

Mike