what bits to use for machining ti?

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clockworkfish

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Dec 1, 2010
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will hss work? should i go ahead and get some more fancy carbide bits? What i plan to do is some counter boring, and possibly some lathe work.

side note, when machining your own screws would stainless be better than ti? or visa-versa?
 
C-2 Carbide for the lathe, and a M42 HSS Cobalt End Mill for counter boring. I honestly don't recommend working with titanium unless you have a decent amount of machining knowledge / experience.
 
The only reason why im choosing ti is because there is no heat treat needed. i have a kiln but i dont have the propper set up for working with stainless right now (no plates or ss foil) so i figure ti would be the easier, and oddly enough, cheaper route.
 
Seriously just wait for the funds for your stainless foil / quench plates or send out your work for heat treating. Titanium most likely will not be an easy or inexpensive venture for someone without the proper machinery, tooling, and experience.
 
I don't believe you will make a good cutting knife out of titanium and the effort required to get something done won't be worth it. By the way titanium screws are hard to find and extemely expensive. Frank
 
Frank Niro said:
I don't believe you will make a good cutting knife out of titanium and the effort required to get something done won't be worth it. By the way titanium screws are hard to find and extemely expensive. Frank
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i dont plan on making the blade from ti, just the liners. And why not just make the screws from ti rodstock? Mainly was asking because i wanted to make my own pivot screws since i dont like the way that many of the ones that are sold look

also i have access to some good ole big hefty mills and a nice big old hefty lathe,and both with digital readouts as well as bits but mostly hss bits
 
Titanium is work hardening, if you don't use proper feeds and speeds in conjunction with a flood coolant system you're going to end up with a poor surface finish, seizing, galling, smears, and you'll destroy your tooling prematurely.
 
for a 1/8th inch bit with 2 flutes go 44.0064 ipm at 2444.8 rpm while flooding with coolant, does that look right?
 
clockworkfish said:
for a 1/8th inch bit with 2 flutes go 44.0064 ipm at 2444.8 rpm while flooding with coolant, does that look right?
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No. Try 4.4 IPM. You misplaced a decimal somewhere.

Ti is usually run slow, fed moderately high chip load per tooth and shallow depth of cut. The thing to keep in mind is that it is twice as strong as steel but half as stiff. So a low chip load leads to smearing rather than cutting. So you need to feed it pretty hard to actually cut. But because the cutting forces are high you need to keep your actual depth of cut on the low side.

Are you using carbide or HSS? The reason I ask is that 80 SFM is high for HSS in Ti, but low for carbide.
 
When i was looking at the milling specs for 6al4v it said between 80 and 24 sfm, should i work from the low end with hss?
 
Eh, we dont do a whole lot of titanium, but would usually run 6al4v at 30-50sfm with hss tooling, and up to 150sfm with carbide. Of course, theres more to speeds and feeds than just the cutting material and material to be cut. Depending on what you're doing the cutting on, i'd probably start on the lower end of the scale.
 
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