How to cut & polish titanium??

RokJok

RokJok

Gold Member
Joined
Oct 6, 2000
Messages
4,107
Below is a pic of a titanium blade (my first) I'm working on at present. I have a couple of terribly FNG questions about working with the material. Please excuse my extreme ignorance of the requested info.

I've already looked at prior threads here on cutting Ti. The only solid recommendation seemed to be using bi-metallic blades (by Lenox maybe?) which I assume would be used in a bandsaw. Unfortunately, I don't have a bandsaw in my shop yet.

I'm working with a sheet of 0.080" Ti and, to say the least, found it dang tough to cut. Yeah, I know, Ti is starting at the tough end of the materials spectrum for a neophyte. ;) I burned through three Handi-Discs (carbide coated fiberglass substrate discs) making about 14" worth of roughing cuts, so am looking for more durable and appropriate cutting alternatives. I also burned the temper from a 1/4" solid carbide cutter roughing out the handle shape. The carbide will still cut, but has turned a nice dark blue. The blade currently has a full convex working (not polished) edge finished to 120 grit Norton 3x18" belt running on my woodworking belt sander. To say the least, it still needs a boatload of work done on it.

1. Could I use a table or circular saw with carbide tipped blades and make a series of very shallow but increasingly deeper cuts?
2. Will a bandsaw cut Ti? (could be a good excuse to go buy a bandsaw since I still have enough Ti in the sheet for about 7 or 8 more blades)
3. Will Ti chew the diamonds off a diamond-plated blade? (think masonry cutting blade)
4. Should I simply do stock removal on O1 or other standards steels for a while until I figure out the process? (I already know the answer to this one is "YES!") ;)

Also, is there a generally accepted standard procedure for polishing Ti? I assume that at worst I could use consecutively finer grit belts in my belt sander to do the job.

Many thanks in advance for all info,
-- Greg --
 
I have alot of respect for Ti. Very strong for its weight and very resilant to the elements. I purchased a wood stand up band saw a while back when builders square was going out of business. In hindsight if I did it over again I would buy a metal band saw from say enco or grizzly. They sell for under $200.00 and cut either horizontaly or you can flip it up and saw verticaly with a small work table attached. The problem with wood saws is that they run way too fast. I had to reduce the pulley on the drive to get it to an acceptable speed. I went through plent of 90" blades at $20.00 a pop. With the reduction pulley it probably still wasnt slow enough either.

I went through many band saw blades and the bi-metal seem to work the best for me. I seem to still burn them up at times and have recently gone to friction cutting. This is where I put the fast speed pulley back on the band saw, run it as fast as it will go and it cuts my .075 Ti literially like butter.

As far as other methods for cutting Ti I have used little cutoff wheels on the foredom for slitting the liners but you tend to go thru alot of them and they smell like $hit! I currently use Carbide cutoff wheels in the mill,lathe or drill press to slit the liners. Bad thing about this is they are very expensive.

I do some file work on Ti and use my foredom with either carbide burrs or diamond tip bits. The diamond bits are realitively cheap but they tend to burn up after a while. I had an ole timer tell me he dips his diamond burrs in mineral spirits ocassionaly when he uses them and they last longer. I tried that but it tends to splatter and I didnt like that.

Ti like everything else can be polished by bringing it down in finer grits. Just takes time and elbow grease. I take my knife usually down to 400/600 grit and then to the buffer if I want anything polished. I found that polished Ti doesnt look that good. Kinda looks cloudy looking. Also if you polish Ti and then color it it tends to rub/wear off real quick! I had to redue a few of my early knives for this reason.

As far as your other questions, I havnt tried them so I cant help there. Hope some of this helps.
 
I gotta ask -- what alloy of titanium are you using to make a blade from? I have yet to find an alloy except one very exotic one that will harden enough to make a servicable blade.
 
I have a Bosh Progressor jig saw in my shop which is by far the best jig saw I've ever owned or used.

Bosh makes a special application carbide blade that will cut just about anything. I have used it to cut 1/8" carbon fiber like butter and a little bit of Ti as well.

These blades don't have carbide teeth, the entire length of the blade is covered in coarse, rough carbide and just chews up everything.

I'm not sure if anyone else makes them or not but you'll need the Bosh saw to use the ones I'm speaking of because Bosh has a special shank to fit their tools.

If need be you can get the saw and the blades from www.coastaltool.com

The blades are part number T118AHM.

I bought my saw locally and have a hardware store that stocks the bits so you may be able to find them locally as well.
 
Thank you guys for the quick replies. I appreciate your input.

-- Plain Ol Bill -- "I gotta ask -- what alloy of titanium are you using to make a blade from? I have yet to find an alloy except one very exotic one that will harden enough to make a servicable blade."
I don't have facilities for hardening, so I'm just doing strict stock removal, i.e. grinding off whatever doesn't look like a knife. :) I got the Ti at a salvage yard and am not sure of the alloy. Here are some numbers on the back of the sheet that may indicate what alloy it actually is:
MIL T-9046 JAB 1 AM2 AMS4911 H
RM16AL-4V ANN

After doing a bit more searching in the Shoptalk Archive, found that this alloy is 6AL4V per Mr Smyth (thanks Jim!).
http://www.bladeforums.com/forums/showthread.php?s=&threadid=143207
I'm not sure if this is an appropriate alloy for a blade, but it's certainly hard stuff! :D

CPirtle, I've seen those grit jigsaw blades around and will have to try them out. Thanks for the tip. I seem to recall that I may even have some already in one of my "still packed up" boxes here somewhere. Next time I'm buying a big honkin' shop that happens to have a house attached, instead of a house that happens to have a garage on it that gets used part-time as shop space. ;)
 
I have been an avid woodworker and carver for years. I always had a shop at my parents house in their spare 2 car garage.

When my wife and I moved about an hour away it got impractical for me to do any work in my shop so we moved into a 3 bedroom apartment and I commondeered the 3rd bedroom for a shop. It was a 10x10 room and I had 2 work benches, a bunch of hand tools, a rolling tool chest, 2 mountain bikes, a floor standing scroll saw and a ton of other stuff packed in there. The rest of my big equipment was mothballed at my parents house.

When we started shopping for houses my number one priority was room for a shop.

We ended up buying a house with an 1800 square foot basement of which 900 square feet is now shop. We've only been there a couple months so I'm not back in business yet completely but just about. I plan to start making my own fixed blades this fall once things settle down a little bit, can't wait!

Lately I've developed an addiction to sub 5" OAL fixed blades and carry them clipped to my pocket in a custom sheath for work instead of folders. I plan on starting off there.

If the Ti doesn't work out for you there are places like Koval and Texas Knife you can send the piece to have it HT'd, that's what I plan to do. Or just start with Talonite :D

Good luck!
 
Below is a pic of a titanium blade (my first) I'm working on at present.
Click to expand...

Hey Greg
IMHO, I have good news and bad news for you.:(

The bad is, titanium just won't make a good blade.
tempered or not.:(

good news is you'll have a nice butter Knife/letter opener there.:)

Can I ask how you happened to pick TI for a blade?:confused:
some good Knife steels are less expensive to use.
I'm not tying to be funny here just interested in Why?
:confused:
 
Ti really isnt a good blade material as was pointed out, but its good to learn on easy to work/cheaper pieces. Hard to get a good edge on Ti that wont dull to quick. There is Beta Ti out there that Mission uses that seems to be pretty good, but the 6AL4V (6%Aluminum/4% Validium)is too soft to cut effectively.

RocJok, Dont be afraid to use normal type steels for the blade when you get down the road a bit. If you go to a local knife show you can pick up a piece pretty reasonable and if the heat treat kinda intimedates you, get the blade as close to finished as you can and send it to me and I will heat treat it for ya with my blades. I pretty much only use stainless steels,440C,420V,440V,154CM & D2. This way I can air cool them. (Dont like the hot oil quench!)
 
Friction cutting works great. That's mil-spec 6-4 Ti which as everyone says won't Rc very high. If you can get something like 15-3 (triple three), it can be brought (heat treated) to the upper Rc forties which isn't too bad.
 
Cutting 6Al4V ti on a metal cutting bandsaw is a total piece of cake. Using a good bimetal blade from the knife supply houses, you should be able to get months out of a blade cutting both steel and titanium. Buy a HF, Delta or Enco bandsaw for under $200 and invest in the good blade. End of story.
 
I started with Ti simply because I bumped into it while browsing around the salvage yard. I thought, "Hmmmmmmm, titanium. Don't they make knives out of that stuff, like for diving? Lets try this stuff out."

I've got a quick question brought on by the news that Ti doesn't make a very good edge retention material. Why is the edge retention so low when this Ti is so incredibly hard to cut and grind?

Is it that the material matrix is soft (giving an easily deformed edge = quick dulling) but incredibly strong (not easily torn matrix = tough removal of material via cutting/grinding)??? I suspect so because when I was grinding the edge into place with 50 grit belts, there was a feather edge formed on the edge that was about 1/16" in length. :eek: That struck me as being a really long feather to form and not grind off. OTOH this sheet of Ti seems to simply be a really hard material, or at least that's my impression.

Thanks also for the info on working with steel and heat treat. CPirtle, way to go on getting a good size shop!! Yeah, I'm jealous. :D Peter, thanks for the bandsaw & blade recommendation. I've got Jet and Porter-Cable/Delta inventory surplus outlets within about a 40 minutes drive, so bandsaw shopping may be on my list for next week. ;)
 
You must log in or register to reply here.
Back
Top