Cutting slots in Titanium

S

Scooter

Joined
Jul 13, 1999
Messages
103
I'm going to attempt to make my first liner lock. (I'll make one first from aluminum or something) I understand approx. how things go together and such but as I have never worked with titanium (let alone seen any), I have a question or two.

When cutting the spring from the liners, what do you use? I don't have a milling machine so it would have to be with hand tools or some sorta jig/drill press or something.

How hard is titanium to cut/drill/tap etc?

I was thinking of trying a small diamond cutoff wheel that Lee Valley tools sells for dremel type tools (it's cheap, a few bucks) - do you think this will last long enough to cut through several inches of titanium?

Any help would be appreciated.

Thanks in advance.

Darren
 
I have used two techniques to cut out the locking bar from the liner.

The first technique is to drill a hole at the point where the locking face (front of the bar) meets the cut that defines the side of the bar. This allows me to use a very narrow band saw blade to make first the cut across the locking face, then turn 90-degrees in the hole, and make the cut straight down the liner. This could also be done with a jeweler's saw.

The second technique, which I now prefer, is to make the short cut across the locking face with a bandsaw (or any other saw, so long as the cut is straight). Then I take the liner and place it horizontally in a vise that can slide smoothly along my drill press table (for poor man's freehand miling). I chuck a Dremel cutoff wheel in the drill press, lower it to the correct depth, and lock the stop. By running the drill press and sliding the liner (in the vise) against the cutoff wheel, I can make a perfectly straight, burrless cut which meets the other cut at 90 degrees. It usually takes 10-15 minutes and several cutoff wheels, but the result are very nice.

This trick of using a cutoff wheel in the drill press and a sliding vise is also a good way to make evenly spaced, parallel grooves in a variety of materials.

------------------

-Corduroy
"Why else would a bear want a pocket?"

Little Bear Knives
Drew Gleason:
adg@student.umass.edu
 
Sorry, you had a couple of questions I missed!

Re: diamond wheels for Dremels. I have had no luck with these so far. I bought a few inexpenx\sive ones anf found their cutting very poor, they mainly just heated the material up. This might actually work to cut Ti, because it becomes strangely ductile at 1600 F and can be friction-cut, but I'm not optimistic about the diamond wheels. I've also tried varius tiny circular saws. My opinion is that the abrasive cutoff wheeels massively outperform these other methods, cutting through every hard material with ease. I'd get a bunch of these, they're the #1 Dremel accessory in my book!

Re: drilling/tapping Ti. Titanium can do a number on conventional HSS bits, because it becomes ductile and "grabs" when heated - so as soon as the bits get dull, or if they are run too fast, cutting action will decrease rapidly and bits will be damaged. Also, Ti can form some wicked burrs when the bits dull and more pressure is needed. On the other hand, sharp, new cobalt bits can go through Ti with ease. HSS works, but cobalt will, in my experience, more than make up for the price difference in both endurance and ease of use. Either way, use low speeds, lots of cutting fluid, and when bits start to dull, relegate them to other tasks (like handle materials) or toss them, and get fresh bits.

-Drew
 
Scooter,
I cut the slot in the liner using a slitting saw. The saw blade is held using a saw arbor
in my drill press. I drilled and filed a slot
into a piece of 1/2" thick steel. I place this steel plate into a cheap cross slide vise that i got from a woodworkers supply catalog (i think it cost 50 bucks). The vise is bolted down onto my drill press table. I
then clamp my liner onto the steel plate and line it up making sure that the saw cuts in the right spot. Run your drill press at the lowest speed and slowly feed the saw into the liner. Make sure that you use plenty of cutting fluid (i use COOL TOOL II). I don't have a milling machine either so i had to improvise.
BTW, you can buy the slitting saw and the arbor from Sheffield's Knifemakers Supply.

Hope this helps.
Barry
http://albums.photopoint.com/j/AlbumIndex?u=126319&a=926274
 
I use a foredom tool which is just a dremmel on steriods! I use dremmel cut off wheels #409 if I remember right. I drill a hole to where the liner is split and a hole to where the end of the liner/split ends up. I hand cut the first cut to the first drill hole. Trying to keep it as square as possible. This is what meets the back of the blade. I have also used my drill press. I have a vise mounted on the table and can clamp the liner in there and just move the vise with the hand cranks to make a perfect straight cut. If you use alot of tapping fluid you can cut a full liner with 1 cutoff wheel. If you don't you can go thru 4 or 5 pretty easy.

After the first cut I change to cutting length wise and cut about 1 inch worth and then go to the bandsaw and finish up the split with it.

Just a few notes on liner locks. The angle of the back of the blade should be around 7 1/2 degrees. Liner cut flat. Also don't forget where the detent ball for the liner lock goes. It needs to remain on the blade when opened and closed. Hope this helps!
 
Thanks very much guys!

I just got a fax from Sheffield, so I'm looking into that one.

Thanks for the other ideas as well.

Best regards,

Darren.
 
I have to go along with Barry on the slitting saw. One thing to note is if you don't want to buy expensive cutting fluid, go to the store and get a bottle of Dawn dishwashing liquid it will work fine and is also bio-degradable. Put some of it in your cooling bucket and it will keep the grindings off of the top of the water.

------------------
Curtis Wilson -
Wilson's Custom Knives, Engraving, and Scrimshaw
 
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