Knife #13 Mini-WIP: Now for something completely different.

Erin Burke

Well-Known Member
Hey Guys. Y'all probably know by now that I keep a camera in my shop whenever I build anything. So, while I hadn't planned on making a WIP for Knife #13, I have a few progress photos that I just have to share. It's like my therapy. :biggrin:

Knife #13 is a COMPLETELY new animal for me. There are a TON of firsts taking place in the following photos:
  • First folding knife of any kind.
  • First balisong (with the exception of a Typhoon kit that I put together a few years ago).
  • First time working with Titanium.

These are just a few.

The design for this knife is actually based on a fixed blade that I made a year back (Knife #6).

I really liked this design shape for an EDC, but just can't bring myself to carry a fixed blade. I really like balisongs (in fact I EDC a BM-42mc every day), so it seems natural that I started plotting to turn the design into a butterfly. Oh... and did I mention it is for me!

The first thing that I did to make this work was take a nice profile photo of Knife #6 and import the image into AutoCAD as a scaled raster file. Then I "traced" the profile and began playing with pivot and stop pin locations to establish the open and closed configurations. Lots of circles everywhere. :3: The image below shows a "cleaned-up" version of the original CAD design.

So the next step in the process was to map-out the handle design to some XY coordinates accompanied by a list of operations. Here's one of my paper working copies.

It should be noted that I do not have any CNC capabilities on my mill (but I do have some decent DROs), so all of these XY locations were hand-cranked. This next photo show some holes appearing in a sheet of 0.13" 6AL-4V Ti.


It took me a while to get to this point and I learned some things:
  • It is important to have good bits for drilling Ti. HF jobbers are NOT up to the task. I broke three of them in three holes. After buying some MSC "made in USA" screw machine bits, I never broke another.
  • It is important to have the correct cutting speed when drilling Ti. I found that 20-30sfpm worked for me with the MSC cobalt bits. With carbide end mills I ran around 60-70sfpm.
  • Ti does NOT like my Kobalt brand cutting fluid. Drilling was much smoother "dry" using multiple "pecks" to allow the bit to cool and remove "coils/chips"... usually three pecks per hole (for #31 bit).

Please note, I'm showing how I am building this knife... not necessarily the best way to build this knife. :shush: I'm sure there are better methods out there.

Next, I cut the handles from the Ti sheet and began profiling them on the grinder. Just a side note here... Ti sparks will cause any steel dust that happens to be floating on the top of your water bucket to go Zzzzzt Poof (or at least that is the technical term for it):34:.


This is where I started to think "this just might work".

Shortly after this point (while working on my first attempt at a blade - now in garbage) I discovered that 1/4" pivot bushings will NOT fit in a 0.25" reamed hole. :49:

And shortly after THIS if discovered barrel laps and ordered a few. Three cheers for barrel laps! :35:

Somewhere amidst the pivot bushing size/barrel lap ordering fiasco, I decided to build a pocket clip. I really like the clip on my BM-42mc, and decided to build something similar. So, I bought some 0.05" 6AL-4V from ebay, lit the torch and started bending. I also recessed the clip attachment point into the handle using a 5/32" end mill. I think that it turned out OK.

Next it was time to start the blade (actually my second start at a blade, as I screwed up the stop hole/notches on blade #1 - see above). I'm using 1/8" 1080 on this one. As with most things on this knife, the blade started by drilling a bunch of holes.

Here is the roughly profiled blade "dry fit" to the rough handles.

And here are a couple of "dry fit" photos of the knife with the blade ground and heat-treated.


As of today, progress is at a standstill until I get a 3/16" end mill in the mail. This will allow me to tighten up the blade play and finalize the handle-fit. After that, I'll start shaping and rounding the handles. My design also calls for a spring latch... which I still have to figure out. I'll keep you posted.
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Well-Known Member
Great write up and awesome work!

(Btw, one of your pics is duplicated... the one that talks about starting the blade with a bunch of holes)

Bill T

Well-Known Member
It's a beautiful knife and so is #6 Erin . And what a cool approach to doing the handles . It puts it in the realm of possible - with some tweeking - for us without a mill . I would probably spent a year trying to fit each handle side in a single narrow bar ... wondering why it wasn't working so well .. Great Wip !

Erin Burke

Well-Known Member
Thanks guys... and BRad, you're right, I did somehow managed to screw up the photos. They should be fixed now. I also added some orange text to let y'all know that I messed up the first blade as well. The one pictured is my second attempt. I didn't mention it, but I also did two different heat treats on the second blade. I tried to do a clay coated hamon on a profiled blank (without bevels). I ground the bevels after HT... with frequent dips in the bucket to keep things cool. Turned out that my hamon ended up riding the edge, leaving some soft spots. Fortunately I had enough meat at the edge to reapply clay and try again. If anything, I think that I may have hardened too much of the blade this time. It may be easier to see after I finish polishing and etch.


Well-Known Member
Erin I have looked at some of your other WIP's and once again all I can say is wow! you sure have some talent.

Erin Burke

Well-Known Member
Awesome way to drill all those holes. I might have to look into some DROs for my mini mill

Thanks Alistair... like I said above, this may not be the best way to do it. But it has worked for me so far. It would have been impossible, as far as I'm concerned, without the DROs. I cannot imagine working without them. :22:

What type of mini-mill do you have?


Well-Known Member
Thanks Alistair... like I said above, this may not be the best way to do it. But it has worked for me so far. It would have been impossible, as far as I'm concerned, without the DROs. I cannot imagine working without them. :22:

What type of mini-mill do you have?

One of the Seig X2 versions. I have the pulley drive conversion for it which makes a huge difference. Another thing that would be good is stops on the X and Y parts of the table, would make some things easier for sure.


Erin Burke

Well-Known Member
No progress to report today, but I did get a fun package in the mail from MSC last night. There were only three little items in this deceptively expensive package.

  1. 3/4" ball end mill
  2. Rubber tapping adapter
  3. package of three springs

Guess which item was the most expensive... nearly four times the cost of the other two combined? Those who know know. :3::sad:

Two of these items will be used on this knife, one won't. Any guesses.

Erin Burke

Well-Known Member
A little Action

Hey Folks,

I completed this knife this morning. I haven't had time to take fancy photos yet, but I did shoot a quick action vid. Never mind the mediocre flipping... my flipping skillz (and videography skillz:what!:) are not nearly as well developed as my bo-staff skillz or my computer-hacking skillz. :shush::9:


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