Carbidizing help please.

Lyon

Lyon

Well-Known Member
Hi all,

I am working on a folding knife with a titanium liner. I was doing the final fit of the lock bar and some how it is now too deep on the lock face. (This is my first time doing this BTW) I am pretty sure that the voltage I was using to carbidize the lock bar was too high (25V) and I ate away the face a little bit.

I am using my home made titanium anodizer to Carbidize the lock bar. From the reading I have done I should be able to build up the lock bar surface a little bit. I have done a fair bit of experimenting but I can't get it to work. I am using a 5 amp variac power supply converted over to DC. The carbide end mill is mounted in a dremel engraver. The positive lead is on the carbide end mill. I have tried voltage's from 13 - 40v.

Any help is greatly appreciated.
 
If you're trying to build up to make up the difference for a lock that is too short via carbadizing.....it's a loosing proposition. In general you won't be able to build up the face to anything that will extend the lock face. I'm assuming the knife has a liner thickness that would allow you to peen the lockbar in order to lengthen it? That would be my first choice.
 
I agree completely with Ed. I've found myself it the same situation a couple of times and carbidizing the lock face to lengthen the lock just doesn't work. The carbide will not build up enough to make any difference. Like Ed said, peening the tip of the lock bar a little or using a flat faced punch will likely gain you enough length for the lock to engage properly. That's how I've solved the problem on my liner locks.
 
Did you try reversing the polarity?
I seem to remember the carbide depositing better when the part is positive, and the carbide is negative.
 
Fellhoelter,

Yeah I tried reversing the polarity. It didn't seam to help.:15:

I also tried a lot of different voltages. I did 5V increments until I blew the fuse in my power supply. I tried a power supply with less amperage (mine is 5 amp). I tried different tip thicknesses for the carbide. I tried different speeds of moving across the work piece. The nice thing is I got a lot of experience in how fast the titanium comes off of the lock bar under a variety of different circumstances!

For the record. I would recommend voltages in the 15V range on a 5 amp power supply (I was looking for a steady nonviolent spark that didn't want to stick when moved slow). It is also helpful to avoid contact with the edges of the lockbar so that they don't get worn down. Since I was working on a liner lock this was more important. To help I brought the carbide down to a bit of a point for better control and kept it moving across the face without being in a hurry but not staying in one place ether.
 
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