I need help with a linerlock design...

[jaegar]

Hi,
I'm working on designing and making my own linerlock. I've followed several designer's methods to make it, including Bob Terzuola, Don Robinson, and Ray Rogers.

None are coming out quite right however. I came up with a design I liked, made an aluminum prototype, and it seemed to work. I went on to cutting the titanium for the liners, and after looking at them, it seems the design needs some tweaking.
Due to money constraints, I'd like to be able to save the titanium I cut out. Therefore I've worked on a slightly different design, using the ti. that I have.

Here is the original:

The red (1)s show where I want to put a thumb disk, and where it will lay when closed.

The green circle is my problem. As you can see, when open, the blade spine does not meet the top of the handle. I would prefer for the spine to at least be even, if not above the top of the handle.

I think I could make this design work, just grinding down the back edge of the liners. I'm not sure though.

Here is the changed one:

(this is an outline of the ti liners I have already cut out. I can't increase the size of the liners, as stated above.)

As you can see by the green circles, I've added a little thumb stop to the blade, and raised the blade spine to meet the ti. liners. The problem comes when the blade is closed. This is shown where I filled in with red. The corner of the blade tang sticks out, It needs to be in, but that would take me back to the original problem.

Some side notes are that the pivot hole is slighly off center for that liner in the revised design.
Another is I'm not sure if I alloted enough space for the spacer in the back, shown by the blue circle.

I realize this is probably hard to understand, I'm sorry . Any help you can give would be greatly appreciated. I'll be glad to clarify anything necessary.

I could just trash the liners and start over, I've got more titanium. That stuff isn't cheap though, and I'd like to be as conserving as possible.
Thanks!
-Brian-

 

[bartblade]

i think the design is great the way it is. i say make it and if u dont like it then u know what not to do next time.

 

[bartblade]

i do have one thing to add though not from expirence but from examination of liner lockers instead of making the blade and lock match and lock side by side. i think a new design should be tried where the blade has a slott to accept the lock and kind of over lap the 2 together and to garentee the lock lever dose not slip past the blade and have to pull on the spine of the blade to get it to unlock. i know it is usually the cheaper knives that do this but i think that it would be a great improvement to the liner lock design.

 

[STR]

Years ago when I first took interest in making folders I made very primitive but sturdy liner lock prototypes out of brass. Very thick work hardened brass. Some of those I gave away to my brothers just to have and was quite surprised to see some of them nearly 20 years later after being used and carried but still functioning fine. I guess I should not be surprised since the original liner locking electricians knives were work hardened brass also.

I have a couple of patterns I've used. You can do them any number of ways. I make my spacer bar/ blade stop all one piece but for years I used the end cuts of a 3/16" drill bit as my stop pin fitted between the liner and lock. If you do this technique you can use G10 or Micarta or even wood for your spacer bar. I have also done them using barrel pivot pins cut to the right length to function as spacers that screw down. The little cut off discs you can buy at Lowes or Sears work quite well for cutting these down IMO and can certainly be made to work. I have done it this way countless times. I use these cut off discs to cut my locks out also. They cut right through the hardests steels.

Here is a pic of a knife I designed and have built several of. If it gives you anything to go by feel free to use it. You can see one I'm currently building for a fellow forum member here at this link from start to finish, as well as, some other knives I'm woking on at this time. Good luck. http://www.knifeforums.com/ubbthrea...=737199&page=0&view=collapsed&sb=5&o=&fpart=1

 

[jaegar]

Forgot to say that another problem is with the location of the thumb disk. It seems too far, that you would need a large thumb to work it. I've got larger hands, so it works for me. Also, it will be my personal EDC. So it's not really a big deal, but I can't for the life of me figure out how to fix it if it were for someone else.
That's one of the big problems.
Thanks for the help,
STR: I'll be using a stop pin. It'll probably be 3/16" but the designs show 1/8" . Never thought of drills, I was going to use a pivot pin (expensive ).
-Brian-

 

[STR]

I'd stick with the design. Start out with the 1/8 stop and get the knife together. There have been times in the past when I did that and the lock up wasn't as tight as I liked. Then by going up to the next size stop pin it brought things back up to a nice tight fit. Just leave enough room all around the stop for the possibility of going up in size later. It could be years later if the lock up gets loose and then an easy fix up to bring it back to tight is by just making the stop pin slightly bigger in diameter.

 

[jaegar]

ok, I think I've fixed it.
I'll move the pivot approx 1/16" closer to the spine. This illiminates the previous problem from the closed position. However, it does create problems at the spine, with the belly of the tang sticking out. That's not such a big deal, because I think it's ok to grind that back. I'll work some more on paper and if it works, post my results.
-Brian-

 

[Chuck Gedraitis Knives]

The easiest way to figure out where everything needs to go is to take your drawing and photo copy it. Then cut out the blade form one drawing and the handle from the other. Put a pin through the pivot holes and open and close it. This helps you locate the pivot and make sure there is room for the spacer. If things are off just move the pivot location on the handle, not the blade.

The other thing you have to consider is that in your drawing it looks like the blade will fall off of the lock when it is half closed. I'd check it and maybe put a cutout in the tang of the blade.

To keep the top corner of the blade hidden when closed you need to curve the front of your liners down to cover it.

In your second drawing you would have more room for the spacer if you raised the point of the blade a little and didn't have it close so far into the knife.
Good luck,
Chuck

 

[jaegar]

yup, fixed it.

I moved the pivot around a bit, added a little metal to the blade, adjusted the back spacer size, and place the thumb disc in a good spot. Perfect...well almost .

-striper, I have been using paper designs and cutting them out...it's a great method. You were almost right about the lock. I hadn't considered that, and when I tested it, it barely made it. I've adjusted for that, and fixed that problem, thanks.
I would change the liners, but they're already cut out. Next time I'll do that.

I appreciate all comments, thanks for helping me work through this headache.

I'll post pictures of the completed knife.
-Brian-