Lock Stick and what is the actual cause of it? How to prevent it. (without sharpie)

[nosaj750]

I'm sure this has been covered but when you search lock stick you get a lot of results returned.

I've been making flipper/folders now for a few months and have been selling what I've been making so can't complain one bit. But, it seems my lock cutting procedure is lacking consistency sine I get some lockups that don't stick, then I'll get one that does stick. I think I know what the actual cause is but, would like to hear from more experienced makers and their solution to this problem if possible. It seems the lock face on my blade isn't 100% flat on the ones that stick. With a little sanding with a fine grit and use it seems to dissipate but, it would be nice if the extra time to get it just right wasn't necessary.

My current procedure is to file by hand at 8 degrees with the lock face on the frame flat. I have noticed a few higher end knives I've owned that actual angle the lock face on the frame and blade which seems to work great but, haven't tried that method yet.


Thanks for the info and help with this.

 

[Frank Niro]

Cut that 8 degres with ease . First place a 120 grit belt on your grinder with a platen.Place a 1/8" X 1" strip of metal 7/8" from the flat platen on the table. I hold mine down with 2 layers of masking tape. Do not regrind to a finer size. I size the leaf with a 16 grit and do cut say a 20 degree back angle on it. This combination will give you what you want . I use a small stand with just a 3/16 leg about 2 1/2" long to hold the leaf open to do the leaf.
Frank

 

[nosaj750]

Cut that 8 degres with ease . First place a 120 grit belt on your grinder with a platen.Place a 1/8" X 1" strip of metal 7/8" from the flat platen on the table. I hold mine down with 2 layers of masking tape. Do not regrind to a finer size. I size the leaf with a 16 grit and do cut say a 20 degree back angle on it. This combination will give you what you want . I use a small stand with just a 3/16 leg about 2 1/2" long to hold the leaf open to do the leaf.
Frank

Thanks Frank, I think I can visualize your setup. Any chance you have a picture of it you can share? If not no big deal I'm pretty sure I understand what your doing. I do have a question that just came to mind. Do you cut the lock face before you fit it with the lockbar on the frame?

I've been cutting my lockbar in the liner or frame, place my stop pin, cut lockpin slot in the blade, then hand file my 8 degree lock face and fit the blade to the lockbar. I do it this way so I can file more off the lock face on the blade if needed to give a good snug fit.

 

[Frank Niro]

Sorry about no pictures. I still don't know how.
I cut the outline of the blade with the pivot hole drilled and reamed. The blade is fitted to turn and sit in a liner cut to outline. I now cut the notch in the back of the blade for the leaf spring. This also helps to make it easy since it is flat without bevels cut. That idiots way of cutting the blade notch works every time on every type of blade. I fortunately came up with that method soon after I started to make liner locks. The only concern is to not go too deep and leave enough room for the washers to fit on the pivot without interfering with the leaf when it is cut.
The leaf I cut both length wise and to length after I have fitted in the back bar or perhaps for you the stop pin. The detent is not done until the folder is completely assembled and working correctly. I use a 55 carbide drill bit.
To do liners cut two rectangles of the material to be used; drill and ream the pivot hole in each; I then cut out one liner drill the holes for the scale, bolster, and back bar. This placed on top of the other liner with that drilled pivot hole used to position and clamped. I start drilling the holes and after just one or two place pins, drill bits of the right size in these holes to help maintain alignment.
Frank