Thoughts on liner locks

G'day from down-under,

One of the problems I have with liner locks are the front bolsters, in most of the designs and pictures I have seen the bolsters are held on with 2 screws (the pivot plus one behind it), and the problem I have with that is the front of the bolster is unsupported ie. forward of the pivot pin the bolster and the liners are not held together. To me this is an inherent weekness, one can get around it by loctiting the bolster to the liner but that defeats the purpose of the screws and the other solution would be to have a screw in each corner (which I have no problem with structurely). However this would tend to clutter the bolsters with screws and I like to make a piece with a nice clean appearance.
I'm interested to get other peoples' thoughts and possible alternatives.

Regards from Australia.

Neil I make mine the same way, the pivot pin and one screw behind it. I haven't seen any problem with a bolster shifting or moving around, or haven't heard of it from anyone else. If you prefer to use two screws in the bolster, you may want to try a hidden pivot pin , that way you will have a screw in the front and rear of the bolster.I think Jason H does a lot of his that way.

One alternative is to mill the bolster and liner as a single integral unit. That solves the problem, mut could present a machining challenge.

Thanks gents,
I've considered both those possiblities and more than likely go with the way Terry builds his.

Hi Neil,I Have done bolsters on liner locks four ways and have not seen any problems develop. I have used both types of screwing,meaning pivot screw showing and another screw on the scale side, hidden pivot screw and one screw on each end of bolster, bolsters attached with 4 pins riveted and with hard silver solder used at approximately 1500 degres with 301 half hard spring stainless steal that maintains full ellastisity even after all that heat. When screws are used I always used blue loctite to lock them in place. All my liner locks have been made with non adjustable pivot screws . The screw system allows for more lea way in the making perhaps, and is really quite strong unless of cours someone is looking for a pry bar and then that is what he should have and not a knife! Frank.

Thanks Frank, I'm not sure what you mean by non-adjustable pivot screws, I was going to loctite my screws anyway.

Some liner locks are made so that the pivot screws can be easily turned which of course can allow for a gravity knife. By the way you and others may be interested in the screw sizing gizzmo I use. Sorry I don't know how to send a picture so I hope I describe this okay because it sure is handy. Cut two pieces of .050 or there abouts of titanium or spring stainless steel about 5/16" wide and 3" long. At one end of each piece drill a hole with a no.33 drill (I guess a 1/8 will work also). Place an arc of approx. 3/32 on one of the pieces. Place the two pieces together with a no.4 screw and mark where the end of the arced piece touches the flat piece.At this point drill a hole of clearance size in the center of the flat piece say no.43 for a no 2x56 screw. I'm sure you are ahead of me now. You can size screws down in no time without all the hassle of having to screw in and out of some holding plate. Make a screw gizzmo for each size and you are really in business. Frank

I didn't see this till now... I have had good luck with using hidden pivot pins. The knife is COMPLETELY assembled without bolsters or scales. Bolsters get 2 screws each, scales get 2. The beauty of this is you can move your pivot around the knife to get the geometry right. The ideal pivot placement is not dead center of the bolster, it's down about a 60/40 split. This allows the blade to rotate, clear the stop pin with the bottom of the blade, etc... This works for me and allows a smaller screw (0-80), I mean, I don't like showing off a 4-40 ss screw when I can show off a couple of gold plated 0-80's on some mokume or damascus. Just my 2 cents.

I love rivetting! and therefore treat my liner locks the same way as I do lock or spring back folders. I use 2 by 1/16" rivets of the same material as the bolsters to fix the bolsters to the liners. I then solder to exclude fluids and improve appearance and finallly rivet the pivot pin and stop pin in the bolster face and finish as normal. No you can't dismantle my knives easily but they don't fall apart either and to date I have had no complaints. I do not use washers but scrape a clearance "pedestal" in both liners, as done in lock backs and grind a small
clearance groove to allow the locking leaf to move fully out of the way of the blade when closing the knife.(This allows for ball or punched retainer pawl)

I spot weld or use screws.The spot welds are quick and permanent for bolsters.I use screws where I'll need to remove them later.(ie, etching or anodizing the bolsters)

Re: Thoughts on liner locks.

In an e-mail chat with Don Cowles, he suggested I joined your mob, to share my wisdom with you. Don?t know about wisdom but as my old grandmother always said, even a blind chuck can find a grain, so who know. With regard to the bolster on liner locks I have tried several different ways to solve the problem. On all my knives, the back? bone? is the full length of the knife and is serving as stop for the blade in open position. On the knives with bolster the front screw in the spine is also securing the bolster, usually with thread in one side. This gives a very rigid connection and because the pivot pin is 6mm and is continuing right through the blade, liners and bolsters with adjustable screw my feeling is that this is not the weak link on the knife. On a few knives I have added two 2mm screws from the inside of the front of the liner, with thread in the bolster only partly through so it won?t show on the finished unit, but I don?t think it is of any practical benefit. If the bolster is Mokume or other soft material, which can?t be relied upon to hold a thread, the front screw in the spine is hidden and a 2-1/2mm screw added behind the pivot. After reading Neil?s folder instruction I have made one with SS bolsters riveted on (Thanks Neil) and it is now at the engraver (can?t wait to get it back) but I like the thought of being able to take it apart especially with regard to maintenance of the pivot.
Peter.

www.markerknives.com

Welcome, Peter! I'm glad you're here!

Don

Hej Peter. Godt at se dig!

Welcome Peter ...!

Make yourself at home here. If you ever need anything, make sure you let us know. We're trying to redefine the custom knife net. If this resource can do anything to benefit you, we want to hear about it ... OK?

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Alex