Flattened Detent ball for flipper

Matt, thank you so much for stopping by and giving us your insight! I've read your posts a couple of times and took a lot away from it with the most important part being the contact (ball in hole) meeting at 90 degrees. Of course this makes complete sense and gave me the "aha!" moment. I, for one, am going to order some carbide drill bits between .050 and .080 and gradually open up the hole until the ball drops in to that sweet spot.

My only question to you, Matt, is could you please explain how you "back cut" the detent hole? And is it even necessary if the hole is large enough to already accommodate the ball if the offset between the two is still in place enough to hold the tension without slop?

The tricky part would seem to be opening up the hole just enough to accommodate the ball as explained above but not enough to lose the tension and cause play. If starting with enough offset there should be enough wiggle room to experiment.

Mark
 
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Okay, I looked at the knife again and halfway answered my own question.

In this picture you can see the two shiny spots on either side of the hole. To the top and in between these the inside of the hole is chamfered down at an angle. What is the procedure to do that? Fixture on a mill coming in from the backside at an angle?

Mark
 
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Dude your way over thinking and over measuring this, lol. I back cut this using my hand held carving tool and a carbide dental bit. The way I get my fit is when drilling the detent hole with the knife assembled. The blade is held closed with just a bit of tension using blue tape. Everyone has their own way of doing this to get the same result. Hope this helps.
Matt
 
Lol. You're right.

I'm going to back cut mine when I get home and see if that allows the ball to drop in.

Thanks again Matt! You da man!
 
Good stuff here guys! Couple questions;

What are the two small spots ground either side of the hole for?

Why is the hole not centered with the detent ball track?

Thanks.
 
Hey Don. Matt explains the two little side holes in post 23. They were a side effect of the "back cut". The path looks a little misaligned but it looks a bit better in person.

How 'bout some of your detent tricks?

I worked on my EDC some...
 
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Just from looking at your video I can tell you a couple of things. Your flipper tab is WAY to far back from the center of the pivot to have ANY real leverage to help you open your knife using the flipper tab. If you redesigned your knife to where the flipper tab was forward of the center line of your pivot with just a very basic standard detent set up your knife would have flipped a thousand times better and you probably would not have needed any of the info I mentioned. This is the exact same thing I did when I made my first flipper.

So with that said some designs you just can never do this to. It will make your life easier if you do make/design your flippers with this in mind. I just remembered this is the exact reason I switched to building all my knives with internal stop pins! It really opens up a lot of space to design a flipper tab with it further forward. At the time Lee told me to do this and I have ever since.

I didnt want to really come out and say this earlier because it is a much harder way to make a flipper but.... you can overcome the worst flipper tab placement with a detent set up like I now use in my knives and I describe in my past posts. It is a much harder knife for most makers to build! I really really recommend that you build your flipper tab into your design with the tab as far forward of the center line of your pivot when the blade is in the closed position and the flipper tab is pointing up.

So of course its up to you guys and your skill level but I wish in the beginning someone had told me this! Lol. There just were not many people building flippers at the time and the flippers that were around just did not work without some wrist flick to get the blade open all the way.

The first flipper I ever felt that worked with no wrist flick was probably a Ken Onion with Speedsafe. The first flipper I got that worked the way I build my knives now was a Phil B and I think a Cobra. Im talking before I started making knives so pre 2002 or so? I had no idea how Phils knife worked so good at the time except he built one super smooth ass flipper! Lol. It didnt really need a lot of stored energy in the detent for them to work so it was not an obvious thing to me at the time until several years later when I started building flippers. So I guess Im rambling, hope it helps! Matt
 
Thanks Matt, your insight is always appreciated!

Internal stop pins are something I was always planning to get to, eventually. In a flipper everything is a compromise and finding the right balance is a personal venture. With my knife, for instance, I am happy to get a 4:5 blade to handle ratio which I don't often see. I am also content with a flipper tab on the small side and less obtrusive as well as being able to get 4 3/8" of usable real estate on a 5" handle. However, moving the flipper forward 1/10" to where yours is will only have me lose that same amount of usable grip area and I think that's a very fair trade off.

Matt, hope you come around here more often.

Mark
 
Varga Knives said:
Hey Don. Matt explains the two little side holes in post 23. They were a side effect of the "back cut". The path looks a little misaligned but it looks a bit better in person.

How 'bout some of your detent tricks?

I worked on my EDC some...
Click to expand...

OK, I missed that part. Thanks.

As for any detent tricks I have, I don't know. I drill a shallow 1/16" hole at the end of detent trail, then try it, if not strong enough I enlarge it a bit, keep doing this until I like how it works. I do not drill through the hole in the lock tab to locate the hole, have been planning to try this again. I don't make flippers, so this way probably no good here.

Great info Matt. Thanks!
 
I'm no expert, but use a larger detent ball. I use 3/32" and the larger ball will need more pressure to overcome to open and it pulls the blade shut from 3/8" out. Rides smooth as silk.


Peter
 
Flipper article in Blade mag by RJ Martin right now, Part II. Haven't read it yet, but is about tips on how to make. Might be helpful?
 
Thank you again guys. Been working on a batch, should be getting to fitting the detents a little later today (hopefully). Will report back my results
 
What size washer are you using versus height of the detent ball?

from what I understand on a flipper you should have the detent ball protruding out .015" for a .015" washer. You can go .016 to .017 for faster flip, but I'm guessing your flipper tab has to be in the perfect position to make the action smooth.

I'm not an expert by any means btw. I'm still working up the courage to tackle my first flipper.

Nick
 
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