WIP...a new "Flipper"

Discussion in 'Ed Caffrey, MS "The Montana Bladesmith"' started by EdCaffreyMS, Oct 28, 2009.

  1. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    This is something I'm working on, well, actually this one is gona be for me to carry and test before I offer the design for sale.

    Here's the semi-working pattern and the knife in its early stages:
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    The liners are .060 6-4 Titanium, with a Ti backbar, and the blade is Mosaic Damascus.

    [​IMG]

    Here's a close up of how I build my "floating pin" design. The liners and blade are drilled with a 3/32" bit for the open and closed stop positions, then another hole is drilled around the 1/2 way point in the arc of travel. I then use a 7/64" mill to complete the cut in the liners. I personally like this method better than cutting an arc in the blade, as it creates fewer issues. I also use a 3/32" pin rather than a larger pin....I've found that it creates more room within the liners, and after carrying one for over 5 years, have found that anything much larger is overkill. The only disadvantage to cutting the liners instead of the blade is that it can sometimes limit the ways you can mount a pocket clip (I always use "tip-down" mount style for pocket clips)
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    Later this morning I'll rough grind the blade and get it heat treated. As I continue through the steps I'll take more pics and post them on this thread.
     
  2. StephanFowler

    StephanFowler Well-Known Member

    hey Ed, forgive my naivety but is there a particular reason that BOTH liners need the slot? seems like you could keep the side with the clip solid (ie. no slot) but still slot the other side.

    I wouldn't think that there's enough torque to override the single side stop? so ostensibly the slot on both liners is basically overkill?
     
  3. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    Hi Stephan!

    I tried that method once, and it didn't work out well. At first everything worked great with a single slot, but over time (about 6 months) as the pivot bushing "wore in", the blade developed a slight "tilt" to the side that wasn't slotted. After trearing down the folder and taking the micrometer to it, the bushing was about .003 out of round, which was causing the blade to tilt ever so slightly. I replaced the 416 bushing with a new one, and it worked fine again, but over time the same thing happened. Thats wen I decided to stick with slotting both liners. In reality slotting both liners was no more difficult than slotting one. I'll post some pics later of the fixture that I built for the slotting.....its very simple and works very well...and the best part is that I didn't have to lay down the $$$ for a rotary table for the mill!

    The result could also have been because of the way I build my folders. I leave the bushing .0005 to .001 longer than the blade is thick (depending on what kind of action I want the finished folder to exhibit, and "clamp" the liners down on the bushing with the pivot screws, which forces the blade to pivot on the OD of the bushing. I used to do it the other way around..where the bushing was pressed into the blade and the ID of the bushing rotated on the pivot, but that wore very quickly (I suspect because there was less surface area and the wear was more concentrated on the ID of bushing).

    My conclusion was that because the pin was "stopping" against only one side, the "slamming"/"torque" of opening and closing the blade MAY have been part of the problem...but all I can be sure of is that when I slot both liners the problem never crops up.
     
  4. steve shiffer

    steve shiffer Active Member

    Ed thanks for taking the time to do the WIP! Great stuff!
     
  5. cdent

    cdent Well-Known Member

    Boy that floating pin looks real handy for rigging up an assisted opening system. Nice test project.

    Take care, Craig
     
  6. SHostetler

    SHostetler Well-Known Member

    Ed,
    I'm waiting with baited breath for the pictures of your slotting jig!!!

    Steve
     
  7. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    Next, the liner slotting jig....

    When I was first taught about slotting the liners for the Floating pin design, I hung my head because I thought I was going to have to purchase a rotary table for the mill. A pretty expensive, and somewhat limited use tool in my shop. After mulling it over I decided to try to make a jig. This what I came up with.....

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    Its an old tooling plate that I had built and didn't use much. I installed a 1/8" pivot on one end, and a 3/16" pivot on the other end. When I use this jig, the first thing I do is to locate the open and closed stop positions of the folder I'm working on. I simply do this by eye, and since I use a 3/32" stop pin in most of my folders, I simply drill a 3/32" hole through both liners and the blade (while its annealed) for both positions. I then stack the liners and just lay the blade on the pivot, and then drill a hole approx 1/2 way through what will be the arc of travel. That is where I start milling out the slot.

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    One of the most important things in a folder is to be able to disassemble and reassemble it many times, and each time ALL of the parts MUST go back into their EXACT location...you simply cannot do that with screws and countersinks. To that end ALL of my folder have 1/16" hardened pins that go through the backbar and both liners.....
    [​IMG]

    This also allows me to remove the backbar, and "stack" the liners when milling out the slot for the "floating pin". OK, back to the slot.....
    Its a very simple matter to stack the liners, then place the pivot hole onto the pivot in the tool plate/jig. I place a washer under the liners to prevent them from getting dinged up, and then using a spacer and a screw, gently tighten so that you can rotate the liners by hand. You can use either an end mill, or a carbide cutter to cut the slot.....but try to use a size larger than your stop pin (a 3/32" pin will not go into a 3/32" slot!) The whole key is to be very careful when you reach the open/closed stop holes you drilled earlier....you can mill through them, but if the mill/cutter touches the back of the hole, you've just changed where the blade will stop. I do this whole thing by hand....which mean I am holding onto the liners, and turning them with hand pressure only. You have to be careful and pay attention!! Sometime the cutter wants to "grab" or "pull", and you have to be ready for that!!!! Otherwise your going to break cutters, mess up liners, or worse, get yourself hurt.
    [​IMG]
     
  8. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    OK, ONWARD!

    Next, I have heat treated the blade...since this blade is Mosaic Damascus, I used my Salt Tank, normalized it 3X, then brought it to 1550F and quneched. As soon as it was cool enough to handle, I cleaned most of the excess heat treating salts off, and got it into the tempering oven for 3, 2-hour cycles at 415F.
    [​IMG]

    Once the heat treating was complete, its time to surface grind the blade to the correct thickness....in this case my backbar is .155, and the washers I use are .010. So, if I take .155, subtract the thickness of the two washers (.020), I come up with .135 for a finished thickness on the blade....
    [​IMG]

    Once the blade is the correct thickness, I will "lap in" the pivot bushing with 800 grit lapping compound.... sorry but I could get pics of this part...didn't have enough hands!

    Up next..... Since our blade is to the correct thickness, now its time to make sure the pivot bushing is also correct. Depending on the particular knife, and the action I want it to have, I will finish my bushings down .0005 to .001 wider than the blade is thick....this means I can "clamp" the pivot screws down tight, and not bind up the action. I use a simple hardened plate... .100 thick, with holes that are tight fitting for the bushings I use....
    [​IMG]

    The bushing is "close" because I will often place it in the blade when I'm doing the final surface grinding, and take it out the last few passes before the blade is complete. All I need to do now is gently remove material until its the exact thickness I need. Using a granite plate and 320 grit....with just hand/finger pressure....
    [​IMG]

    Next....
    This is where I finish grind my blades....I always leave blades overly thick at the edge before heat treating to help solve what would otherwise be "issues". I start my finish grinds with a new 50 grit belt, take the blade to nearly complete, then go straight to a new 400 grit belt. Basically all I do with the 400 is take the 50 grit scratches out, and convex the edge (on those blades that get convex edges). From there I go to the finish bench and hand sand. The 50 to 400 grit jump works well enough for me, that I can start with 600 hand sanding, and have no problems. Since this is a damascus blade, 600 is as far as I will go prior to etching.
    [​IMG]

    Next installment.....We'll layout and cut the lockbar!
     
  9. JAWilliams

    JAWilliams KNIFEMAKER

    Great so far and can't wait for the rest of the pics.
     
  10. Steven Kelly

    Steven Kelly Forum Owner & Moderator

    Nice Job So far Ed!!!!
    You are really taking this whole thing step by step for everyon...

    When this tutorial is all finished, everyone should send you $34.95...
    Isn't that about the price of a decent video these days??? :) :) :) :) :) :)
     
  11. cdent

    cdent Well-Known Member

    Hey wait a minute, no sound on my copy:haha:.

    Great tutorial, Craig
     
  12. Jim Poling

    Jim Poling Well-Known Member

    Thanks for the great WIP and informative instuction ED. After playing gost during the knife chat and "hearing" you use the term floating pin, I was goint to drop a line and ask what you ment but now after reading this I won't need to bother you.

    Jim P.
     
  13. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    Laying out and cutting the lock

    OK, let's move along with setting up and cutting out the lock. This step requires a little thought on the knifemakers part. The lock bar must be wide enough to provide enough spring tension, but no so wide as to be stiff. Secondly you must consider the length of the lockbar in relationship to the knife your making. As a general rule, my lock bars are always at least 2 1/2" long, and most of the time closer to 3". The longer the lock bar, the less bend you have to put into it, and the less likely it is that the lock bar will bind against the inside of the handle scales if you get a bit too much bend in it.

    I use a small straight edge, measure the length that suits the particular size folder, then draw a line with a fine black magic marker.
    [​IMG]

    I have already ground a 7 1/2 degree bevel on the back of the blade, which is the angle I use on all of my folders.

    [​IMG]

    I have a specific disc grinder set up in the shop, who's only purpose is putting this angle on the lock area of folders. I grind to no finer than 220 on this cut, then install the blade on the liner and using the 7 1/2 degree angle as a guide, I use a very fine scribe and scribe that line onto the liner.
    [​IMG]

    Next, I drill a 1/8" hold through the liner at the back end of what will be the lock bar....this helps reduce the force of the lock bar, and prevents any fatigue fractures from occurring later down the road. Using my milling machine and a high speed cut-off disc, I cut the long axis of the lock.....

    [​IMG]

    [​IMG]

    Many times I cannot make a complete cut on the milling machine, and in those instances, I will complete the cut with a die grinder, with the same type of cut-off disc.

    The front cut, or what will be the locking face of the liner gets cut on the bandsaw, with a fine tooth blade. In this case its an 18 tpi blade. I cut this portion so that I LEAVE the scribe line, and will lightly grind it down later to get the lock-up I desire.

    [​IMG]

    Now comes the tedious job of fitting the lock. There's no magic formula...its grind and fit, grind and fit...and hope you don't over do it!
     
  14. Cubane

    Cubane Well-Known Member

    When you are figuring the lock bar out do you do any thinking about the detent ball position as well?
     
  15. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    I don't worry about the detent until everything else is done...I'll explain that in the next post.
     
  16. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    Onward!

    Now that the lock is cut, and I have it fitted, its time to move on to the rest of the knife.

    At first I was going to use G10 for the scales, but as often happens with me, something "cool" comes to mind and I run with it. In this case I decided I was gong to do full Titanium scales....then an even better idea came. How about full Ti scales with "Pearl Windows"?

    I started out with.140 Ti for the scales, cut them to rough shape, then attached them to the liners with screws. Then I ground them to the correct profile, using the liners as a guide.

    [​IMG]

    I simply drilled a series of holes in each liner, being careful to ensure they were centered and lined up with the long axis of the scales. I then used a countersink on each hole. The holes range from 3/8" for the largest, to 1/8" for the smallest. The screw holes are all for 2-56 torx heads, so the holes were drilled with a #44 bit, and the tops counterbored to accommodate the screw heads.

    I then put each scale on the mill, and milled out an area for the pearl inserts to fit...
    [​IMG]

    [​IMG]

    [​IMG]

    The next step was to finish out the scales on the grinder, by contouring them to the shape I wanted, and then finished them out with 600 grit by hand.
    [​IMG]

    Next I bead blasted the scales and anodized them...them to add a little "zing", I hand sanded the center area of the scales clean with 600, and re-anodized them to achieve the dual color scheme.

    [​IMG]

    With that portion completed, its time to install the detent. I tried for a long time to do the measuring thing with the detent, and it just never worked for me. The solution I came up with is very simple, and is about a fool-proof as it gets. I assemble the folder, minus the scales. Using only light hand pressure to hold the blade closed, I then drill through the liner and into the blade with a #55 Hi-Roc drill bit. After that I place a shim between the liner and the blade (usually a Popsicle stick) and drill through the liner with a #53 drill bit. (That is the correct size for press fitting a 1/16" detent ball).

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    I have found that this method works extremely well for me, and it eliminates all the hassles and mistakes of trying to measure, mark, and drill.

    OK, now that the folder is nearing completion, and since the blade is Mosaic Damscus, its time to etch the blade. First I put on a pair of latex gloves to protect the blade from fingerprints or any body oils. After a good cleaning with acetone, followed up by Windex, I make sure the blade is completely dry.

    The key to a smooth action on any Damascus folder is to mask off those areas that are contact points.... the washer area, the path of the detent, and the lock face. I accomplish this with clear fingernail polish.
    [​IMG]

    [​IMG]

    After letting the fingernail polish dry. The entire blade goes into the etch tank (Ferric Chloride) for about 15 mins. Once the etch is to my satisfaction, I neutralize the blade in TSP, then scrub it off with water and #0000 steel wool.
    [​IMG]

    On this particular blade I wanted high contrast, so I used a baking lacquer finish....sorry but I couldn't get pics of that process...didn't have enough hands to do it and take pics at the same time.

    The next steps I complete were the dual Ti thumb studs, and the clip. Basically all of the parts are now done.

    [​IMG]

    All that remains is to assemble everything! About the only other thing I can think to mention is that when I assemble/adjust the folder, I use a tiny dab of "Super Lube" synthetic grease on the pivot, and a dab of red loctite on the pivot screws.

    Take A look at the thread titles "WIP....The Finished Flipper" for pics of the completed knife.
    I'm always happy to answer any questions!
     
    Last edited: Nov 4, 2009
  17. Cubane

    Cubane Well-Known Member

    Thanks Ed,

    I'll definitely be referring to this thread when I begin my first flipper.

    Alistair
     
  18. Chuck Gedraitis Knives

    Chuck Gedraitis Knives Well-Known Member

    Ed,
    Thanks for the WIP, it's nice to see how other makers make their knives.
    Do you find that you have a problem getting the knife to flip properly with the flipper so far back behind the pivot? I have tried various positions and the best one for me is to have the flipper even with or in front of the pivot.
    Thanks,
    Chuck
     
  19. SPAknives

    SPAknives Well-Known Member

    WOW ED!!! This is freakin awsome!!! I just finished my first folder and I am getting started on my next one, so this is very inspiring to me.. That floating pin feature is way cool!! Love the whole knife!! Glad to see you are on Knife Dogs.
     
  20. EdCaffreyMS

    EdCaffreyMS Forum Owner - Moderator

    Chuck: This was my first attempt at a Flipper design. After playing with this one for a while I think it would be easier to "flip" it if its designed as you stated. I made the action pretty loose on this one to aid in the "flipping" feature, but can certainly see where that could be improved with re-designing the tab. I'm gona carry this one around for a while and see how it works out.

    Shane: You building folders now? Good on ya! Its certainly something that I never get tired of building....each one seems to present new and different problems to solve!
     

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