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Any advice on attaching G10 bolsters

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by jawilder, Mar 14, 2012.

  1. jawilder

    jawilder

    Jun 27, 2006
    I am working on a set of knives for the kitchen and would like to use red G10 scales with black G10 bolsters. I plan to use loveless or corbys for the scales but won't use G10 bolsters unless I can find a way to attach them mechanically.

    Sure, I love epoxy but don't want to use it alone. I know that with brass/stainless bolsters you can peen them on, but I don't want metal pins running through my black bolsters, and don't even know if you can peen onto G10 anyways.

    Has anyone ever experimented with making G10 corbies, or something similar so I can get a mechanical bond on the bolsters?

    If I can't get it figured out I'll use metal, but would really like to get this figured out.

    Can you thread/tap G10?

    Thanks,
    Jason
     
  2. Remyrw

    Remyrw

    Jun 17, 2010
    How much of a mechanical bond do you want? Could you do a hidden pin just to reinforce the glue joint? There are micarta rods, but it won't match exactly, but maybe if you do a contrasting color and use it as a design element instead of a flaw it would work well.
     
  3. jawilder

    jawilder

    Jun 27, 2006
    I was able to get some micarta rod at the knife show in Ft. Worth this past saturday. What I am looking for is something that will hold the bolsters on without the aid of any epoxy at all. I will still add epoxy to seal the joint, but want all of the strength to come from the pins/screws/whatevwer. I would love for it to be uniform. In the back of my mind I am thinking "Black G10 Corby" and I know that no one sells them (that I know of). But am just wondering if they can be made and how well the threads will hold. It seems there would be a demand for something like this since more makers are using black G10 rods for pins.
    Jason
     
  4. Nebulae

    Nebulae

    Aug 24, 2009
    Do you really need a corby. I always use stainless pins, usually not peened and epoxy, and there is no way my scales are coming off. So for a bolster on a kitchen knife, I wouldnt think you would need a mechanical bond that strong.
     
  5. OTK

    OTK

    389
    Feb 10, 2010
    You don't. Rough up the underside of the bolster and tang, clean thoroughly, and use a steel pin for added strength. How strong would a g10 corby even be? Not too strong I'd imagine. I've snapped a few steel corby bolts.

    If you are set on no pins, drill a blind hole in the bolster and corresponding hole in the tang and let the epoxy form a fastener.
     
  6. Remyrw

    Remyrw

    Jun 17, 2010
    If you do decide on a g10 pin or some sort, pay careful attention to orientation when you're done, the texture isn't omnidirectional.
    Personally, if you have that little confidence in your adhesive, use a different one. The couple I use will bond G10 to steel with enough strength to require destruction of the materials to remove them. I put pins in because folks expect them, they add an aesthetic element, and since I use mostly mosaic these days they add a fair bit of eye candy that adds value. Their addition of strength to the system is not a big factor in my decision. Maybe, if I was making large choppers, I'd feel differently, but even then, thousands of pounds per square inch of hold seems fairly sufficient and I have yet to have one of mine come off, pins or not (a lot of my test knives and personal stuff doesn't get pins).
     
  7. jawilder

    jawilder

    Jun 27, 2006
    I guess my concern is that these knives will be a wedding present that, ideally, will be used throughout their lives. I use West G-Flex and have no doubt that epoxy and regular pins will hold for several years but I am hoping to find something that will last for several lifetimes. I've read glue wars enough times to learn that all epoxy will eventually fail and will come off quicker in an extreme enviornment (like the dishwasher)

    Most hunting knives get used a few times a year but stored for most of their life. In that case, epoxy and pins are good enough, but a kitchen knife gets used every day and I can't guarentee they won't be put in the dishwasher down the road.

    I would rather switch to brass or stainless bolsters that are peened than to rely on epoxy alone. I have twisted corbys in half also but they were cross threaded and I applied too much torque to overcorrect the problem For that matter, I have snapped SAE 8 bolts before with enough torque. I know that nothing in indistructable but I also know that a mechanical bolt will always outlast a chemical bond.

    Jason.
     
  8. Remyrw

    Remyrw

    Jun 17, 2010
    I haven't personally run them through the dishwasher a few hundred times and then hammered on them, but loctite/henkel e-120hp, which is what I am using these days, is specifically designed to handle large temp swings and shocks. The dishwasher isn't likely to bother it much. Regardless, it's your call, and there's no question that you're right, adding the mechanical hold, done right, does make it pretty much a sure thing no matter what they do to it.

    Here's the data sheet on e-120 if anyone's curious. http://tds.loctite.com/tds5/docs/HYSAE-120HP-EN.PDF
     
    Last edited: Mar 14, 2012
  9. jawilder

    jawilder

    Jun 27, 2006
    Thanks for the info Remy. Can you get the e-120 local or does it have to be ordered?
    Jason
     
  10. Remyrw

    Remyrw

    Jun 17, 2010
    Depends on who you have locally. I guess, given that Loctite's actually a local company, I could probably go buy it in person, but I order it off Amazon or from RS Hughes. It's a system though, the glue cartridge, applicator and tips. Some folks try to work without the applicator or tips but I think if you're going to use a high end industrial adhesive, use it the way it's designed to be used.

    A little goes a long way with this stuff, and I really like working with it. No issues with thick glue lines or having it squeeze out everywhere... It's nice and easy to get a fairly thin layer and it will squeeze out or into your glue cavities without a ton of pressure. Cleanup's easier than a lot of stuff I've used and it's a fairly slow cure time, so lots of time to do the cleanup. The 120 minute work time is about right, so lots of time to get everything in place, positioned and clamped. Even if you have some sort of interruption you're probably ok. To me, as long as it's appropriate for the materials, it's just about the ideal knife making adhesive. Obviously it's not perfect for every material, but it covers most of what we use.
     
  11. james terrio

    james terrio Sharpest Knife in the Light Socket Moderator

    Apr 15, 2010
    I completely agree with your statement that you insist on a mechanical means of holding the bolsters and scales on :thumbup:

    I suspect machining your own G10 Corbies would be far more trouble than it's worth. Since you want a clean look (no metal pins showing) on the bolsters, here is my suggestion:

    Drill matching sets of blind holes in the bolster material, and the scales, parallel to the blade. These will accept small steel pins that will mate the bolster to the scale on-end... sort of like dowels or biscuits joining two panels of a table-top or door.

    Now, grind the back of the bolster and front of the scale at 45degrees each, so the scale "overlaps" the bolster. Often called a "dovetail" bolster (although it's not really a dovetail; more of a mitre, I suppose), this looks really cool. Assemble them together with SS pins in the blind holes you made and your favorite epoxy; you now have essentially a solid piece from which to shape your finished scale.

    If this doesn't make sense, I'll make you a drawing. I thank you for bringing this up and making me think about it, I think it would look great and not sacrifice any strength in the handle.

    Since you've already said you're going to use bolts to attach the "scale" part, and the bolster is held to the scale both by the hidden pins and by the scale overlapping it, I'd bet my grinder that it will never come apart.

    Incidentally, yes, you can peen pins into G10 the same as you would with wood or bone.
     
    Last edited: Mar 14, 2012
  12. Remyrw

    Remyrw

    Jun 17, 2010
    Now that's a darn good idea.
     
  13. james terrio

    james terrio Sharpest Knife in the Light Socket Moderator

    Apr 15, 2010
    I'm not as dumb as I look :D

    Actually, I can't take credit for the idea, cabinetmakers and such have been doing this sort of thing for centuries.

    I really do think it will work well and look awesome, though :thumbup:
     
  14. watercrawl

    watercrawl

    422
    Jun 2, 2006
    I've done what James described using a cut, small diameter screw. I felt the threads would help strengthen the joint.

    Haven't heard back from the owner in some two years.
     
  15. jawilder

    jawilder

    Jun 27, 2006
    James, is this what you have in mind? If so, it seems like it would sure work!

    [​IMG]

    Jason
     
  16. Remyrw

    Remyrw

    Jun 17, 2010
    visually, I'd prefer it angled the other way, if you care :) oh, and that's a really short blade :D
     
  17. Nebulae

    Nebulae

    Aug 24, 2009
    dude its a kitchen knife not a tank! Horizontal pins are pretty difficult to do, especially considering that since it is a kitchen knife the scales will probly be pretty thin. But that would probably be one of the most thoroughly designed handles I have seen it should be indestructable.
     
  18. jawilder

    jawilder

    Jun 27, 2006
    I would prefer them to go the other way too, but I think this would give it more strength as the miter on the scales would help to hold the bolsters down. If they were mitered the other way with the bolster on top then only the pins and glue would be holding the bolsters on. This way the scales, pins, and glue are all working to hold them in place and the only way they could pop off would be at a diagonal towards the blade.

    Sort blade :)

    Nebulae, I think a lot of people underestimate how well a kitchen knife needs to be built. They are usually the only knives that are used every day aside from pocket knives. I have had to rehandle more kitchen knives than hunting knives.

    On my kitchen knives I use 1/4" scales so I think the pins could be 1/16. I would think you could put them in the middle because with thin scales, you know you won't be taking off too much material.
     
  19. watercrawl

    watercrawl

    422
    Jun 2, 2006
    Especially when used by a working chef....all day, every day. They are horribly hard on knives. Extremely hot, wet environment is rough on even the most well made knife.
     
  20. Nebulae

    Nebulae

    Aug 24, 2009
    fair enough. Maybe I should take another look at how sturdy I do my handles.
     

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