Long fasteners for thick blades

[Paul Knife]

I am looking for long hidden fasteners or bolts or Corbys or panel connectors for a 7/16, 8/16, 9/16 thick blade x 2 so the handle will be around 1 inch thick. The handle is not for a knife but for a non-cutting tool that is made in the same way as a knife with a wooden handle.

I don't like the Corby's all that much. Are there countersunk bolts available that are countersunk both sides where I can screw the male into the female easily and then file the male head off flat or vice versa. I want to end up with perfect flat circular heads both small and large ones, from 3/16 to 1/2in diameter, with no slot or hex or other indent showing. I think the hole diameter should be about half the head diameter. Both heads should be the same size. It can be a common hole size through the blades and SS as I don't think I need bolt edges abutting the steel but I may be wrong there.
I would appreciate your help or comments.
Thanks,
Paul

[Ray Rogers]

When I've made handles that were too thick for the standard Loveless bolts I usually use I would go to the hardware store and buy a stainless 8-32 screw in whatever length I wanted and use that with the standard Loveless nuts.

It sounds like you don't like the little 'cresent moon' that you get with Loveless bolts so the next best suggestion I can come up with is simply get some stainless rod in the diameter you want, cut off a piece and tap a blind hole in it. Buy a long screw and cut the threaded part off as you need it. A machine shop could easily tap the nuts for you if you don't feel up to it. That would give you a round featureless surface after you grind off the excess length which you would use to tighten the screws ....

[Paul Knife]

Thanks, Ray. I like your idea. Should I tap a hole at both ends and put a countersink machine screw piece in each end, then file off the heads flush? However I am still looking for something off-the-shelf first. As I have not tried any of the fasteners I don't know what to do yet. I don't understand Corby's. It looks like they hardly have any wood between the handle and the blade. If true their purpose seem to be to keep the handle/blade in place relative to each other instead of also clamping down.

I will glue the stainless steel plate to the handle sides but still like to have bolts or screws for extra safety and they should clamp down slightly on all three pieces.

I don't know if tubular rivets (no thread) would even give enough of a clamping force. Screws or bolts are probably a lot better. I think Corby's are still out for the above reason. Instead of buying a variety of fasteners and try them all I like to zero in on a good solution.

I appreciate more inputs.
Thanks,
Paul

[Ray Rogers]

Are you familiar with Loveless bolts? They are by far the easiest solution to your problem but it seemed to me you wouldn't care for the look of them. Anyway, I don't understand what you were asking about countersinking machine screws since what i described was based on tapping a blind hole. That doesn't require any screws at all, just a piece of All-Thread or the threaded part of a long screw with the head removed. Here is a different description of the same thing: you need to make two nuts which will be threaded on to the ends of a threaded rod. The nuts are simply a piece of rod material of any diameter you like with a hole drilled part way into the nut and threaded. Each of the two nuts is screwed onto the end of a threaded rod (All-Thread or a screw with the head removed) and the length adjusted to fit your handle thickness. This gives you all the clamping pressure you could ever ask for. You said something about gluing a steel plate to the handle - forget that unless you also use some bolts as glue cannot be relied on to hold (it can, but usually won't for most people). If this still isn't clear, look at the website of some of the knife supply places or catalogs if you have them (you should!!) and see what a Loveless bolt looks like. A picture is worth a thousand words...

[Paul Knife]

Thanks, Ray. That will work. Now I understand it better, I think: The single diameter rod for the nut would penetrate the handle side e.g. halfway or less to provide clamping force on enough wood. I can then cut off the extra rod length outside the handle on both sides, then file it flush leaving me with perfect flat single circles.

Yes, I had seen the Loveless bolts, They would work great but I did not like the screw end circle showing on both sides within the larger nut circle. I like the clean flat single solid circle look of kitchen knives much better.

The problem with most websites is that they show the hidden bolts or screws only --- for purchase. They hardly ever show them on installation, with cross-sectional views of wood and blade and fastener. It's also disappointing that they often don't provide a dimensioned drawing with the fastener Often there is only a description of head size, length, etc., e.g. omitting the length of the nut or other information. I know there are always many sizes but one example detailed installation drawing per type of fastener would be helpful, or an example drawing with a table for all sizes with dimensions A, B, C, D, etc., as is done for many other parts.

There are no water-resisting superglues? I'm hoping the glue will be so good all around that the user will never ever see a gap between blade and wood. That would be my purpose for the glue, with the fasteners as extra safety in case the glue fails or deteriorates after two or more years. That would be too optimistic for wood-stainless steel?

[Ray Rogers]

You need a set of catalogs from the major vendors. They often have example drawings of how various products like bolts are used and sometimes even have the dimensions you mentioned. I figured you wouldn't like the cut end of the threaded rod showing which is why I specified a blind hole. That makes them a little harder to use but it conceals the threaded rod.

There are water resistant epoxies but the way you said it made me think you were relying on the glue for part of the handle's integrity. As I replied, that can work but usually doesn't in the long haul. Most of us who have tried many types of glue over the years have settled on Acra-Glas as being the most durable. It doesn't shrink (so gaps stay filled), is near totally water proof and doesn't break down under UV light. Not many glues can cover all those bases. It is also very strong. You can get it from Jantz or Brownell's ....

[Paul Knife]

Thanks, Ray. I will finally try Jantz Acra-Glas this week for the first time and glue the handles to the metal and see how good the bond is, how easy it is to work with and if the glue layer is 'paper thin' or uniform thin everywhere. Can Acra-Glas also be used as a locking compound for the fasteners (I selected flathead screws with a threaded spacer) or is it better to use something else? I don't know yet if I can rely on the fasteners to clamp the pieces or if I should glue and clamp with clamps first, then after curing install the fasteners. Any comments are appreciated.

[Ray Rogers]

The bond will be as good as your preparation allows - good prep, good bond. But, as far as I'm concerned, the epoxy is there to seal the area under the scales so water can't get under there. How good the bond is after that point doesn't matter, that's what the bolts are for.

I'm not 100% sure what you mean by 'threaded spacers' but if you're talking about the threaded nuts that are used with Loveless bolts and if you countersunk them then they will provide all the clamping power you need. Acra-Glas is thin and uniform if you mix it correctly. To mix it correctly, you mix equal portions of the two components (the easiest way to do this is with a syringe) and then you stir the mixture constantly for four full minutes. It will get thinner as it is mixed. Then, smear it on the scales and in the holes for the bolts so that it gets inside the threads and in the holes for the nuts. Clean off the excess and let it dry at least over night, 24 hours is better. After everything sets up, grind off the screw heads and any extra bolt length on the other side ....

[Paul Knife]

Thanks, Ray. I am hoping that the glue by itself is strong and reliable enough for several years. The parts are used outdoors, also in the rain sometimes, but they are always stored inside or in a garage after use. Ideally my wood-metal-wood sandwich consumer part would last ten years without the glue failing and without refinishing the wood exterior. It worries me a little that you rely on the bolts or did you mean AFTER moisture eventually gets to it? My intent for the fasteners was for 1) the 'safety' look and 2) in the extremely rare case that the glue fails, even partially, that the pieces still stay together without injuring the user.

[Ray Rogers]

I rely on bolts because in 99.9% of the cases scales on full tang knives absolutely will pop off after a while if the glue is the only thing holding them. As soon as you torques the knife a few times and get a little flex in the handle area the glue starts to weaken. How long it hold depends on how well you prepped the metal and the wood, what kind of wood and glue were used, and how the knife is used. AcraGlas is waterproof and sunlight won't break it down and it holds very, very well on properly prepared surfaces but it is just glue. I know, there are guys here who can quote examples of hard use knives built with full tangs, wood scales, held together by glue where the knives have survived years of use. The sad truth of the matter is that there are so many variables involved that the average knife maker is going out on a limb if he builds a knife that way. It will be fine and work great until the day it doesn't. That might take 10 years but in most cases probably quite a bit less.

If long term durability is your goal then AcraGlas under stabilized wood scales reinforced by bolts is the way to go. That combo will last far longer than 10 years even if it is used hard and not cared for very well. Properly cared for, I'd expect it to last for generations .

So, I don't understand your fasteners but if they hold the scales on the knife then things should be good. A knife handle using only glue to hold the scales and the odds are not so good ...

[Paul Knife]

OK, Ray, as it for an odd-shaped and roundish non-cutting tool the forces are somewhat different than on a knife, although the wood-metal-wood sandwich construction is very similar and there will also be some torque during usage. Sorry I cannot divulge more about the shape and function. The part will be made in several sizes (for very small hands up to large two-handers). 6 will work for the smaller parts but I may go to 9 per part for all of them if the cost is low enough. The cost is the reason why Loveless bolts and Corbys are still out. I want to make a test production run of some 100 to 200 parts and I can buy the fasteners in boxes of 1000.
Thanks again for your help.

[Paul Knife]

What kind of sanding helps to achieve a good bond with Acra-Glas? Is 80 grit on both wood and metal a little too coarse? I like to use 120 or 150 grit instead but don't know if that is wise.

[Ray Rogers]

80 is not too coarse but the best prep that the Glue Wars determined was sand blasting for the metal parts. In the normal course of knife making it isn't necessary to sandblast the tang but if you want the very best bond possible then sand blasting is the way. And then, the tang must remain absolutely clean - no finger prints! - until the glue is applied.

From what I understand of what you're doing you do plan to have some type of pin/bolt/fastener in there somewhere and that is a good thing whatever it is. Tool handles, knives or otherwise, are subject to many different kinds of forces that can be applied from many different directions. Not all of those forces come from the anticipated use of the tool. For instance, drop a knife and have it strike the floor on the edge of a scale and the shear force will probably be sufficient to pop off any scale that is secured by glue alone....