Brass bolsters on a bushcraft knife. Bad idea? If not, is epoxy enough to hold them in place or is a pin a must?

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Cornwallis

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Except for the final sharpening, this knife is finished. What are people's opinions on brass bolsters on bushcraft knives? I don't baton (I think it's mostly stupid) except for small kindling. Are pins through the bolsters necessary with modern epoxy? I used AEB-L steel. HT was done at 1950 for 15 minutes with a plate and compressed air quench, immediately followed (right before reaching room temperature) by a dry ice/isopropyl cold treatment for 1 hour, followed by two 2-hour tempers, the first at 300F and the second at 330F. The handle is African Blackwood with red G10 liners and a brass bolster. This is my first time making and using a bolster. The knife is slightly handle heavy even though I removed material before heat treatment. There are a few flaws with the perpendicular red liner because it did not seat all the way and I didn't catch it because I used black epoxy. I mostly fixed it by carefully removing material and replacing with red-dyed clear epoxy. Next time I will use clear epoxy so I can see that everything is properly seated. For now this is just a hobby but when I retire and get a little better I might start selling.
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The first time the blade is flexed near the guard, it will pop off.
Bolster should be soldered or pinned in place. The reason they are called "bolsters" is that they bolster the knife's strength in that area.
 
As Bill said, they will fall off easily. The epoxy joint is so thin you could likely pop it off with your fingers if you tried hard. Any tap or flex will make the bond fail.
You might be able to still salvage it by using a 1/8" carbide drill and making two rivet holes and adding pins through the brass and tang.
 
Stacy E. Apelt - Bladesmith said:
As Bill said, they will fall off easily. The epoxy joint is so thin you could likely pop it off with your fingers if you tried hard. Any tap or flex will make the bond fail.
You might be able to still salvage it by using a 1/8" carbide drill and making two rivet holes and adding pins through the brass and tang.
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Really? Why doesn't a scale pop off easily then? Scales are typically only strengthened by several pins that are lightly epoxied some distance from the ricasso, so why doesn't the scale pop off near the ricasso then? Also, the "bolster" is epoxied onto a G10 liner which connects to a pin. So, are you saying the brass will necessarily separate from the knife? Maybe it will, maybe it won't.

I was also told by people here that I can't grind AEB-L before HT without it warping. Well guess what, the knife you're looking at was taken down to .030 before HT. I think a lot of you just repeat things you were taught by someone else. I'm not saying you're wrong, but I am saying I'm not convinced.
 
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Cornwallis said:
Really? Why doesn't a scale pop off easily then? Scales are typically only strengthened by several pins that are lightly epoxied some distance from the ricasso, so why doesn't the scale pop off near the ricasso then? Also, the "bolster" is epoxied onto a G10 liner which connects to a pin. So, are you saying the brass will necessarily separate from the knife? Maybe it will, maybe it won't.

I was also told by people here that I can't grind AEB-L before HT without it warping. Well guess what, the knife you're looking at was taken down to .030 before HT. I think a lot of you just repeat things you were taught by someone else. I'm not saying you're wrong, but I am saying I'm not convinced.
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It will separate , and I am 100 % sure about that :)
 
" Really? Why doesn't a scale pop off easily then? Scales are typically only strengthened by several pins that are lightly epoxied some distance from the ricasso, so why doesn't the scale pop off near the ricasso then? Also, the "bolster" is epoxied onto a G10 liner which connects to a pin. So, are you saying the brass will necessarily separate from the knife? Maybe it will, maybe it won't...."

I stand corrected. I've only done a couple thousand handles, and have been working with resins and epoxies for around 60 years. so I probably don't know much about it.

In answer to the questions about epoxied scales
Scales do pop off easily on a knife if only epoxied on. Even with pins, they often lift up at the ricasso. Peening the pins or using mechanical fasteners like Corby bolts or Loveless Bolts is the strongest method.

Why doesn't a scale pop of if a bolster can?
A scale is five or more times the surface area of a bolster and has much greater bonding area.
A scale is not smooth metal, nor brass (which does not epoxy well). Brass does not epoxy well at all to another piece of smooth material like G-10.
The bolster/liner look like they were tightly clamped when epoxied. This creates a situation called a glue starved joint. Glue starved joints are very weak and fail at the least stress or blow. There are probably 100 guys reading this thread who may chime in saying they over-clamped a scale and had it pop right off while sanding or when it got dropped.
 
Also, since you want to talk about accurate statements, change your profile information or the super mods will likely ban you. You are not 120 years old.
 
Thanks, that was the kind of answer I was looking for. However, I don't care how many knives you've made, I only care for rational explanations. Maybe you should spend some time working on your huge ego and less time making knives.
 
I don't sell my knives, so I'm free to do whatever I want. If this knife is for your own use, then use it, test it, see what happens. If the bolster stays on then great. If not, try pinning it next time.
 
Richard338 said:
I don't sell my knives, so I'm free to do whatever I want. If this knife is for your own use, then use it, test it, see what happens. If the bolster stays on then great. If not, try pinning it next time.
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Yep, that's the bottom line. Test and see what happens. Just thought I'd see if anyone else had actually tried this. Just curious. However, this place is apparently not for the curious and that has been duly noted by me. I can see why Cliff Stamp was banned. He asked too many questions. Knock knock.... Who's there? Vee ask zee questions!!!!
 
Cornwallis said:
Yep, that's the bottom line. Test and see what happens. Just thought I'd see if anyone else had actually tried this. Just curious. However, this place is apparently not for the curious and that has been duly noted by me. I can see why Cliff Stamp was banned. He asked too many questions. Knock knock.... Who's there? Vee ask zee questions!!!!
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Seriously ? You asked questions but you don t like answers you get ? If you know that bolster would not separate why you ask here ?
Knock knock ..gt !
 
Natlek said:
Seriously ? You asked questions but you don t like answers you get ? If you know that bolster would not separate why you ask here ?
Knock knock ..gt !
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I like answers with explanations, not assertions. I already knew that a pinned bolster is stronger than one that is just epoxied. I was looking for an explanation like the one the moderator finally gave me, not that the knife is going to break if I don't do something a certain way. If I'm not allowed to question the answers I get then what's the point of this forum?
 
Cornwallis said:
I like answers with explanations, not assertions. I already knew that a pinned bolster is stronger than one that is just epoxied. I was looking for an explanation like the one the moderator finally gave me, not that the knife is going to break if I don't do something a certain way. If I'm not allowed to question the answers I get then what's the point of this forum?
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We also like answer with explanation .Would you please explain why your ABL did not wrap ? I'm all ears to hear an explanation , since many here have problems with ABL .
About your knife and brass bolster , glue some piece of brass to some steel in same way as you do on that knife and make some test ...I bet that it will FALL easy !
BTW , nice knife i like it !
 
Have a look at the Raven Armory PK1 Bushcraft Knife. One of the few designs that has bolsters. Designed by Paul Kirtley, who knows more than a bit about bushcraft. That said, most people who know about bushcraft and design a knife for it do not include bolsters.

C Cornwallis why did you decide to put bolsters on this knife?

When I started out I put brass bolsters on a number of knives, but fairly soon came to the conclusion that they were not needed or beneficial for the bushcraft type knives I was making. Regardless of how they are fastened, they add mass and unless that mass is adding performance it is just dead weight. The mass is located at the least useful place for improving chopping, or balancing a heavy blade. Bolsters can help protect the front of the handle scales, but stabilized wood, tropical wood never mind G10 and Micarta are tough enough that they don’t require that protection. It is much harder to shape a bevel on the front of a brass bolsters than it is on a wood scale. Bevelled scales make it easier to keep the blade/handle transition clean and dry.

In the past I did a bunch of adhesive testing that included brass to steel. Shear strength wasn’t bad, but peel strength was poor with the hard epoxies I used. I agree that brass doesn’t stick well compared to other materials used in knives. Peel is what you get at the blade/handle junction. If you have a stiff blade or never apply lateral stress to the blade, you may never notice a latent weakness. However, this is the sort of thing that can bite a chap in the butt once he has sold a few knives…otherwise apparently sensible people do the darnedest things with knives…like expecting that they can baton on a bushcraft knife ;)
 
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Natlek said:
We also like answer with explanation .Would you please explain why your ABL did not wrap ? I'm all ears to hear an explanation , since many here have problems with ABL .
About your knife and brass bolster , glue some piece of brass to some steel in same way as you do on that knife and make some test ...I bet that it will FALL easy !
BTW , nice knife i like it !
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I discussed it in other threads. The short answer is everyone is mostly right, it IS best to grind post HT if you can, but if you have thick enough stock you can get away with grinding the edge down to .03 to .04 before HT. I used .125 stock and plate quenched then spine-first quenched into the dry ice. Very little warping, enough to remove with light peening on one blade. This blade had such minor warping (almost none) that I just fixed it when grinding the final edge post HT. I did not grind fast or get the blade too hot.
 
C Cornwallis It would have been reasonable to ask Stacy for more clarification when he answered your question. But you also attacked his character. Why? Because he took the time to offer you free advice? I don't agree with Stacy about everything, but he's on here trying to help people regularly - with advice, but also with sending free materials or tools to people that need them. Maybe your ego is the one that needs to be checked when someone is just answering a question that you asked.
 
On a cold day when you are "Bushcrafting" and you whack the spine to cut through a branch that shock will cause those glued on bolsters to fall off.
 
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