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Modifying a Blade Shape


Duncs

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I’ve got a Bench Mark Rescue knife and it’s bloody terrible. So much for buying by brand name...

The blade shape is pretty useless and both the blade (straight and serrated parts) and the seatbelt cutter are as blunt as a butter knife.

So rather than chuck it in the cupboard (or bin) I thought I’d see if I can make it useful. If I stuff it up I haven’t lost anything.

Sharpening the seatbelt cutter shouldn’t be hard - I just need to get the right bit to pull it apart.

For the blade, I want to give it a continuous curve like a skinner rather than two straight edges with an angle between them like it does now.

Do any of you blade makers have any suggestions on what to do and not to do to change the shape? Do I need to avoid heating it? Should I be quenching it in something if I do?

Or should I just chuck it in the bin and save my time? :)

And suggestions on sharpening the serrated part would be great. I’ve got a bench grinder with a paper wheel on it. I can stick other standard wheels on it too as long as I know what to use.

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Thanks!

Duncs

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Duncs i would reshape that angled part of the blade to a curve with a hand file then use a lansky to shapen.
It will take a while to sharpen but will be fine. Ive done this with a knife that had a broken tip, worked well.

Im thinking heat should be avoided.

I know nothing about doing it properly so u might get better advice from somebody else but as i said this way worked well for me.

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That’s an ugly blade. I know nothing about knives but a bit about steel. Avoid heat if you can so you don’t change the properties of the steel.

having said that though. Given the shape of the blade it’s obviously a knife maker with no self respect so the blade is probably crap steel and not heat hardenable. If this is the case. Shape it with a 5” grinder. Or just bin it.

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Use a belt sander to reshape the blade constantly dipping in water to keep the blade cool.take your time when you rush you increase the chance of overheating the steel,if you overheat it the steel will go soft and not hold an edge. Nothing ventured nothing gained 

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Duncs, many years ago I snapped the tip (about 20mm) off this Gerber blade while trying to dig a broadhead out of a tree. I used a bench grinder and frequently cooled in water while reshaping. It still works fine, doesn't hold an edge for too long, normally take the legs off a few pigs and it needs a sharpen, although I suspect that is due to the grade steel as it gets blunt the whole way not just the tip.

I would like to upgrade one day, just can't find the right all rounder knife for me.....

IMG20190423040433.jpg

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Duncs, you’ll have to decide if the effort is worth the reward. Personally, I’d probably just throw it in the tool box & use it as a utility knife.

I’ve never been a fan of either tanto style or partially serrated blades.

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Thanks for the tips guys - I’ll take a shot at it and see how I go.

Any recommendation on which grit sandpaper or wheel that I should use to reshape it?

Its supposedly a “rescue knife” and the plan was to use it for road crash call outs but, like you’ve all said, the blade design is rubbish.

I’ve taken a closer look at the seatbelt cutter and I’m not going to bother with it.  Its never going to work and if I can get the blade right then it won’t matter anyway.

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When you grind it don’t use gloves. If it’s hot to the touch cool the steel or you will change the temper and lose your edge holding ability. If you see pretty colours in the steel you’ve gone too far

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On 22/04/2019 at 10:52 PM, ben338 said:

Duncs i would reshape that angled part of the blade to a curve with a hand file then use a lansky to shapen.
It will take a while to sharpen but will be fine. Ive done this with a knife that had a broken tip, worked well.

 

1 hour ago, Seb said:

When you grind it don’t use gloves. If it’s hot to the touch cool the steel or you will change the temper and lose your edge holding ability. If you see pretty colours in the steel you’ve gone too far

The more I think about it, the more I think Ben’s suggestion to use a file is the way to go for me. I don’t have a heap of metal to remove and it’ll stop me getting accidentally carried away :) 

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slow with water for cooling if you haven't got a wet wheel is the way to go, if steel is heated it's not the end, you'd just have to heat it, quench it and then temper it again.

Go on youtube there's lots of videos of the right colour heat to temper steel .

I am not an expert but still managed to bring a few knives back to life including a very thick stainless pig sticker.

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I don’t have a heap to take off so a file will probably do the job.

Here’s what I’m thinking.

5c77322be48c8be3559cbc2dfec3b900.jpg

If I take it back to the yellow line it should be useable.

Still looking for suggestions on sharpening the serrated part?

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On 24/04/2019 at 8:20 PM, Duncs said:

I don’t have a heap to take off so a file will probably do the job.

Here’s what I’m thinking.

5c77322be48c8be3559cbc2dfec3b900.jpg

If I take it back to the yellow line it should be useable.

Still looking for suggestions on sharpening the serrated part?

Mate, based on your profile, I would say you are not too far away from me. I have a belt grinding set up for making knifes that would re-profile this easily. Shoot me a PM if you want to come over and use my grinding set up.

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