Design critique please NOW A WIP

Matt Markell

Matt Markell

Joined
May 12, 2012
Messages
846
Hello ShopTalk, how's it going?

This is my design for a small modified sheepsfoot blade.

gBLkt.png


Planned specs are:

7" OAL, 1" height
.113 CPM 3V tempered to 60HRC
Full Flat Right Hand Chisel Grind with back microbevel

One note, I usually design my knives facing to the left. Even though I drew the bevel on the left side, it will be a right handed grind.

I'm planning to use an epoxy-soaked paracord handle.

My goal when I started designing this knife was to come up with something that I could use and abuse in my knifemaking shop. Almost more of a tool then a knife. The main idea was to have a blade that could make accurate scoring cuts, could be used to cut leather cleanly and for opening boxes while being light weight and tough. Cutting performance became a driving factor, hence the FFG and thinness.

The problem when you start making blades that thin is chipping and edge damage. CPM 3V is commonly touted for its toughness. When used on a chopper it can be tempered down to a low HRC for incredible toughness and on a small knife it can be tempered to a high HRC using its toughness to prevent the chipping that commonly occurs at high HRC. I'm taking a middle ground at 60 though that is one thing I would like you guy's opinions on. Remember that this blade is meant to be used and abused.

I like the design but I'm not set on blade steel yet though 3V seems like it would work well. I'd really appreciate everyones advice here. Eventually I'd like to make a carbidized Ti version as well.

So, what do you guys think? Is it good, is it awful, is it so mind numbingly stupid/brilliant that I should be instituted/applauded? Or is it just meh?

Thanks for looking
 
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Sounds well thought out to me. :)

That should make for a very handy utility knife/shop tool. :thumbup:

FWIW- My leather cutting knives are 1/16" thick O1 at 61 Rc and ground to pretty much zero. I think your design is great for a leather knife, but I would make the blade a bit narrower (easier for contour cutting in the thick leather) and half that thickness if going with 3V. But that's just IMHO in regard to a leather cutting knife. For general utility I wouldn't change anything. (other than I'm not much of a chisel grind guy :p ;) ).

Please post it up when you get it made in steel. :)
 
First, I hope you grind it for right hand, its drawn for left hand! I really like the shape, but I am a bit biased towards sheepsfoot blades. Personally, if doing fine work I would use a kiridashi or slipjoint, and leave the heavy cutting for a blade like this. Paracord wrap is fine for small neckers, but on a larger knife it will be a pain. I say throw some scales on there and make it a real knife.

Otherwise, I really like the shape!


-Xander
 
That's outstanding! Very well thought out in every aspect :thumbup: 3V at 60Rc is an excellent choice. Just be sure to sand it very close to your desired finish before HT. It's a real pain to hand-satin afterwards.
 
gimmjr, I have made an early prototype in 5/32" 1084 with black linen micarta and I really like how it came out. Thin and light are my big goals though and I really like the grippiness of the p-cord. I may do scales but they will be thin, no more then 1/4" ea.

Nick, I'm glad you like it, I must be on to something :D It is more of a general utility knife more then a leather only knife and I expect it to see hard use fairly often. I think I will stick with 3/32". The primary bevel will be ground to almost zero grind then a microbevel will be applied to the flat side to bring it to sharp. Very near zero ground but tougher.

Xander, I forgot to put it in my post originally but I edited this in:
One note, I usually design my knives facing to the left. Even though I drew the bevel on the left side, it will be a right handed grind.
Click to expand...
At 7" OAL, it is pretty small and could work as a necker though I see it as being more of a back pocket knife.

Here's a pic of the prototype, a few things have been changed since then:
mjHT3.jpg

It's the one on the left.


So, SCALES. That might work well actually, I see some G-10 with Anso style texturing coming :D
 
james terrio said:
That's outstanding! Very well thought out in every aspect :thumbup: 3V at 60Rc is an excellent choice. Just be sure to sand it very close to your desired finish before HT. It's a real pain to hand-satin afterwards.
Click to expand...

Glad you like it, I will take your advice to heart. I read somewhere (I think it was you that said it) that 3V is a mind numbing screaming bitchfest to hand finish :eek: Either a stonewashed or scotchbrite satin finish that hides scratches would work well I think.
 
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I changed the location of some of the lightening/structural holes, pulling them away from the edge. I also added two 1/4" holes so I can use chain ring bolts to attach handle scales. I drew in a handle layout and cleaned up my drill targets, the old design was kinda crazy with 'em.

jkiFH.png


Thanks for looking
 
Nice work! I make a model that is very similar to that and find it to be a great overall design.

Your prototypes look killer, great grinds and shaping.
 
Ok. I tried not too. But I couldn't stop myself. Brace yourselves for horrible pictures, this is now a WIP! :eek:

This started innocently enough, a printed design, a piece of 3/32" 1095. Nothing to see here right? Wrong!

QfNtH.jpg


I superglued the design to the steel and then went ahead and drilled my holes. This is where I ran into really my only problem. I had designed the holes to be 1/2" and 1/4" holes all around but apparently I scaled them wrong in my design. They quite simply wouldn't fit. I ended up drilling the 1/2" holes and using 9/64" for the rest except for the lanyard hole which is 17/64". The 17/64" hole came out a little too close to the edge of the handle so I extended the handle just a hair when I profiled. I drill my pinstock and lanyard tubes holes 1/64th oversized hence the odd numbers.

Drilling 1/2" holes:
15sp2.jpg


Moving on to 9/64":
HJ0fI.jpg


All holes drilled including the 17/64"
xMHyr.jpg


I use a sawzall with a metal cutting blade to rough my profile.
lNHG1.jpg


Here we are fresh of the 6" disk sander. My 4x36's belt sander is broken but the disk works fine. Until my Pheer arrives I make do with it.
kvyd4.jpg


Cleaned up the index finger area with the bench grinder. Who says they are useless?
52o2x.jpg


Now I'm about to grind the bevel on the disk sander. I mark out roughly where I want my grind lines.
SyTHK.jpg


I threw on a fresh 80 grit AO PSA disk and went to town. First pass:
vKdDZ.jpg


Second pass:
vaATF.jpg


Third and final pass:
5Puwy.jpg


I draw filed things to level the grind then sanded most of it to 220.
yVEMK.jpg


My hillbilly surface grinder. That's 100 grit.
9GJHo.jpg


And here we are next to a little chisel ground bushcraft knife made from the same bar of 1095
fCVu5.jpg


I took them outside so I could get some decent light:
zvi8Q.jpg


It's a very nice size, balanced a little blade heavy right now though that will even out once I put a handle on. I am going to use black micarta and 1/8" stainless pinstock for handle material.
rjhAS.jpg


My hands are about a Large and this fits them perfectly. Not bad for a 7" knife. Very comfortable.
rIV5r.jpg


A shot of the bushcrafter.
vTroc.jpg


And the last one. Two knives just chillin' out.
zDTiN.jpg


I still have a LOT of work to do but I'll probably get these to Darrin Sanders soon for HT. These are too nice for my firepit and canola oil.

Thanks for looking guys, any and all comments are greatly appreciated!
 
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Man, I just wish I could go work in my shop today! Great work, I'm jealous! Be sure to break the edges on the holes before heat treat. Either a countersink or a larger drill bit work well!


-Xander
 
fast14riot said:
Man, I just wish I could go work in my shop today! Great work, I'm jealous! Be sure to break the edges on the holes before heat treat. Either a countersink or a larger drill bit work well!


-Xander
Click to expand...

Will do! I'll countersink the smaller holes and probably use sandpaper wrapped around a rod to chamfer the big 1/2"er's. Thanks for the advice!
 
Well, here's what will hopefully be the last version. This one is all 1/4" and 1/2" holes for simplicity and so that I can use 1/4" chain ring bolts for scales. Should provide a very nice balance between ease of creation, light weight and strength. I'm pretty happy with it now.

CfCVB.png


Thanks for looking
 
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sshbiker said:
Nice job! I have that exact same model of surface grinder. :)

-Shawn Hatcher
Click to expand...

Haha, I usually use the 4x36 for that but I'm roughing it since it broke (all the way this time)
It works a lot faster then I thought it would.

I still have a few scratches I need to sand out before HT but it's coming along.
 
Nice work Matt, I really like the design! Following with excitement...
 
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