how to make serrations?

B

bartblade

Joined
Nov 4, 2002
Messages
344
ive been working on doing a serrated knife but just havent mastered the concepts. i was wondering if anyone could walk me through making serrations like spyderco's so i can sharpen them easily.


i was also wondering if anyone knew or had an idea of why production knives put the serrations on the back half of the blade instead of the front; to me it would make more sence to put them on the front. when i cut stuff latley i have to use the tip and belly and not so much the part nearest the handle.

hmm guess i m gonna have to make a knife of my own design for the work i do.

thanks, dale
 
Never having made serrations myself I cannot help much. I believe many people start out using a combination of files - a chainsaw file and triangular file for example - and work carefully to keep the spacing even. I've heard of people milling them in too, which would help to measure out the spacing. Maybe someone who knows what they're doing will jump in with real information.

As far as placement goes, I think putting them at the front of the blade would be a mistake. Serrations are generally meant to cut fibrous material like rope and webbing, so they are placed near the handle to allow more strength and control. I can't think of an application where having them at the front of the blade would be beneficial. I think skinning with a serrated edge would be a big mess...

That being said though, getting things the way we want them is one of the main drivers for making knives in the first place. ;) There's a lot to be said for having specialized tools for specific jobs. Good luck, and keep us posted what you come up with. It does sound interesting.
 
Thanks for posting the interesting thread. I'll let that soak in for a while but I have to admit that I still feel a little prejudiced away from this idea. Frankly, serrations are not my cup of tea at all and none of the knives I carry have them. But it's obvious they have their uses and if I were cutting heavy stuff regularly I'm sure I'd change my tune quickly. Opening mail and reams of paper etc doesn't require a very aggressive edge. :D I'm looking forward to what others have to say about this.
 
Serrations can easily be made with a surface grinder, a magnetic sine chuck, and pre-shaped grinding wheels. This is pretty much how Spyderco does it, however I am sure their grinder is cnc-controlled and with a full-time operator running it to do just that. How do you spell BORING? :rolleyes:
 
thanks guys those threads back up my ideas; but i do also believe there is a specific function for the designs. i just think the production knives are all heading for one function.


how would you go about surfacing a grinding wheel to make serrations? that looks to be the fastest and most efective way to make serrations.

i have done a blade or 2 with serrations but could not seem to keep it semetrical even with scribed lines both vertical and horizontal marking where i wanted the serrations to meet. the problem was controlling the files. i have been contemplating if i cant find a wheel to do it the best way would be to file the blade on edge to keep it even then file on the side to depth.
 
Another idea is to use a checkering file, say 20 lpi and sharpen from the other side ala Ginsu... :D

Craig
 
Hey Bart,

I think JHiggins nailed it.But I couldn't say for sure.Having spend a lot of time in Die & Machine shops I would guess that they are done by "Form Grinding" the wheel would be dressed to cut 4,6,8 or however many serations they can dress on a given wheel.Depending on wheel width.This is all a Hypothesis , not having seen it done.I'll bet it would work though.
 
You can purchase wheel dressers that will dress any given radius on a surface grinder's wheel.JHiggins sounded pretty sure about spyderco's method and might know their technique.If i had to guess,I would say that a fixture was built that had a gang set-up of diamond dressers that were specially made for the profile of the serrations.they "probably" clamped it to the mag chuck lifted the wheel up to clear it.Started the table going back and forth and plunged the wheel into the dresser until they cleaned the wheel up.If you were going to do one or two blades you could easily dress a single radius on a 1/4 " wide wheel that was brought to 1/8" wide about 1/2" up the wheel.Purchase a radius dresser from MSC or J&L and dress your rad.The one's I have seen are on a pivot with an adjuster screw that you can set your rad ; position the dresser correctly & swing it on the pivot until you get the desired rad on the wheel.Position your Blade on the mag chuck.Probably better on a sine plate thats on the mag then start the table going and plunge the wheel to the desired depth a couple 10ths a pass.Raise your wheel,dial over on the Y axis, and start all over again until you have the number of serrations that you want.You could always use a carborundum stick and a radius gauge and just dress a rad by hand too.That would be the cheapest route as radius dressers are pretty pricey!!Back to JHiggens spelling lesson,I dont think he was spelling the right word.I think it is "How do you spell M-O-N-K-E-Y"
 
There are places you can send your knife off to get serrations - that's the route I'd go. Sorry I don't have any names/links off the top of my head. I just remember a shop in MD that does sharpening - they'll put serrations on for a few bucks.
 
To be honest, if I hand only one or two to do, I think I would use a carbide ball endmill...Grinding a wheel for one or two probably isn't worth it...This would also help with the size of the serrations...You could go to smaller ball endmills to achieve a tighter serration. This is coming from a machinist/toolmaker point of view...

hth..


Bill
 
I just made a kayaking knife simlar in shape to Benchmade's River/dive knife. I put the serrations at the tip, for the first inch or so. I had also recognized that I was mainly using the tip for cutting, especially if I would be slashing at a rope, line, net, etc.

I used a 3/32 chainsaw file (Home Depot, about $3.00) and a small round file from a jewlers file kit (also Home Depot, $12.00 for the whole kit). I alternated 2 small, one lg. I did one full seration at a time, finishing it to the full depth before moving onto the next. That way I could space them evenly. I think it took about 15 minutes to do a real good job.

After heat treating, I just sharpened them up with my GATCO sharpener using the serrated edge stone on 29 deg. I'd post a pic but our camera just went on a trip to Chicago with my girlfriend. Hope this helps.
Scott
 
Agreed bhyde.Simplicity is always best.I was answering a grinding question though.And like I said "Hypothetically" , because I don't know how it is done.The question gave me "tunnel vision".:) Ball Mill sounds best for a couple:thumbup:
 
hey scott did you use the depth gauge that comes with the chainsaw file also did you file the what would become the edge first and then the angle for the sides or did you just file the sides till it came down on the cutting edge?

all that talk about sending it off is out of the question for me i dont have the money or think it would be trully a knife i made if i sent it off to get profiled for serrations that in my mind would be cheating and i could just go out and buy a kit knife and say i made it. i mean its a start but its still cheating im my mind.

last of all i dont have a mill or anything fancy like that all my equipment i use costs less than $80.00 per machine i have.

lets see i use a 1/2" binch grinder, a 4, 1/2" hand grinder wich also serves as my way to cut out all my steel and profile them into what i think looks like a knife. a 1x30" belt sander, a 4x36" belt sander, a small table top drill press, hand files, hamers, a rail road anvil, a home made charcoal forge w a disgarded rainbow vacume as the air supply some vinager and about a gallon of sulfuric acid and a 12 volt battery charger, i have just recently got a depth gauge/ scribe for my edge center lines
 
Bartblade,
I ground the knife just like it was going to be a plain edge. After grinding, I polished the knife and just before heat treating, added the serrations. I started at the tip, scribed a mark, then began filing at about 29 deg. I continued filing until the serration met the cutting edge of the knife, and then went a little more. I used my Spyderco Military as a guide to how far I should go, and how the serrations should look. Next, I scribed another mark and then used the small jewlers file. Again, I made the complete serration before moving on to the next. I alternated 1 lg, 2 small for just over an inch. It looks close enough to factory for me! By the way, you can get those chainsaw files in 3/32, 5/32 or 7/32 if you want larger serrations. Good luck.
Scott
 
would it work to make a tool for a mill that could work like a slitting saw
i think i might give that a shot when i get my mill as i have a friend with a lathe jhiggins what do you think
 
You must log in or register to reply here.
Back
Top