grinding question

Jeff Pearce

Jeff Pearce

KNIFE MAKER
How do you make your knives, Do you grind before or after heat treat? and why do you do it that way. I am a new maker and have lots of dumb questions. Thank's guys. ...by the way i grind after heat treat....
 
If I'm using 1/8" stock I don't grind until after HT then I get a nice straight blade with the plate quench. With 3/16" stock I'll do a little bit of a rough grind just to get rid of some of the steel while it's soft :)
 
I grind after heat treat to make it easier to use a surface grinder or a disc grinder to make sure the parts are flat. I make slip joints and sometimes a small liner lock most of the time using 3/32 stock.

It takes a little more care to keep cool and a little more expense for belts. It just works better for me that way.


Craig
 
I grind after heat treating on most blades - doesn't matter if it's carbon or stainless. Thick stock, especially out of tough to grind steels, I will grind before heat treat. I also grind before heat treat if I just decide to make something out of the blue.
 
Great question and answers ! Now for the next question for grinding after HT.

What type and grit of belt do you begin grinding with ?

I'm just wondering if using say a 40 or 60grit Blaze to grind 95% of the blade may go a long way in reducing heat build up.

Do to my rookie status I've been doing the majority of my grinding with a 120 grit. Slower removal = smaller mistakes is my thinking but it does take me a few hours minimum to grind a 4" blade.

Just curious what you guys think on this so I can decide which belts to add to my next order.

Thanks guys, Josh
 
I forge, and I actually grind a blade 3x during the process of making a knife. First comes the forging....
Grind #1: This is done with a 7" angle grinder to remove all the forge scale and with some practice you can do a decent job of rough grinding the entire thing. I use the angle grinder because forge scale is super tough stuff and will just eat belts by the bucket fulls.

Grind #2: This is my actual rough grinding where I smooth out the profile, and flats, then set up/in the primary bevels. This is done with a 50 grit belt, then cleaned up to at least 120 grit prior to heat treating. (anything less than 120 and you run the risk of stress risers...which can cause tiny cracks during the hardening step)

Grind #3: This is my finish grind. It starts with a NEW 50 grit belt, and I take the blade to nearly complete. I then go straight to a 400 grit belt, clean up all the 50 grit scratches, give the blade a convex edge, then I normally go to hand finishing after that.

Some types of knives dictate that I go about it differently. For example if the blade is very thin (1/8" or less) I will often heat treat, then grind, in an attempt to prevent warpage.
 
I grind first, then heat treat. Folder, I would heat and then grind.
 
Josh Dabney said:
using say a 40 or 60grit Blaze to grind 95% of the blade
Click to expand...

Thats pretty much what I do. I grind so much different than I did when I was a newer maker, I used to use 4 or 5 different grits (if your hand finishing you still might need that many grits) and I always ground my blades as close as possible to finished dimensions because I thought it was too hard to grind all that material while it was hard with out burning the blade.

Well with the new abrasives we have these days (blaze orange belts for example) thats not really a problem, a 40g BO belt doesn't even seem to notice that the steel is hard. I've also learned that when you get into the finer grits you really need to have your lines set and be very close to your finished edge thickness. With normal AO belts if you go tring to move your grind lines very much you wear out the belt in the blink of an eye and then your generating higher heat and these funky little secondary grind lines that pop up and then you start chasing them...... Well, if you been there you know exacly what I'm talking about.
 
Les,
Ahhh. Your description of newbie grinding rings alot of bells here, LOL. Thanks for offering your input here. I have figured out for myself the hard way that belts 220 and up are for scratch refinement only and do little more than friction heat the blade if attempting to grind.

This thread makes me believe 2 things are causing me issues. Grinding too thin before HT and not grinding far enough with a rough belt.

Thanks again, -Josh
 
Great answers That is what i thought i would here . several different answers. I think if you ask 20 makers you would get 20 different ways to build a knife...that is what makes it so fun.
 
As I have been told oh so many times, you will find what works best for you. Then grab it and run with it. Jeff you need to place the orange handled knife closer to me so I can grab it and run2thumbs
 
I have been grinding A2, D2, and 440C in 1/8" and 3/32 thickness.

I do my profiling and most of my edge bevel grinding prior to heat treat. After heat treat I do light finishing on the blade, clean it up, hand sand for a satin finish or use micron belts, cork with polishing grit for mrror finish. Then I grind on my final edge.

I'm new at this, I'm only on my 5th knife and none are completely finished. This way is working for me so far.

Thanks,
 
cdhumiston,
One thing on D2. I'm finishing some D2 blades and have never use D2 before and to me they are hard to do a lot of finishing after HT particularly on the flats.

Art
 
Remember that after heat treaing blades are much harder and of course will require a courser grit to accomplish the removal of metal. Frank
 
I grind about 50 /50.
I used to grind mostly before but after warping a couple blades I changed my procedure. That sucks wasting my work.
 
When doing folders I am using ATS34 and the only grinding I do prior to HT is profiling. I do all other grinding after HT and with good belts I cant tell the difference. I start with a 60g then go to 120g then 400 gator. I like the 400 machine finish but sometimes I will hand sand up to 800.
For straight knives I only use carbon steel. I grind my primary bevel making sure to get the plunges the way I want them then go to 120g then HT. After HT I go back to 60g, then 180 gator then 400 gator, then hand finish to 800.

Sean
 
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