Warp, please advise...

[DustinY]

Okay, here i am, growing more and more concerned with my ability to do anything and my respect level growing immensely for the people that do this (i hate that in a sense i feel like i SHOULD be good at something instantly), but i'm having an issue.

This knife is RWL-34 and i'm grinding post HT, but it doesn't seem as sparky as the 52100 i was grinding last week. I set aside my integral handle knife (i was waiting on mini files for the bolster, they came today!! ) but i decided to get into this knife. ALSO, i plan to buy the bubble jig, because the only way currently that i'm able to get a flat bevel is with a jig - but there is almost no room for adjustment with a jig or trying to address mistakes.

I'm going to test the knife tomorrow to see if it skates a file - but it's not grinding like its hard, idk. The dude i sent it off to makes knives, but idk (I want to disclose, i'm very fucking new and could just be incredibly stupid), but that isn't why this post is here - i'm trying to figure out if i got it to hot and this is SOL or if its caused because i have more material off of one side than the other (and its uneven, etc).

The center scribe and 45 it in has helped immensly, this guy is actually okay, not great, not even good, but okay. But it has this mild bend - and i'm trying to figure out if i can do anything about this (was going to start to walk it up grits - and then taper the tang).


Pictures are of the bevels (the left side is wavy but the curve goes to the right?) and the knife resting on my granite surface plate (when looking down the knife it's really hard to see with my eyes).

Not easy to see here - warp is directed into the granite plate.

She's a shiner - warped and bent up.

Really need to game plan my plunges - and start them much further back and work to the final spot - ran up the handle :/ but at least the bevel is a straight line.

Uneven side :/

Advice as always is appreciated, thanks for being so helpful - i really need to find a mentor close that wants free beer or extra money.

 

[Rhinoknives1]

I grind post HT, dip and grind , watch for steam .. when you see it, dunk again & grind. You should be able to bring out that slight warp. Start with a fresh 120g it you can get it out by grinding on the apex of the warp, drop to 60g for a few passes. Only send your blades to a known shop. There’s JT here . I use Paul Nox at Buck Knives .. clean up your recasso by grinding Tang up with a 120 to even , then how you finish. Patience is a virtue while learning to grind ...

 

[DustinY]

I grind post HT, dip and grind , watch for steam .. when you see it, dunk again & grind. You should be able to bring out that slight warp. Start with a fresh 120g it you can get it out by grinding on the apex of the warp, drop to 60g for a few passes. Only send your blades to a known shop. There’s JT here . I use Paul Nox at Buck Knives .. clean up your recasso by grinding Tang up with a 120 to even , then how you finish. Patience is a virtue while learning to grind ...

Noted - i do dunk after EVERY pass, i never see steam, and i make sure to monitor everything (occasionally touching it even to ensure its cooling). I'll try to find the apex and grind it down. I sent all my other blades to JT, these were a test batch to a friend who said he could do it - i'm honestly concerned.

 

[Rhinoknives1]

Noted - i do dunk after EVERY pass, i never see steam, and i make sure to monitor everything (occasionally touching it even to ensure its cooling). I'll try to find the apex and grind it down. I sent all my other blades to JT, these were a test batch to a friend who said he could do it - i'm honestly concerned.

did someone say Free Beer??
Try the file test. If you hear a Screeeh! It’s harden. I usually do two-passes. Just so you know , my reasoning is water boils at 212 degrees so I’m fine there. The temper on these air Hardening Steels is 350-400 something. That’s way I know I can work till steam. I do agree that it will be a bit easier to grind if you angle the Ricassio to a more vertical angle ... IMB it’s good that you’re learning to do this by hand. It will help in the further.. keep going!

 

[DustinY]

did someone say Free Beer??
Try the file test. If you hear a Screeeh! It’s harden. I usually do two-passes. Just so you know , my reasoning is water boils at 212 degrees so I’m fine there. The temper on these air Hardening Steels is 350-400 something. That’s way I know I can work till steam. I do agree that it will be a bit easier to grind if you angle the Ricassio to a more vertical angle ... IMB it’s good that you’re learning to do this by hand. It will help in the further.. keep going!

It skates a file, it feels so much different than 52100 though, but i guess it's a completely different steel. We'll see if i can salvage this guy.

 

[Rhinoknives1]

It skates a file, it feels so much different than 52100 though, but i guess it's a completely different steel. We'll see if i can salvage this guy.

RWL-34 It is a tad different than bearing steel 52100 which is a lot lower in Chromium. Look at a side by side of the two Steels. The higher Chromium makes it abrade differently..

 

[DustinY]

RWL-34 and the steel i tested from JT is AEB-L & i had two more 52100 blanks i tested.

Is it AEB-L or other SS? It is a tad different than bearing steel 52100 which is a lot lower in Chromium. Look at a side by side of the two Steels

 

[Fred.Rowe]

With a tempering temperature of 350-400 it is possible to straighten blades in an oven, an Evenheat or other electric oven would be best but this can be done in a kitchen oven if the heat setting can be maintained. It's just a matter of clamping the blade to a section of angle iron and shimming it enough to get the warp out. place this in the oven at tempering temps for a couple of hours. Most of the time the warp will be overcome by doing this. This technique is a good one to learn. All of us have blades that warp on us; there are so many variables involved that it is hard to cover all of them.
Enjoy the process, Fred

 

[DustinY]

With a tempering temperature of 350-400 it is possible to straighten blades in an oven, an Evenheat or other electric oven would be best but this can be done in a kitchen oven if the heat setting can be maintained. It's just a matter of clamping the blade to a section of angle iron and shimming it enough to get the warp out. place this in the oven at tempering temps for a couple of hours. Most of the time the warp will be overcome by doing this. This technique is a good one to learn. All of us have blades that warp on us; there are so many variables involved that it is hard to cover all of them.
Enjoy the process, Fred

Fred! i NEED A BUBBLE JIG!

 

[coldsteelburns]

A quick tip if you use your household oven to temper or correct warps is to put something with a decent amount of mass in there to help even and stabilize the heat. I only use some kiln shelf in mine because I've found it to be pretty stable without, but a cheap hard fire brick would also work. Also, if you can fit it, put the blade (with the shim jig and clamps etc) in a deep pan and cover it with a few layers of foil to keep in protected from more direct heat spikes from the firing element. The added mass will make it take longer to reach temp, but it worth to extra stability imho. I just put the kiln shelf in the bottom of the pan for my tempering.

Your bevels are looking pretty good Just curious, what type of jig have you been using? Is it the kind where the tang is attached to a backing and most of the blade hangs off to the side, or does it have something to firmly back the blade as well?

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)

 

[DustinY]

A quick tip if you use your household oven to temper or correct warps is to put something with a decent amount of mass in there to help even and stabilize the heat. I only use some kiln shelf in mine because I've found it to be pretty stable without, but a cheap hard fire brick would also work. Also, if you can fit it, put the blade (with the shim jig and clamps etc) in a deep pan and cover it with a few layers of foil to keep in protected from more direct heat spikes from the firing element. The added mass will make it take longer to reach temp, but it worth to extra stability imho. I just put the kiln shelf in the bottom of the pan for my tempering.

Your bevels are looking pretty good Just curious, what type of jig have you been using? Is it the kind where the tang is attached to a backing and most of the blade hangs off to the side, or does it have something to firmly back the blade as well?

~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)

Paul, as always, wonderful advise. I'm worried about wrecking the HT if i try this? It wasn't there before i started grinding? I'm using a DD work rest that backs the blade (this is the biggest blade really that can be done on the one i bought - the larger knife i did really ground differently with the unsupported blade not getting the same amount of material removed.

 

[Scaniaman]

The knives I have made so far have been mostly RWL. Very few sparks when grinding that, both pre and post HT.

 

[Stacy E. Apelt - Bladesmith]

RWL-34 is a stainless high alloy steel. 52100 is a simple carbon steel with low alloy. You aren't going to get the sparks from stainless steel when grinding that you get from carbon steel.

Grinding post-HTR can be made easier and more consistant by installing a Kool-Moist type system. Not having to dip and return the blade to the belt every few seconds saves time and makes grinding passes evener … without fear of burning the edge or tip.

Tip warp can be straightened after grinding by heating to 400F for 30 minutes and then straightening while hot. I do it cold usually, but that has some degree of risk.

 

[DustinY]

RWL-34 is a stainless high alloy steel. 52100 is a simple carbon steel with low alloy. You aren't going to get the sparks from stainless steel when grinding that you get from carbon steel.

Grinding post-HTR can be made easier and more consistant by installing a Kool-Moist type system. Not having to dip and return the blade to the belt every few seconds saves time and makes grinding passes evener … without fear of burning the edge or tip.

Tip warp can be straightened after grinding by heating to 400F for 30 minutes and then straightening while hot. I do it cold usually, but that has some degree of risk.

Would you use the shim and vice method or three bars welded on jaws? Thanks for the advice Stacy!

 

[Stacy E. Apelt - Bladesmith]

Make a pair of drop over shimming jigs with some 6-8 gauge copper wire brazed on a piece of copper so there are two wires hanging over one vise jaw and one on the other. Obviously you could use steel for making this, but copper is better.

Here is a simple build for one:
Cut three pieces of copper round wire 3" long. 6 or 8 gauge bare copper grounding wire from Home Depot is good.

Bend each into an "L" with the short leg around 1/2". Flatten the short leg on the anvil with the long leg hanging down over the side.

Cut two strips of 14 to 16 gauge copper sheet around 8" to 10" long (4" to 6" longer than the width of your vise jaws ). If you want a perfect fit , make a template of the strip on your vise top by fitting/folding a 1" wide strip of stiff paper to the top.

Braze the short legs on the strips of copper - one centered on one sheet and the two spaced about 1.5" apart. This will make them hang down over the vise jaws as a three point jig.

Set the strips in place and gently close the jaws to hold them. Bend the ends of the strips to fit the top of your vise jaws.

Add some rare earth magnets if needed to hold the jig in place in use. A strip of duct tape will also hold them in place.

You can make a copper jaw cover in a similar fashion that slips over the steel vise jaws to protect blades clamped in the vise. Copper jaw protectors are a very professional addition to your vise for knife work.
You can buy these to fit Wilton and other vises, but you can easily make them for much less. They look like a four legged half crab before fitting on the vise. You bend the legs to wrap around the jaws and vise top.
The same setup can be used to make the above copper straightening jig using sheet copper and brazing the rods on the down faces.

 

[JTknives]

I abandoned the tempering and clamping in favor of surface peening. Some steels like to move more then others. 15n20 for my stays rock solid where Abel likes to bow towards the area where more material is removed. I use a carbide faced hammer and gently tap the inside curve of a bow and she straightens right out. I just rushed out a gift blade for my mother-in-law and it was trying to get away from me but it settled down quickly using the surface peening. As I was hallow grinding the edge bevels it was moving. So I would stop and give it a little tap tap and back to grinding. It shows up the most towards the tip where it starts to thin out. The blade is .06 thick aebl at 62rc and hallow ground on a 12” wheel. Good size blade so nice a flexie. I lined the scales in place with soft copper tube. I used a round nose punch to swage and flare the tube over and fill the counter sunk pockets in the scales.

 

[JTknives]

P.S.
We will be manufacturing and selling straightening hammers on our website after the New Years.

 

[Fred.Rowe]

What do you do with the ding, from that carbide faced hammer? Asking for a friend.

 

[Stacy E. Apelt - Bladesmith]

Sand/grind it away.

 

[TheEdge01]

I abandoned the tempering and clamping in favor of surface peening. Some steels like to move more then others. 15n20 for my stays rock solid where Abel likes to bow towards the area where more material is removed. I use a carbide faced hammer and gently tap the inside curve of a bow and she straightens right out. I just rushed out a gift blade for my mother-in-law and it was trying to get away from me but it settled down quickly using the surface peening. As I was hallow grinding the edge bevels it was moving. So I would stop and give it a little tap tap and back to grinding. It shows up the most towards the tip where it starts to thin out. The blade is .06 thick aebl at 62rc and hallow ground on a 12” wheel. Good size blade so nice a flexie. I lined the scales in place with soft copper tube. I used a round nose punch to swage and flare the tube over and fill the counter sunk pockets in the scales.

Gorgeous knife!!!! I bet your mother in law will be one happy lady.