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Burning the Point / Choil or Heel Area

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Michael Samdahl
Posts: 31
Eminent Member Apprentice Bladesmith
Topic starter
 

Greetings,

 

I am making progress on my next batch of knives and I am noticing that at one part of the process or another I am seeing some hay color show up in the point or the heel area of the blade. Is there any tricks for fighting against this? I have tried:

- Using only new belts

- Leaving these areas a little thicker until belt/polishing progression. (This causes issues of unevenness that I have to fix in the polishing/finishing stage)

- Slowing down in the middle of the knife for start and stops and moving quickly on the ends. .

- More time hand sanding

 

I know the answer is most likely "Well, Don't burn it", or "get better", but any quick hints or tips would be much appreciated. 

Respectfully
Michael

 
Posted : 19/04/2024 10:34 am
Joshua C States
Posts: 312
Reputable Member Journeyman Bladesmith (5yr)
 

I'm assuming this is post tempering or the finish grind.

How often do you quench/dip the blade while grinding? Generally speaking you shouldn't be grinding long enough to build up the heat to break temper. Quench/dip more frequently. 
What grit is this typically happening at? I have found this will happen most likely at 220 grit on the 2x72, so I stopped using 220 grit belts on blades. I use the disc for 220 and higher grits on blades. 
If this is happening at 120 or lower grits, you are probably pressing too hard. Ceramic grits need some pressure to break the crystals and provide fresh abrasive, but it's a delicate dance between too much and too little.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 19/04/2024 10:35 pm
Michael Samdahl
Posts: 31
Eminent Member Apprentice Bladesmith
Topic starter
 

Joshua C States,

Hey thank you Sir, I will try that going forward. I believe it may be at the 220 stage, but I will pay closer attention in the next build for sure. I do quench dip quite often, I usually make one pass before dipping. My passes consist of starting in the middle of the bevel, progress back to the heal or choil of the blade and then moving back to the point. I try and spend as little time as possible on the point as this has happened in the past. 

Respectfully
Michael

 
Posted : 22/04/2024 4:01 pm
Posts: 153
Estimable Member Apprentice Bladesmith
 

 

I absolutely love this very cheap modification to my 2x72.  It allows for continuous cooling mist while grinding.  In fact I find my hands get cold now in a long session!

 

You can pick these sprayers up on Amazon https://www.amazon.ca/dp/B08QZ6N264?psc=1&ref=ppx_yo2ov_dt_b_product_details&fbclid=IwAR1IjQj1FBRDBY0i5979Z4FJ0aUfMBUL926nHq5PjXOGVM4zq7D-WvNs66c for a very reasonable price.

I uses a dewalt compressor for an air supply https://www.homedepot.ca/product/dewalt-heavy-duty-60-gallon-165-psi-pancake-compressor/1000848535?eid=PS_GOOGLE_D00_Corporate_GGL_Shopping_All-Products_All+Products__PRODUCT_GROUP_pla-294357661102&gad_source=1&gclid=CjwKCAjwoa2xBhACEiwA1sb1BPLEuzYjkKSkVEk49DujtYnMdBKaq4uzzzRC1wosBcPCz4A8i9l3WhoCcTgQAvD_BwE&gclsrc=aw.ds

Since adding this I have not had to do the dunking method.  I simply adjust the spray to the amount of cooling required.

Bob Bryenton
Solar Storm Group Ltd.
Phone: (780) 953-0016
Email: [email protected]
https://www.solarstorm.ca

“The only way of finding the limits of the possible is by going beyond them into the impossible" -- Arthur C. Clarke

 
Posted : 26/04/2024 1:04 pm
Michael Samdahl
Posts: 31
Eminent Member Apprentice Bladesmith
Topic starter
 

Wendell Bryenton,

 

I think we had purchased one of those and just not added it. Reason being in some earlier discussions with folks they recommended against if as it would "make it difficult to see the working material during passes". I have noticed that if I am not carful to watch my work while grinding that I can get off the flat and create false edges. Any thoughts on that? I will hook up the waterline since you suggest it, but I want to make sure I am not creating new problems for myself whilst fixing old ones. 

Respectfully
Michael

 
Posted : 29/04/2024 12:38 pm
Posts: 153
Estimable Member Apprentice Bladesmith
 

I really had no issues with seeing my work.  The mist wasn’t that strong, just enough to keep the blade wet.  I also had it pointed more to the edge of the belt.  More by accident than thought.  The only issue I had was my hands were actually getting cold.  Since we have similar weather, that may be your issue too.

Bob Bryenton
Solar Storm Group Ltd.
Phone: (780) 953-0016
Email: [email protected]
https://www.solarstorm.ca

“The only way of finding the limits of the possible is by going beyond them into the impossible" -- Arthur C. Clarke

 
Posted : 29/04/2024 3:56 pm
Joshua C States
Posts: 312
Reputable Member Journeyman Bladesmith (5yr)
 

Posted by: Michael Samdahl

I will hook up the waterline since you suggest it, but I want to make sure I am not creating new problems for myself whilst fixing old ones. 

Be prepared to deal with that water. It goes somewhere and usually it goes everywhere.

@Wendel Bryenton, how do you deal with the spray?

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 29/04/2024 11:01 pm
Posts: 153
Estimable Member Apprentice Bladesmith
 

90% looks to be going into the five gallon pail under the grinder.  the pail is mounted about 10" to the bottom of belt.  It doesnt really use that much water. I feed it from old one gallon milk jugs and get about 1.5hr / gallon.  There is some that gets on the floor, but that just makes me do a bit more cleanup.  Doesnt really look to be any more water on the floor that the drips and splashes from dunking moving the blade.  It worked really well on the sword because a 5 gallon pail wouldnt have been big enough to dunk while grinding.

Bob Bryenton
Solar Storm Group Ltd.
Phone: (780) 953-0016
Email: [email protected]
https://www.solarstorm.ca

“The only way of finding the limits of the possible is by going beyond them into the impossible" -- Arthur C. Clarke

 
Posted : 30/04/2024 7:12 am
Michael Samdahl
Posts: 31
Eminent Member Apprentice Bladesmith
Topic starter
 

Wendell Bryenton,

 

I haven't got the system set up yet, but I laughed when I saw Joshua C States statement. Even when I use a sponge to cool the back of my platen while grinding I get waster that runs up the belt and immediately into my safety glasses. Maybe its just my 2x72" (Beaumont) that has more spray in tracking system than usual, but I do understand the "It goes somewhere and usually it goes everywhere." Great words Mr. States.

Respectfully
Michael

 
Posted : 30/04/2024 5:29 pm
Joshua C States
Posts: 312
Reputable Member Journeyman Bladesmith (5yr)
 

Posted by: Wendell Bryenton

It worked really well on the sword because a 5 gallon pail wouldnt have been big enough to dunk while grinding.

Look around for one of those cheap upright air compressors that has died. The tanks make great slack tubs. Just cut the top off, close the drain cock and fill with water. 30” of dipping.

And another thing guys, enough with the “Mr. States”. I know I’m old but no need to remind me! 😎 

just Josh is fine

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

 
Posted : 30/04/2024 6:35 pm
Kevin Stinson
Posts: 129
Estimable Member Apprentice Bladesmith
 

Posted by: Michael Samdahl

am making progress on my next batch of knives and I am noticing that at one part of the process or another I am seeing some hay color show up in the point or the heel area of the blade. Is there any tricks for fighting against this?

What size grinder are you using? Weight finishing belts like 220 have more grit in contact with the blade, and that will heat thin sections up faster especially if you're using a single-speed motor with lightweight belts. A variable speed drive 2x72 grinder set slower will help keep it cooler. You can't go wrong with a Tormek T-4. They are more expensive than the clones, but they also dont spray water.

 
Posted : 30/04/2024 7:22 pm
Posts: 153
Estimable Member Apprentice Bladesmith
 

I do use a variable speed grinder. Velocity Grinder I ordered 2HP and VFD.  no regrets on the purchase.  the spray is more off to the side of the belt, so its not going directly on the belt.  In the picture, I am moving the blade right to left so the blade grinds and then gets sprayed.  

The other real advantage I like is that it seems to really cut down on the dust as the dust is "wet" and doesnt appear to fly around near as much.  I can really notice it on the mask filters as they arent getting as dirty as fast.

Bob Bryenton
Solar Storm Group Ltd.
Phone: (780) 953-0016
Email: [email protected]
https://www.solarstorm.ca

“The only way of finding the limits of the possible is by going beyond them into the impossible" -- Arthur C. Clarke

 
Posted : 30/04/2024 8:57 pm
Michael Samdahl
Posts: 31
Eminent Member Apprentice Bladesmith
Topic starter
 

Joshua C States,

I will do my best to call you Josh, but my dad turns 78 this year and I am third gen service, so old time habits are burnt into my brain pretty hard.

 Kevin Stinson,

I have a Beaumont KMG TX - 2x72, 2HP. It was the first big purchase for our shop, and I legitimately work in the shop has come to screeching halt if anything is wrong with it. I heard the same statement from Joshua states, and it seems like any use of 220 grit or higher needs to be just light pressure and brand new belts. 

Wendell Bryenton

I am just going to find a way to get that thing running in the shop. (Once I finish this next project of course) haha.

Respectfully
Michael

 
Posted : 01/05/2024 10:25 am
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