Grinding bevels pre or post heat treat

Busto said:
Did you cut out blanks or just profile from rectangular stock??? That makes a difference on Belt Life. Cutting a blank close to dimension will give you less to grind and belt should last 20-30 profiles(36 grit ceramic).

Since these are your first Blanks to Grind and you have a bubble jig stick with Flat Grinds. I would concentrate on basics not chasing a Hamon that should come after you perfect your grinding skills. Once you can control a good flat grind even on both sides of the blade then you can try hollow grinding which take a little more control to get good even hollows on both sides.
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Using used belts for profiles is a great way to justify junking the belts sooner. Profile with old and use the new fir the bevels.
 
Storm W said:
Using used belts for profiles is a great way to justify junking the belts sooner. Profile with old and use the new fir the bevels.
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I get that....but if you use the belt to grind the Entire Profile from a rectangular bar stock to Finished profile in lieu of cutting a blank within 1/16" or less of finished profile. My Question was: Did he cut the Blank with a saw first or Grind it all to dimension?? Huge difference in the amount of Belt Wear.
 
12345678910 said:
You didn't ask this, but instead of 5 different designs, try 30 of the same pattern and an easier grinding steel.

Repetition and perfection on the same thing until you move to something different.

I consider 36 grit too coarse for me. If you're profiling with it - it's way too easy to strip the grit.
The first time I profiled, I could feel the grit flying off and hitting me in the face however it wasn't a ceramic belt.
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I do have a micrometer.

I considered doing all the same profile. It makes sense to do the same profile over and over again until I am able to be consistent. I also know that taking more knowledgeable people's advice is really wise. Too late for that one, but I do plan to begin with 60 grit and do flat grinds. 60 grit doesn't go wrong quite as fast if I am screwing up but still will cut pretty quick.

Fred, thanks for the support and willingness to help with your number if I need to call. Obviously you want your customers to be successful and not just purchasers. I plan to post pictures when I am done grinding.

Busto, I profiled basically from rectangular stock...cut some excess off with a grinder, but After I screwed up and put a groove in one of them I decided to just profile from rectangular stock. I was too excited to get going on the 2x72.
 
Randydb said:
Busto, I profiled basically from rectangular stock...cut some excess off with a grinder, but After I screwed up and put a groove in one of them I decided to just profile from rectangular stock. I was too excited to get going on the 2x72.
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That process eats belts quickly...I understand the excitement of getting started and you know now how expensive using belts
that way can be.
 
If you are going to make batches of several units of the same pattern, it may pay off (in time and consumables) to get them cut with waterjet out of a sheet. Nesting programs would definitely get the most use out of the metal. If you go with plasma, you need to dress the edges (dross).
 
Randydb said:
I do have a micrometer.

I considered doing all the same profile. It makes sense to do the same profile over and over again until I am able to be consistent. I also know that taking more knowledgeable people's advice is really wise. Too late for that one, but I do plan to begin with 60 grit and do flat grinds. 60 grit doesn't go wrong quite as fast if I am screwing up but still will cut pretty quick.

Fred, thanks for the support and willingness to help with your number if I need to call. Obviously you want your customers to be successful and not just purchasers. I plan to post pictures when I am done grinding.

Busto, I profiled basically from rectangular stock...cut some excess off with a grinder, but After I screwed up and put a groove in one of them I decided to just profile from rectangular stock. I was too excited to get going on the 2x72.
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R Randydb , you need contact wheel for profiles , flat platen behind belt don t like to grind thin steel...With contact wheel and right speed you can profile hundred knifes like that /from rectangular stock / on your first picture with one belt . . . .
 
Don't let the word "JIG" in a name confuse you. The old definition of a jig was a device or tool to hold your work as you perform a task. Today, the term gets applied in a much broader way. I have seen entire machines to do automated processes called jigs (eg. - double hollow grinding jig)

A Bubble Jig isn't a jig in the newer meaning … it is a tool. It is no more cheating than a carbide faced shoulder jig, or an articulated work rest. It isn't "cheating" to use good tools. It isn't cheating to use a TW-90 instead of a HF 1" belt sander. A good carpenter isn't cheating when he uses a 4 foot level to check a floor. You aren't cheating to use a Bubble Jig to know the angle you are holding a blade at. After making a few dozen blades with the Bubble Jig, you will have learned how to hold you arms and body in order to keep the bevels even. The Bubble Jig has taught you better skills, not done them for you. After that, you may use the Bubble Jig on some knives and not on others. I think those who start on one stay with them on most of their knives. People like me who learned by making lots of badly ground blades in the beginning and then tried the Bubble Jig years later find them helpful, but our habits are hard to break. That said, there are times when I pull the Bubble Jig out and do a swedge or similar grind where it makes the task much easier and more accurate.

The jig I don't recommend is a filing jig. Besides some of its physical limitations, it teaches you nothing. If you filed 100 blades on a filing jig and then went to hand file or hand grind a blade it would be a completely new task that you have gained no skills at.

My point is that if you use the jig to do a task and you are in charge of the results, then it is a good tool. If you use a jig to do something for you that you can't control, then it really isn't a good tool.
 
Randydb said:
Hi,


One other question. I profiled these using a 36 grit belt. How many blanks should I be able to profile before a belt is done. I can see this one is done after 8 profiles....probably should have been changed after 7 as the last one was a lot slower and hotter as I did it.

Thanks, I am pretty excited about grinding bevels!View attachment 1094187
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I don t think that 36 grit belt is best choice for profiling / maybe WORN one properly fractured not glazed / thin blade . Especially not on flat ceramic plate behind belt .Try higher grit and you would be surprised...On which speed you run your new grinder ?
I profile my kitchen knife /1.5-2mm / on 100 grit zirconia belts and they last forever . . .. .
 
Busto said:
That process eats belts quickly...I understand the excitement of getting started and you know now how expensive using belts
that way can be.
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It was sort of exciting to watch how quickly the belt took the excess steel off. Took less than 5 minutes a blade to profile.

N Natlek I have an 8" contact wheel. I ran my 2x72 at 60hz on the vfd....no clue what speed that was, but it took stuff off pretty fast if I put reasonable pressure on it. Why does a contact wheel work better than a ceramic platen?

M Mikel_24 I think I will likely get a bunch of AEB-L blades cut out and hardened from JTKnives when he gets his plasma cutter going. I will only ship once then to have heat treated, profiled AEB-L blanks ready to grind bevels.

My goal is to be able to grind bevels well enough to grind blanks for the knives my grade 7 students make this fall. This year's crew made some beautiful bird and trout knives with blanks made for us by Cariboo Knives. I will post pictures soon. It's a really cool leaving present for them.
 
I did the beginnings of my first bevel flat grind. 10 degrees angle on the bubble jig, 60 grit belt. So now my two sides are fairly equal and I am at 1.5 mm thickness at the blade edge. Do I go to 5 degrees now and stick with 60 grit?

I can see that my bevels are not perfect. Some parts are a bit wider than others parts....but generally that will get taken care of when I change angles if I do a good job of even pressure when I grind...right?


IMG_1394 (1).jpg IMG_1395 (1).jpg
 
Spalted said:
You didnt say what kind of belt you were using, I use 3m ceramic belts and could profile give or take 25 on a belt.
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I grind the entire profile from a rectangular bar stock and have no problem profiling a couple dozen blades with a belt. I like using a 60grit way better, the 36 grit is like getting sandblasted. I could probably profile a blade like that in 2 mins with a used belt. Now if I could just get good grinding the bevels :rolleyes:
 
If the edge is slightly thicker, than it will be at heat treat, change angles, the five degree is fine. At this point the edge thickness should be the same from plunge to tip.
Watch the height of the grinds, make them the same on both sides. If one grind line is lower than the other, grind that side and bring it up to match the other side. When you do, the edge will be centered on the blade. I didn't notice the thickness of your steels; but if you are wanting a distal taper in each blade, it is best done [before] the bevels are ground. It is easier to grind bevels with the distal taper completed. It can be done as you go, but you are fighting against it as you grind. If you want the information on grinding the distal taper I can supply that. Let me know.
Stay with the 60 grit belt until you are almost at the end of grinding the bevels; if you have a 120 or in the ballpark, change to that as you put the pre heat treat surface on the bevels, as you are finishing the bevels, pre heat treat.

There is an order to grinding any blade. Some things are the same for all of them. Always finish the ricasso area to a 400 grit on both sides. Make the ricasso the same thickness all the way around it, top side bottom side. Then grind the bevels. This should be self explanatory. You don't want to finish the ricasso after the bevels are ground.

Relax when you grind. There is no hurry when using this tool.

Regards, Fred
 
Spalted said:
I grind the entire profile from a rectangular bar stock and have no problem profiling a couple dozen blades with a belt. I like using a 60grit way better, the 36 grit is like getting sandblasted. I could probably profile a blade like that in 2 mins with a used belt. Now if I could just get good grinding the bevels :rolleyes:
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Are you using the 984f belts by 3M? I like all their belts, they all seem to track well.
 
Randy,
Welcome!
I use a 36 G for flat grinding when working on a knife that 2 3/4" to 3" or more at the Heel, other wise, A Ceramic 60G will work fine on those smaller blades you have profiled.

Years ago I was tired of the grit hitting me in the face & the dust getting in my eyes, So I wear Goggles over my prescription glasses and a face shield like they had in shop class. Also I sit down to grind so my face is where the action is!

Always protect your eyes, Ears and Lungs when doing this work. Any fine dust will destroy your lungs over time... If you have never had the sensation of not being able to breathe?
I had a lung collapse years ago and its a horrible sensation that you don't want!
 
I have a respirator, hearing protection and face shield over my reading glasses when I grind.

Fred.Rowe Fred.Rowe I was using an orange 60 grit Norton belt. Why does it matter if you do the ricasso before or after grinding?

I understand what distal taper is, but I am going to hold off doing that yet.
 
Randydb said:
I have a respirator, hearing protection and face shield over my reading glasses when I grind.

Fred.Rowe Fred.Rowe I was using an orange 60 grit Norton belt. Why does it matter if you do the ricasso before or after grinding?

I understand what distal taper is, but I am going to hold off doing that yet.
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The ricasso is the foundation of the knife which everything is based from.
 
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