Off Topic Grinder Fatigue

[Cushing H.]

I was grinding a Santoku a couple days ago (CPM154, 62 rockwell, Wa style tang). got into the now-enjoyed "Zen" of grind, dip, look, grind, dip, look, correct/extend bevel, straighten Shinogi, thin edge, check edge thickness, grind more to thin, etc etc, etc, move up to finer belts, check coarser marks are removed, go finer, etc, etc (finish with scotch bright)..... go back and correct the grind marks that I did not see until now, then go back up the grits, etc, etc...

Two hours later I was done. definitely not perfect (I still can not get a dead straight shinogi, probably need to hand sand for that) ... and so am still "blending". Still .... like has occurred before, I was TIRED (and had d little headache). It is not like I was running laps around the track or something .... but the focus and concentration of identifying what needs to be corrected, and making those fine corrections just takes a lot of energy, and almost always leaves me pretty drained.

Is it just me getting old .... or does the process affect others the same way?

 

[Tom Lewis]

Well, I am 72 years old and my back and neck do get tired. I have done enough grinding so that the mental aspect is no problem but the physical part is. I could not grind for 8 hours straight. I start getting tired after an hour or so.

 

[Mark van Elteren]

I don't know if it makes a difference, but I sit while grinding bevels, and most grinding work for that matter. I find it easier to stay stable, and my lower back doesn't hurt as much afterwards. When I got my grinder, I would get tired after about an hour. I can now do a couple of hours straight, but I find it more productive to grind for an hour, do something else for a few minutes (taking photos of finished knives, preparing handle material, stabilizing ...), and then continue. That way I get more done and I am less tired at the end.

Another thing I found helps me personally is to wear earplugs and earmuffs on top - my grinder is pretty loud, and it is hard to concentrate with that noise.

 

[weo]

I still can not get a dead straight shinogi, probably need to hand sand for that

In my experience, it's hard to keep most belts tight enough to be dead flat to the platen on the grinder. Think about this like hand sanding, if you don't have the paper tight to your sanding stick, you will wash out the lines.

 

[Cushing H.]

In my experience, it's hard to keep most belts tight enough to be dead flat to the platen on the grinder. Think about this like hand sanding, if you don't have the paper tight to your sanding stick, you will wash out the lines.

Makes sense. I do “pretty well” until the bevel gets shallow (which i want for the edge quality) then it starts to fall apart ... not in terms of overgrinding the flat ... but in terms of waviness. I keep trying for the sake of practice ... but eventually give up and start blending to the flat (which seems to work for family and friends, but i would not try for a knife to sell). One of these days though i will give it a solid try

 

[John mc c]

I'm a fit mid 40s lifting weights and keeping fit for over 20 years and after a days grinding I do be wiped out,neck,arms and shoulders pretty tired
I do be grinding forged knives and use alot of pressure which is harder work than stock removal from bar stock
Out of forging by hand,hand sanding or grinding,I think a day of grinding is the hardest

 

[john april]

if it takes 2 hours to grind a blade, i am thinking the belt is moving too slow.

 

[Cushing H.]

if it takes 2 hours to grind a blade, i am thinking the belt is moving too slow.

Possibly. For the main grind i use 60 grit and about 70% on the VFD. I am just not yet comfortable going higher than that. I typically do fairly long kitchen knives, and a FFG ... that is a lot of metal to remove. Most of my time is spent carefully thinning the edge uniformly and evenly down to about 0,008 - 0.006 while keeping (or making) the grind flat from edge to spine ... that is what takes the concentration and time. So ... maybe 20 minutes getting the rough grind done, maybe an hour thinning and refining, then maybe snother half hour running up through the grits for final refining of the edge thickness and getting rid of grind marks. I have wondered how that compares. Not my intent with this thread ... but i guess this is as good a place as any if someone wants to comment...

 

[Mitchell Knives]

I jacked up my back about 6 months ago, so standing at the grinder for long periods tends to aggravate it. I may start sitting down when grinding to see if that helps. Other than that, I have no real discomfort when grinding.

 

[Brock Cutlery]

Possibly. For the main grind i use 60 grit and about 70% on the VFD. I am just not yet comfortable going higher than that. I typically do fairly long kitchen knives, and a FFG ... that is a lot of metal to remove. Most of my time is spent carefully thinning the edge uniformly and evenly down to about 0,008 - 0.006 while keeping (or making) the grind flat from edge to spine ... that is what takes the concentration and time. So ... maybe 20 minutes getting the rough grind done, maybe an hour thinning and refining, then maybe snother half hour running up through the grits for final refining of the edge thickness and getting rid of grind marks. I have wondered how that compares. Not my intent with this thread ... but i guess this is as good a place as any if someone wants to comment...

I remember the days when my grinder was too fast. I think I got comfortable at full speed at about 18 months or something like that, part time grinding.
One thing I did learn over the years is that a faster belt is actually easier to grind with. Your blade won't want to skip around as much with belt grab.

 

[Cushing H.]

I remember the days when my grinder was too fast. I think I got comfortable at full speed at about 18 months or something like that, part time grinding.
One thing I did learn over the years is that a faster belt is actually easier to grind with. Your blade won't want to skip around as much with belt grab.

Interesting. Thanks. Right now though I have a vibration that kicks in between about 70 and 80 %. I am not comfortable jumping from 65 to 90 yet. Gotta figure out where that vibration is coming from so I can “sneak up” the RPMs.