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Consistency in the finish grind. Photo heavy.


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In the quest for less hand finishing and more consistent finish grinds.
Based on a conversation on another forum.
I decided to do a study of grinds with the same weight belt with the same dimensions.
The only one like that I can find is the Trizac gator.
The first pic is the grind after the A300.
The rest are labeled on the blade. 100,65,45,30
You can see as I go the plunge was polished.
Also I was looking at the speed of the machine.
The 300,100 and 45 were running at about half speed on my machine.
The 45 and 30 were very very slow.
Here is a video link to the speed my grinder was running at and what it sounds like pedal to the metal for contrast.

https://www.facebook.com/100009870520784/videos/259019844437031/

My next part of the research will be to take Rhinowet 500 paper and see if it will remove these last vertical scratches and how quickly they will.
All feedback is welcome.
Thanks for looking.

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grindstudy6.jpg

grindstudy7.jpg

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Haha, I actually sold a rifle to buy my grinder, so I totally feel your pain   So, I checked out around to see if I could find out where I had read that A45 belts were equivalent to 400 grit. A few

I love the Trizact Gator belts. I usually go to hand sanding at 220 right off the A45, and if I did my grinding properly it doesn't take long to get to 400 or 600.

In the quest for less hand finishing and more consistent finish grinds. Based on a conversation on another forum. I decided to do a study of grinds with the same weight belt with the same dimensions.

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Start with a wet/dry paper at the same grit as your last belt and sand at right angles to the last grind. I use WD-40 as a lubricant. When you have all, and I mean all of the last scratches out then go onto the next finer grit of paper at right angles to the first paper. If you have problems getting the grind lines out with the first grade of paper it's probably because you left grind lines from earlier grinder belts and you will have to back up and get those larger scratches out.

 

Doug

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Right on Doug.
I'm familiar with hand sanding.
Kind of too familiar, which is why I'm working to get a better ground finish before hand sanding.
Basically that blade is at 500ish ground.
But belt speed and belt contouring of the platen have all created challenges to a decent, not perfect but decent flat grind.

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I love the Trizact Gator belts. I usually go to hand sanding at 220 right off the A45, and if I did my grinding properly it doesn't take long to get to 400 or 600.

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Carrying on with this study.
I took 800 grit Rhinowet paper and went to work to see how long it would take to polish out the grinder marks.
So from an A30 to 800 grit.
It took less than 45 minutes.
The plunge ate up some time but I had to figure out a block to conform to the radius.
Other than that it was very very fast.

finishpolish1.jpg

finishpolish2.jpg

finsihpolish3.jpg

finishpolish4.jpg

finishpolish5.jpg

finishpolish6.jpg

 

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I love the Trizact Gator belts. I usually go to hand sanding at 220 right off the A45, and if I did my grinding properly it doesn't take long to get to 400 or 600.

 

Man, you are going down in the grit from the A45, since that belt corresponds to 400 grit I believe. I may have to try that since I go from A45 to 600 grit paper, and it takes forever to get the A45 marks out.

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Man, you are going down in the grit from the A45, since that belt corresponds to 400 grit I believe. I may have to try that since I go from A45 to 600 grit paper, and it takes forever to get the A45 marks out.

 

Wes, I'm going from A30 to 800.

I will be doing another today and seeing if the result is consistent.

The thing is I used the Trizac from A300 all the way down.

That way the belt itself rides the same over the platen.

This is different than using say a blaze 50,80,120 and then jumping to a different belt for 220 or higher.

The problem is that the belt ride changes the grind.

No two flats end up being the same flat so to speak.

So I had to solve that problem.

I think this solves it.

Past that. being able to slow the 45 and 30 way way way down was the only way this is possible.

And it may be that the belt itself is made to be used that way and we don't know it because we aren't talking to the maker.

Just a few thoughts.

 

 

A16 = 1000 grit, A30 = 500 grit, A45 = 280 grit, A65 = 220, A100 = 150

 

i thought a45 was 400 grit for the longest.... :(

Its close, its just that from micron to grit is a weird translation.

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That is one gorgeous finish, JJ!

 

And Wes, yeah, A45 is about 280 grit. It just polishes to look finer, especially if you use belt lube like I do. Stepping back to 220 paper really speeds up getting all the grinder marks out.

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Alan thanks I am working towards tightness in all the aspects, this being just one, as you know.
Tim, yes this blade is heat treated.
There is actually an Auto Hamon in it funny enough.
Seems 11 second oil is doing that for me on every blade except 1084

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JJ,

 

Thanks for posting this. It is very helpful.

 

Would you care to elaborate on your hand sanding technique, particularly around the plunge line.

 

I am amazed how the perpendicular (to the plunge) lines are so clean and uninterrupted.

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JJ,

 

Thanks for posting this. It is very helpful.

 

Would you care to elaborate on your hand sanding technique, particularly around the plunge line.

 

I am amazed how the perpendicular (to the plunge) lines are so clean and uninterrupted.

So on this one, for whatever reason I ended up with a pretty good perpendicular.

And I used the belts starting at A45 to polish the inside of the plunge.

This is tricky because its easy to roll over the plunge into the ricasso.

The belt is about 1/4" off the side of the platen and running super super slow.

And I roll it into the plunge.

This is also tricky because you can end up angleing the plunge and creating a sweeping plunge.

Not a bad look, I just did it on another piece but, for me, was it what I intended?

After working the belt I go to had finishing.

Because I am starting at 800 I go right to the horizontal sanding.

I have a variety of blocks ranging from steel, to corian and then corian with either leather or foam rubber glued on one face.

The plunge in my opinion should be sanded first.

So I do that. In this case the edge of the leather backer stuck out and allowed me to match whatever radius is there.

I sanded the plunge first with the grind lines and then horizontal.

I whip the block up into the plunge and allow it to roll a little over the ricasso.

It is after all 800 grit paper.

I'm using Rhino wet paper which is the best I've ever used.

Must be used wet.

I use black magic tire cleaner for my lubricant.

Anyhow, the plunge is polished and I honestly need to make some more kinds of blocks for getting in there.

They do end up in about any configuration possible unless you are like a few of the ABS guys Nick Wheeler to name specifically who uses a radiused steel block that matches the exact angle he wants and sands the blade on the steel block like a japanese stone.

He has a video of it.

Well worth watching.

Anyhow, back to my method.

I start with a steel block and do my work until all the scratches are gone and then I move to a soft block to knock down the steel blocks passes.

This to me softens the scratch marks.

You could go softer and softer using up to 4 sets of blocks.

I never use more than 3.

Then I take fresh paper and I pull from the ricasso to the tip to straighten my lines.

Usually for something like the ABS journeyman stamp you would go to 800 and then back up a grit and use 600 paper for the final look.

I just did it at 800, its fine, no J-hooks or wurls.

So pull the paper and use the paper like its free.

One or two pulls and as soon as you feel it stop cutting move on to another piece.

I used less than two sheets to finish this blade.

That's about $3.

Well worth the waste.

If that isn't clear, or you have any other questions please feel free.

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Thanks for all that info! I still need a belt-grinder to use a lot of it :P But you also have some good techniques for hand sanding I wasn't fully aware of (I just have more basic methods... ) I am definitely going to make a a few more sanding blocks now!

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Thanks for all that info! I still need a belt-grinder to use a lot of it :P But you also have some good techniques for hand sanding I wasn't fully aware of (I just have more basic methods... ) I am definitely going to make a a few more sanding blocks now!

Yep, a variety of blocks helps a lot.

As does a variety of files in smother and smoother cuts.

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A16 = 1000 grit, A30 = 500 grit, A45 = 280 grit, A65 = 220, A100 = 150

 

i thought a45 was 400 grit for the longest.... :(

 

That is one gorgeous finish, JJ!

 

And Wes, yeah, A45 is about 280 grit. It just polishes to look finer, especially if you use belt lube like I do. Stepping back to 220 paper really speeds up getting all the grinder marks out.

 

Holy crap, how have I gone this long thinking it was near 400(I am really wondering where I got that from...). I am pretty sure you both just shaved hours off of my sanding time. Thank you gentlemen.

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Holy crap, how have I gone this long thinking it was near 400(I am really wondering where I got that from...). I am pretty sure you both just shaved hours off of my sanding time. Thank you gentlemen.

Wes if you can get the full assortment from A300 to the A30 and see what they do.

I just did another blade and it is great.

34 minutes to do one side at 800 on a 9" blade.

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Well, looks like I have to break down and get some Rhynowet... Which one do you get, JJ, the redline or the plus line?

I get the red.

The lowest I use is 280. Then I bought 400, 500, 600, 800, 1200, 2000, 2500 just to see what did what.

I can tell you the 28 is like an eraser.

It just cuts.

Must be used wet.

I haven't had a chance to really do a lot of tests with it but 600 will remove the 280 very quickly too.

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Wes if you can get the full assortment from A300 to the A30 and see what they do.

I just did another blade and it is great.

34 minutes to do one side at 800 on a 9" blade.

 

I use A160 thru to A45, but after reading your thorough handing sanding lesson, I think that I will be substantially changing out how I do things. Getting the j-hooks and whorls out has always been a nightmare. I use a steel block, and then finish with a wood block with leather glued to it. What benefit do you feel the corian has? Also, I will go to 800, and then go over the blade with a ultrafine scotchbrite pad. Hmm. You have given me a lot to think on and try. Thanks!

Edited by Wes Detrick
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I had the same exact system Wes.. and i would get to A65 and think.... this feels JUST LIKE A45 lol

 

I dunno what my fix is for the variable control deal. Im using a grizzly so she's just wide open all the time. Do i have to turn the machine off and use it while its slowing down? :(

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