Hollow grinding... is this normal?

REK Knives

REK Knives

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Knifemaker / Craftsman / Service Provider
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Tried 2 different hollow grinding wheels (one from contact rubber corp) and both do this where they leave striations in a "pattern" sorta, just wondering if this is normal or not? It's only visible in the right lighting, I think it may come from side to side run out on the wheel even though the face is true but again, I'm not sure.

This is at 220 grit...

i-L3tw4j2-X2.jpg


Can't really see it in this pic...

i-8HZxcMt-X2.jpg
 
You didn't say what grit was used here. Go to the next or more finer grits and see what you get.
Frank
 
Is your wheel smooth or sereated? I have seen smaller grits show up that way when not using a smooth wheel.
 
I will toss my opinion in as well. It looks like you used a pretty course belt to make your bevel. No problem...just hit the bevel a few strokes with a new 100 grit or 120 grit belt and watch those grooves get much finer...then a 220 grit belt and if you like that a 320 grit belt and a 400. Everything should look much better Try a gator belt in 100 or 65...they smooth things out as well. Larry P.S. You could try an 80 grit blaze and a slower speed to grind you initial bevel and see what it looks like then...it should be a little finer and more even scratch pattern than your photo.. .just my opinion. LL

vUcbKh2m.jpg
 
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Frank Niro said:
You didn't say what grit was used here. Go to the next or more finer grits and see what you get.
Frank
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hey Frank, the pics are at 220 grit... Will do!

Josh Rider said:
Do you grind wet or dry? I've seen streaks after using a belt cleaner.
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I grind wet most of the time, but I believe I have this issue wet or dry I will have to check.

argel55 said:
Is your wheel smooth or sereated? I have seen smaller grits show up that way when not using a smooth wheel.
Click to expand...

It is smooth, but thanks for the suggestion!

LARRYZ10 said:
I will toss my opinion in as well. It looks like you used a pretty course belt to make your bevel. No problem...just hit the bevel a few strokes with a new 100 grit or 120 grit belt and watch those grooves get much finer...then a 220 grit belt and if you like that a 320 grit belt and a 400. Everything should look much better Try a gator belt in 100 or 65...they smooth things out as well. Larry P.S. You could try an 80 grit blaze and a slower speed to grind you initial bevel and see what it looks like then...it should be a little finer and more even scratch pattern than your photo.. .just my opinion. LL
Click to expand...

Thanks for chiming in Larry. This is at 220 and it has a nice finish with all the deeper scratches being fully erased. Here are a couple pics of the final product, it turned out nice, but those striations are visible in the right lighting at the right angle. Maybe I'll try a higher grit to see. This was finished w/ a jflex belt - i will pay more attention on future hollow grinds if I'm having the same issue w/ gator trizacts. I know I've had this issue before several times though - just though it was "natural"

DSC_0064-X2.jpg

DSC_0066-X2.jpg
 
razor-edge-knives said:
hey Frank, the pics are at 220 grit... Will do!



I grind wet most of the time, but I believe I have this issue wet or dry I will have to check.



It is smooth, but thanks for the suggestion!



Thanks for chiming in Larry. This is at 220 and it has a nice finish with all the deeper scratches being fully erased. Here are a couple pics of the final product, it turned out nice, but those striations are visible in the right lighting at the right angle. Maybe I'll try a higher grit to see. This was finished w/ a jflex belt - i will pay more attention on future hollow grinds if I'm having the same issue w/ gator trizacts. I know I've had this issue before several times though - just though it was "natural"

DSC_0064-X2.jpg

DSC_0066-X2.jpg
Click to expand...

Josh, It looks very good finished. I think it should have looked a little smoother after a 220 grit belt but it finished great. Maybe use another brand of 220 grit belt on the next one and see if the same thing happens. Larry
 
LARRYZ10 said:
Josh, It looks very good finished. I think it should have looked a little smoother after a 220 grit belt but it finished great. Maybe use another brand of 220 grit belt on the next one and see if the same thing happens. Larry
Click to expand...

Ok thanks Larry, I'll give it a shot and pay closer attention to what belts I'm having the issue w/ and which ones I'm not.
 
Sorry, but that doesn't create a reason for the handle carving unless it's a copy and the original is rated as being real special.
Just me. That folder still looks to be a GREAT piece of work!!!
Frank
 
Might be deeper grooves left by too much pressure with the courser grits that can't be removed as you get to the finer grits?

I have seen it in other materials, but just my 2 cents.

Sent from my SM-G900V using Tapatalk
 
You mentioned the finish was from a j-flex belt. It my be from the knocking effect created by the joint. It use to bug the hell out of me, especially when they were close to worn out. Since changing to compact grain belts (VSM product) and cork belts many years ago, my finish in finer grits improved immediately.

Both type of belt are much thicker so do not nock at all. They are also much stiffer and may take some getting use to. An added bonus is the ridiculous long life you get from these type of belts. Might be worth a try, hope they work for you.
 
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